Molecules

14 pages, 1464 KiB

Open AccessArticle

Post-Catalytic Complexes with Emtricitabine or Stavudine and HIV-1 Reverse Transcriptase Reveal New Mechanistic Insights for Nucleotide Incorporation and Drug Resistance

by Nicole Bertoletti, Albert H. Chan, Raymond F. Schinazi and Karen S. Anderson

Molecules 2020, 25(20), 4868; https://doi.org/10.3390/molecules25204868 - 21 Oct 2020

Cited by 5 | Viewed by 3290

Abstract

Human immunodeficiency virus 1 (HIV-1) infection is a global health issue since neither a cure nor a vaccine is available. However, the highly active antiretroviral therapy (HAART) has improved the life expectancy for patients with acquired immunodeficiency syndrome (AIDS). Nucleoside reverse transcriptase inhibitors [...] Read more.

Human immunodeficiency virus 1 (HIV-1) infection is a global health issue since neither a cure nor a vaccine is available. However, the highly active antiretroviral therapy (HAART) has improved the life expectancy for patients with acquired immunodeficiency syndrome (AIDS). Nucleoside reverse transcriptase inhibitors (NRTIs) are in almost all HAART and target reverse transcriptase (RT), an essential enzyme for the virus. Even though NRTIs are highly effective, they have limitations caused by RT resistance. The main mechanisms of RT resistance to NRTIs are discrimination and excision. Understanding the molecular mechanisms for discrimination and excision are essential to develop more potent and selective NRTIs. Using protein X-ray crystallography, we determined the first crystal structure of RT in its post-catalytic state in complex with emtricitabine, (-)FTC or stavudine (d4T). Our structural studies provide the framework for understanding how RT discriminates between NRTIs and natural nucleotides, and for understanding the requirement of (-)FTC to undergo a conformation change for successful incorporation by RT. The crystal structure of RT in post-catalytic complex with d4T provides a “snapshot” for considering the possible mechanism of how RT develops resistance for d4T via excision. The findings reported herein will contribute to the development of next generation NRTIs. Full article

(This article belongs to the Special Issue A Special Issue in Honor of Prof. Duane D. Miller)

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16 pages, 2605 KiB

Open AccessArticle

Structure of a DNA G-Quadruplex Related to Osteoporosis with a G-A Bulge Forming a Pseudo-loop

by Martina Lenarčič Živković, Jan Rozman and Janez Plavec

Molecules 2020, 25(20), 4867; https://doi.org/10.3390/molecules25204867 - 21 Oct 2020

Cited by 4 | Viewed by 3558

Abstract

Bone remodeling is a fine-tuned process principally regulated by a cascade triggered by interaction of receptor activator of NF-κB (RANK) and RANK ligand (RANKL). Excessive activity of the RANKL gene leads to increased bone resorption and can influence the incidence of osteoporosis. Although [...] Read more.

Bone remodeling is a fine-tuned process principally regulated by a cascade triggered by interaction of receptor activator of NF-κB (RANK) and RANK ligand (RANKL). Excessive activity of the RANKL gene leads to increased bone resorption and can influence the incidence of osteoporosis. Although much has been learned about the intracellular signals activated by RANKL/RANK complex, significantly less is known about the molecular mechanisms of regulation of RANKL expression. Here, we report on the structure of an unprecedented DNA G-quadruplex, well-known secondary structure-mediated gene expression regulator, formed by a G-rich sequence found in the regulatory region of a RANKL gene. Solution-state NMR structural study reveals the formation of a three-layered parallel-type G-quadruplex characterized by an unique features, including a G-A bulge. Although a guanine within a G-tract occupies syn glycosidic conformation, bulge-forming residues arrange in a pseudo-loop conformation to facilitate partial 5/6-ring stacking, typical of G-quadruplex structures with parallel G-tracts orientation. Such distinctive structural features protruding from the core of the structure can represent a novel platform for design of highly specific ligands with anti-osteoporotic function. Additionally, our study suggests that the expression of RANKL gene may be regulated by putative folding of its G-rich region into non-B-DNA structure(s). Full article

(This article belongs to the Special Issue Advances in Nucleoside/Nucleotides and Nucleic Acid Chemistry: A Theme Issue in Honor of Prof. Dr. Piet Herdewijn)

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26 pages, 1206 KiB

Open AccessReview

Use of Biodegradable, Chitosan-Based Nanoparticles in the Treatment of Alzheimer’s Disease

by Eniko Manek, Ferenc Darvas and Georg A. Petroianu

Molecules 2020, 25(20), 4866; https://doi.org/10.3390/molecules25204866 - 21 Oct 2020

