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A special issue of Molecules (ISSN 1420-3049).

Deadline for manuscript submissions: closed (31 August 2010) | Viewed by 622338

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Special Issue Editor

Dr. Renato Bruni

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Guest Editor

Department of Food and Drug, Università di Parma, Parma, Italy
Interests: phytochemistry; herbal and medicinal plants; plant bioactives; extraction and characterisation of natural compounds; botanicals
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Antioxidants of plant origin are likely one of the most studied class of natural, functional compounds and they play a relevant role in a variety of commercial uses, ranging from phytocosmetics to nutraceuticals, from medicinal plants to pharmaceuticals. Their key role in the prevention of the onset of a wide range of pathologies and conditions related to oxidative stress (inflammation and cardiovascular diseases, aging related disorders, mutagenesis, cancer prevention to name a few) make them an attractive class of phytochemicals for the promotion of human health. Moreover, their efficacy as safe preservatives for foods, fodder and cosmetic formulations broaden the horizon of their applications.

Contributions for this issue, both in form of original research and review articles, may cover all aspects of plant antioxidants chemistry, biochemistry and biology, e.g. quantification, variability and efficacy of dietary and non-dietary antioxidants from plant sources and agroindustrial waste material; development of new protocols and methods based on chemical or biological systems for the evaluation of in vivo and in vitro antioxidant capacity; clinical and nutritional trials focused on the antioxidant properties of plant secondary metabolites; pharmacodynamics and pharmacokinetics of natural antioxidants; relationships between antioxidant properties and human health promotion; elucidation of antioxidant mechanisms; innovative techniques of antioxidants delivery and protocols for the extraction, isolation, structural characterization of new natural antioxidants will be welcomed, on condition that an adequate evaluation of their efficacy is provided. Papers regarding the relationships between natural antioxidant content and stabilization of cosmetic, fodder and food products will be also taken into consideration.

Dr. Renato Bruni
Guest Editor

Keywords

antioxidants metabolism
antioxidants quantification
dietary antioxidants
lipid peroxidation
natural antioxidants
oxidative stress
plant secondary metabolites
radical scavengers
total antioxidant capacity

Related Special Issues

Antioxidants in International Journal of Molecular Sciences (18 articles)
Dietary Antioxidants in Nutrients (9 articles)

Published Papers (38 papers)

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552 KiB

Open AccessArticle

Licocalchone-C Extracted from Glycyrrhiza Glabra Inhibits Lipopolysaccharide-Interferon-γ Inflammation by Improving Antioxidant Conditions and Regulating Inducible Nitric Oxide Synthase Expression

by Sara Franceschelli, Mirko Pesce, Isabella Vinciguerra, Alessio Ferrone, Graziano Riccioni, Patruno Antonia, Alfredo Grilli, Mario Felaco and Lorenza Speranza

Molecules 2011, 16(7), 5720-5734; https://doi.org/10.3390/molecules16075720 - 06 Jul 2011

Cited by 61 | Viewed by 10434

Abstract

The genus Glycyrrhiza consists of about 30 species, amoung these, G. glabra is the source of several phenolic compounds, known as flavonoids, such as licoagrodin, licoagrochalcones, licoagroaurone and licochalcone C, kanzonol Y, glyinflanin B and glycyrdione A, which have shown various pharmacological activities, including antitumor, antiparasitic, antileishmanial, anti-ulcer and antioxidative effects. Among these compounds, licochalcone C was isolated but its biology has not been fully examined. In our study we reproduced an inflammatory state by treating THP-1 (human myelomonocytic leukaemia) cells with pro-inflammatory stimuli, such as LPS and IFN-γ and we investigated the possible antioxidant activity of licochalcone C at a concentration of 50 μM. Our results show that treatment with licochalcone C attenuates the LPS-IFN-γ-induced inflammatory response by significantly decreasing the expression and activity of iNOS via NFκB (nuclear factor kappa-B), by influencing extracellular O₂⁻ production, and by modulating the antioxidant network activity of SOD (superoxide dismutase), CAT (catalase) and GPx (glutathione peroxidase) activity. Based on these results we hypothesize that Licochalcone C has antioxidant properties since it reduces the production of superoxide radicals and consequently reduces the activity of iNOS. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Antioxidant Properties and Antioxidant Compounds of Various Extracts from the Edible Basidiomycete Grifola Frondosa (Maitake)

by Jan-Ying Yeh, Li-Hui Hsieh, Kaun-Tzer Wu and Cheng-Fang Tsai

Molecules 2011, 16(4), 3197-3211; https://doi.org/10.3390/molecules16043197 - 15 Apr 2011

Cited by 85 | Viewed by 12432

Abstract

Grifola frondosa is an edible mushroom currently available in Taiwan. Ethanolic, cold-water and hot-water extracts were prepared and their antioxidant properties were investigated. At 1 mg/mL, G. frondosa T1 and T2 cold-water extracts showed high reducing powers of 1.02 and 0.50, respectively. Chelating abilities on ferrous ions of G. frondosa T1 and T2 were higher for cold-water extracts than for ethanolic and hot-water extracts. For the scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, G. frondosa T1 and T2 extracts were effective in the following order: ethanolic > hot-water > cold-water. The G. frondosa hot-water extract showed high scavenging ability on superoxide anions. Total phenols, flavonoids, ascorbic acid and α-tocopherol are the major antioxidant components found in the various G. frondosa extracts. Based on EC₅₀ values ( Full article

(This article belongs to the Special Issue Antioxidants)

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326 KiB

Open AccessArticle

Structure of Dihydrochalcones and Related Derivatives and Their Scavenging and Antioxidant Activity against Oxygen and Nitrogen Radical Species

by Alexandre L. A. Bentes, Rosivaldo S. Borges, Waldinei R. Monteiro, Luiz G. M. De Macedo and Cláudio N. Alves

Molecules 2011, 16(2), 1749-1760; https://doi.org/10.3390/molecules16021749 - 21 Feb 2011

Cited by 52 | Viewed by 11587

Abstract

Quantum mechanical calculations at B3LYP/6-31G** level of theory were employed to obtain energy (E), ionization potential (IP), bond dissociation enthalpy (O-H BDE) and stabilization energies (DE_iso) in order to infer the scavenging activity of dihydrochalcones (DHC) and structurally related compounds. Spin density calculations were also performed for the proposed antioxidant activity mechanism of 2,4,6-trihydroxyacetophenone (2,4,6-THA). The unpaired electron formed by the hydrogen abstraction from the phenolic hydroxyl group of 2,4,6-THA is localized on the phenolic oxygen at 2, 6, and 4 positions, the C₃ and C₆ carbon atoms at ortho positions, and the C₅ carbon atom at para position. The lowest phenolic oxygen contribution corresponded to the highest scavenging activity value. It was found that antioxidant activity depends on the presence of a hydroxyl at the C2 and C4 positions and that there is a correlation between IP and O-H BDE and peroxynitrite scavenging activity and lipid peroxidation. These results identified the pharmacophore group for DHC. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

The Relationships between Phenolic Content, Pollen Diversity, Physicochemical Information and Radical Scavenging Activity in Honey

by Annamaria Giorgi, Moira Madeo, Johann Baumgartner and Giuseppe Carlo Lozzia

Molecules 2011, 16(1), 336-347; https://doi.org/10.3390/molecules16010336 - 07 Jan 2011

Cited by 29 | Viewed by 9484

Abstract

Honey is rich in different secondary plant metabolites acting as natural antioxidants and contributing to human health. Radical scavenging activity (RSA) is related to antioxidant activity, while the correlation between the phenolic content and RSA is often weak. Consequently, exclusive information on phenolics is often insufficient to qualify the RSA and the health promoting effects of honey. The paper deals with a case study of honey samples originating from the alpine areas of Italy’s Lombardia and Veneto regions and realized by standard physicochemical and statistical analytical methods. In pure honey, the total phenolic content and the RSA were measured in spectrophotometric tests with the 2,2-diphenyl-1-picrylhydrazyl (DPPH·) free radical and Folin-Ciocalteu assays, respectively. Melissopalynological data was used to qualify pollen diversity through rank-frequency curves separating the samples into two groups. On the basis of physicochemical data, the samples were analyzed through multivariate classification and ranking procedures resulting in the identification of an outlier. Elimination of the outlier produced a high correlation between the total phenolic content and RSA in the two pollen diversity groups. The case study suggests that, after disregarding outliers, the RSA activity can be satisfactorily qualified on the basis of phenolics with pollen diversity as a covariate. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Fully Automated Spectrometric Protocols for Determination of Antioxidant Activity: Advantages and Disadvantages

by Jiri Sochor, Marketa Ryvolova, Olga Krystofova, Petr Salas, Jaromir Hubalek, Vojtech Adam, Libuse Trnkova, Ladislav Havel, Miroslava Beklova, Josef Zehnalek, Ivo Provaznik and Rene Kizek

