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Natural Active Agents Against Bacteria, Fungi and Parasites

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Natural Products Chemistry".

Deadline for manuscript submissions: closed (31 December 2019) | Viewed by 74690

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Special Issue Editors

Prof. Dr. Maria Daglia

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Guest Editor

Department of Drug Sciences, University of Pavia, Pavia, Italy
Interests: food chemistry and analysis; food supplements; functional foods; chromatographic and spectrophotometric methods; natural compounds; polyphenols; antioxidant activity; anti- inflammatory activity; epigenetic effect of food components-mirnas; preclinical studies
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Annabella Vitalone

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Guest Editor

Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University of Rome, Rome, Italy
Interests: safety assessment of herbal products; phytovigilance; medicinal plants used for weight control

Dr. Simone Carradori

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Guest Editor

Department of Pharmacy, University “G. d'Annunzio” of Chieti-Pescara, Chieti, Italy
Interests: medicinal chemistry; food chemistry; natural products and their semi-synthetic derivatives; structure–activity relationships
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Recently, we accepted an invitation to serve as Guest Editors for this Special Issue, "Discovery of Natural Active Agents against Bacteria, Fungi and Parasites” of the journal Molecules (ISSN 1420-3049 https://www.mdpi.com/journal/molecules). In this regard, we would be pleased if you would agree to contribute an original research paper, a short communication, or a focus review to this issue. Provided below is some information that you may find useful in your consideration of this invitation.

This Special Issue aims to collect and disseminate some of the most significant and recent contributions in the interdisciplinary area of pharmacology, pharmacognosy, and food/medicinal chemistry, with a particular emphasis on the (biotechnological) production, isolation and characterization, biological effects, uses, and analysis of semi-synthetic and natural products. The main applications of these natural active compounds must be strictly focused on microbial (bacterial, fungal and viral) infections, parasite eradication, food contamination and preservation, inhibition of biofilm production and resistance development, herbal formulations, new mechanism of action, structure-activity elucidation, and chemically modified natural compounds with improved biological activity. The biological activity of natural extracts without a proper chemical characteriztion will not be considered.

Prof. Dr. Maria Daglia
Prof. Dr. Simone Carradori
Prof. Dr. Annabella Vitalone
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

antimicrobial agents
food contamination
innovative (micro)extraction procedures
synthetic derivatives inspired by natural scaffolds
food and food supplements analyses
pharmaco-toxicological activities
physiological activities of food and food components
uses of medicinal plants and fungi
biofilm and resistance

Published Papers (14 papers)

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Research

19 pages, 3736 KiB

Open AccessArticle

Indole-Containing Phytoalexin-Based Bioisosteres as Antifungals: In Vitro and In Silico Evaluation against Fusarium oxysporum

by Andrea Angarita-Rodríguez, Diego Quiroga and Ericsson Coy-Barrera

Molecules 2020, 25(1), 45; https://doi.org/10.3390/molecules25010045 - 21 Dec 2019

Cited by 11 | Viewed by 4229

Abstract

There is a continuous search for more reliable and effective alternatives to control phytopathogens through different strategies. In this context, indole-containing phytoalexins are stimuli-induced compounds implicated in plant defense against plant pathogens. However, phytoalexins’ efficacy have been limited by fungal detoxifying mechanisms, thus, the research on bioisosteres-based analogs can be a friendly alternative regarding the control of Fusarium phytopathogens, but there are currently few studies on it. Thus, as part of our research on antifungal agents, a set of 21 synthetic indole-containing phytoalexin analogs were evaluated as inhibitors against the phyopathogen Fusarium oxysporum. Results indicated that analogs of the N,N-dialkylthiourea, N,S-dialkyldithiocarbamate and substituted-1,3-thiazolidin-5-one groups exhibited the best docking scores and interaction profiles within the active site of Fusarium spp. enzymes. Vina scores exhibited correlation with experimental mycelial growth inhibition using supervised statistics, and this antifungal dataset correlated with molecular interaction fields after CoMFA. Compound 24 (tert-butyl (((3-oxo-1,3-diphenylpropyl)thio)carbonothioyl)-l-tryptophanate), a very active analog against F. oxysporum, exhibited the best interaction with lanosterol 14α-demethylase according to molecular docking, molecular dynamics and molecular mechanic/poisson-boltzmann surface area (MM/PBSA) binding energy performance. After data analyses, information on mycelial growth inhibitors, structural requirements and putative enzyme targets may be used in further antifungal development based on phytoalexin analogs for controlling phytopathogens. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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17 pages, 4664 KiB

