Molecules

21 pages, 10099 KiB

Open AccessArticle

Investigating the Fluid–Solid Interaction of Acid Nonionic Nanoemulsion with Carbonate Porous Media

by Cláudio Regis dos Santos Lucas, Yanne Katiussy Pereira Gurgel Aum, Edson de Andrade Araújo, Tereza Neuma de Castro Dantas, Elayne Andrade Araújo, Talles Nóbrega Sousa and Pedro Tupã Pandava Aum

Molecules 2020, 25(6), 1475; https://doi.org/10.3390/molecules25061475 - 24 Mar 2020

Cited by 12 | Viewed by 3239

Abstract

The subject of rock–fluid interaction is important in cases where flow through porous media is occurring. One special case is when the fluid reacts with the porous matrix. In this case, the mass transfer and reaction rate control the dissolution pattern. This article [...] Read more.

The subject of rock–fluid interaction is important in cases where flow through porous media is occurring. One special case is when the fluid reacts with the porous matrix. In this case, the mass transfer and reaction rate control the dissolution pattern. This article aimed to study the interaction between an acid nanoemulsion system and a carbonate porous media. Nanoemulsions were developed to retard the rock’s dissolution and to promote the formation of conductivity channels. Nanoemulsions were prepared using ALK100 (alkyl alcohol ethoxylate) and RNX110 (alkylphenol ethoxylate) (nonionic surfactants), sec-butanol (co-surfactant), xylene isomers (oil phase), and a solution of HCl (aqueous phase). The obtained systems were characterized in terms of surface tension, droplet diameter, and reactivity. X-ray fluorescence/diffraction (XRF/XRD) and X-ray microtomography (microCT) were performed on carbonate porous media samples treated with the acid systems in order to observe the effects of the fluid–rock interaction. The results showed that the acid nanoemulsion, presenting a low oil content formulation, showed the low surface tension and droplet size characteristic of nanoemulsions. It was experimentally verified that the reactivity in the nanoemulsion media was mass-transfer-retarded, and that the wormhole pattern was verified under the studied conditions. Full article

(This article belongs to the Section Molecular Liquids)

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28 pages, 1112 KiB

Open AccessFeature PaperReview

Alternative Woods in Enology: Characterization of Tannin and Low Molecular Weight Phenol Compounds with Respect to Traditional Oak Woods. A Review

by Ana Martínez-Gil, Maria del Alamo-Sanza, Rosario Sánchez-Gómez and Ignacio Nevares

Molecules 2020, 25(6), 1474; https://doi.org/10.3390/molecules25061474 - 24 Mar 2020

Cited by 17 | Viewed by 4449

Abstract

Wood is one of the most highly valued materials in enology since the chemical composition and sensorial properties of wine change significantly when in contact with it. The need for wood in cooperage and the concern of enologists in their search for new [...] Read more.

Wood is one of the most highly valued materials in enology since the chemical composition and sensorial properties of wine change significantly when in contact with it. The need for wood in cooperage and the concern of enologists in their search for new materials to endow their wines with a special personality has generated interest in the use of other Quercus genus materials different from the traditional ones (Q. petraea, Q. robur and Q. alba) and even other wood genera. Thereby, species from same genera such as Q. pyrenaica Willd., Q. faginea Lam., Q. humboldtti Bonpl., Q. oocarpa Liebm., Q. stellata Wangenh, Q. frainetto Ten., Q. lyrata Walt., Q. bicolor Willd. and other genera such as Castanea sativa Mill. (chestnut), Robinia pseudoacacia L. (false acacia), Prunus avium L. and P. cereaus L. (cherry), Fraxinus excelsior L. (European ash) and F. americana L. (American ash) have been studied with the aim of discovering whether they could be a new reservoir of wood for cooperage. This review aims to summarize the characterization of tannin and low molecular weight phenol compositions of these alternative woods for enology in their different cooperage stages and compare them to traditional oak woods, as both are essential to proposing their use in cooperage for aging wine. Full article

(This article belongs to the Special Issue Alcoholic Beverages Aging Technologies)

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11 pages, 2141 KiB

Open AccessArticle

A Powdered Simulant of Triacetone Triperoxide (TATP) for Safe Testing of X-ray Transmission Screening Equipment

by Mitja Vahčič, David Anderson, John Seghers, Hanne Leys, Miguel Ruiz Oses, Grzegorz Rarata, Maximino Fernández García, Rosana Prados Román and Daniel Pellico Escudero

Molecules 2020, 25(6), 1473; https://doi.org/10.3390/molecules25061473 - 24 Mar 2020

Cited by 1 | Viewed by 9924

Abstract

Explosives detection systems (EDS) based on X-ray are used at airports to screen baggage for the presence of explosives. Once EDS are installed in airports, however, it can be challenging to test the EDS equipment and verify that it continues to perform at [...] Read more.

Explosives detection systems (EDS) based on X-ray are used at airports to screen baggage for the presence of explosives. Once EDS are installed in airports, however, it can be challenging to test the EDS equipment and verify that it continues to perform at the highest level, because of the impracticality of introducing bulk explosives into civil aviation airports. The problem is particularly acute for sensitive homemade explosives, such as triacetone triperoxide (TATP). This paper describes our work to develop a safe, accurate and stable simulant for TATP for EDS based on X-ray transmission. Bulk quantities of TATP were synthesised and characterised especially for this project, and we describe the unique challenges and safety considerations of collecting this data. Our calculations show that the expanded measurement uncertainty with a coverage factor of k = 2 is 5.7% for bulk density and 1.0% for Zeff at 24 months. Full article

(This article belongs to the Special Issue Advanced Chemistry of Energetic Materials)

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12 pages, 2079 KiB

Open AccessArticle

Photocrosslinking of cDNA Display Molecules with Their Target Proteins as a New Strategy for Peptide Selection

by Takuya Terai, Tomoyuki Koike and Naoto Nemoto

Molecules 2020, 25(6), 1472; https://doi.org/10.3390/molecules25061472 - 24 Mar 2020

Cited by 3 | Viewed by 4696

Abstract

Binding peptides for given target molecules are often selected in vitro during drug discovery and chemical biology research. Among several display technologies for this purpose, complementary DNA (cDNA) display (a covalent complex of a peptide and its encoding cDNA linked via a specially [...] Read more.

Binding peptides for given target molecules are often selected in vitro during drug discovery and chemical biology research. Among several display technologies for this purpose, complementary DNA (cDNA) display (a covalent complex of a peptide and its encoding cDNA linked via a specially designed puromycin-conjugated DNA) is unique in terms of library size, chemical stability, and flexibility of modification. However, selection of cDNA display libraries often suffers from false positives derived from non-specific binding. Although rigorous washing is a straightforward solution, this also leads to the loss of specific binders with moderate affinity because the interaction is non-covalent. To address this issue, herein, we propose a method to covalently link cDNA display molecules with their target proteins using light irradiation. We designed a new puromycin DNA linker that contains a photocrosslinking nucleic acid and prepared cDNA display molecules using the linker. Target proteins were also labeled with a short single-stranded DNA that should transiently hybridize with the linker. Upon ultraviolet (UV) light irradiation, cDNA display molecules encoding correct peptide aptamers made stable crosslinked products with the target proteins in solution, while display molecules encoding control peptides did not. Although further optimization and improvement is necessary, the results pave the way for efficient selection of peptide aptamers in multimolecular crowding biosystems. Full article

(This article belongs to the Special Issue Structure, Interaction, Reaction, and Function of Biomolecules in Multimolecular Crowding Biosystems)

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25 pages, 1679 KiB

Open AccessReview

Current Landscape and Emerging Fields of PET Imaging in Patients with Brain Tumors

by Jan-Michael Werner, Philipp Lohmann, Gereon R. Fink, Karl-Josef Langen and Norbert Galldiks

Molecules 2020, 25(6), 1471; https://doi.org/10.3390/molecules25061471 - 24 Mar 2020

Cited by 31 | Viewed by 6118

Abstract

The number of positron-emission tomography (PET) tracers used to evaluate patients with brain tumors has increased substantially over the last years. For the management of patients with brain tumors, the most important indications are the delineation of tumor extent (e.g., for planning of [...] Read more.