Molecules 2010, 15(12), 8618-8640; https://doi.org/10.3390/molecules15128618 - 29 Nov 2010

Cited by 117 | Viewed by 14129

Abstract

The aim of this study was to describe behaviour, kinetics, time courses and limitations of the six different fully automated spectrometric methods - DPPH, TEAC, FRAP, DMPD, Free Radicals and Blue CrO₅. Absorption curves were measured and absorbance maxima were found. All methods were calibrated using the standard compounds Trolox^® and/or gallic acid. Calibration curves were determined (relative standard deviation was within the range from 1.5 to 2.5 %). The obtained characteristics were compared and discussed. Moreover, the data obtained were applied to optimize and to automate all mentioned protocols. Automatic analyzer allowed us to analyse simultaneously larger set of samples, to decrease the measurement time, to eliminate the errors and to provide data of higher quality in comparison to manual analysis. The total time of analysis for one sample was decreased to 10 min for all six methods. In contrary, the total time of manual spectrometric determination was approximately 120 min. The obtained data provided good correlations between studied methods (R = 0.97 – 0.99). Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Antiproliferative Activity, Antioxidant Capacity and Tannin Content in Plants of Semi-Arid Northeastern Brazil

by Joabe Gomes de Melo, Thiago Antônio De Sousa Araújo, Valérium Thijan Nobre de Almeida e Castro, Daniela Lyra de Vasconcelos Cabral, Maria Do Desterro Rodrigues, Silene Carneiro do Nascimento, Elba Lúcia Cavalcanti de Amorim and Ulysses Paulino De Albuquerque

Molecules 2010, 15(12), 8534-8542; https://doi.org/10.3390/molecules15128534 - 24 Nov 2010

Cited by 87 | Viewed by 16452

Abstract

The objective of this study was to evaluate antiproliferative activity, antioxidant capacity and tannin content in plants from semi-arid northeastern Brazil (Caatinga). For this study, we selected 14 species and we assayed the methanol extracts for antiproliferative activity against the HEp-2 (laryngeal cancer) and NCI-H292 (lung cancer) cell lines using the (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazole) (MTT) method. In addition, the antioxidant activity was evaluated with the DPPH (2,2-diphenyl-2-picrylhydrazyl) assay, and the tannin content was determined by the radial diffusion method. Plants with better antioxidant activity (expressed in a dose able to decrease the initial DPPH concentration by 50%, or IC₅₀) and with higher levels of tannins were: Poincianella pyramidalis (42.95 ± 1.77 µg/mL IC₅₀ and 8.17 ± 0.64 tannin content), Jatropha mollissima (54.09 ± 4.36µg/mL IC₅₀ and 2.35 ± 0.08 tannin content) and Anadenanthera colubrina (73.24 ± 1.47 µg/mL IC₅₀ and 4.41 ± 0.47 tannin content). Plants with enhanced antiproliferative activity (% living cells) were Annona muricata (24.94 ± 0.74 in NCI-H292), Lantana camara (25.8 ± 0.19 in NCI-H292), Handroanthus impetiginosus (41.8 ± 0.47 in NCI-H292) and Mentzelia aspera (45.61 ± 1.94 in HEp-2). For species with better antioxidant and antiproliferative activities, we suggest future in vitro and in vivo comparative studies with other pharmacological models, and to start a process of purification and identification of the possible molecule(s) responsible for the observed pharmacological activity. We believe that the flora of Brazilian semi-arid areas can be a valuable source of plants rich in tannins, cytotoxic compounds and antioxidant agents. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Antioxidant, Anti-Inflammatory and Anti-Influenza Properties of Components from Chaenomeles speciosa

by Li Zhang, Yong-Xian Cheng, Ai-Lin Liu, Hai-Di Wang, Ya-Ling Wang and Guan-Hua Du

Molecules 2010, 15(11), 8507-8517; https://doi.org/10.3390/molecules15118507 - 22 Nov 2010

Cited by 84 | Viewed by 14741

Abstract

The fruit of Chaenomeles speciosa is a traditional Chinese medicine used for the treatment of dyspepsia and various inflammatory diseases. In the present study, we evaluated the potential radical scavenging capacity, and activity against nitrous oxide, inflammatory cytokines production and neuramindase (NA) of its isolates. The results showed that 3,4-dihydroxybenzoic acid (1) displayed higher inhibitory activities on DPPH and NA with IC₅₀ values of 1.02 mg/mL and 1.27 mg/mL respectively, and quercetin (2) also showed significant inhibitory action on DPPH and NA, with IC₅₀values of 3.82 mg/mL and 1.90 mg/mL. Compounds 1, 2 and methyl 3-hydroxybutanedioic ester (3) could inhibit the production of TNF-a by 22.73%, 33.14% and 37.19% at 5 mg/mL (P < 0.05) compared with the control. In addition, compound 2 was found to be active on the release of IL-6 in RAW264.7 macrophage cells, with an inhibitory rate of 39.79% (P < 0.05). The anti-inflammatory effect of compound 3 is disclosed for the first time in this study. Avian influenza is usually accompanied by virus invasion followed by the occurrence of oxidative stress and serious inflammation, so the multiple effects of the isolates may play a cocktail-like role in the treatment of avian influenza, and C. speciosa components, especially quercetin, might be a potent source for anti-viral and anti-inflammatory agents. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Selective Inhibitory Effect of Epigallocatechin-3-gallate on Migration of Vascular Smooth Muscle Cells

by Dong-Wook Han, Mi Hee Lee, Byeong-Ju Kwon, Hye-Lee Kim, Suong-Hyu Hyon and Jong-Chul Park

Molecules 2010, 15(11), 8488-8500; https://doi.org/10.3390/molecules15118488 - 19 Nov 2010

Cited by 11 | Viewed by 9609

Abstract

In order to prevent restenosis after angioplasty or stenting, one of the most popular targets is suppression of the abnormal growth and excess migration of vascular smooth muscle cells (VSMCs) with drugs. However, the drugs also adversely affect vascular endothelial cells (VECs), leading to the induction of late thrombosis. We have investigated the effect of epigallocatechin-3-gallate (EGCG) on the proliferation and migration of VECs and VSMCs. Both cells showed dose-dependent decrease of viability in response to EGCG while they have different IC₅₀ values of EGCG (VECs, 150 mM and VSMCs, 1050 mM). Incubating both cells with EGCG resulted in significant reduction in cell proliferation irrespective of cell type. The proliferation of VECs were greater affected than that of VSMCs at the same concentrations of EGCG. EGCG exerted differential migration-inhibitory activity in VECs vs. VSMCs. The migration of VECs was not attenuated by 200 mM EGCG, but that of VSMCs was significantly inhibited at the same concentration of EGCG. It is suggested that that EGCG can be effectively used as an efficient drug for vascular diseases or stents due to its selective activity, completely suppressing the proliferation and migration of VSMCs, but not adversely affecting VECs migration in blood vessels. Full article

(This article belongs to the Special Issue Antioxidants)

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686 KiB

Open AccessArticle

Antioxidant-Prooxidant Properties of a New Organoselenium Compound Library

by Daniel Plano, Ylenia Baquedano, Elena Ibáñez, Iosu Jiménez, Juan Antonio Palop, Julian E. Spallholz and Carmen Sanmartín

Molecules 2010, 15(10), 7292-7312; https://doi.org/10.3390/molecules15107292 - 21 Oct 2010