Cited by 54 | Viewed by 6140

Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that affects more than 24 million people worldwide and represents an immense medical, social and economic burden. While a vast array of active pharmaceutical ingredients (API) is available for the prevention and possibly treatment of [...] Read more.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that affects more than 24 million people worldwide and represents an immense medical, social and economic burden. While a vast array of active pharmaceutical ingredients (API) is available for the prevention and possibly treatment of AD, applicability is limited by the selective nature of the blood-brain barrier (BBB) as well as by their severe peripheral side effects. A promising solution to these problems is the incorporation of anti-Alzheimer drugs in polymeric nanoparticles (NPs). However, while several polymeric NPs are nontoxic and biocompatible, many of them are not biodegradable and thus not appropriate for CNS-targeting. Among polymeric nanocarriers, chitosan-based NPs emerge as biodegradable yet stable vehicles for the delivery of CNS medications. Furthermore, due to their mucoadhesive character and intrinsic bioactivity, chitosan NPs can not only promote brain penetration of drugs via the olfactory route, but also act as anti-Alzheimer therapeutics themselves. Here we review how chitosan-based NPs could be used to address current challenges in the treatment of AD; with a specific focus on the enhancement of blood-brain barrier penetration of anti-Alzheimer drugs and on the reduction of their peripheral side effects. Full article

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13 pages, 4006 KiB

Open AccessArticle

Effects of Tangerine Essential Oil on Brain Waves, Moods, and Sleep Onset Latency

by Supaya Chandharakool, Phanit Koomhin, Jennarong Sinlapasorn, Sarunnat Suanjan, Jantamas Phungsai, Noppharat Suttipromma, Sumethee Songsamoe, Narumol Matan and Apsorn Sattayakhom

Molecules 2020, 25(20), 4865; https://doi.org/10.3390/molecules25204865 - 21 Oct 2020

Cited by 27 | Viewed by 10743

Abstract

Tangerine (Citrus tangerina) is one of the most important crops of Thailand with a total harvest that exceeds 100,000 tons. Citrus essential oils are widely used as aromatherapy and medicinal agents. The effect of tangerine essential oil on human brain waves [...] Read more.

Tangerine (Citrus tangerina) is one of the most important crops of Thailand with a total harvest that exceeds 100,000 tons. Citrus essential oils are widely used as aromatherapy and medicinal agents. The effect of tangerine essential oil on human brain waves and sleep activity has not been reported. In the present study, we therefore evaluated these effects of tangerine essential oil by measurement of electroencephalography (EEG) activity with 32 channel platforms according to the international 10–20 system in 10 male and 10 female subjects. Then the sleep onset latency was studied to further confirm the effect on sleep activity. The results revealed that different concentrations, subthreshold to suprathreshold, of tangerine oil gave different brain responses. Undiluted tangerine oil inhalation reduced slow and fast alpha wave powers and elevated low and mid beta wave powers. The subthreshold and threshold dilution showed the opposite effect to the brain compared with suprathreshold concentration. Inhalation of threshold concentration showed effectively decreased alpha and beta wave powers and increased theta wave power, which emphasize its sedative effect. The reduction of sleep onset latency was confirmed with the implementation of the observed sedative effect of tangerine oil. Full article

(This article belongs to the Special Issue Fragrant Molecules with Pharmacological Activities)

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19 pages, 1392 KiB

Open AccessReview

The Function and Mechanism of Lipid Molecules and Their Roles in The Diagnosis and Prognosis of Breast Cancer

by Rui Guo, Yu Chen, Heather Borgard, Mayumi Jijiwa, Masaki Nasu, Min He and Youping Deng

Molecules 2020, 25(20), 4864; https://doi.org/10.3390/molecules25204864 - 21 Oct 2020

Cited by 39 | Viewed by 6540

Abstract

Lipids are essential components of cell structure and play important roles in signal transduction between cells and body metabolism. With the continuous development and innovation of lipidomics technology, many studies have shown that the relationship between lipids and cancer is steadily increasing, involving [...] Read more.