The number of positron-emission tomography (PET) tracers used to evaluate patients with brain tumors has increased substantially over the last years. For the management of patients with brain tumors, the most important indications are the delineation of tumor extent (e.g., for planning of resection or radiotherapy), the assessment of treatment response to systemic treatment options such as alkylating chemotherapy, and the differentiation of treatment-related changes (e.g., pseudoprogression or radiation necrosis) from tumor progression. Furthermore, newer PET imaging approaches aim to address the need for noninvasive assessment of tumoral immune cell infiltration and response to immunotherapies (e.g., T-cell imaging). This review summarizes the clinical value of the landscape of tracers that have been used in recent years for the above-mentioned indications and also provides an overview of promising newer tracers for this group of patients. Full article

(This article belongs to the Special Issue Radiolabelled Molecules for Brain Imaging with PET and SPECT)

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22 pages, 1511 KiB

Open AccessArticle

Environmental Risk and Risk of Resistance Selection Due to Antimicrobials’ Occurrence in Two Polish Wastewater Treatment Plants and Receiving Surface Water

by Joanna Giebułtowicz, Grzegorz Nałęcz-Jawecki, Monika Harnisz, Dawid Kucharski, Ewa Korzeniewska and Grażyna Płaza

Molecules 2020, 25(6), 1470; https://doi.org/10.3390/molecules25061470 - 24 Mar 2020

Cited by 41 | Viewed by 4548

Abstract

In this study, a screening of 26 selected antimicrobials using liquid chromatography coupled to a tandem mass spectrometry method in two Polish wastewater treatment plants and their receiving surface waters was provided. The highest average concentrations of metronidazole (7400 ng/L), ciprofloxacin (4300 ng/L), [...] Read more.

In this study, a screening of 26 selected antimicrobials using liquid chromatography coupled to a tandem mass spectrometry method in two Polish wastewater treatment plants and their receiving surface waters was provided. The highest average concentrations of metronidazole (7400 ng/L), ciprofloxacin (4300 ng/L), vancomycin (3200 ng/L), and sulfamethoxazole (3000 ng/L) were observed in influent of WWTP2. Ciprofloxacin and sulfamethoxazole were the most dominant antimicrobials in influent and effluent of both WWTPs. In the sludge samples the highest mean concentrations were found for ciprofloxacin (up to 28 μg/g) and norfloxacin (up to 5.3 μg/g). The removal efficiency of tested antimicrobials was found to be more than 50% for both WWTPs. However, the presence of antimicrobials influenced their concentrations in the receiving waters. The highest antimicrobial resistance risk was estimated in influent of WWTPs for azithromycin, ciprofloxacin, clarithromycin, metronidazole, and trimethoprim and in the sludge samples for the following antimicrobials: azithromycin, ciprofloxacin, clarithromycin, norfloxacin, trimethoprim, ofloxacin, and tetracycline. The high environmental risk for exposure to azithromycin, clarithromycin, and sulfamethoxazole to both cyanobacteria and eukaryotic species in effluents and/or receiving water was noted. Following the obtained results, we suggest extending the watch list of the Water Framework Directive for Union-wide monitoring with sulfamethoxazole. Full article

(This article belongs to the Special Issue Pharmaceutical Residues in the Environment)

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14 pages, 3606 KiB

Open AccessArticle

Effect of GDM Pairing on PEMFC Performance in Flow-Through and Dead-Ended Anode Mode

by Yannick Garsany, Cornelius H. Bancroft, Robert W. Atkinson III, Keith Bethune, Benjamin D. Gould and Karen E. Swider-Lyons

Molecules 2020, 25(6), 1469; https://doi.org/10.3390/molecules25061469 - 24 Mar 2020

Cited by 3 | Viewed by 3577

Abstract

Asymmetric gas diffusion media (GDM) pairing, which feature distinct GDM at the anode and cathode of the proton electrolyte membrane fuel cell (PEMFC), enhance water management compared to symmetric pairing of GDM (anode and cathode GDM are identical). An asymmetric pairing of Freudenberg [...] Read more.

Asymmetric gas diffusion media (GDM) pairing, which feature distinct GDM at the anode and cathode of the proton electrolyte membrane fuel cell (PEMFC), enhance water management compared to symmetric pairing of GDM (anode and cathode GDM are identical). An asymmetric pairing of Freudenberg GDM (H24C3 at anode and H23C2 at cathode) reduces ohmic resistances by up to 40% and oxygen transport resistances by 14% en route to 25% higher current density in dry gas flows. The asymmetric GDM pairing effectively hydrates the membrane electrode assembly (MEA) while minimizing liquid water saturation in the cathode compared to a commonly used symmetric GDM pairing of SGL 29BC at the anode and cathode. Superior water management observed with asymmetric GDM in flow-through mode is also realized in dead-ended anode (DEA) mode. Compared to the symmetric GDM pairing, the asymmetric GDM pairing with Freudenberg GDM increases cell voltage at all current densities, extends and stabilizes steady-state voltage behavior, slows voltage decay, and vastly reduces the frequency of anode purge events. These results support that the asymmetric Freudenberg GDM combination renders the PEMFC less prone to anode water saturation and performance loss from the anticipated increase in water back-diffusion during DEA mode operation. Full article

(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))

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18 pages, 6285 KiB

Open AccessArticle

Impact of Pd Loading on CO₂ Reduction Performance over Pd/TiO₂ with H₂ and H₂O

by Akira Nishimura, Tadaaki Inoue, Yoshito Sakakibara, Masafumi Hirota, Akira Koshio and Eric Hu

Molecules 2020, 25(6), 1468; https://doi.org/10.3390/molecules25061468 - 24 Mar 2020

Cited by 9 | Viewed by 3439

Abstract

This study investigated the impact of molar ratio of CO₂ to reductants H₂O and H₂, as well as Pd loading weight on CO₂ reduction performance with Pd/TiO₂ as the photocatalyst. The Pd/TiO₂ film photocatalyst is [...] Read more.

This study investigated the impact of molar ratio of CO₂ to reductants H₂O and H₂, as well as Pd loading weight on CO₂ reduction performance with Pd/TiO₂ as the photocatalyst. The Pd/TiO₂ film photocatalyst is prepared by the sol-gel and dip-coating process to prepare TiO₂ film and the pulse arc plasma method is used to dope Pd on TiO₂ film. The prepared Pd/TiO₂ film was characterized by SEM, EPMA, STEM, EDS, and EELS. This study also investigated the performance of CO₂ reduction under the illumination condition of Xe lamp with or without ultraviolet (UV) light. As a result, it is revealed that when the molar ratio of CO₂/H₂/H₂O is set at 1:0.5:0.5, the best CO₂ reduction performance has been obtained under the illumination condition of Xe lamp with and without UV light. In addition, it is found that the optimum Pd loading weight is 3.90 wt%. The maximum molar quantities of CO and CH₄ produced per unit weight of photocatalyst are 30.3 μmol/g and 22.1 μmol/g, respectively, for the molar ratio of CO₂/H₂/H₂O = 1:0.5:0.5 under the condition of Xe lamp illumination with UV light. With UV light, C₂H₄ and C₂H₆, as well as CO and CH₄ are also produced by the Pd/TiO₂ film photocatalyst prepared in this study. Full article

(This article belongs to the Special Issue Photocatalytic CO₂ Reduction)

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10 pages, 2254 KiB

Open AccessCommunication

Microwave Assisted Synthesis of 4-Phenylquinazolin-2(1H)-one Derivatives that Inhibit Vasopressor Tonus in Rat Thoracic Aorta

by Rafaela Teixeira, Talita Menengat, Gabriel Andrade, Bruno Cotrim, Cristiano Ponte, Wilson C. Santos and Gabriel Resende

Molecules 2020, 25(6), 1467; https://doi.org/10.3390/molecules25061467 - 24 Mar 2020

Cited by 2 | Viewed by 2674

Abstract

Quinazolinones have pharmacological effects on vascular reactivity through different mechanisms. We synthesized 4-phenylquinazolin-2(1H)-one derivatives under microwave irradiation and tested them on the rat thoracic aorta. The prepared compounds 2a–2f were obtained in about 1 h with suitable yields (31–92%). All derivatives produced vasorelaxant [...] Read more.