Cited by 85 | Viewed by 13136

Abstract

The present study describes the biological evaluation of a library of 59 organo-selenium compounds as superoxide (O₂^─) generators and cytotoxic agents in human prostate cancer cells (PC-3) and in breast adenocarcinoma (MCF-7). In order to corroborate that the biological activity for selenium compounds depends on the chemical form, a broad structural variety is presented. These structures include selenocyanates, diselenides, selenoalkyl functional moieties and eight newly synthesized symmetrically substituted dithioselenites and selenylureas. Eleven of the derivatives tested showed high levels of superoxide generation in vitro via oxidation of reduced glutathione (GSH) and nine of them were more catalytic than the reference compound, diselenodipropionic acid. Eighteen of the library compounds inhibited cell growth more than or similar to reference chemotherapeutic drugs in PC-3 and eleven were more potent cytotoxic agents than etoposide in the MCF-7 cell line. Considering both parameters (superoxide generation and cell cytotoxicity) compounds B1, C6 and C9 displayed the best therapeutic profiles. Considering that many diselenide compounds can generate superoxide (O₂^─) in vitro via oxidation of GSH and other thiols, the analogue B1, that contains a diselenide moiety, was selected for a preliminary mechanistic investigation, which . revealed that B1 has apoptogenic effects similar to camptothecin mediated by reactive oxygen species (ROS) in lymphocytic leukemia cells (CCRF-CEM) and affected the MCF-7 cell-cycle in G₂/M and S-phases. Full article

(This article belongs to the Special Issue Antioxidants)

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276 KiB

Open AccessArticle

Effects of Different Maturity Stages on Antioxidant Content of Ivorian Gnagnan (Solanum indicum L.) Berries

by Denis N’Dri, Luca Calani, Teresa Mazzeo, Francesca Scazzina, Massimiliano Rinaldi, Daniele Del Rio, Nicoletta Pellegrini and Furio Brighenti

Molecules 2010, 15(10), 7125-7138; https://doi.org/10.3390/molecules15107125 - 15 Oct 2010

Cited by 34 | Viewed by 10338

Abstract

Gnagnan (Solanum indicum L.) is a spontaneous plant widely distributed in Ivory Coast. During ripening stages, Solanum indicum L. presents different colours (green, yellow and red) and is reported to contain several albeit poorly characterized antioxidant compounds. This paper describes in detail the antioxidant profile (ascorbic acid, carotenoids and polyphenols), antioxidant capacity (FRAP test and Folin-Ciocalteau assay) and the colour changes of Gnagnan berries at different ripening levels. Ascorbic acid content was similar in green and yellow berries, but significantly lower in red ones. Red berries showed a higher content of carotenoids compared to green and yellow ones. Regarding polyphenols, several phenolic acids and flavonoids were found in all berries. The content of caffeoylquinic acids, caffeic acid, flavonol glycosides and naringenin was higher in red berries, while the content of p-coumaric acid and feruloylquinic acids was similar among the three colours. The FRAP assay increased with the ripening process, whereas total polyphenols were similar among berries. Significant differences were found for the colorimetric indexes among products of different degrees of ripening. The present results show the important role of the ripening stage in increasing the antioxidant content of Gnagnan berries. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Evaluation of Antioxidant Capacity and Synergistic Associations of Quinonemethide Triterpenes and Phenolic Substances from Maytenus ilicifolia (Celastraceae)

by Vânia Aparecida de Freitas Formenton Macedo dos Santos, Daniela Pereira dos Santos, Ian Castro-Gamboa, Maria Valnice Boldrin Zanoni and Maysa Furlan

Molecules 2010, 15(10), 6956-6973; https://doi.org/10.3390/molecules15106956 - 11 Oct 2010

Cited by 39 | Viewed by 10735

Abstract

This work describes the isolation of the secondary metabolites identified as the quinonemethides maytenin (1) and pristimerin (2) from Maytenus ilicifolia extracts obtained from root barks of adult plants and roots of seedlings and their quantification by high performance liquid chromatography coupled to a diode array detector. The electrochemical profiles obtained from cyclic voltammetry and a coulometric detector coupled to high-performance liquid chromatography contributed to the evaluation of their antioxidant capacity. The antioxidant properties of individual components and the crude extracts of the root barks of Maytenus ilicifolia were compared and the possible synergistic associations of quinonemethide triterpenes and phenolic substances were investigated by using rutin as a model phenolic compound. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

In Vitro Antioxidant Properties, HIV-1 Reverse Transcriptase and Acetylcholinesterase Inhibitory Effects of Traditional Herbal Preparations Sold in South Africa

by Ashwell R. Ndhlala, Jeffrey F. Finnie and Johannes Van Staden

Molecules 2010, 15(10), 6888-6904; https://doi.org/10.3390/molecules15106888 - 08 Oct 2010

Cited by 22 | Viewed by 13822

Abstract

The antioxidant potentials for fourteen multipurpose traditional herbal preparations sold in South Africa were determined using the DPPH radical scavenging, ferric reducing power and β-carotene-linoleic acid model system, the anti-HIV-1 reverse transcriptase (RT) enzyme inhibitory effects using an ELISA kit and acetylcholinesterase (AChE) enzyme inhibition using the microtitre plate assay. Nine of the herbal mixtures (Umzimba omubi, Umuthi wekukhwehlela ne zilonda, Mvusa ukunzi, Umpatisa inkosi, Imbiza ephuzwato, Vusa umzimba, Supreme one hundred, Sejeso herbal mixture Ingwe^® and Ingwe^® special muti) exhibited higher antioxidant potentials, while only four (Imbiza ephuzwato, Ingwe^® muthi mixture, Sejeso herbal mixture Ingwe^® and African potato extract^TM) showed potent activity against the RT enzyme. Nine mixtures (Imbiza ephuzwato, Umpatisa inkosi, African potato extract^TM, Sejeso herbal mixture Ingwe^®, Vusa umzimba; Ingwe^® muthi mixture, Ibhubezi™, Lion izifozonke Ingwe^® and Ingwe^® special muti) showed AChE enzyme inhibitory activity greater than 50%. The observed activity exhibited by some of the herbal mixtures gives some credence to the manufacturers’ claims and goes part of the way towards validating their use against certain conditions such as oxidative stress, HIV/AIDS proliferation and some mental conditions. It is however, desirable to carry out further studies to determine the effects of mixing plant species/parts in one mixture on the antioxidant potency as well as isolating active constituents from the herbal mixtures. Full article

(This article belongs to the Special Issue Antioxidants)

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269 KiB

Open AccessArticle

Antioxidant Activities of Caragana sinica Flower Extracts and Their Main Chemical Constituents

by Zhi-Gang Tai, Le Cai, Lin Dai, Wei-Jun Sun, Wei Zhe, Ya-Bin Yang, Qiu-E Cao and Zhong-Tao Ding

Molecules 2010, 15(10), 6722-6732; https://doi.org/10.3390/molecules15106722 - 28 Sep 2010

Cited by 19 | Viewed by 12269

Abstract

The edible flowers of Caragana sinica are used in China a kind of health-promoting vegetable. In this study, the antioxidant activities of its ethanol extract, as well as its petroleum ether, ethyl acetate, n-butanol and water fractions, were evaluated through in vitro model systems including the DPPH, FRAP and β-carotene bleaching methods. Among the C. sinica flower extracts the ethyl acetate fraction was the most effective. Correlation analysis suggested that flavonoids might be the major contributors to the high antioxidant activity of this flower. Six flavonoids including quercetin (1), isoquercitrin (2), rutin (3), quercetin-3′-O-methyl-3-O-α-L-rhamnopyranosyl (1→6)-β-D-glucopyranoside (4), typhaneoside (5) and quercetin-3-O-β-D-glucopyranosyl(1→2)[α-L-rhamnopyranosyl (1→6)]-β-D-glucopyranoside (6), were isolated from this flower for the first time. Their contents were determined by a HPLC method. Compounds 3 and 4 were found to be the major flavonoids, with concentrations of 1.20 ± 0.07 and 3.94 ± 0.12 mg/g dry sample, respectively. These results demonstrated that the C. sinica flowers may be valuable natural antioxidant sources and are potentially applicable in the health food industry. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Evaluation of Crocus sativus L. Stigma Phenolic and Flavonoid Compounds and Its Antioxidant Activity

by Ehsan Karimi, Ehsan Oskoueian, Rudi Hendra and Hawa Z.E. Jaafar

Molecules 2010, 15(9), 6244-6256; https://doi.org/10.3390/molecules15096244 - 06 Sep 2010