Open AccessArticle

Inhibitory Effects of Myrtucommuacetalone 1 (MCA-1) from Myrtus Communis on Inflammatory Response in Mouse Macrophages

by Samreen Soomro, M. Ahmed Mesaik, Farzana Shaheen, Noureen Khan, Sobia Ahsan Halim, Zaheer Ul-Haq, Rafat Ali Siddiqui and Muhammad Iqbal Choudhary

Molecules 2020, 25(1), 13; https://doi.org/10.3390/molecules25010013 - 18 Dec 2019

Cited by 6 | Viewed by 2861

Abstract

(1) Introduction: Reactive oxygen species (ROS) and nitric oxide (NO) are key signaling molecules that play important roles in the progression of inflammatory disorders. The objective of this study was to explore the use of myrtucommuacetalone-1 (MCA-1), as a novel compound of natural origin and a potential anti-inflammatory agent. (2) Methodology: The anti-inflammatory potential of MCA-1, which was isolated from Myrthus communis Linn, was determined by assaying superoxide, hydrogen peroxide, and nitric oxide production in macrophages. Furthermore, the effects of the compound were analyzed via phosphorylation and translocation of the transcription factor NF kappa B, which is a key regulator of iNOS activation. The effect of MCA-1 on the inducible nitric oxide synthase (iNOS) enzyme was also examined using in silico docking studies. The anticancer potential for MCA-1 was evaluated with an MTT cytotoxic assay. (3) Results: In stimulated macrophages, MCA-1 inhibited superoxide production by 48%, hydrogen peroxide by 53%, and nitric oxide (NO) with an IC₅₀ of <1 µg/mL. MCA-1 also showed a very strong binding pattern within the active site of the inducible nitric oxide synthase enzyme. Furthermore, 25 µg/mL of MCA-1 inhibited inducible nitric oxide synthase expression and abolished transcription factor (NFκB) phosphorylation and translocation to the nucleus. Cytotoxicity analyses of MCA-1 on 3T3 mouse fibroblasts, CC1 liver cell line, J774.2, macrophages and MDBK bovine kidney epithelial cell, yielded IC₅₀ values of 6.53 ± 1.2, 4.6 ± 0.7, 5 ± 0.8, and 4.6 ± 0.7, µg/mL, respectively. (4) Conclusion: Our results suggest that MCA-1, a major phloroglucinol-type compound, shows strong anti-inflammatory activity and has a potential to be a leading therapeutic agent in the future. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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7 pages, 844 KiB

Open AccessArticle

Screening Effective Antifungal Substances from the Bark and Leaves of Zanthoxylum avicennae by the Bioactivity-Guided Isolation Method

by Yongtong Xiong, Guan Huang, Zongli Yao, China Zhao, Xiang Zhu, Qinglai Wu, Xudong Zhou and Junkai Li

Molecules 2019, 24(23), 4207; https://doi.org/10.3390/molecules24234207 - 20 Nov 2019