Lipids are essential components of cell structure and play important roles in signal transduction between cells and body metabolism. With the continuous development and innovation of lipidomics technology, many studies have shown that the relationship between lipids and cancer is steadily increasing, involving cancer occurrence, proliferation, migration, and apoptosis. Breast cancer has seriously affected the safety and quality of life of human beings worldwide and has become a significant public health problem in modern society, with an especially high incidence among women. Therefore, the issue has inspired scientific researchers to study the link between lipids and breast cancer. This article reviews the research progress of lipidomics, the biological characteristics of lipid molecules, and the relationship between some lipids and cancer drug resistance. Furthermore, this work summarizes the lipid molecules related to breast cancer diagnosis and prognosis, and then it clarifies their impact on the occurrence and development of breast cancer The discussion revolves around the current research hotspot long-chain non-coding RNAs (lncRNAs), summarizes and explains their impact on tumor lipid metabolism, and provides more scientific basis for future cancer research studies. Full article

(This article belongs to the Special Issue Lipids in Health and Disease)

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44 pages, 14772 KiB

Open AccessReview

Past, Present and Future Perspectives on Halloysite Clay Minerals

by Marina Massaro, Renato Noto and Serena Riela

Molecules 2020, 25(20), 4863; https://doi.org/10.3390/molecules25204863 - 21 Oct 2020

Cited by 111 | Viewed by 9661

Abstract

Halloysite nanotubes (HNTs), clay minerals belonging to the kaolin groups, are emerging nanomaterials which have attracted the attention of the scientific community due to their interesting features, such as low-cost, availability and biocompatibility. In addition, their large surface area and tubular structure have [...] Read more.

Halloysite nanotubes (HNTs), clay minerals belonging to the kaolin groups, are emerging nanomaterials which have attracted the attention of the scientific community due to their interesting features, such as low-cost, availability and biocompatibility. In addition, their large surface area and tubular structure have led to HNTs’ application in different industrial purposes. This review reports a comprehensive overview of the historical background of HNT utilization in the last 20 years. In particular it will focus on the functionalization of the surfaces, both supramolecular and covalent, following applications in several fields, including biomedicine, environmental science and catalysis. Full article

(This article belongs to the Special Issue Recent Research Advance in the Halloysite Nanotubes Field)

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18 pages, 2081 KiB

Open AccessArticle

Chemical Composition and Bioactivity of Essential Oil of Ten Labiatae Species

by Mengting Liu, Feiya Luo, Zhixing Qing, Huichao Yang, Xiubin Liu, Zihui Yang and Jianguo Zeng

Molecules 2020, 25(20), 4862; https://doi.org/10.3390/molecules25204862 - 21 Oct 2020

Cited by 14 | Viewed by 3533

Abstract

Using antibiotics as feed additives have been successively banned worldwide from 1986; therefore, it is an urgent task to finding safe and effective alternatives. As natural products of plant origin, essential oils (EOs) are an outstanding option due to their reported bioactivity. In [...] Read more.

Using antibiotics as feed additives have been successively banned worldwide from 1986; therefore, it is an urgent task to finding safe and effective alternatives. As natural products of plant origin, essential oils (EOs) are an outstanding option due to their reported bioactivity. In this research, ten EOs of Labiatae species were extracted by steam distillation and its chemical constituents were identified by gas chromatography-mass spectrometry (GC-MS). A total of 123 chemical compounds, including alkenes, phenols, aldehydes and ketones, were identified. The results of antioxidant activity carried out through DPPH free radical scavenging (DPPH) and ferric reducing antioxidant power (FRAP), showing that EOs of Ocimum basilicum Linn. (ObEO), Thymus mongolicus Ronn. (TmEO), Origanum vulgare Linn. (OvEO) and Mosla chinensis Maxim. (McEO) have strong antioxidant activities. Their 50%-inhibitory concentration (IC₅₀) value was <1.00, 1.42, 1.47 and 1.92 μg/mL, respectively; and their FRAP value was 1536.67 ± 24.22, 271.84 ± 4.93, 633.71 ± 13.14 and 480.66 ± 29.90, respectively. The results of filter paper diffusion showing that McEO, OvEO and TmEO inhibition zone diameter (IZD) are all over 30 mm. The results of two-fold dilution method showed that McEO, OvEO and TmEO have strong antibacterial activities against Staphylococcus aureus (S. aureus) and their minimal inhibitory concentrations (MIC) value was 1 μL/mL, 2 μL/mL, and 2 μL/mL, respectively. In conclusion, the results in this work demonstrate the possibility for development and application of EOs as potential feed additives. Full article

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18 pages, 3147 KiB

Open AccessArticle

Bio-Guided Isolation of Acetogenins from Annona cherimola Deciduous Leaves: Production of Nanocarriers to Boost the Bioavailability Properties

by Maria Teresa Gutiérrez, Alexandra G. Durán, Francisco J. R. Mejías, José M. G. Molinillo, Diego Megias, Manuel M. Valdivia and Francisco A. Macías

Molecules 2020, 25(20), 4861; https://doi.org/10.3390/molecules25204861 - 21 Oct 2020

Cited by 13 | Viewed by 3832

Abstract

Annonaceous acetogenins (ACGs) are lipophilic polyketides isolated exclusively from Annonaceae. They are considered to be amongst the most potent antitumor compounds. Nevertheless, their applications are limited by their poor solubility. The isolation of ACGs from Annona cherimola leaves, an agricultural waste, has not [...] Read more.