Cited by 195 | Viewed by 19819

Abstract

Saffron (Crocus sativus L.) belongs to the Iridaceae family. The stigma of saffron has been widely used as spice, medicinal plant, and food additive in the Mediterranean and Subtropical countries. Recently, attention has been paid to the identification of new sources of safe natural antioxidants for the food industry. The antioxidant activities of spices are mainly attributed to their phenolic and flavonoid compounds. Saffron is one of the spices believed to possess antioxidant properties, but information on its antioxidant activity and phenolic, flavonoids compound are rather limited, therefore this research was carried out to evaluate the antioxidant activity of saffron stigmas extracted with different solvents. The phenolic and flavonoid compounds of saffron were also examined using reversed phase (RP)-HPLC. Results showed that saffron stigma possess antioxidant activity. The free radical scavenging and ferric reducing power activities were higher for the methanolic extract of saffron stigma at a concentration of 300 μg/mL, with values of 68.2% and 78.9%, respectively, as compared to the corresponding boiling water and ethanolic extracts, but the activities were lower than those of antioxidant standards such as BHT and α-tocopherol. The obtained total phenolics value for methanolic saffron extract was 6.54 ± 0.02 mg gallic acid equivalent (GAE)/g dry weight (DW), and for total flavonoids, 5.88 ± 0.12 mg rutin equivalent/g DW, which were also higher than values obtained from the ethanolic and boiling water extracts. In addition, the RP-HPLC analyses indicated the presence of gallic acid and pyrogallol as two bioactive compounds. In summary, saffron stigmas showed antioxidant activity and methanol appeared to be the best solvent to extract the active components, among which the presence of gallic acid and pyrogallol might contribute towards the stigma’s antioxidant properties. Hence, saffron stigma could be applied as a natural antioxidant source for industrial purposes. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Antioxidant Capacity of Pure Compounds and Complex Mixtures Evaluated by the ORAC-Pyrogallol Red Assay in the Presence of Triton X-100 Micelles

by Max Romero, Benjamin Rojano, Jaime Mella-Raipán, Carlos David Pessoa-Mahana, Eduardo Lissi and Camilo López-Alarcón

Molecules 2010, 15(9), 6152-6167; https://doi.org/10.3390/molecules15096152 - 01 Sep 2010

Cited by 32 | Viewed by 10779

Abstract

The protective effect of different antioxidants and complex mixtures on the consumption of pyrogallol red (PGR) induced by peroxyl radicals was studied in the absence and presence of Triton X-100 micelles. The presence of micelles decreased significantly the protection of PGR afforded by lipophilic antioxidants (β-carotene, octyl gallate), while no effect of micelles was observed for hydrophilic antioxidants such as Trolox, caffeic acid, gallic acid, and ascorbic acid. In the presence of complex mixtures a clear effect of Triton X-100 micelles was also observed in the protection afforded by wines, tea infusions, and seed extracts of Eugenia jambolana and Myrciaria cauliflora. On the other hand, no effect of micelles was observed for orange juice and pulp fruit extracts. The ORAC (Oxygen Radical Absorbance Capacity) index was evaluated in the absence (ORAC-PGR) and presence of Triton X-100 micelles (ORAC-PGRMIC). Triton X-100 micelles affect ORAC-PGR values of antioxidants in a lipophilicity-dependent way. From the obtained results, we conclude that ORAC-PGR and ORAC-PGRMIC assays could be considered as an alternative to estimate the antioxidant ability (ORAC-PGR) and to infer the association to Triton X-100 micelles (ORAC-PGR/ORAC-PGRMIC) of pure antioxidants and their complex mixtures. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle

Antiradical and Cytoprotective Activities of Several C-Geranyl-substituted Flavanones from Paulownia tomentosa Fruit

by Aleš Zima, Jan Hošek, Jakub Treml, Jan Muselík, Pavel Suchý, Gabriela Pražanová, Ana Lopes and Milan Žemlička

Molecules 2010, 15(9), 6035-6049; https://doi.org/10.3390/molecules15096035 - 31 Aug 2010

Cited by 43 | Viewed by 10858

Abstract

Antiradical and cytoprotective activities of several flavanones isolated from Paulownia tomentosa (Thunb.) Steud. (Scrophulariaceae) have been evaluated using different in vitro and in vivo methods. The capacity of flavanones to scavenge radicals was measured in vitro by means of DPPH and ABTS assays, the inhibition of hydroxyl radicals produced in Fenton reactions, FRAP, scavenging superoxide radicals using enzymatic and nonenzymatic assays and the inhibition of peroxynitrite-induced nitration of tyrosine. The in vivo testing involved measuring the cytoprotective effect of chosen flavanones against alloxan-induced diabetes in mice. The activity of tested compounds was expressed either as a Trolox^® equivalent or was compared with rutin or morine as known antioxidant compounds. The highest activity in most tests was observed for diplacone and 3´-O-methyl-5´-hydroxydiplacone, and the structure vs. the antioxidant activity relationship of geranyl or prenyl-substituted flavonoids with different substitutions at the B and C ring was discussed. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
Screening of Natural Antioxidants from Traditional Chinese Medicinal Plants Associated with Treatment of Rheumatic Disease
by Ren-You Gan, Lei Kuang, Xiang-Rong Xu, Yuan Zhang, En-Qin Xia, Feng-Lin Song and Hua-Bin Li

Molecules 2010, 15(9), 5988-5997; https://doi.org/10.3390/molecules15095988 - 30 Aug 2010
Cited by 91 | Viewed by 13138
Abstract
In order to find new sources of natural antioxidants, the antioxidant capacities of 50 medicinal plants associated with treatment of rheumatic diseases were systemically evaluated using the ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, and their total phenolic contents [...] Read more.

In order to find new sources of natural antioxidants, the antioxidant capacities of 50 medicinal plants associated with treatment of rheumatic diseases were systemically evaluated using the ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, and their total phenolic contents were measured by the Folin–Ciocalteu method. Their antioxidant activities of some of these plants were analyzed for the first time. The FRAP and TEAC assay results suggested that the antioxidant compounds in these plants possessed free radicals scavenging activity and oxidant reducing power. A positive linear correlation between antioxidant capacities and total phenolic contents implied that phenolic compounds in these plants could be the main components contributing to the observed activities. The results showed that Geranium wilfordii, Loranthus parasiticus, Polygonum aviculare, Pyrrosia sheaeri, Sinomenium acutum and Tripterygium wilfordii possessed the highest antioxidant capacities and total phenolic content among 50 plants tested, and could be rich potential sources of natural antioxidants. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
Evaluation of Antioxidant Potential of Lavandula x intermedia Emeric ex Loisel. 'Budrovka': A Comparative Study with L. angustifolia Mill.
by Biljana Blažeković, Sanda Vladimir-Knežević, Adelheid Brantner and Maja Bival Štefan

Molecules 2010, 15(9), 5971-5987; https://doi.org/10.3390/molecules15095971 - 30 Aug 2010
Cited by 70 | Viewed by 14126
Abstract
A Croatian indigenous cultivar of lavandin, Lavandula x intermedia 'Budrovka' (Lamiaceae) was studied for the phenolic acids, flavonoids, anthocyanins, procyanidins and total tannins, as well as total polyphenols content, in the flower, inflorescence stalk and leaf ethanolic extracts. Antioxidant potentials on these plant [...] Read more.

A Croatian indigenous cultivar of lavandin, Lavandula x intermedia 'Budrovka' (Lamiaceae) was studied for the phenolic acids, flavonoids, anthocyanins, procyanidins and total tannins, as well as total polyphenols content, in the flower, inflorescence stalk and leaf ethanolic extracts. Antioxidant potentials on these plant part extracts were assessed by the DPPH free radical scavenging activity, iron chelating activity, reducing power, lipid peroxidation inhibition properties and total antioxidant capacity assays. All results were compared with those of Lavandula angustifolia, the only member of the Lavandula genus officially used in modern phytotherapy. Based on the results of our parallel study, we may suggest that Lavandula x intermedia 'Budrovka' is as potent an antioxidant as Lavandula angustifolia and the antioxidant activity of the Lavandula extracts is mainly due to the presence of rosmarinic acid. A good correlation was found between the polyphenol contents and antioxidant activities of the extracts Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
Antioxidant Activity of Butyl- and Phenylstannoxanes Derivedfrom 2-, 3- and 4-Pyridinecarboxylic Acids
by Alicia Corona-Bustamante, Juan Manuel Viveros-Paredes, Angelina Flores-Parra, Ana Lilia Peraza-Campos, Francisco J. Martínez-Martínez, María Teresa Sumaya-Martínez and Ángel Ramos-Organillo

Molecules 2010, 15(8), 5445-5459; https://doi.org/10.3390/molecules15085445 - 09 Aug 2010
Cited by 57 | Viewed by 14569
Abstract
In vitro antioxidant activity for 12 stannoxanes derived from Ph₃SnCl (compounds 1-3), Ph₂SnCl₂ (compounds 4-6), Bu₃SnCl (compounds 7-9), and Bu₂SnCl₂ (compounds 10-12 [...] Read more.