Cited by 14 | Viewed by 2649

Abstract

To find good antifungal substances by the bioactivity-guided isolation method, we tracked down the effective antifungal substances in the bark and leaves of Zanthoxylum avicennae, and isolated three antifungal compounds 1, 2, and 3. The structures were identified as xanthyletin, luvangetin, and avicennin by ¹H-NMR, ¹³C-NMR, and HRMS spectra. Particularly, compound 2 had several isomers, and the ¹H-NMR spectra of 2 in different solvents showed a significant difference. To determine the stereo structure of 2, a single crystal was prepared and identified by X-ray diffraction as Luvangetin. Moreover, the difference of ¹H-NMR data of 2 between in solvent dimethyl sulfoxide-d₆ (DMSO-d₆) and deuterated chloroform (CDCl₃), and other reported isomers were discussed for the first time. The bioassay results indicated that the three compounds 1, 2, and 3 displayed low to high antifungal activities against tested phytopathogenic fungi. In particular, all compounds 1, 2, and 3 showed excellent antifungal activities against Pyricularia oryzae and Z. avicennae, with the values of half maximal effective concentration (EC₅₀) ranging from 31 to 61 mg/L, and compound 3 was also identified as a more potent inhibitor against Fusaium graminearum (EC₅₀ = 43.26 ± 1.76 mg/L) compared with fungicide PCA (phenazine-1-carboxylic acid) (EC₅₀ = 52.34 ± 1.53 mg/L). The results revealed that compounds 1, 2, and 3 were the main antifungal substances of Z. avicennae, and can be used as lead compounds of a fungicide, which has good development value and prospect. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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18 pages, 959 KiB

Open AccessArticle

Chemical Characterization and Evaluation of the Antibacterial Activity of Essential Oils from Fibre-Type Cannabis sativa L. (Hemp)

by Ramona Iseppi, Virginia Brighenti, Manuela Licata, Antonella Lambertini, Carla Sabia, Patrizia Messi, Federica Pellati and Stefania Benvenuti

Molecules 2019, 24(12), 2302; https://doi.org/10.3390/molecules24122302 - 21 Jun 2019

Cited by 84 | Viewed by 9758

Abstract

Volatile terpenes represent the largest group of Cannabis sativa L. components and they are responsible for its aromatic properties. Even if many studies on C. sativa have been focused on cannabinoids, which are terpenophenolics, little research has been carried out on its volatile terpenic compounds. In the light of all the above, the present work was aimed at the chemical characterization of seventeen essential oils from different fibre-type varieties of C. sativa (industrial hemp or hemp) by means of GC-MS and GC-FID techniques. In total, 71 compounds were identified, and the semi-quantitative analysis revealed that α- and β-pinene, β-myrcene and β-caryophyllene are the major components in all the essential oils analysed. In addition, a GC-MS method was developed here for the first time, and it was applied to quantify cannabinoids in the essential oils. The antibacterial activity of hemp essential oils against some pathogenic and spoilage microorganisms isolated from food and food processing environment was also determined. The inhibitory effects of the essential oils were evaluated by both the agar well diffusion assay and the minimum inhibitory concentration (MIC) evaluation. By using the agar diffusion method and considering the zone of inhibition, it was possible to preliminarily verify the inhibitory activity on most of the examined strains. The results showed a good antibacterial activity of six hemp essential oils against the Gram-positive bacteria, thus suggesting that hemp essential oil can inhibit or reduce bacterial proliferation and it can be a valid support to reduce microorganism contamination, especially in the food processing field. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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9 pages, 250 KiB

Open AccessArticle

In Vitro Antimicrobial Activity of Essential Oils against Salmonella enterica Serotypes Enteritidis and Typhimurium Strains Isolated from Poultry

by Valentina Virginia Ebani, Simona Nardoni, Fabrizio Bertelloni, Giovanni Tosi, Paola Massi, Luisa Pistelli and Francesca Mancianti

Molecules 2019, 24(5), 900; https://doi.org/10.3390/molecules24050900 - 04 Mar 2019

Cited by 35 | Viewed by 4025

Abstract

Salmonella enterica serotype Enteritidis and S. enterica serotype Typhimurium are frequently present among poultry and are associated with outbreaks of human salmonellosis. The study investigated the in vitro antimicrobial activity of essential oils (EOs) obtained from Aloysia triphylla, Cinnamomum zeylanicum, Cymbopogon citratus, Litsea cubeba, Mentha piperita, Syzygium aromaticum against S. Enteritidis and S. Thyphimurium strains previously isolated from poultry. A 1:1 mixture of C. zeylanicum and S. aromaticum was also tested. The activity of all compounds was evaluated against the yeast Saccharomyces cerevisiae, commonly used as probiotic. The highest antibacterial activity was observed for C. zeylanicum (minimum inhibitory concentrations (MICs) ranging from 1.26 mg/mL to 0.63 mg/mL), S. aromaticum (MICs from 2.637 mg/mL to 0.164 mg/mL) and the mixture (MICs from 1.289 mg/mL to 0.322 mg/mL). No activity was recorded against S. cerevisiae. The results suggest a possible use of C. zeylanicum and S. aromaticum, alone or in combination, in the farm environment for disinfection and in poultry diet, combined with S. cerevisiae administration, for an integrated approach to avoid Salmonella intestinal colonization. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