Annonaceous acetogenins (ACGs) are lipophilic polyketides isolated exclusively from Annonaceae. They are considered to be amongst the most potent antitumor compounds. Nevertheless, their applications are limited by their poor solubility. The isolation of ACGs from Annona cherimola leaves, an agricultural waste, has not been reported to date. Molvizarin (1) cherimolin-1 (2), motrilin (3), annonacin (4) and annonisin (5) are isolated for the first time from A. cherimola deciduous leaves. Annonacin was found to be four- and two-times more potent in tumoral cells (HeLa, 23.6% live cells; IGROV-1, 40.8% live cells for 24 h) than in HEK-293 at 50 µM (24 h, 87.2% live cells). Supramolecular polymer micelles (SMPMs) were synthesized to encapsulate the major ACG isolated, annonacin, in order to improve its solubility in aqueous media. The bioavailability of this compound was increased by a factor of 13 in a simulated human digestive system when compared with free annonacin and an encapsulation efficiency of 35% was achieved. In addition, the cytotoxic activity of SMPMs that hosted annonacin (100 µM, 24 h, 5.8% live cells) was increased compared with free annonacin in water (100 µM, 24 h, 92% live cells). These results highlight the use of by-products of A. cherimola, and their pure compounds, as a promising source of anticancer agents. The use of SMPMs as nanocarriers of ACGs could be an alternative for their application in food field as nutraceutical to enhance the administration and efficacy. Full article

(This article belongs to the Special Issue Trends in Bioactive Natural Products Research: Isolation, Structural Elucidation and Biological Assays)

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12 pages, 2534 KiB

Open AccessArticle

Assessment of Soybean Oil Oxidative Stability from Rapid Analysis of its Minor Component Profile

by Ana S. Martin-Rubio, Patricia Sopelana and María D. Guillén

Molecules 2020, 25(20), 4860; https://doi.org/10.3390/molecules25204860 - 21 Oct 2020

Cited by 7 | Viewed by 3586

Abstract

The minor components of vegetable oils are important for their oxidative stability. In order to know to what extent they can influence oil behaviour under oxidative conditions, two commercial soybean oils, one virgin and the other refined, both with very similar compositions in [...] Read more.

The minor components of vegetable oils are important for their oxidative stability. In order to know to what extent they can influence oil behaviour under oxidative conditions, two commercial soybean oils, one virgin and the other refined, both with very similar compositions in acyl groups but differing in their minor component profiles, were subjected to accelerated storage conditions. They were characterized by ¹H nuclear magnetic resonance (NMR) and direct immersion solid-phase microextraction coupled to gas chromatography/mass spectrometry (DI-SPME-GC/MS), while oil oxidation was monitored by ¹H-NMR. The lower levels of tocols and sterols in the virgin oil, together with its higher free fatty acid content when compared to the refined one, result in a lower oxidative stability. This is deduced from faster degradation of acyl groups and earlier generation of hydroperoxides, epoxides, and aldehydes in the virgin oil. These findings reveal that commercial virgin soybean oil quality is not necessarily higher than that of the refined type, and that a simple and rapid analysis of oil minor components by DI-SPME-GC/MS would enable one to establish quality levels within oils originating from the same plant species and similar unsaturation level regarding composition in potentially bioactive compounds and oxidative stability. Full article

(This article belongs to the Special Issue Food and Drug Analysis Ⅱ)

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14 pages, 1872 KiB

Open AccessArticle

Callus Culture of Thai Basil Is an Effective Biological System for the Production of Antioxidants

by Saher Nazir, Hasnain Jan, Duangjai Tungmunnithum, Samantha Drouet, Muhammad Zia, Christophe Hano and Bilal Haider Abbasi

Molecules 2020, 25(20), 4859; https://doi.org/10.3390/molecules25204859 - 21 Oct 2020

Cited by 31 | Viewed by 5532

Abstract

Thai basil is a renowned medicinal plant and a rich source of bioactive antioxidant compounds with several health benefits, with actions to prevent of cancer, diabetes and cardiovascular disease. Plant cell and tissue culture technologies can be routinely established as an important, sustainable [...] Read more.