In vitro antioxidant activity for 12 stannoxanes derived from Ph₃SnCl (compounds 1-3), Ph₂SnCl₂ (compounds 4-6), Bu₃SnCl (compounds 7-9), and Bu₂SnCl₂ (compounds 10-12), was assayed qualitatively by the chromatographic profile with 1,1-diphenyl-2-picrylhydrazil (DPPH) method and by two quantitative methods: the DPPH radical scavenging activity and Ferric-Reducing Antioxidant Power (FRAP) assays. The results were compared with those obtained with the starting materials 2-pyridine- carboxylic acid (I), 3-pyridinecarboxylic acid (II) and 4-pyridinecarboxylic acid (III), as well as with standard compounds, such as vitamin C and vitamin E, respectively. The in vitro antiradical activity with DPPH of diphenyltin derivative 5 showed a very similar behavior to vitamin C at a 20 µg/mL concentration, whereas according to the FRAP method, compound 8 was better. This difference is due to the mechanism of the antioxidant process. The Structure-Activity Relationships (SAR) for both methods is also reported. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
Synthesis of β-Maltooligosaccharides of Glycitein and Daidzein and their Anti-Oxidant and Anti-Allergic Activities
by Kei Shimoda and Hiroki Hamada

Molecules 2010, 15(8), 5153-5161; https://doi.org/10.3390/molecules15085153 - 29 Jul 2010
Cited by 19 | Viewed by 7994
Abstract
The production of β-maltooligosaccharides of glycitein and daidzein using Lactobacillus delbrueckii and cyclodextrin glucanotransferase (CGTase) as biocatalysts was investigated. The cells of L. delbrueckii glucosylated glycitein and daidzein to give their corresponding 4'- and 7-O-β-glucosides. The β-glucosides of glycitein and daidzein [...] Read more.

The production of β-maltooligosaccharides of glycitein and daidzein using Lactobacillus delbrueckii and cyclodextrin glucanotransferase (CGTase) as biocatalysts was investigated. The cells of L. delbrueckii glucosylated glycitein and daidzein to give their corresponding 4'- and 7-O-β-glucosides. The β-glucosides of glycitein and daidzein were converted into the corresponding β-maltooligosides by CGTase. The 7-O-β-glucosides of glycitein and daidzein and 7-O-β-maltoside of glycitein showed inhibitory effects on IgE antibody production. On the other hand, β-glucosides of glycitein and daidzein exerted 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity and supeoxide-radical scavenging activity. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
Antioxidant Properties of European Cranberrybush Fruit (Viburnum opulus var. edule)
by Otakar Rop, Vojtech Reznicek, Magdalena Valsikova, Tunde Jurikova, Jiri Mlcek and Daniela Kramarova

Molecules 2010, 15(6), 4467-4477; https://doi.org/10.3390/molecules15064467 - 23 Jun 2010
Cited by 77 | Viewed by 16749
Abstract
In the literature there is little available information concerning European cranberrybush fruit (Viburnum opulus var. edule). This plant can be cultivated, even in harsh climatic conditions, because of its low environmental demands, and it is possible to harvest the fruit even [...] Read more.

In the literature there is little available information concerning European cranberrybush fruit (Viburnum opulus var. edule). This plant can be cultivated, even in harsh climatic conditions, because of its low environmental demands, and it is possible to harvest the fruit even in the snow cover. The aim of this study was to determine the content of polyphenolics, antioxidant activity, flavonoids and vitamin C in the fruit of three cultivars ´Leningradskaya otbornaya´, ´Souzga´ and ´Taezny rubiny´ of this species. In the case of polyphenolics, high contents [up to 8.29 g of gallic acid/kg of fresh mass (FM)] were observed. The 1,1´-diphenyl-2-picrylhydrazyl (DPPH) and 2,2´-azinobis-3-ethyl-benzthiazino-6-sulphonic acid (ABTS) tests were applied to determine antioxidant activity, which was also high in comparison with other fruit species. The corresponding correlations between the polyphenolic content and antioxidant activity were in case of the DPPH test r² = 0.88 and for the ABTS test r² = 0.98. For comparison, the scavenging activity towards reactive oxygen species (superoxide anion, hydroxyl radical and nitric oxide) was determined by using a 25% fruit extract of particular cultivars. Antioxidant efficiency was also assessed using the rat liver slice model. Furthermore, the contents of flavonoids and vitamin C were assayed, giving values of 4.89 g/kg and 1.64 g/kg FM, respectively. The work should contribute to the popularization of this species as a promising crop plant in human nutrition. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
Oak (Quercus frainetto Ten.) Honeydew Honey—Approach to Screening of Volatile Organic Composition and Antioxidant Capacity (DPPH and FRAP Assay)
by Igor Jerković and Zvonimir Marijanović

Molecules 2010, 15(5), 3744-3756; https://doi.org/10.3390/molecules15053744 - 25 May 2010
Cited by 47 | Viewed by 12589
Abstract
Two samples of oak honeydew honey were investigated. Headspace solid-phase microextraction (HS-SPME) combined with GC and GC/MS enabled identification of the most volatile organic headspace compounds being dominated by terpenes(mainly cis- and trans-linalool oxides). The volatile and less-volatile organic composition of [...] Read more.

Two samples of oak honeydew honey were investigated. Headspace solid-phase microextraction (HS-SPME) combined with GC and GC/MS enabled identification of the most volatile organic headspace compounds being dominated by terpenes(mainly cis- and trans-linalool oxides). The volatile and less-volatile organic composition of the samples was obtained by ultrasonic assisted extraction (USE) with two solvents (1:2 (v/v) pentane -diethyl ether mixture and dichloromethane) followed by GC and GC/MS analysis. Shikimic pathway derivatives are of particular interest with respect to the botanical origin of honey and the most abundant was phenylacetic acid (up to 16.4%). Antiradical activity (DPPH assay) of the honeydew samples was 4.5 and 5.1 mmol TEAC/kg. Ultrasonic solvent extracts showed several dozen times higher antiradical capacity in comparison to the honeydew. Antioxidant capacity (FRAP assay) of honeydew samples was 4.8 and 16.1 mmol Fe²⁺/kg, while the solvent mixture extracts showed antioxidant activity of 374.5 and 955.9 Fe²⁺/kg, respectively, and the dichloromethane extracts 127.3 and 101.5 mmol Fe²⁺/kg. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
The Cinnamon-Derived Dietary Factor Cinnamic Aldehyde Activates the Nrf2-Dependent Antioxidant Response in Human Epithelial Colon Cells
by Georg Thomas Wondrak, Nicole F. Villeneuve, Sarah D. Lamore, Alexandra S. Bause, Tao Jiang and Donna D. Zhang

Molecules 2010, 15(5), 3338-3355; https://doi.org/10.3390/molecules15053338 - 07 May 2010
Cited by 130 | Viewed by 22810
Abstract
Colorectal cancer (CRC) is a major cause of tumor-related morbidity and mortality worldwide. Recent research suggests that pharmacological intervention using dietary factors that activate the redox sensitive Nrf2/Keap1-ARE signaling pathway may represent a promising strategy for chemoprevention of human cancer including CRC. In [...] Read more.