Quinazolinones have pharmacological effects on vascular reactivity through different mechanisms. We synthesized 4-phenylquinazolin-2(1H)-one derivatives under microwave irradiation and tested them on the rat thoracic aorta. The prepared compounds 2a–2f were obtained in about 1 h with suitable yields (31–92%). All derivatives produced vasorelaxant effects with IC₅₀ values ranging from 3.41 ± 0.65 µM to 39.72 ± 6.77 µM. Compounds 2c, 2e and 2f demonstrated the highest potency in endothelium-intact aorta rings (IC₅₀ 4.31 ± 0.90 µM, 4.94 ± 1.21 µM and 3.41 ± 0.65 µM respectively), and they achieved around 90% relaxation (30 μM). In aorta rings without an endothelium, the effect of compound 2f was abolished. Using the MTT assay to test for cell viability, only compound 2b induced cytotoxicity at the maximum concentration employed (30 µM). The results show that vasorelaxation by 4-phenylquinazolin-2(1H)-one derivatives might depend on the activation of a signalling pathway triggered by endothelium-derived factors. Full article

(This article belongs to the Section Medicinal Chemistry)

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14 pages, 6523 KiB

Open AccessArticle

Impact of Pesticide Type and Emulsion Fat Content on the Bioaccessibility of Pesticides in Natural Products

by Ruojie Zhang, Zipei Zhang, Ruyi Li, Yunbing Tan, Shanshan Lv and David Julian McClements

Molecules 2020, 25(6), 1466; https://doi.org/10.3390/molecules25061466 - 24 Mar 2020

Cited by 12 | Viewed by 3290

Abstract

There is interest in incorporating nanoemulsions into certain foods and beverages, including dips, dressings, drinks, spreads, and sauces, due to their potentially beneficial attributes. In particular, excipient nanoemulsions can enhance the bioavailability of nutraceuticals in fruit- and vegetable-containing products consumed with them. There [...] Read more.

There is interest in incorporating nanoemulsions into certain foods and beverages, including dips, dressings, drinks, spreads, and sauces, due to their potentially beneficial attributes. In particular, excipient nanoemulsions can enhance the bioavailability of nutraceuticals in fruit- and vegetable-containing products consumed with them. There is, however, potential for them to also raise the bioavailability of undesirable substances found in these products, such as pesticides. In this research, we studied the impact of excipient nanoemulsions on the bioaccessibility of pesticide-treated tomatoes. We hypothesized that the propensity for nanoemulsions to raise pesticide bioaccessibility would depend on the polarity of the pesticide molecules. Bendiocarb, parathion, and chlorpyrifos were therefore selected because they have Log P values of 1.7, 3.8, and 5.3, respectively. Nanoemulsions with different oil contents (0%, 4%, and 8%) were fabricated to study their impact on pesticide uptake. In the absence of oil, the bioaccessibility increased with increasing pesticide polarity (decreasing Log P): bendiocarb (92.9%) > parathion (16.4%) > chlorpyrifos (2.8%). Bendiocarb bioaccessibility did not depend on the oil content of the nanoemulsions, which was attributed to its relatively high water-solubility. Conversely, the bioaccessibility of the more hydrophobic pesticides (parathion and chlorpyrifos) increased with increasing oil content. For instance, for chlorpyrifos, the bioaccessibility was 2.8%, 47.0%, and 70.7% at 0%, 4%, and 8% oil content, respectively. Our findings have repercussions for the utilization of nanoemulsions as excipient foods in products that may have high levels of undesirable non-polar substances, such as pesticides. Full article

(This article belongs to the Special Issue Recent Advances in the Bioaccessibility and Bioavailability of Food Bioactives)

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24 pages, 8656 KiB

Open AccessReview

Antagonists of Vitamin K—Popular Coumarin Drugs and New Synthetic and Natural Coumarin Derivatives

by Kinga Kasperkiewicz, Michał B. Ponczek, Jacek Owczarek, Piotr Guga and Elżbieta Budzisz

Molecules 2020, 25(6), 1465; https://doi.org/10.3390/molecules25061465 - 24 Mar 2020

Cited by 66 | Viewed by 8538

Abstract

Many natural coumarins and their chemically synthesized analogs and derivatives exert diverse properties, such as anticancer, antioxidant, anti-inflammatory, or anticoagulant, with the latter being of the utmost importance. The widely used warfarin, acenocoumarol, and phenprocoumon exert anticoagulant properties by inhibiting the vitamin K [...] Read more.

Many natural coumarins and their chemically synthesized analogs and derivatives exert diverse properties, such as anticancer, antioxidant, anti-inflammatory, or anticoagulant, with the latter being of the utmost importance. The widely used warfarin, acenocoumarol, and phenprocoumon exert anticoagulant properties by inhibiting the vitamin K epoxide reductase complex. In this interdisciplinary review, we present biochemical principles of the coagulation processes and possible methods for their tuning based on the use of coumarins. We also summarize chemical methods of synthesis of coumarins and discuss structures and properties of those that have been used for a long time, as well as newly synthesized compounds. Brief information on the clinical use of coumarins and other anticoagulant drugs is given, including the severe effects of overdosing and methods for reversing their action. Full article

(This article belongs to the Special Issue Synthesis and Bioactivity of Coumarin and Coumarin Derivatives)

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15 pages, 7155 KiB

Open AccessArticle

Effect of Instant Controlled Pressure-Drop on the Non-Nutritional Compounds of Seeds and Sprouts of Common Black Bean (Phaseolus vulgaris L.)

by Anaberta Cardador-Martínez, Yara Martínez-Tequitlalpan, Tzayhri Gallardo-Velazquez, Xariss M. Sánchez-Chino, Jorge Martínez-Herrera, Luis Jorge Corzo-Ríos and Cristian Jiménez-Martínez

Molecules 2020, 25(6), 1464; https://doi.org/10.3390/molecules25061464 - 24 Mar 2020

Cited by 14 | Viewed by 3559

Abstract

The common bean is an important caloric-protein food source. However, its nutritional value may be affected by the presence of non-nutritional compounds, which decrease the assimilation of some nutrients; however, at low concentrations, they show a beneficial effect. Germination and treatment by controlled [...] Read more.