13 pages, 1259 KiB

Open AccessArticle

Hop Extract Acts as an Antioxidant with Antimicrobial Effects against Propionibacterium Acnes and Staphylococcus Aureus

by Natalja Weber, Klaus Biehler, Kay Schwabe, Birgit Haarhaus, Karl-W. Quirin, Uwe Frank, Christoph M. Schempp and Ute Wölfle

Molecules 2019, 24(2), 223; https://doi.org/10.3390/molecules24020223 - 09 Jan 2019

Cited by 52 | Viewed by 7645

Abstract

Acne is associated with hyperkeratosis, elevated levels of skin sebum and growth of Propionibacterium acnes (P. acnes) and Staphylococcus aureus (S. aureus). Furthermore, P. acnes promotes inflammation by inducing IL-6 production and oxidative stress. The aim of this study was to assess the antioxidant, anti-inflammatory and antibacterial potential of a hop-CO₂-extract with 50% humulone and lupulone. The susceptibility of P. acnes and S. aureus to the hop extract was tested by using the broth microdilution technique. The minimal inhibitory concentrations (MIC) for P. acnes and S. aureus were 3.1 and 9.4 µg/mL, respectively. In addition, the hop extract showed an antioxidative effect with a half maximal inhibitory concentration (IC₅₀) of 29.43 µg/mL as well as additional anti-inflammatory effects by reducing the IL-6 expression (IC₅₀: 0.8 µg/mL). In addition, a gel formulation with 0.3% hop extract (w/w) had antibacterial activity against P. acnes and S. aureus (inhibition zone value: 5.5 mm and 3 mm, respectively) which was significantly superior to the placebo gel. The positive control (a gel with the antibiotic clindamycin) showed an inhibition zone of 9 mm. Due to its antioxidant, anti-inflammatory and antibacterial effects hop extract might be a treatment option for acne-prone skin. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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26 pages, 5132 KiB

Open AccessArticle

Chromatographic Analyses, In Vitro Biological Activities, and Cytotoxicity of Cannabis sativa L. Essential Oil: A Multidisciplinary Study

by Gokhan Zengin, Luigi Menghini, Antonella Di Sotto, Romina Mancinelli, Francesca Sisto, Simone Carradori, Stefania Cesa, Caterina Fraschetti, Antonello Filippi, Letizia Angiolella, Marcello Locatelli, Luisa Mannina, Cinzia Ingallina, Valentina Puca, Marianna D’Antonio and Rossella Grande

Molecules 2018, 23(12), 3266; https://doi.org/10.3390/molecules23123266 - 10 Dec 2018

Cited by 107 | Viewed by 7861

Abstract

Due to renewed interest in the cultivation and production of Italian Cannabis sativa L., we proposed a multi-methodological approach to explore chemically and biologically both the essential oil and the aromatic water of this plant. We reported the chemical composition in terms of cannabinoid content, volatile component, phenolic and flavonoid pattern, and color characteristics. Then, we demonstrated the ethnopharmacological relevance of this plant cultivated in Italy as a source of antioxidant compounds toward a large panel of enzymes (pancreatic lipase, α-amylase, α-glucosidase, and cholinesterases) and selected clinically relevant, multidrug-sensible, and multidrug-resistant microbial strains (Staphylococcus aureus, Helicobacter pylori, Candida, and Malassezia spp.), evaluating the cytotoxic effects against normal and malignant cell lines. Preliminary in vivo cytotoxicity was also performed on Galleria mellonella larvae. The results corroborate the use of this natural product as a rich source of important biologically active molecules with particular emphasis on the role exerted by naringenin, one of the most important secondary metabolites. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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10 pages, 1826 KiB