Colorectal cancer (CRC) is a major cause of tumor-related morbidity and mortality worldwide. Recent research suggests that pharmacological intervention using dietary factors that activate the redox sensitive Nrf2/Keap1-ARE signaling pathway may represent a promising strategy for chemoprevention of human cancer including CRC. In our search for dietary Nrf2 activators with potential chemopreventive activity targeting CRC, we have focused our studies on trans-cinnamic aldehyde (cinnamaldeyde, CA), the key flavor compound in cinnamon essential oil. Here we demonstrate that CA and an ethanolic extract (CE) prepared from Cinnamomum cassia bark, standardized for CA content by GC-MS analysis, display equipotent activity as inducers of Nrf2 transcriptional activity. In human colon cancer cells (HCT116, HT29) and non-immortalized primary fetal colon cells (FHC), CA- and CE-treatment upregulated cellular protein levels of Nrf2 and established Nrf2 targets involved in the antioxidant response including heme oxygenase 1 (HO-1) and γ-glutamyl-cysteine synthetase (γ-GCS, catalytic subunit). CA- and CE-pretreatment strongly upregulated cellular glutathione levels and protected HCT116 cells against hydrogen peroxide-induced genotoxicity and arsenic-induced oxidative insult. Taken together our data demonstrate that the cinnamon-derived food factor CA is a potent activator of the Nrf2-orchestrated antioxidant response in cultured human epithelial colon cells. CA may therefore represent an underappreciated chemopreventive dietary factor targeting colorectal carcinogenesis. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
Antioxidant Capacity of Macaronesian Traditional Medicinal Plants
by Lucélia Tavares, Dina Carrilho, Meenu Tyagi, David Barata, Ana Teresa Serra, Catarina Maria Martins Duarte, Rui Oliveira Duarte, Rodrigo Pedro Feliciano, Maria Rosário Bronze, Paula Chicau, Maria Dalila Espírito-Santo, Ricardo Boavida Ferreira and Cláudia Nunes Dos Santos

Molecules 2010, 15(4), 2576-2592; https://doi.org/10.3390/molecules15042576 - 12 Apr 2010
Cited by 48 | Viewed by 17345
Abstract
The use of many traditional medicinal plants is often hampered by the absence of a proper biochemical characterization, essential to identify the bioactive compounds present. The leaves from five species endemic to the Macaronesian islands with recognized ethnobotanical applications were analysed: Apollonias barbujana [...] Read more.

The use of many traditional medicinal plants is often hampered by the absence of a proper biochemical characterization, essential to identify the bioactive compounds present. The leaves from five species endemic to the Macaronesian islands with recognized ethnobotanical applications were analysed: Apollonias barbujana (Cav.) Bornm., Ocotea foetens (Ainton) Baill, Prunus azorica (Mouill.) Rivas-Mart., Lousã, Fern. Prieto, E. Días, J.C. Costa & C. Aguiar, Rumex maderensis Lowe and Plantago arborescens Poir. subsp. maderensis (Dcne.) A. Hans. et Kunk.. Since oxidative stress is a common feature of most diseases traditionally treated by these plants, it is important to assess their antioxidant capacity and determine the molecules responsible for this capacity. In this study, the antioxidant capacity of these plants against two of the most important reactive species in human body (hydroxyl and peroxyl radicals) was determined. To trace the antioxidant origin total phenol and flavonoid contents as well as the polyphenolic profile and the amount of trace elements were determined. There was a wide variation among the species analysed in what concerns their total leaf phenol and flavonoid contents. From the High Performance Liquid Chromatography (HPLC) electrochemically detected peaks it was possible to attribute to flavonoids the antioxidant capacity detected in A. barbujana, O. foetens, R. maderensis and P. azorica extracts. These potential reactive flavonoids were identified for A. barbujana, R. maderensis and P. azorica. For R. maderensis a high content (7 mg g^-1 dry weight) of L-ascorbic acid, an already described antioxidant phytomolecule, was found. A high content in selenomethionine (414.35 μg g^-1 dry weight) was obtained for P. arborescens subsp. maderensis extract. This selenocompound is already described as a hydroxyl radical scavenger is reported in this work as also possessing peroxyl radical scavenging capacity. This work is a good illustration of different phytomolecules (flavonoids, organic acids and selenocompounds), presents in leaves of the five traditional medicinal plants endemic to Macaronesia, all exhibiting antioxidant properties. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
Assessment of Antioxidant Capacity and Cytotoxicity of Selected Malaysian Plants
by Lai Teng Ling, Ammu Kutty Radhakrishnan, Thavamanithevi Subramaniam, Hwee Ming Cheng and Uma D. Palanisamy

Molecules 2010, 15(4), 2139-2151; https://doi.org/10.3390/molecules15042139 - 25 Mar 2010
Cited by 62 | Viewed by 15603
Abstract
Thirteen Malaysian plants; Artocarpus champeden, Azadirachta indica, Fragaria x ananassa, Garcinia mangostana, Lawsonia inermis, Mangifera indica, Nephelium lappaceum, Nephelium mutobile, Peltophorum pterocarpum, Psidium guajava and Syzygium aqueum, selected for their use in traditional medicine, were subjected to a variety of assays. Antioxidant [...] Read more.

Thirteen Malaysian plants; Artocarpus champeden, Azadirachta indica, Fragaria x ananassa, Garcinia mangostana, Lawsonia inermis, Mangifera indica, Nephelium lappaceum, Nephelium mutobile, Peltophorum pterocarpum, Psidium guajava and Syzygium aqueum, selected for their use in traditional medicine, were subjected to a variety of assays. Antioxidant capability, total phenolic content, elemental composition, as well as it cytotoxity to several cell lines of the aqueous and ethanolic extracts from different parts of these selected Malaysian plants were determined. In general, the ethanolic extracts were better free radical scavengers than the aqueous extracts and some of the tested extracts were even more potent than a commercial grape seed preparation. Similar results were seen in the lipid peroxidation inhibition studies. Our findings also showed a strong correlation of antioxidant activity with the total phenolic content. These extracts when tested for its heavy metals content, were found to be below permissible value for nutraceutical application. In addition, most of the extracts were found not cytotoxic to 3T3 and 4T1 cells at concentrations as high as 100 μg/mL. We conclude that although traditionally these plants are used in the aqueous form, its commercial preparation could be achieved using ethanol since a high total phenolic content and antioxidant activity is associated with this method of preparation. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessArticle
Antioxidant Properties of Cap and Stipe from Coprinus comatus
by Bo Li, Fei Lu, Xiaomin Suo, Haijuan Nan and Bin Li

Molecules 2010, 15(3), 1473-1486; https://doi.org/10.3390/molecules15031473 - 09 Mar 2010
Cited by 48 | Viewed by 11309
Abstract
Coprinus comatus, also called chicken drumstick mushroom, is currently commercially available in China. Hot water and ethanolic extracts were prepared from cap and stipe of C. comatus fruit bodies and their antioxidant properties were studied. Ethanolic extract from stipe showed high antioxidant [...] Read more.

Coprinus comatus, also called chicken drumstick mushroom, is currently commercially available in China. Hot water and ethanolic extracts were prepared from cap and stipe of C. comatus fruit bodies and their antioxidant properties were studied. Ethanolic extract from stipe showed high antioxidant activity (80.6%) at 1 mg/mL. Reducing power of hot water extracts from cap was 1.653 at 10 mg/mL. Extracts from cap showed better scavenging ability on DPPH (57.9% at 1 mg/mL) than stipe ones. Ethanolic extracts were more effective in scavenging ability on hydroxyl radicals (57.4–61.3% at 5 mg/mL) than hot water extracts. Ethanolic extracts showed moderate scavenging ability on superoxide radicals (46.3–47.0% at 20 mg/mL). Naturally occurring antioxidant components including total phenols (3.60–20.00 mg/g), tocopherols (0.58–11.93 mg/g), flavonoids (0.19–3.52 mg/g) and polysaccharides (58.52–547.86 mg/g) were found in the extracts. Overall, extracts from cap were more effective for the antioxidant properties assayed. Full article

(This article belongs to the Special Issue Antioxidants)

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Review

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Open AccessReview
Antioxidant Therapy as a Potential Approach to Severe Influenza-Associated Complications
by Noboru Uchide and Hiroo Toyoda

Molecules 2011, 16(3), 2032-2052; https://doi.org/10.3390/molecules16032032 - 28 Feb 2011
Cited by 108 | Viewed by 15602
Abstract
With the appearance of the novel influenza A (H1N1) virus 2009 strain we have experienced a new influenza pandemic and many patients have died from severe complications associated with this pandemic despite receiving intensive care. This suggests that a definitive medical treatment for [...] Read more.