The common bean is an important caloric-protein food source. However, its nutritional value may be affected by the presence of non-nutritional compounds, which decrease the assimilation of some nutrients; however, at low concentrations, they show a beneficial effect. Germination and treatment by controlled pressure-drop (DIC, French acronym of Détente Instantanée Contrôlée) are methods that modify the concentration of these components. The objective of this work was to evaluate the change in the non-nutritional composition of bean seeds and sprouts by DIC treatment. The results show that with the germination, the concentration of phenolic and tannin compounds increased 99% and 73%, respectively, as well as the quantity of saponins (65.7%), while phytates and trypsin inhibitors decreased 26% and 42%, respectively. When applying the DIC treatment, the content of phytates (23–29%), saponins (44%) and oligosaccharides increased in bean sprouts and decreased phenolic compounds (4–14%), tannins (23% to 72%), and trypsin inhibitors (95.5%), according to the pressure and time conditions applied. This technology opens the way to new perspectives, especially to more effective use of legumes as a source of vegetable protein or bioactive compounds. Full article

(This article belongs to the Special Issue Opportunities and Challenges in High Pressure Processing of Foods)

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17 pages, 2187 KiB

Open AccessArticle

Essential Oil-Based Design and Development of Novel Anti-Candida Azoles Formulation

by Rania Hamdy, Bahgat Fayed, Alshaimaa M. Hamoda, Mutasem Rawas-Qalaji, Mohamed Haider and Sameh S. M. Soliman

Molecules 2020, 25(6), 1463; https://doi.org/10.3390/molecules25061463 - 24 Mar 2020

Cited by 26 | Viewed by 3745

Abstract

Candida is the most common fungal class, causing both superficial and invasive diseases in humans. Although Candida albicans is the most common cause of fungal infections in humans, C. auris is a new emergent serious pathogen causing complications similar to those of C. [...] Read more.

Candida is the most common fungal class, causing both superficial and invasive diseases in humans. Although Candida albicans is the most common cause of fungal infections in humans, C. auris is a new emergent serious pathogen causing complications similar to those of C. albicans. Both C. albicans and C. auris are associated with high mortality rates, mainly because of their multidrug-resistance patterns against most available antifungal drugs. Although several compounds were designed against C. albicans, very few or none were tested on C. auris. Therefore, it is urgent to develop novel effective antifungal drugs that can accommodate not only C. albicans, but also other Candida spp., particularly newly emergent one, including C. auris. Inspired by the significant broad-spectrum antifungal activities of the essential oil cuminaldehyde and the reported wide incorporation of azoles in the antifungal drugs, a series of compounds (UoST1-11) was designed and developed. The new compounds were designed to overcome the toxicity of the aldehyde group of cuminaldehyde and benefit from the antifungal selectivity of azoles. The new developed UoST compounds showed significant anti-Candida activities against both Candida species. The best candidate compound, UoST5, was further formulated into polymeric nanoparticles (NPs). The new formula, UoST5-NPs, showed similar activities to the nanoparticles-free drug, while providing only 25% release after 24 h, maintainng prolonged activity up to 48 h and affording no toxicity. In conclusion, new azole formulations with significantly enhanced activities against C. albicans and C. auris, while maintaining prolonged action and no toxicities at lower concentrations, were developed. Full article

(This article belongs to the Special Issue Recent Research Advances in Essential Oils: From Green Extraction and Synthesis to Sustainable Applications and Utilization)

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27 pages, 2711 KiB

Open AccessReview

Dynamic Flow Approaches for Automated Radiochemical Analysis in Environmental, Nuclear and Medical Applications

by Jixin Qiao

Molecules 2020, 25(6), 1462; https://doi.org/10.3390/molecules25061462 - 24 Mar 2020

Cited by 14 | Viewed by 4180

Abstract

Automated sample processing techniques are desirable in radiochemical analysis for environmental radioactivity monitoring, nuclear emergency preparedness, nuclear waste characterization and management during operation and decommissioning of nuclear facilities, as well as medical isotope production, to achieve fast and cost-effective analysis. Dynamic flow based [...] Read more.

Automated sample processing techniques are desirable in radiochemical analysis for environmental radioactivity monitoring, nuclear emergency preparedness, nuclear waste characterization and management during operation and decommissioning of nuclear facilities, as well as medical isotope production, to achieve fast and cost-effective analysis. Dynamic flow based approaches including flow injection (FI), sequential injection (SI), multi-commuted flow injection (MCFI), multi-syringe flow injection (MSFI), multi-pumping flow system (MPFS), lab-on-valve (LOV) and lab-in-syringe (LIS) techniques have been developed and applied to meet the analytical criteria under different situations. Herein an overall review and discussion on these techniques and methodologies developed for radiochemical separation and measurement of various radionuclides is presented. Different designs of flow systems with combinations of radiochemical separation techniques, such as liquid–liquid extraction (LLE), liquid–liquid microextraction (LLME), solid phase extraction chromatography (SPEC), ion exchange chromatography (IEC), electrochemically modulated separations (EMS), capillary electrophoresis (CE), molecularly imprinted polymer (MIP) separation and online sensing and detection systems, are summarized and reviewed systematically. Full article

(This article belongs to the Special Issue Modern Flow Analysis)

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16 pages, 1290 KiB

Open AccessArticle

Brassica incana Ten. (Brassicaceae): Phenolic Constituents, Antioxidant and Cytotoxic Properties of the Leaf and Flowering Top Extracts

by Natalizia Miceli, Emilia Cavò, Monica Ragusa, Francesco Cacciola, Luigi Mondello, Laura Dugo, Rosaria Acquaviva, Giuseppe Antonio Malfa, Andreana Marino, Manuela D’Arrigo and Maria Fernanda Taviano

Molecules 2020, 25(6), 1461; https://doi.org/10.3390/molecules25061461 - 24 Mar 2020

Cited by 27 | Viewed by 4870

Abstract

Brassica incana Ten. is an edible plant belonging to the Brassicaceae family. In this work, the phenolic composition and the antioxidant and cytotoxic properties of the hydroalcoholic extracts obtained from the leaves and the flowering tops of B. incana grown wild in Sicily [...] Read more.

Brassica incana Ten. is an edible plant belonging to the Brassicaceae family. In this work, the phenolic composition and the antioxidant and cytotoxic properties of the hydroalcoholic extracts obtained from the leaves and the flowering tops of B. incana grown wild in Sicily (Italy) were studied for the first time. A total of 17 and 20 polyphenolic compounds were identified in the leaf and in the flowering top extracts, respectively, by HPLC-PDA-ESI-MS analysis. Brassica incana extracts showed in vitro antioxidant properties; the leaf extract displayed greater radical scavenging activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test than the flowering top extract (IC₅₀ = 1.306 ± 0.049 mg/mL and 2.077 ± 0.011 mg/mL), which in turn had a stronger ferrous ion chelating ability than the other (IC₅₀ = 0.232 ± 0.002 mg/mL and 1.147 ± 0.016 mg/mL). The cytotoxicity of the extracts against human colorectal adenocarcinoma (CaCo-2) and breast cancer (MCF-7) cell lines was evaluated through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the lactic dehydrogenase (LDH) release determination. The extracts showed cytotoxic efficacy against Caco-2 cells, with the flowering top extract being the most effective (about 90% activity at the highest concentration tested). In the brine shrimp lethality bioassay, the extracts exhibited no toxicity, indicating their potential safety. Full article

(This article belongs to the Special Issue Bioactive Phenolic and Polyphenolic Compounds)

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14 pages, 8961 KiB

Open AccessArticle

In Vitro Activities of MMV Malaria Box Compounds against the Apicomplexan Parasite Neospora caninum, the Causative Agent of Neosporosis in Animals

by Joachim Müller, Pablo A. Winzer, Kirandeep Samby and Andrew Hemphill

Molecules 2020, 25(6), 1460; https://doi.org/10.3390/molecules25061460 - 24 Mar 2020

Cited by 5 | Viewed by 3509

Abstract

(1) Background: Neospora caninum is a major cause of abortion in cattle and represents a veterinary health problem of great economic significance. In order to identify novel chemotherapeutic agents for the treatment of neosporosis, the Medicines for Malaria Venture (MMV) Malaria Box, a [...] Read more.