Thai basil is a renowned medicinal plant and a rich source of bioactive antioxidant compounds with several health benefits, with actions to prevent of cancer, diabetes and cardiovascular disease. Plant cell and tissue culture technologies can be routinely established as an important, sustainable and low-cost biomass source to produce high-value phytochemicals. The current study aimed at developing an effective protocol to produce Thai basil leaf-derived callus cultures with sustainable and high production of biomass and antioxidants as an alternative of leaves production. MS basal medium with various concentrations of plant growth regulators (PGRs) compatible with nutraceutical applications (i.e., gibberellic acid (GA₃) and 6-benzylaminopurine (BAP) either alone or in combination with naphthalene acetic acid (NAA)) were evaluated. Among all tested PGRs, the combination BAP:NAA (5 mg/L:1 mg/L) yields the maximum biomass accumulation (fresh weight (FW): 190 g/L and dry weight (DW): 13.05 g/L) as well as enhanced phenolic (346.08 mg/L) production. HPLC quantification analysis indicated high productions of chicoric acid (35.77 mg/g DW) and rosmarinic acid (7.35 mg/g DW) under optimized callus culture conditions. Antioxidant potential was assessed using both in vitro cell free and in vivo cellular antioxidant assays. Maximum in vitro antioxidant activity DPPH (93.2% of radical scavenging activity) and ABTS (1322 µM Trolox equivalent antioxidant capacity) was also observed for the extracts from callus cultures grown in optimal conditions. In vivo cellular antioxidant activity assay confirmed the effective protection against oxidative stress of the corresponding extract by the maximum inhibition of ROS and RNS production. Compared to commercial leaves, callus extracts showed higher production of chicoric acid and rosmarinic acid associated with higher antioxidant capacity. In addition, this biological system also has a large capacity for continuous biomass production, thus demonstrating its high potential for possible nutraceutical applications. Full article

(This article belongs to the Special Issue Plant In Vitro Systems as an Effective Tool for In Vivo Biocatalysis of Bioactive Natural Products)

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22 pages, 3730 KiB

Open AccessFeature PaperArticle

Synthesis and Antiplasmodial Activity of Novel Fosmidomycin Derivatives and Conjugates with Artemisinin and Aminochloroquinoline

by Despina Palla, Antonia I. Antoniou, Michel Baltas, Christophe Menendez, Philippe Grellier, Elisabeth Mouray and Constantinos M. Athanassopoulos

Molecules 2020, 25(20), 4858; https://doi.org/10.3390/molecules25204858 - 21 Oct 2020

Cited by 11 | Viewed by 3910

Abstract

Malaria, despite many efforts, remains among the most problematic infectious diseases worldwide, mainly due to the development of drug resistance by Plasmodium falciparum. The antibiotic fosmidomycin (FSM) is also known for its antimalarial activity by targeting the non-mevalonate isoprenoid synthesis pathway, which is [...] Read more.

Malaria, despite many efforts, remains among the most problematic infectious diseases worldwide, mainly due to the development of drug resistance by Plasmodium falciparum. The antibiotic fosmidomycin (FSM) is also known for its antimalarial activity by targeting the non-mevalonate isoprenoid synthesis pathway, which is essential for the malaria parasites but is absent in mammalians. In this study, we synthesized and evaluated against the chloroquine-resistant P. falciparum FcB1/Colombia strain, a series of FSM analogs, derivatives, and conjugates with other antimalarial agents, such as artemisinin (ART) and aminochloroquinoline (ACQ). The biological evaluation revealed four new compounds with higher antimalarial activity than FSM: two FSM-ACQ derivatives and two FSM-ART conjugates, with 3.5–5.4 and 41.5–23.1 times more potent activities than FSM, respectively. Full article

(This article belongs to the Special Issue Biological Activities of Natural Products)

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15 pages, 2811 KiB

Open AccessArticle

Antibacterial Efficacy and Mechanism of Mannosylerythritol Lipids-A on Listeria monocytogenes

by Xiayu Liu, Qin Shu, Qihe Chen, Xinxin Pang, Yansha Wu, Wanyi Zhou, Yajing Wu, Jianrui Niu and Xinglin Zhang

Molecules 2020, 25(20), 4857; https://doi.org/10.3390/molecules25204857 - 21 Oct 2020

Cited by 21 | Viewed by 2979

Abstract

Mannosylerythritol lipids-A (MEL-A) is a novel biosurfactant with excellent surface activity and potential biomedical applications. In this study, we explored the antibacterial activity and the underlying mechanisms of MEL-A against the important food-borne pathogen Listeria monocytogenes. The bacterial growth and survival assays [...] Read more.