With the appearance of the novel influenza A (H1N1) virus 2009 strain we have experienced a new influenza pandemic and many patients have died from severe complications associated with this pandemic despite receiving intensive care. This suggests that a definitive medical treatment for severe influenza-associated complications has not yet been established. Many studies have shown that superoxide anion produced by macrophages infiltrated into the virus-infected organs is implicated in the development of severe influenza-associated complications. Selected antioxidants, such as pyrrolidine dithiocabamate, N-acetyl-L-cysteine, glutathione, nordihydroguaiaretic acid, thujaplicin, resveratrol, (+)-vitisin A, ambroxol, ascorbic acid, 5,7,4-trihydroxy-8-methoxyflavone, catechins, quercetin 3-rhamnoside, iso- quercetin and oligonol, inhibit the proliferation of influenza virus and scavenge superoxide anion. The combination of antioxidants with antiviral drugs synergistically reduces the lethal effects of influenza virus infections. These results suggest that an agent with antiviral and antioxidant activities could be a drug of choice for the treatment of patients with severe influenza-associated complications. This review article updates knowledge of antioxidant therapy as a potential approach to severe influenza-associated complications. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessReview
Thiol Signalling Network with an Eye to Diabetes
by Elena Matteucci and Ottavio Giampietro

Molecules 2010, 15(12), 8890-8903; https://doi.org/10.3390/molecules15128890 - 06 Dec 2010
Cited by 74 | Viewed by 10606
Abstract
Redox regulatory system controls normal cellular functions. Controlled changes in redox couples potential serve as components for signal transduction, similarly to the phosphorylation cascade. Cellular redox biology requires both compartimentalisation and communication of redox systems: the thermodynamic disequilibrium of the major redox switches [...] Read more.

Redox regulatory system controls normal cellular functions. Controlled changes in redox couples potential serve as components for signal transduction, similarly to the phosphorylation cascade. Cellular redox biology requires both compartimentalisation and communication of redox systems: the thermodynamic disequilibrium of the major redox switches allows rapid and sensitive responses to perturbations in redox environments. The many oxidation states of sulphur are found in numerous sulphur species with distinct functional groups (thiols, disulphides, polysulphides, sulphenic, sulphinic and sulphonic acids, etc.), which participate in a complicated network of sulphur-based redox events. Human diseases such as diabetes mellitus and its cardiovascular complications have been associated with increased production of reactive oxygen species and perturbations of thiol redox homeostasis. The review surveys literature related to some etiopathogenic aspects and therapeutic perspectives. The dual toxic-protective property of sulphydryl-donor molecules in experimental settings proposes the general problem of designing antioxidants for therapeutic use. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessReview
Phenolic-Compound-Extraction Systems for Fruit and Vegetable Samples
by Patricia Garcia-Salas, Aranzazu Morales-Soto, Antonio Segura-Carretero and Alberto Fernández-Gutiérrez

Molecules 2010, 15(12), 8813-8826; https://doi.org/10.3390/molecules15128813 - 03 Dec 2010
Cited by 433 | Viewed by 26071
Abstract
This paper reviews the phenolic-compound-extraction systems used to analyse fruit and vegetable samples over the last 10 years. Phenolic compounds are naturally occurring antioxidants, usually found in fruits and vegetables. Sample preparation for analytical studies is necessary to determine the polyphenolic composition in [...] Read more.

This paper reviews the phenolic-compound-extraction systems used to analyse fruit and vegetable samples over the last 10 years. Phenolic compounds are naturally occurring antioxidants, usually found in fruits and vegetables. Sample preparation for analytical studies is necessary to determine the polyphenolic composition in these matrices. The most widely used extraction system is liquid-liquid extraction (LLE), which is an inexpensive method since it involves the use of organic solvents, but it requires long extraction times, giving rise to possible extract degradation. Likewise, solid-phase extraction (SPE) can be used in liquid samples. Modern techniques, which have been replacing conventional ones, include: supercritical fluid extraction (SFE), pressurized liquid extraction (PLE), microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE). These alternative techniques reduce considerably the use of solvents and accelerate the extraction process. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessReview
Antioxidant Vitamins and Their Use in Preventing Cardiovascular Disease
by Dan Farbstein, Adena Kozak-Blickstein and Andrew P. Levy

Molecules 2010, 15(11), 8098-8110; https://doi.org/10.3390/molecules15118098 - 09 Nov 2010
Cited by 83 | Viewed by 12222
Abstract
Atherosclerosis remains one of the leading causes of death in Western populations. Subsequent to the discovery that oxidative stress plays a pivotal role in the development and progression of atherosclerosis, vitamins C and E, along with other antioxidants, were studied as potential therapies [...] Read more.

Atherosclerosis remains one of the leading causes of death in Western populations. Subsequent to the discovery that oxidative stress plays a pivotal role in the development and progression of atherosclerosis, vitamins C and E, along with other antioxidants, were studied as potential therapies for the disease. However, while in vitro and in vivo studies showed promising antiatherogenic effects for vitamins C and E, clinical trials in which patients were given high doses of vitamin E or C showed no benefit and even possible harm. This review will attempt to summarize the known mechanistic data regarding the biochemical effects of vitamins C and E and their relevance to atherosclerosis, and offer an explanation for the failure of clinical trials to show that supplementation with these vitamins provides any benefit when given indiscriminately. We provide one example of how pharmacogenomics may be used to identify a sub-population which may indeed benefit from antioxidant supplementation. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessReview
Plant Phenolics: Extraction, Analysis and Their Antioxidant and Anticancer Properties
by Jin Dai and Russell J. Mumper

Molecules 2010, 15(10), 7313-7352; https://doi.org/10.3390/molecules15107313 - 21 Oct 2010
Cited by 2924 | Viewed by 84707
Abstract
Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such [...] Read more.

Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. In the last few years, the identification and development of phenolic compounds or extracts from different plants has become a major area of health- and medical-related research. This review provides an updated and comprehensive overview on phenolic extraction, purification, analysis and quantification as well as their antioxidant properties. Furthermore, the anticancer effects of phenolics in-vitro and in-vivo animal models are viewed, including recent human intervention studies. Finally, possible mechanisms of action involving antioxidant and pro-oxidant activity as well as interference with cellular functions are discussed. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessReview
The Nrf2 System as a Potential Target for the Development of Indirect Antioxidants
by Kyeong-Ah Jung and Mi-Kyoung Kwak

Molecules 2010, 15(10), 7266-7291; https://doi.org/10.3390/molecules15107266 - 20 Oct 2010
Cited by 374 | Viewed by 23149
Abstract
Oxidative stress causes damage to multiple cellular components such as DNA, proteins, and lipids, and is implicated in various human diseases including cancer, neurodegeneration, inflammatory diseases, and aging. In response to oxidative attack, cells have developed an antioxidant defense system to maintain cellular [...] Read more.

Oxidative stress causes damage to multiple cellular components such as DNA, proteins, and lipids, and is implicated in various human diseases including cancer, neurodegeneration, inflammatory diseases, and aging. In response to oxidative attack, cells have developed an antioxidant defense system to maintain cellular redox homeostasis and to protect cells from damage. The thiol-containing small molecules (e.g. glutathione), reactive oxygen species-inactivating enzymes (e.g. glutathione peroxidase), and phase 2 detoxifying enzymes (e.g. NAD(P)H: quinine oxidoreductase 1 and glutathione-S-transferases) are members of this antioxidant system. NF-E2-related factor 2 (Nrf2) is a CNC-bZIP transcription factor which regulates the basal and inducible expression of a wide array of antioxidant genes. Following dissociation from the cytosolic protein Keap1, a scaffolding protein which binds Nrf2 and Cul3 ubiquitin ligase for proteasome degradation, Nrf2 rapidly accumulates in the nucleus and transactivates the antioxidant response element in the promoter region of many antioxidant genes. The critical role of Nrf2 has been demonstrated by various animal studies showing that mice with a targeted disruption of the nrf2 gene are prone to develop lesions in response to environmental toxicants/carcinogens, drugs, and inflammatory insults. In this review, we discuss the role of the Nrf2 system, with particular focus on Nrf2-controlled target genes and the potential pleiotropic effects of Nrf2 activation of indirect antioxidants. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessReview
Role of Oxidant Scavengers in the Prevention of Ca²⁺ Homeostasis Disorders
by Carmen Galan, Isaac Jardín, Natalia Dionisio, Ginés Salido and Juan A. Rosado

Molecules 2010, 15(10), 7167-7187; https://doi.org/10.3390/molecules15107167 - 15 Oct 2010
Cited by 19 | Viewed by 10365
Abstract
A number of disorders, such as Alzheimer disease and diabetes mellitus, have in common the alteration of the redox balance, resulting in an increase in reactive oxygen species (ROS) generation that might lead to the development of apoptosis and cell death. It has [...] Read more.