(1) Background: Neospora caninum is a major cause of abortion in cattle and represents a veterinary health problem of great economic significance. In order to identify novel chemotherapeutic agents for the treatment of neosporosis, the Medicines for Malaria Venture (MMV) Malaria Box, a unique collection of anti-malarial compounds, were screened against N. caninum tachyzoites, and the most efficient compounds were characterized in more detail. (2) Methods: A N. caninum beta-galactosidase reporter strain grown in human foreskin fibroblasts was treated with 390 compounds from the MMV Malaria Box. The IC₅₀s of nine compounds were determined, all of which had been previously been shown to be active against another apicomplexan parasite, Theileria annulata. The effects of three of these compounds on the ultrastructure of N. caninum tachyzoites were further investigated by transmission electron microscopy at different timepoints after initiation of drug treatment. (3) Results: Five MMV Malaria Box compounds exhibited promising IC₅₀s below 0.2 µM. The compound with the lowest IC₅₀, namely 25 nM, was MMV665941. This compound and two others, MMV665807 and MMV009085, specifically induced distinct alterations in the tachyzoites. More specifically, aberrant structural changes were first observed in the parasite mitochondrion, and subsequently progressed to other cytoplasmic compartments of the tachyzoites. The pharmacokinetic (PK) data obtained in mice suggest that treatment with MMV665941 could be potentially useful for further in vivo studies. (4) Conclusions: We have identified five novel compounds with promising activities against N. caninum, the effects of three of these compounds were studies by transmission electron microscopy (TEM). Their modes of action are unknown and require further investigation. Full article

(This article belongs to the Special Issue Purposing and Repurposing of Antimalarial Agents)

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14 pages, 2397 KiB

Open AccessFeature PaperArticle

A Self-Assembling NHC-Pd-Loaded Calixarene as a Potent Catalyst for the Suzuki-Miyaura Cross-Coupling Reaction in Water

by Arnaud Peramo, Ibrahim Abdellah, Shannon Pecnard, Julie Mougin, Cyril Martini, Patrick Couvreur, Vincent Huc and Didier Desmaële

Molecules 2020, 25(6), 1459; https://doi.org/10.3390/molecules25061459 - 24 Mar 2020

Cited by 13 | Viewed by 4836

Abstract

Nanoformulated calix[8]arenes functionalized with N-heterocyclic carbene (NHC)-palladium complexes were found to be efficient nano-reactors for Suzuki-Miyaura cross-coupling reactions of water soluble iodo- and bromoaryl compounds with cyclic triol arylborates at low temperature in water without any organic co-solvent. Combined with an improved [...] Read more.

Nanoformulated calix[8]arenes functionalized with N-heterocyclic carbene (NHC)-palladium complexes were found to be efficient nano-reactors for Suzuki-Miyaura cross-coupling reactions of water soluble iodo- and bromoaryl compounds with cyclic triol arylborates at low temperature in water without any organic co-solvent. Combined with an improved one-step synthesis of triol arylborates from boronic acid, this remarkably efficient new tool provided a variety of 4′-arylated phenylalanines and tyrosines in good yields at low catalyst loading with a wide functional group tolerance. Full article

(This article belongs to the Special Issue Carbon Ligands: From Fundamental Aspects to Applications)

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16 pages, 3012 KiB

Open AccessArticle

Oligomeric Procyanidin Nanoliposomes Prevent Melanogenesis and UV Radiation-Induced Skin Epithelial Cell (HFF-1) Damage

by Yashu Chen, Fenghong Huang, David Julian McClements, Bijun Xie, Zhida Sun and Qianchun Deng

Molecules 2020, 25(6), 1458; https://doi.org/10.3390/molecules25061458 - 24 Mar 2020

Cited by 17 | Viewed by 3738

Abstract

The potential protective effect of nanoliposomes loaded with lotus seedpod oligomeric procyanidin (LSOPC) against melanogenesis and skin damaging was investigated. Fluorescence spectroscopy showed that, after encapsulation, the LSOPC-nanoliposomes still possessed strong inhibitory effects against melanogenesis, reducing the activity of both monophenolase and diphenolase. [...] Read more.

The potential protective effect of nanoliposomes loaded with lotus seedpod oligomeric procyanidin (LSOPC) against melanogenesis and skin damaging was investigated. Fluorescence spectroscopy showed that, after encapsulation, the LSOPC-nanoliposomes still possessed strong inhibitory effects against melanogenesis, reducing the activity of both monophenolase and diphenolase. Molecular docking indicated that LSOPC could generate intense interactive configuration with tyrosinase through arene–H, arene–arene, and hydrophobic interaction. An ultraviolet radiated cell-culture model (human foreskin fibroblast cell (HFF-1)) was used to determine the protective effects of the LSOPC-nanoliposomes against skin aging and damage. Results showed that LSOPC-nanoliposomes exerted the highest protective effects against both ultraviolet B (UVB) and ultraviolet A (UVA) irradiation groups compared with non-encapsulated LSOPC and a control (vitamin C). Superoxide dismutase (SOD) and malonaldehyde (MDA) assays demonstrated the protection mechanism may be related to the anti-photooxidation activity of the procyanidin. Furthermore, a hydroxyproline assay suggested that the LSOPC-nanoliposomes had a strong protective effect against collagen degradation and/or synthesis after UVA irradiation. Full article

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18 pages, 4002 KiB

Open AccessArticle

Carbon and Nitrogen Isotope Ratios of Food and Beverage in Brazil

by Luiz A. Martinelli, Gabriela B. Nardoto, Maria A. Z. Perez, Geraldo Arruda Junior, Fabiana C. Fracassi, Juliana G. G. Oliveira, Isadora S. Ottani, Sarah H. Lima, Edmar A. Mazzi, Taciana F. Gomes, Amin Soltangheisi, Adibe L. Abdalla Filho, Eduardo Mariano, Fabio J. V. Costa, Paulo J. Duarte-Neto, Marcelo Z. Moreira and Plinio B. Camargo

Molecules 2020, 25(6), 1457; https://doi.org/10.3390/molecules25061457 - 24 Mar 2020

Cited by 16 | Viewed by 5745

Abstract

Several previous studies on targeted food items using carbon and nitrogen stable isotope ratios in Brazil have revealed that many of the items investigated are adulterated; mislabeled or even fraud. Here, we present the first Brazilian isotopic baseline assessment that can be used [...] Read more.

Several previous studies on targeted food items using carbon and nitrogen stable isotope ratios in Brazil have revealed that many of the items investigated are adulterated; mislabeled or even fraud. Here, we present the first Brazilian isotopic baseline assessment that can be used not only in future forensic cases involving food authenticity, but also in human forensic anthropology studies. The δ¹³C and δ¹⁵N were determined in 1245 food items and 374 beverages; most of them made in Brazil. The average δ¹³C and δ¹⁵N of C₃ plants were −26.7 ± 1.5‰, and 3.9 ± 3.9‰, respectively, while the average δ¹³C and δ¹⁵N of C₄ plants were −11.5 ± 0.8‰ and 4.6 ± 2.6‰, respectively. The δ¹³C and δ¹⁵N of plant-based processed foods were −21.8 ± 4.8‰ and 3.9 ± 2.7‰, respectively. The average δ¹³C and δ¹⁵N of meat, including beef, poultry, pork and lamb were -16.6 ± 4.7‰, and 5.2 ± 2.6‰, respectively, while the δ¹³C and δ¹⁵N of animal-based processed foods were −17.9 ± 3.3‰ and 3.3 ± 3.5‰, respectively. The average δ¹³C of beverages, including beer and wine was −22.5 ± 3.1‰. We verified that C-C₄ constitutes a large proportion of fresh meat, dairy products, as well as animal and plant-based processed foods. The reasons behind this high proportion will be addressed in this study. Full article

(This article belongs to the Special Issue Isotopic Techniques for Food Science)

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16 pages, 2486 KiB

Open AccessArticle

Interaction of Catechins with Human Erythrocytes

by Katarzyna Naparlo, Grzegorz Bartosz, Ireneusz Stefaniuk, Bogumil Cieniek, Miroslaw Soszynski and Izabela Sadowska-Bartosz

Molecules 2020, 25(6), 1456; https://doi.org/10.3390/molecules25061456 - 24 Mar 2020

Cited by 13 | Viewed by 3403

Abstract

The aim of this study was to characterize the interaction of chosen catechins ((+)-catechin, (−)-epigallocatechin (EGC), and (−)-epigallocatechin gallate (EGCG)) with human erythrocytes and their protective effects against oxidative damage of erythrocytes. Uptake of the catechins by erythrocytes was studied by fluorimetry, their [...] Read more.