Mannosylerythritol lipids-A (MEL-A) is a novel biosurfactant with excellent surface activity and potential biomedical applications. In this study, we explored the antibacterial activity and the underlying mechanisms of MEL-A against the important food-borne pathogen Listeria monocytogenes. The bacterial growth and survival assays revealed a remarkable antibacterial activity of MEL-A. Since MEL-A is a biosurfactant, we examined the cell membrane integrity and morphological changes of MEL-A-treated bacteria by biochemical assays and flow cytometry analysis and electron microscopes. The results showed obvious damaging effects of MEL-A on the cell membrane and morphology. To further explore the antibacterial mechanism of MEL-A, a transcriptome analysis was performed, which identified 528 differentially expressed genes (DEGs). Gene ontology (GO) analysis revealed that the gene categories of membrane, localization and transport were enriched among the DEGs, and the analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways demonstrated significant changes in the maltodextrin ABC transporter system and stress response system. Furthermore, the growth of L. monocytogenes could also be significantly inhibited by MEL-A in milk, a model of a real food system, suggesting that MEL-A could be potentially applied as an natural antimicrobial agent to control food-borne pathogens in the food industry. Full article

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23 pages, 2951 KiB

Open AccessArticle

Formulation of Creams Containing Spirulina Platensis Powder with Different Nonionic Surfactants for the Treatment of Acne Vulgaris

by Liza Józsa, Zoltán Ujhelyi, Gábor Vasvári, Dávid Sinka, Dániel Nemes, Ferenc Fenyvesi, Judit Váradi, Miklós Vecsernyés, Judit Szabó, Gergő Kalló, Gábor Vasas, Ildikó Bácskay and Pálma Fehér

Molecules 2020, 25(20), 4856; https://doi.org/10.3390/molecules25204856 - 21 Oct 2020

Cited by 16 | Viewed by 9643

Abstract

Natural products used in the treatment of acne vulgaris may be promising alternative therapies with fewer side effects and without antibiotic resistance. The objective of this study was to formulate creams containing Spirulina (Arthrospira) platensis to be used in acne therapy. Spirulina platensis [...] Read more.

Natural products used in the treatment of acne vulgaris may be promising alternative therapies with fewer side effects and without antibiotic resistance. The objective of this study was to formulate creams containing Spirulina (Arthrospira) platensis to be used in acne therapy. Spirulina platensis belongs to the group of micro algae and contains valuable active ingredients. The aim was to select the appropriate nonionic surfactants for the formulations in order to enhance the diffusion of the active substance and to certify the antioxidant and antibacterial activity of Spirulina platensis-containing creams. Lyophilized Spirulina platensis powder (SPP) was dissolved in Transcutol HP (TC) and different types of nonionic surfactants (Polysorbate 60 (P60), Cremophor A6:A25 (CR) (1:1), Tefose 63 (TFS), or sucrose ester SP 70 (SP70)) were incorporated in creams as emulsifying agents. The drug release was evaluated by the Franz diffusion method and biocompatibility was tested on HaCaT cells. In vitro antioxidant assays were also performed, and superoxide dismutase (SOD) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were executed. Antimicrobial activities of the selected compositions were checked against Staphylococcus aureus (S. aureus) and Cutibacteriumacnes (C. acnes) (formerly Propionibacterium acnes) with the broth microdilution method. Formulations containing SP 70 surfactant with TC showed the most favorable dissolution profiles and were found to be nontoxic. This composition also showed significant increase in free radical scavenger activity compared to the blank sample and the highest SOD enzyme activity was also detected after treatment with the cream samples. In antibacterial studies, significant differences were observed between the treated and control groups after an incubation time of 6 h. Full article

(This article belongs to the Special Issue Role of Amphiphil tensides in pharmaceutical formulations)

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19 pages, 2974 KiB

Open AccessArticle

N-[2-(4-Acetyl-1-Piperazinyl)Phenyl]-2-(3-Methylphenoxy)Acetamide (NAPMA) Inhibits Osteoclast Differentiation and Protects against Ovariectomy-Induced Osteoporosis

by Jinkyung Lee, Sun-Hee Ahn, Zhihao Chen, Sohi Kang, Dong Kyu Choi, Changjong Moon, Sang Hyun Min, Byung-Ju Park and Tae-Hoon Lee

Molecules 2020, 25(20), 4855; https://doi.org/10.3390/molecules25204855 - 21 Oct 2020

Cited by 3 | Viewed by 2487

Abstract

Osteoclasts are large, multinucleated cells responsible for bone resorption and are induced in response to the regulatory activity of receptor activator of nuclear factor-kappa B ligand (RANKL). Excessive osteoclast activity causes pathological bone loss and destruction. Many studies have investigated molecules that specifically [...] Read more.