Open AccessArticle

Novel Gel Formulations as Topical Carriers for the Essential Oil of Bidens tripartita for the Treatment of Candidiasis

by Monika Tomczykowa, Magdalena Wróblewska, Katarzyna Winnicka, Piotr Wieczorek, Piotr Majewski, Katarzyna Celińska-Janowicz, Róża Sawczuk, Wojciech Miltyk, Elżbieta Tryniszewska and Michał Tomczyk

Molecules 2018, 23(10), 2517; https://doi.org/10.3390/molecules23102517 - 01 Oct 2018

Cited by 27 | Viewed by 4198

Abstract

The genus Bidens L. (Asteraceae) refers to several species of plants used in traditional phytotherapeutic preparations. B. tripartita, also known as bur marigold, is the most familiar plant and has been known as a remedy for chronic dysentery. The hydrodistilled essential oil of the aerial parts of the Polish B. tripartita was analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) techniques. To exclude any potential toxic effects of the oil on human dermal fibroblasts, the MTT test (methyl thiazolyl tetrazolium) and COMET assay (single-cell gel electrophoresis) were performed. Novel gel formulations as topical carriers for essential oil obtained from B. tripartita were developed and characterized. The bioadhesive properties of the designed preparations in the ex vivo model using the skin of hairless mice were also evaluated. The therapeutic efficacy of the topical formulations is influenced by active phytoconstituents and vehicle characteristics. The antifungal properties of the essential oil of B. tripartita were also tested against Candida species, and this oil appears to be a promising topical anticandidal agent. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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7 pages, 359 KiB

Open AccessArticle

Antimycobacterial Activity of Cinnamaldehyde in a Mycobacterium tuberculosis(H37Ra) Model

by Rafal Sawicki, Joanna Golus, Agata Przekora, Agnieszka Ludwiczuk, Elwira Sieniawska and Grazyna Ginalska

Molecules 2018, 23(9), 2381; https://doi.org/10.3390/molecules23092381 - 18 Sep 2018

Cited by 30 | Viewed by 4773

Abstract

The purpose of the study was to evaluate the antimycobacterial activity and the possible action mode of cinnamon bark essential oil and its main constituent—cinnamaldehyde—against the Mycobacterium tuberculosis ATCC 25177 strain. Cinnamaldehyde was proved to be the main bioactive compound responsible for mycobacterial growth inhibition and bactericidal effects. The antimycobacterial activity of cinnamaldehyde was found to be comparable with that of ethambutol, one of the first-line anti-TB antibiotics. The selectivity index determined using cell culture studies in vitro showed a high biological potential of cinnamaldehyde. In M. tuberculosis cells exposed to cinnamaldehyde the cell membrane stress sensing and envelope preserving system are activated. Overexpression of clgR gene indicates a threat to the stability of the cell membrane and suggests a possible mechanism of action. No synergism was detected with the basic set of antibiotics used in tuberculosis treatment: ethambutol, isoniazid, streptomycin, rifampicin, and ciprofloxacin. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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13 pages, 695 KiB

Open AccessArticle

Chemometric Comparison and Classification of Some Essential Oils Extracted from Plants Belonging to Apiaceae and Lamiaceae Families Based on Their Chemical Composition and Biological Activities

by Cristina Anamaria Semeniuc, Maria-Ioana Socaciu, Sonia Ancuţa Socaci, Vlad Mureșan, Melinda Fogarasi and Ancuţa Mihaela Rotar

Molecules 2018, 23(9), 2261; https://doi.org/10.3390/molecules23092261 - 05 Sep 2018