The aim of this study was to characterize the interaction of chosen catechins ((+)-catechin, (−)-epigallocatechin (EGC), and (−)-epigallocatechin gallate (EGCG)) with human erythrocytes and their protective effects against oxidative damage of erythrocytes. Uptake of the catechins by erythrocytes was studied by fluorimetry, their interaction with erythrocyte membrane was probed by changes in erythrocyte osmotic fragility and in membrane fluidity evaluated with spin labels, while protection against oxidative damage was assessed by protection against hemolysis induced by permanganate and protection of erythrocyte membranes against lipid peroxidation and protein thiol group oxidation. Catechin uptake was similar for all the compounds studied. Accumulation of catechins in the erythrocyte membrane was demonstrated by the catechin-induced increase in osmotic resistance and rigidification of the erythrocyte membrane detected by spin labels 5-doxyl stearic acid and 16-doxyl stearic acid. (−)-Epigallocatechin and EGCG inhibited erythrocyte acetylcholinesterase (mixed-type inhibition). Catechins protected erythrocytes against permanganate-induced hemolysis, oxidation of erythrocyte protein thiol groups, as well as membrane lipid peroxidation. These results contribute to the knowledge of the beneficial effects of catechins present in plant-derived food and beverages. Full article

(This article belongs to the Section Chemical Biology)

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19 pages, 5561 KiB

Open AccessArticle

Underutilized Agricultural Co-Product as a Sustainable Biofiller for Polyamide 6,6: Effect of Carbonization Temperature

by Thomas Balint, Boon Peng Chang, Amar K. Mohanty and Manjusri Misra

Molecules 2020, 25(6), 1455; https://doi.org/10.3390/molecules25061455 - 24 Mar 2020

Cited by 24 | Viewed by 4501

Abstract

Polyamide 6,6 (PA66)-based biocomposites with low-cost carbonaceous natural fibers (i.e., soy hulls, co-product from soybean industry) were prepared through twin-screw extrusion and injection molding. The soy hull natural fiber was pyrolyzed at two different temperatures (500 °C and 900 °C denoted as BioC500 [...] Read more.

Polyamide 6,6 (PA66)-based biocomposites with low-cost carbonaceous natural fibers (i.e., soy hulls, co-product from soybean industry) were prepared through twin-screw extrusion and injection molding. The soy hull natural fiber was pyrolyzed at two different temperatures (500 °C and 900 °C denoted as BioC500 and BioC900 respectively) to obtain different types of biocarbons. The BioC500 preserved a higher number of functional groups as compared to BioC900. Higher graphitic carbon content was observed on the BioC900 than BioC500 as evident in Raman spectroscopy. Both biocarbons interact with the PA66 backbone through hydrogen bonding in different ways. BioC900 has a greater interaction with N-H stretching, while BioC500 interacts strongly with the amide I (C=O stretching) linkage. The BioC500 interrupts the crystallite growth of PA66 due to strong bond connection while the BioC900 promotes heterogeneous crystallization. Dynamic mechanical analysis shows that both biocarbons result in an increasing storage modulus and glass transition temperature with increasing content in the BioC/PA66 biocomposites over PA66. Rheological analysis shows that the incorporation of BioC900 results in decreasing melt viscosity of PA66, while the incorporation of BioC500 results in increasing the melt viscosity of PA66 due to greater filler–matrix adhesion. This study shows that pyrolyzed soy hull natural fiber can be processed effectively with a high temperature (>270 °C) engineering plastic for biocomposites fabrication with no degradation issues. Full article

(This article belongs to the Special Issue Advances in Natural Fiber Composites and Their Interfacial Adhesion)

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11 pages, 1389 KiB

Open AccessArticle

Antinociceptive Effect of Hinokinin and Kaurenoic Acid Isolated from Aristolochia odoratissima L.

by Rosa Mariana Montiel-Ruiz, Marcos Córdova-de la Cruz, Manasés González-Cortázar, Alejandro Zamilpa, Abraham Gómez-Rivera, Ricardo López-Rodríguez, Carlos Ernesto Lobato-García and Ever A. Blé-González

Molecules 2020, 25(6), 1454; https://doi.org/10.3390/molecules25061454 - 24 Mar 2020

Cited by 10 | Viewed by 3156

Abstract

Aristolochia odoratissima L. is employed for the treatment of pain and as an antidote against the poison of venomous animals in traditional medicine. However, reports have not been found, to our knowledge, about the evaluation of the antinociceptive activity of extracts nor about [...] Read more.

Aristolochia odoratissima L. is employed for the treatment of pain and as an antidote against the poison of venomous animals in traditional medicine. However, reports have not been found, to our knowledge, about the evaluation of the antinociceptive activity of extracts nor about the presence of compounds associated with this activity. Thus, the purpose of this work was to evaluate the antinociceptive activity of extracts and compounds isolated from the stems of Artistolochia odoratissima L. The extracts were obtained with solvents of increasing polarity and the compounds were isolated and characterized by column chromatography, HPLC, and NMR. The antinociceptive activity was carried out by the formalin test in mice. Ethyl acetate (AoEA) and methanolic (AoM) extracts decreased the paw licking in both phases of the formalin test. The isolated compounds (kaurenoic acid and hinokinin) from AoEA showed the highest antinociceptive activity in both phases of the formalin test. These results confirmed the analgesic effect of this specie described in traditional medicine and provided a base for a novel analgesic agent. They also allowed an approach for the development of standardized plant extracts with isolated metabolites. Full article

(This article belongs to the Special Issue Natural Products: From Isolation and Identification to Biological Activity)

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17 pages, 1426 KiB

Open AccessArticle

Characterization, Quantification and Quality Assessment of Avocado (Persea americana Mill.) Oils

by Mei Wang, Ping Yu, Amar G. Chittiboyina, Dilu Chen, Jianping Zhao, Bharathi Avula, Yan-Hong Wang and Ikhlas A. Khan

Molecules 2020, 25(6), 1453; https://doi.org/10.3390/molecules25061453 - 24 Mar 2020

Cited by 28 | Viewed by 6008

Abstract

Avocado oil is prized for its high nutritional value due to the substantial amounts of triglycerides (TGs) and unsaturated fatty acids (FAs) present. While avocado oil is traditionally extracted from mature fruit flesh, alternative sources such as avocado seed oil have recently increased [...] Read more.