Osteoclasts are large, multinucleated cells responsible for bone resorption and are induced in response to the regulatory activity of receptor activator of nuclear factor-kappa B ligand (RANKL). Excessive osteoclast activity causes pathological bone loss and destruction. Many studies have investigated molecules that specifically inhibit osteoclast activity by blocking RANKL signaling or bone resorption. In recent years, we screened compounds from commercial libraries to identify molecules capable of inhibiting RANKL-induced osteoclast differentiation. Consequently, we reported some compounds that are effective at attenuating osteoclast activity. In this study, we found that N-[2-(4-acetyl-1-piperazinyl)phenyl]-2-(3-methylphenoxy)acetamide (NAPMA) significantly inhibited the formation of multinucleated tartrate-resistant acid phosphatase (TRAP)-positive cells from bone marrow-derived macrophages in a dose-dependent manner, without cytotoxic effects. NAPMA downregulated the expression of osteoclast-specific markers, such as c-Fos, NFATc1, DC-STAMP, cathepsin K, and MMP-9, at the transcript and protein levels. Accordingly, bone resorption and actin ring formation were decreased in response to NAPMA treatment. Furthermore, we demonstrated the protective effect of NAPMA against ovariectomy-induced bone loss using micro-CT and histological analysis. Collectively, the results showed that NAPMA inhibited osteoclast differentiation and attenuated bone resorption. It is thus a potential drug candidate for the treatment of osteoporosis and other bone diseases associated with excessive bone resorption. Full article

(This article belongs to the Section Medicinal Chemistry)

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35 pages, 3981 KiB

Open AccessReview

Evaluation of Peptide/Protein Self-Assembly and Aggregation by Spectroscopic Methods

by María Florencia Pignataro, María Georgina Herrera and Verónica Isabel Dodero

Molecules 2020, 25(20), 4854; https://doi.org/10.3390/molecules25204854 - 21 Oct 2020

Cited by 118 | Viewed by 21959

Abstract

The self-assembly of proteins is an essential process for a variety of cellular functions including cell respiration, mobility and division. On the other hand, protein or peptide misfolding and aggregation is related to the development of Parkinson’s disease and Alzheimer’s disease, among other [...] Read more.

The self-assembly of proteins is an essential process for a variety of cellular functions including cell respiration, mobility and division. On the other hand, protein or peptide misfolding and aggregation is related to the development of Parkinson’s disease and Alzheimer’s disease, among other aggregopathies. As a consequence, significant research efforts are directed towards the understanding of this process. In this review, we are focused on the use of UV-Visible Absorption Spectroscopy, Fluorescence Spectroscopy and Circular Dichroism to evaluate the self-organization of proteins and peptides in solution. These spectroscopic techniques are commonly available in most chemistry and biochemistry research laboratories, and together they are a powerful approach for initial as well as routine evaluation of protein and peptide self-assembly and aggregation under different environmental stimulus. Furthermore, these spectroscopic techniques are even suitable for studying complex systems like those in the food industry or pharmaceutical formulations, providing an overall idea of the folding, self-assembly, and aggregation processes, which is challenging to obtain with high-resolution methods. Here, we compiled and discussed selected examples, together with our results and those that helped us better to understand the process of protein and peptide aggregation. We put particular emphasis on the basic description of the methods as well as on the experimental considerations needed to obtain meaningful information, to help those who are just getting into this exciting area of research. Moreover, this review is particularly useful to those out of the field who would like to improve reproducibility in their cellular and biomedical experiments, especially while working with peptide and protein systems as an external stimulus. Our final aim is to show the power of these low-resolution techniques to improve our understanding of the self-assembly of peptides and proteins and translate this fundamental knowledge in biomedical research or food applications. Full article

(This article belongs to the Special Issue Understanding Protein/Peptide Self-Assembly using Structural and Biophysical Chemistry)