Cited by 45 | Viewed by 4832

Abstract

This study is focused on the comparison and classification of parsley, lovage, basil, and thyme essential oils (EOs) based on their chemical composition, total phenolic content, antioxidant and antibacterial activities by using appropriate chemometric methods: Principal component analysis (PCA) and hierarchical cluster analysis (HCA). The results showed that parsley, lovage, and thyme EOs are rich in monoterpene hydrocarbons, but basil EO is rich in oxygenated monoterpenes and phenylpropanoids, and that both PCA and HCA separated essential oils into two main groups of which one contains two sub-groups. β-Phellandrene was the major component identified in parsley and lovage EOs, estragole was the major component in basil EO, and p-cymene was the major component in thyme EO. Thyme EO showed the highest level of total phenolics, the highest antioxidant capacity, and exhibited the stronger antibacterial activity, results that were emphasized by both chemometric methods used. Among tested essential oils, the one of parsley was distinguished by a low total TPC, weak antioxidant activity, and weak antibacterial activity against S. enteritidis (ATCC 13076); lovage EO by low TPC, weak antioxidant activity, but moderate antibacterial activity; and basil EO by low TPC, moderate antioxidant activity, and weak antibacterial activity against L. monocytogenes (ATCC 19114). Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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12 pages, 1270 KiB

Open AccessArticle

Antioxidant and Antimutagenic Activities of Different Fractions from the Leaves of Rhododendron arboreum Sm. and Their GC-MS Profiling

by Vandana Gautam, Sukhmeen Kaur Kohli, Saroj Arora, Renu Bhardwaj, Mohsin Kazi, Ajaz Ahmad, Mohammad Raish, Majid Ahmad Ganaie and Parvaiz Ahmad

Molecules 2018, 23(9), 2239; https://doi.org/10.3390/molecules23092239 - 03 Sep 2018

Cited by 20 | Viewed by 3987

Abstract

In this era of urbanization and environmental pollution, antioxidants and antimutagens derived from plants are promising safeguards for human health. In the current investigation, we analyzed the antioxidant and antimutagenic effects of the hexane, chloroform, and ethyl acetate fractions of Rhododendron arboreum Sm. leaves and determined their chemical composition. The different fractions inhibited lipid peroxidation, repressed the production of nitric oxide radicals, and prevented deoxyribose degradation. The antimutagenic activity of the leaf fractions was analyzed against 4-nitro-O-phenylenediamine, sodium azide and 2-aminofluorene mutagens in two test strains (TA-98 and TA-100) of Salmonella typhimurium. The experiment was conducted using pre- and co-incubation modes. The best results were obtained in the pre-incubation mode, and against indirect acting mutagen. The presence of a number of bioactive constituents was confirmed in the different fractions by GC-MS analysis. The study reveals the strong antioxidant and antimutagenic activity of R. arboreum leaves. We propose that those activities of R. arboreum might correspond to the combined effect of the phytochemicals identified by GC-MS analysis. To the best of our knowledge, this is the first report on the antimutagenic activity of R. arboreum leaves. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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13 pages, 2370 KiB

Open AccessArticle

The α-Cyclodextrin/Moringin Complex: A New Promising Antimicrobial Agent against Staphylococcus aureus

by Letizia Romeo, Veronica Lanza Cariccio, Renato Iori, Patrick Rollin, Placido Bramanti and Emanuela Mazzon

Molecules 2018, 23(9), 2097; https://doi.org/10.3390/molecules23092097 - 21 Aug 2018

Cited by 13 | Viewed by 5478

Abstract

Antimicrobial resistance is one of the major clinical concerns, making the discovery of new antimicrobial drugs desirable. Moringin (MOR), the major isothiocyanate produced from Moringa oleifera seeds, could represent an alternative therapeutic strategy to commonly used antibiotics. The aim of our study was to investigate the antimicrobial effect of MOR conjugated with α-cyclodextrin (MOR/α-CD), a complex with an improved solubility and stability in aqueous solutions. Our data demonstrated that MOR/α-CD was able to exert antimicrobial activity against the S. aureus reference strains (ATCC 25923, ATCC 6538, and ATCC BAA-977). Moreover, MOR/α-CD showed bacteriostatic effects (MIC = minimum inhibitory concentration = 0.5 mg/mL) and bactericidal properties (MBC = minimum bactericidal concentration = 1 mg/mL) against the overall assessed strains. In addition, MOR/α-CD showed bactericidal activity against the S. aureus strain ATCC BAA-977 after treatment with erythromycin (Ery), which induced clindamycin-resistance on the erm (A) gene. This evidence led us to assume that MOR/α-CD could be a promising antimicrobial agent against strains with the clindamycin-resistant phenotype (CC-resistant). Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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25 pages, 1477 KiB