Avocado oil is prized for its high nutritional value due to the substantial amounts of triglycerides (TGs) and unsaturated fatty acids (FAs) present. While avocado oil is traditionally extracted from mature fruit flesh, alternative sources such as avocado seed oil have recently increased in popularity. Unfortunately, sufficient evidence is not available to support the claimed health benefit and safe use of such oils. To address potential quality issues and identify possible adulteration, authenticated avocado oils extracted from the fruit peel, pulp and seed by supercritical fluid extraction (SFE), as well as commercial avocado pulp and seed oils sold in US market were analyzed for TGs and FAs in the present study. Characterization and quantification of TGs were conducted using UHPLC/ESI-MS. Thirteen TGs containing saturated and unsaturated fatty acids in avocado oils were unambiguously identified. Compared to traditional analytical methods, which are based only on the relative areas of chromatographic peaks neglecting the differences in the relative response of individual TG, our method improved the quantification of TGs by using the reference standards whenever possible or the reference standards with the same equivalent carbon number (ECN). To verify the precision and accuracy of the UHPLC/ESI-MS method, the hydrolysis and transesterification products of avocado oil were analyzed for fatty acid methyl esters using a GC/MS method. The concentrations of individual FA were calculated, and the results agreed with the UHPLC/ESI-MS method. Although chemical profiles of avocado oils from pulp and peel are very similar, a significant difference was observed for the seed oil. Principal component analysis (PCA) based on TG and FA compositional data allowed correct identification of individual avocado oil and detection of possible adulteration. Full article

(This article belongs to the Special Issue Special Issue in Honor of Professor James D. McChesney on the Occasion of his 80th Birthday)

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18 pages, 8709 KiB

Open AccessArticle

How Sure Can We Be about ML Methods-Based Evaluation of Compound Activity: Incorporation of Information about Prediction Uncertainty Using Deep Learning Techniques

by Igor Sieradzki, Damian Leśniak and Sabina Podlewska

Molecules 2020, 25(6), 1452; https://doi.org/10.3390/molecules25061452 - 23 Mar 2020

Cited by 3 | Viewed by 2963

Abstract

A great variety of computational approaches support drug design processes, helping in selection of new potentially active compounds, and optimization of their physicochemical and ADMET properties. Machine learning is a group of methods that are able to evaluate in relatively short time enormous [...] Read more.

A great variety of computational approaches support drug design processes, helping in selection of new potentially active compounds, and optimization of their physicochemical and ADMET properties. Machine learning is a group of methods that are able to evaluate in relatively short time enormous amounts of data. However, the quality of machine-learning-based prediction depends on the data supplied for model training. In this study, we used deep neural networks for the task of compound activity prediction and developed dropout-based approaches for estimating prediction uncertainty. Several types of analyses were performed: the relationships between the prediction error, similarity to the training set, prediction uncertainty, number and standard deviation of activity values were examined. It was tested whether incorporation of information about prediction uncertainty influences compounds ranking based on predicted activity and prediction uncertainty was used to search for the potential errors in the ChEMBL database. The obtained outcome indicates that incorporation of information about uncertainty of compound activity prediction can be of great help during virtual screening experiments. Full article

(This article belongs to the Special Issue AI in Drug Design)

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22 pages, 5903 KiB

Open AccessArticle

New Cysteine Protease Inhibitors: Electrophilic (Het)arenes and Unexpected Prodrug Identification for the Trypanosoma Protease Rhodesain

by Philipp Klein, Patrick Johe, Annika Wagner, Sascha Jung, Jonas Kühlborn, Fabian Barthels, Stefan Tenzer, Ute Distler, Waldemar Waigel, Bernd Engels, Ute A. Hellmich, Till Opatz and Tanja Schirmeister

Molecules 2020, 25(6), 1451; https://doi.org/10.3390/molecules25061451 - 23 Mar 2020

Cited by 18 | Viewed by 5356

Abstract

Electrophilic (het)arenes can undergo reactions with nucleophiles yielding π- or Meisenheimer (σ-) complexes or the products of the S_NAr addition/elimination reactions. Such building blocks have only rarely been employed for the design of enzyme inhibitors. Herein, we demonstrate the combination of [...] Read more.

Electrophilic (het)arenes can undergo reactions with nucleophiles yielding π- or Meisenheimer (σ-) complexes or the products of the S_NAr addition/elimination reactions. Such building blocks have only rarely been employed for the design of enzyme inhibitors. Herein, we demonstrate the combination of a peptidic recognition sequence with such electrophilic (het)arenes to generate highly active inhibitors of disease-relevant proteases. We further elucidate an unexpected mode of action for the trypanosomal protease rhodesain using NMR spectroscopy and mass spectrometry, enzyme kinetics and various types of simulations. After hydrolysis of an ester function in the recognition sequence of a weakly active prodrug inhibitor, the liberated carboxylic acid represents a highly potent inhibitor of rhodesain (K_i = 4.0 nM). The simulations indicate that, after the cleavage of the ester, the carboxylic acid leaves the active site and re-binds to the enzyme in an orientation that allows the formation of a very stable π-complex between the catalytic dyad (Cys-25/His-162) of rhodesain and the electrophilic aromatic moiety. The reversible inhibition mode results because the S_NAr reaction, which is found in an alkaline solvent containing a low molecular weight thiol, is hindered within the enzyme due to the presence of the positively charged imidazolium ring of His-162. Comparisons between measured and calculated NMR shifts support this interpretation. Full article

(This article belongs to the Special Issue Covalent Inhibitors in Drug Discovery and Chemical Biology)

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15 pages, 2875 KiB

Open AccessArticle

Major Contribution of Caspase-9 to Honokiol-Induced Apoptotic Insults to Human Drug-Resistant Glioblastoma Cells

by Gong-Jhe Wu, Sun-Ta Yang and Ruei-Ming Chen

Molecules 2020, 25(6), 1450; https://doi.org/10.3390/molecules25061450 - 23 Mar 2020

Cited by 7 | Viewed by 3690

Abstract

Temozolomide (TMZ)-induced chemoresistance to human glioblastomas is a critical challenge now. Our previous studies showed that honokiol, a major bioactive constituent of Magnolia officinalis (Houpo), can kill human glioblastoma cells and suppresses glioblastoma growth. This study was further aimed to evaluate the effects [...] Read more.

Temozolomide (TMZ)-induced chemoresistance to human glioblastomas is a critical challenge now. Our previous studies showed that honokiol, a major bioactive constituent of Magnolia officinalis (Houpo), can kill human glioblastoma cells and suppresses glioblastoma growth. This study was further aimed to evaluate the effects of honokiol on human drug-resistant glioblastoma cells and the possible mechanisms. The results by data mining in the cancer genome atlas (TCGA) database and immunohistochemistry displayed that expression of caspase-9 mRNA and protein in human glioblastomas was induced. Human TMZ-resistant U87-MG-R9 glioblastoma cells were selected and prepared from human drug-sensitive U87-MG cells. Compared to human drug-sensitive U87-MG cells, TMZ did not affect viability of U87-MG-R9 glioblastoma cells. Interestingly, treatment with honokiol suppressed proliferation and survival of human drug-resistant glioblastoma cells in concentration- and time-dependent manners. Compared to caspase-8 activation, honokiol chiefly increased activity of caspase-9 in U87-MG-R9 cells. Successively, levels of cleaved caspase-3 and activities of caspase-3 and caspase-6 in human TMZ-tolerant glioblastoma cells were augmented following honokiol administration. In parallel, honokiol triggered DNA fragmentation of U87-MG-R9 cells. Accordingly, treatment of human TMZ-resistant glioblastoma cells with honokiol induced cell apoptosis but did not affect cell necrosis. Fascinatingly, suppressing caspase-9 activity using its specific inhibitors repressed honokiol-induced caspase-6 activation, DNA fragmentation, and cell apoptosis. Taken together, this study has shown the major roles of caspase-9 in transducing honokiol-induced mitochondria-dependent apoptosis in human drug-resistant glioblastoma cells. Thus, honokiol may be clinically applied as a drug candidate for treatment of glioblastoma patients with chemoresistance. Full article

(This article belongs to the Section Natural Products Chemistry)

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15 pages, 1531 KiB

Open AccessArticle

Ellagic Acid Containing Nanostructured Lipid Carriers for Topical Application: A Preliminary Study

by Supandeep Singh Hallan, Maddalena Sguizzato, Gabriella Pavoni, Anna Baldisserotto, Markus Drechsler, Paolo Mariani, Elisabetta Esposito and Rita Cortesi

Molecules 2020, 25(6), 1449; https://doi.org/10.3390/molecules25061449 - 23 Mar 2020

Cited by 32 | Viewed by 5921

Abstract

Ellagic acid (EA) is a potent antioxidant substance of natural origin characterized by poor biopharmaceutical properties and low solubility in water that limit its use. The aim of the present study was to develop lipid-based nanoparticle formulations able to encapsulate EA for dermal [...] Read more.