A number of disorders, such as Alzheimer disease and diabetes mellitus, have in common the alteration of the redox balance, resulting in an increase in reactive oxygen species (ROS) generation that might lead to the development of apoptosis and cell death. It has long been known that ROS can significantly alter Ca²⁺ mobilization, an intracellular signal that is involved in the regulation of a wide variety of cellular functions. Cells have a limited capability to counteract the effects of oxidative stress, but evidence has been provided supporting the beneficial effects of exogenous ROS scavengers. Here, we review the effects of oxidative stress on intracellular Ca²⁺ homeostasis and the role of antioxidants in the prevention and treatment of disorders associated to abnormal Ca²⁺ mobilization induced by ROS. Full article

(This article belongs to the Special Issue Antioxidants)

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Open AccessReview
Potential of the Dietary Antioxidants Resveratrol and Curcumin in Prevention and Treatment of Hematologic Malignancies
by Mareike Kelkel, Claus Jacob, Mario Dicato and Marc Diederich

Molecules 2010, 15(10), 7035-7074; https://doi.org/10.3390/molecules15107035 - 12 Oct 2010
Cited by 92 | Viewed by 16106
Abstract
Despite considerable improvements in the tolerance and efficacy of novel chemotherapeutic agents, the mortality of hematological malignancies is still high due to therapy relapse, which is associated with bad prognosis. Dietary polyphenolic compounds are of growing interest as an alternative approach, especially in [...] Read more.

Despite considerable improvements in the tolerance and efficacy of novel chemotherapeutic agents, the mortality of hematological malignancies is still high due to therapy relapse, which is associated with bad prognosis. Dietary polyphenolic compounds are of growing interest as an alternative approach, especially in cancer treatment, as they have been proven to be safe and display strong antioxidant properties. Here, we provide evidence that both resveratrol and curcumin possess huge potential for application as both chemopreventive agents and anticancer drugs and might represent promising candidates for future treatment of leukemia. Both polyphenols are currently being tested in clinical trials. We describe the underlying mechanisms, but also focus on possible limitations and how they might be overcome in future clinical use – either by chemically synthesized derivatives or special formulations that improve bioavailability and pharmacokinetics. Full article

(This article belongs to the Special Issue Antioxidants)

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216 KiB

Open AccessReview
Cherry Antioxidants: From Farm to Table
by Gianna Ferretti, Tiziana Bacchetti, Alberto Belleggia and Davide Neri

Molecules 2010, 15(10), 6993-7005; https://doi.org/10.3390/molecules15106993 - 12 Oct 2010
Cited by 240 | Viewed by 25980
Abstract
The dietary consumption of fruits and vegetables is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds found in vegetable products. Sweet and sour cherries [...] Read more.

The dietary consumption of fruits and vegetables is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds found in vegetable products. Sweet and sour cherries contain several antioxidants and polyphenols that possess many biological activities, such as antioxidant, anticancer and anti-inflammation properties. The review describes the effect of environment and other factors (such as production, handling and storage) on the nutritional properties of cherries, with particular attention to polyphenol compounds. Moreover the health benefits of cherries and their polyphenols against human diseases such as heart disease, cancers, diabetes are reviewed. Full article

(This article belongs to the Special Issue Antioxidants)

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327 KiB

Open AccessReview
Natural Antioxidants: Fascinating or Mythical Biomolecules?
by Ashwell R. Ndhlala, Mack Moyo and Johannes Van Staden

Molecules 2010, 15(10), 6905-6930; https://doi.org/10.3390/molecules15106905 - 08 Oct 2010
Cited by 211 | Viewed by 16284
Abstract
Research on the use, properties, characteristics and sources of antioxidants especially phenolic compounds, flavonoids, vitamins, synthetic chemicals and some micronutrients began in the late 18^th century. Since then antioxidant research has received considerable attention and over a hundred thousand papers have been [...] Read more.

Research on the use, properties, characteristics and sources of antioxidants especially phenolic compounds, flavonoids, vitamins, synthetic chemicals and some micronutrients began in the late 18^th century. Since then antioxidant research has received considerable attention and over a hundred thousand papers have been published on the subject. This has led to a rampant use of antioxidants in order to try to obtain and preserve optimal health. A number of nutraceuticals and food supplements are frequently fortified with synthetic or natural antioxidants. However, some research outcomes have led to the belief that antioxidants exist as mythical biomolecules. This review provides a critical evaluation of some common in vitro antioxidant capacity methods, and a discussion on the role and controversies surrounding non-enzymatic biomolecules, in particular phenolic compounds and non-phenolic compounds, in oxidative processes in an attempt of stemming the tidal wave that is threatening to swamp the concept of natural antioxidants. Full article

(This article belongs to the Special Issue Antioxidants)

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324 KiB

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The Roles of Phytochemicals in Bronchial Asthma
by Hee Sun Park, So Ri Kim, Ju Ock Kim and Yong Chul Lee

Molecules 2010, 15(10), 6810-6834; https://doi.org/10.3390/molecules15106810 - 04 Oct 2010
Cited by 35 | Viewed by 11859
Abstract
Despite gaps in our knowledge of how phytochemicals interfere with cellular functions, several natural plant products are utilized to prevent or treat a wide range of diseases. Identification of an agent with therapeutic potential requires multiple steps involving in vitro studies, efficacy and [...] Read more.

Despite gaps in our knowledge of how phytochemicals interfere with cellular functions, several natural plant products are utilized to prevent or treat a wide range of diseases. Identification of an agent with therapeutic potential requires multiple steps involving in vitro studies, efficacy and toxicity studies in animal models, and then human clinical trials. This review provides a brief introduction on natural products that may help to treat and/or prevent bronchial asthma and describes our current understanding of their molecular mechanisms based on various in vitro, in vivo, and clinical studies. We focus on the anti-inflammatory and anti-vascular actions of the plant products and other roles beyond the anti-oxidative effects. Full article

(This article belongs to the Special Issue Antioxidants)

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301 KiB

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Honokiol and Magnolol as Multifunctional Antioxidative Molecules for Dermatologic Disorders
by Jui-Lung Shen, Kee-Ming Man, Po-Hsun Huang, Wen-Chi Chen, Der-Cherng Chen, Ya-Wen Cheng, Po-Len Liu, Ming-Chih Chou and Yung-Hsiang Chen

Molecules 2010, 15(9), 6452-6465; https://doi.org/10.3390/molecules15096452 - 16 Sep 2010
Cited by 137 | Viewed by 20919
Abstract
Chinese herbs have been and still are widely used as important remedies in Oriental medicine. Over the recent years, a variety of biologically active constituents have been isolated from these sources and confirmed to have multifunctional activity in experimental studies. Honokiol is a [...] Read more.

Chinese herbs have been and still are widely used as important remedies in Oriental medicine. Over the recent years, a variety of biologically active constituents have been isolated from these sources and confirmed to have multifunctional activity in experimental studies. Honokiol is a small-molecule polyphenol isolated from the genus Magnolia. It is accompanied by other related polyphenols, including magnolol, with which it shares certain biological properties. Recently, honokiol and magnolol have been found to have anti-oxidative, anti-inflammatory, anti-tumor, and anti-microbial properties in preclinical models, without appreciable toxicity. These findings have increased interest in bringing honokiol and magnolol to the clinic as novel therapeutic agents in dermatology. In this review, the findings concerning the major mechanisms of action of honokiol and magnolol are described. Knowledge of the multiple activities of honokiol and magnolol can assist with the development of honokiol and magnolol derivatives and the design of clinical trials that will maximize the potential benefit of honokiol and magnolol in the patient setting for dermatologic disorders. Full article

(This article belongs to the Special Issue Antioxidants)

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