Open AccessArticle

A Polyphenol Rich Extract from Solanum melongena L. DR2 Peel Exhibits Antioxidant Properties and Anti-Herpes Simplex Virus Type 1 Activity In Vitro

by Antonella Di Sotto, Silvia Di Giacomo, Donatella Amatore, Marcello Locatelli, Annabella Vitalone, Chiara Toniolo, Giuseppe Leonardo Rotino, Roberto Lo Scalzo, Anna Teresa Palamara, Maria Elena Marcocci and Lucia Nencioni

Molecules 2018, 23(8), 2066; https://doi.org/10.3390/molecules23082066 - 17 Aug 2018

Cited by 43 | Viewed by 6209

Abstract

DR2B and DR2C extracts, obtained by ethanolic maceration of peel from commercially and physiologically ripe aubergine berries, were studied for the antioxidative cytoprotective properties and anti-HSV-1 activity, in line with the evidence that several antioxidants can impair viral replication by maintaining reducing conditions in host cells. The antioxidative cytoprotective effects against tBOOH-induced damage were assessed in Caco2 cells, while antiviral activity was studied in Vero cells; polyphenolic fingerprints were characterized by integrated phytochemical methods. Results highlighted different compositions of the extracts, with chlorogenic acid and delphinidin-3-rutinoside as the major constituents; other peculiar phytochemicals were also identified. Both samples reduced reactive oxygen species (ROS) production and exhibited scavenging and chelating properties. DR2C partly counteracted the tBOOH-induced cytotoxicity, with a remarkable lowering of lactate metabolism under both normoxia and hypoxia; interestingly, it increased intracellular GSH levels. Furthermore, DR2C inhibited the HSV-1 replication when added for 24 h after viral adsorption, as also confirmed by the reduction of many viral proteins’ expression. Since DR2C was able to reduce NOX4 expression during HSV-1 infection, its antiviral activity may be correlated to its antioxidant properties. Although further studies are needed to better characterize DR2C activity, the results suggest this extract as a promising new anti-HSV-1 agent. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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9 pages, 402 KiB

Open AccessArticle

Biopesticide Activity from Drimanic Compounds to Control Tomato Pathogens

by Iván Montenegro, Alejandro Madrid, Mauricio Cuellar, Michael Seeger, Juan Felipe Alfaro, Ximena Besoain, Juan Pablo Martínez, Ingrid Ramirez, Yusser Olguín and Miryam Valenzuela

Molecules 2018, 23(8), 2053; https://doi.org/10.3390/molecules23082053 - 16 Aug 2018

Cited by 18 | Viewed by 5042

Abstract

Tomato crops can be affected by several infectious diseases produced by bacteria, fungi, and oomycetes. Four phytopathogens are of special concern because of the major economic losses they generate worldwide in tomato production; Clavibacter michiganensis subsp. michiganensis and Pseudomonas syringae pv. tomato, causative agents behind two highly destructive diseases, bacterial canker and bacterial speck, respectively; fungus Fusarium oxysporum f. sp. lycopersici that causes Fusarium Wilt, which strongly affects tomato crops; and finally, Phytophthora spp., which affect both potato and tomato crops. Polygodial (1), drimenol (2), isonordrimenone (3), and nordrimenone (4) were studied against these four phytopathogenic microorganisms. Among them, compound 1, obtained from Drimys winteri Forst, and synthetic compound 4 are shown here to have potent activity. Most promisingly, the results showed that compounds 1 and 4 affect Clavibacter michiganensis growth at minimal inhibitory concentrations (MIC) values of 16 and 32 µg/mL, respectively, and high antimycotic activity against Fusarium oxysporum and Phytophthora spp. with MIC of 64 µg/mL. The results of the present study suggest novel treatment alternatives with drimane compounds against bacterial and fungal plant pathogens. Full article

(This article belongs to the Special Issue Natural Active Agents Against Bacteria, Fungi and Parasites)

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