Ellagic acid (EA) is a potent antioxidant substance of natural origin characterized by poor biopharmaceutical properties and low solubility in water that limit its use. The aim of the present study was to develop lipid-based nanoparticle formulations able to encapsulate EA for dermal delivery. The EA-loaded nanoparticles were prepared using two different lipid compositions, namely tristearin/tricaprylin (NLC-EA1) and tristearin/labrasol (NLC-EA2). The influence of formulations on size, entrapment efficiency, and stability of EA-loaded nanoparticles was investigated. Cryo-TEM and small-angle X-ray scattering (SAXS) analyses showed that no morphological differences are evident among all the types of loaded and unloaded nanostructured lipid carriers (NLCs). The macroscopic aspect of both NLC-EA1 and NLC-EA2 did not change with time. No difference in size was appreciable between empty and drug-containing NLC, thus the nanoparticle diameter was not affected by the presence of EA and in general no variations of the diameters occurred during this time. The entrapment efficiency of both EA-loaded nanoparticles was almost quantitative. In addition, NLC-EA1 maintained EA stability for almost two months, while NLC-EA2 up to 40 days. FRAP (Ferric reducing ability of plasma) assay showed an antioxidant activity around 60% for both the loaded NLC, as compared to the solution. Although both types of NLC are characterized by some toxicity on HaCaT cells, NLC-EA1 are less cytotoxic than NLC-EA2. Taken together these results demonstrated that the inclusion of EA within NLC could improve the water solubility, allowing for a reduction of the dosage. Moreover, both types of NLC-EA maintained a high antioxidant effect and low toxicity. Full article

(This article belongs to the Special Issue Preparation, Characterization, and Effect of Lipid Nanoparticles Used in Different Application Fields)

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14 pages, 3932 KiB

Open AccessArticle

Removal of V(V) From Solution Using a Silica-Supported Primary Amine Resin: Batch Studies, Experimental Analysis, and Mathematical Modeling

by Xi Huang, Zhenxiong Ye, Lifeng Chen, Xujie Chen, Caocong Liu, Yuan Yin, Xinpeng Wang and Yuezhou Wei

Molecules 2020, 25(6), 1448; https://doi.org/10.3390/molecules25061448 - 23 Mar 2020

Cited by 14 | Viewed by 3045

Abstract

Every year, a large quantity of vanadium-containing wastewater is discharged from industrial factories, resulting in severe environmental problems. In particular, V(V) is recognized as a potentially hazardous contaminant due to its high mobility and toxicity, and it has received considerable attention. In this [...] Read more.

Every year, a large quantity of vanadium-containing wastewater is discharged from industrial factories, resulting in severe environmental problems. In particular, V(V) is recognized as a potentially hazardous contaminant due to its high mobility and toxicity, and it has received considerable attention. In this study, a silica-supported primary amine resin (SiPAR) was prepared by in-situ polymerization, and the V(V) adsorption from the solution was examined. The as-prepared resin exhibited fast adsorption kinetics, and it could attain an equilibrium within 90 min for the V(V) solution concentration of 100 mg/L at an optimum pH of 4, whereas the commercial D302 resin required a treatment time of more than 3 h under the same conditions. Furthermore, the maximum adsorption capacity of the resin under optimum conditions for V(V) was calculated to be 70.57 mg/g. In addition, the kinetics and isotherm data were satisfactorily elucidated with the pseudo-second-order kinetics and Redlich–Peterson models, respectively. The silica-based resin exhibited an excellent selectivity for V(V), and the removal efficiency exceeded 97% in the presence of competitive anions at 100 mmol/L concentrations. The film mass-transfer coefficient (k_f) and V(V) pore diffusivity (D_p) onto the resins were estimated by mathematical modeling. In summary, this study provided a potential adsorbent for the efficient removal of V(V) from wastewater. Full article

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27 pages, 8226 KiB

Open AccessArticle

Design, Synthesis and Biological Evaluation of Phenyl Urea Derivatives as IDO1 Inhibitors

by Chuan Zhou, Fangfang Lai, Li Sheng, Xiaoguang Chen, Yan Li and Zhiqiang Feng

Molecules 2020, 25(6), 1447; https://doi.org/10.3390/molecules25061447 - 23 Mar 2020

Cited by 6 | Viewed by 3647

Abstract

Indoleamine 2,3-dioxygenase 1 (IDO1) is a heme-containing intracellular enzyme that catalyzes the first and rate-determining step of tryptophan metabolism and is an important immunotherapeutic target for the treatment of cancer. In this study, we designed and synthesized a new series of compounds as [...] Read more.

Indoleamine 2,3-dioxygenase 1 (IDO1) is a heme-containing intracellular enzyme that catalyzes the first and rate-determining step of tryptophan metabolism and is an important immunotherapeutic target for the treatment of cancer. In this study, we designed and synthesized a new series of compounds as potential IDO1 inhibitors. These compounds were then evaluated for inhibitory activity against IDO1 and tryptophan 2,3-dioxygenase (TDO). Among them, the three phenyl urea derivatives i12, i23, i24 as showed potent IDO1 inhibition, with IC₅₀ values of 0.1–0.6 μM and no compound exhibited TDO inhibitory activity. Using molecular docking, we predicted the binding mode of compound i12 within IDO1. Compound i12 was further investigated by determining its in vivo pharmacokinetic profile and anti-tumor efficacy. The pharmacokinetic study revealed that compound i12 had satisfactory properties in mice, with moderate plasma clearance (22.45 mL/min/kg), acceptable half-life (11.2 h) and high oral bioavailability (87.4%). Compound i12 orally administered at 15 mg/kg daily showed tumor growth inhibition (TGI) of 40.5% in a B16F10 subcutaneous xenograft model and 30 mg/kg daily showed TGI of 34.3% in a PAN02 subcutaneous xenograft model. In addition, the body weight of i12-treated mice showed no obvious reduction compared with the control group. Overall, compound i12 is a potent lead compound for developing IDO1 inhibitors and anti-tumor agents. Full article

(This article belongs to the Special Issue Design, Synthesis, and Biological Evaluation of Enzyme Inhibitors)

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9 pages, 2071 KiB

Open AccessFeature PaperCommunication

Synthesis and Characterization of a Binuclear Copper(II)-dipyriamethyrin Complex: [Cu₂(dipyriamethyrin)(μ₂-1,1-acetato)₂]

by James T. Brewster II, Harrison D. Root, Hadiqa Zafar, Gregory D. Thiabaud, Adam C. Sedgwick, Jiaming He, Vincent M. Lynch and Jonathan L. Sessler

Molecules 2020, 25(6), 1446; https://doi.org/10.3390/molecules25061446 - 23 Mar 2020

Cited by 6 | Viewed by 3693

Abstract

The reaction between dipyriamethyrin and copper(II) acetate [Cu(OAc)₂] afforded what is, to our knowledge, the first transition metal-dipyriamethyrin complex. Molecular and electronic characterization of this binuclear Cu(II) complex via EPR, UV-vis, and single crystal X-ray diffraction analysis revealed marked differences between [...] Read more.

The reaction between dipyriamethyrin and copper(II) acetate [Cu(OAc)₂] afforded what is, to our knowledge, the first transition metal-dipyriamethyrin complex. Molecular and electronic characterization of this binuclear Cu(II) complex via EPR, UV-vis, and single crystal X-ray diffraction analysis revealed marked differences between the present constructs and previously reported binuclear copper(II) hexaphyrin species. UV-vis titration analyses provided evidence for a homotropic positive allosteric effect, wherein the binuclear species is formed without significant intermediacy of a monomeric complex. Full article

(This article belongs to the Special Issue Porphyrinoid Derivatives: Synthesis and Biological Applications)

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