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18 pages, 1347 KiB

Open AccessArticle

Semisynthetic Cardenolides Acting as Antiviral Inhibitors of Influenza A Virus Replication by Preventing Polymerase Complex Formation

by Laurita Boff, André Schreiber, Aline da Rocha Matos, Juliana Del Sarto, Linda Brunotte, Jennifer Munkert, Flaviano Melo Ottoni, Gabriela Silva Ramos, Wolfgang Kreis, Fernão Castro Braga, Ricardo José Alves, Rodrigo Maia de Pádua, Cláudia Maria Oliveira Simões and Stephan Ludwig

Molecules 2020, 25(20), 4853; https://doi.org/10.3390/molecules25204853 - 21 Oct 2020

Cited by 2 | Viewed by 3099

Abstract

Influenza virus infections represent a major public health issue by causing annual epidemics and occasional pandemics that affect thousands of people worldwide. Vaccination is the main prophylaxis to prevent these epidemics/pandemics, although the effectiveness of licensed vaccines is rather limited due to the [...] Read more.

Influenza virus infections represent a major public health issue by causing annual epidemics and occasional pandemics that affect thousands of people worldwide. Vaccination is the main prophylaxis to prevent these epidemics/pandemics, although the effectiveness of licensed vaccines is rather limited due to the constant mutations of influenza virus antigenic characteristics. The available anti-influenza drugs are still restricted and there is an increasing viral resistance to these compounds, thus highlighting the need for research and development of new antiviral drugs. In this work, two semisynthetic derivatives of digitoxigenin, namely C10 (3β-((N-(2-hydroxyethyl)aminoacetyl)amino-3-deoxydigitoxigenin) and C11 (3β-(hydroxyacetyl)amino-3-deoxydigitoxigenin), showed anti-influenza A virus activity by affecting the expression of viral proteins at the early and late stages of replication cycle, and altering the transcription and synthesis of new viral proteins, thereby inhibiting the formation of new virions. Such antiviral action occurred due to the interference in the assembly of viral polymerase, resulting in an impaired polymerase activity and, therefore, reducing viral replication. Confirming the in vitro results, a clinically relevant ex vivo model of influenza virus infection of human tumor-free lung tissues corroborated the potential of these compounds, especially C10, to completely abrogate influenza A virus replication at the highest concentration tested (2.0 µM). Taken together, these promising results demonstrated that C10 and C11 can be considered as potential new anti-influenza drug candidates. Full article

(This article belongs to the Special Issue Natural Organic Substances as Starting Bricks for the Semi-synthesis of New Compounds)

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18 pages, 6854 KiB

Open AccessArticle

Influence of Sputtering Temperature of TiO₂ Deposited onto Reduced Graphene Oxide Nanosheet as Efficient Photoanodes in Dye-Sensitized Solar Cells

by Foo Wah Low, Goh Chin Hock, Muhammad Kashif, Nurul Asma Samsudin, Chien Fat Chau, Amaliyah Rohsari Indah Utami, Mohammad Aminul Islam, Cheng Yong Heah, Yun Ming Liew, Chin Wei Lai, Nowshad Amin and Sieh Kiong Tiong

Molecules 2020, 25(20), 4852; https://doi.org/10.3390/molecules25204852 - 21 Oct 2020

Cited by 5 | Viewed by 3002

Abstract

Renewable solar energy is the key target to reduce fossil fuel consumption, minimize global warming issues, and indirectly minimizes erratic weather patterns. Herein, the authors synthesized an ultrathin reduced graphene oxide (rGO) nanosheet with ~47 nm via an improved Hummer’s method. The TiO [...] Read more.

Renewable solar energy is the key target to reduce fossil fuel consumption, minimize global warming issues, and indirectly minimizes erratic weather patterns. Herein, the authors synthesized an ultrathin reduced graphene oxide (rGO) nanosheet with ~47 nm via an improved Hummer’s method. The TiO₂ was deposited by RF sputtering onto an rGO nanosheet with a variation of temperature to enhance the photogenerated electron or charge carrier mobility transport for the photoanode component. The morphology, topologies, element composition, crystallinity as well as dye-sensitized solar cells’ (DSSCs) performance were determined accordingly. Based on the results, FTIR spectra revealed presence of Ti-O-C bonds in every rGO-TiO₂ nanocomposite samples at 800 cm^–1. Besides, XRD revealed that a broad peak of anatase TiO₂ was detected at ~25.4° after incorporation with the rGO. Furthermore, it was discovered that sputtering temperature of 120 °C created a desired power conversion energy (PCE) of 7.27% based on the J-V plot. Further increase of the sputtering temperature to 160 °C and 200 °C led to excessive TiO₂ growth on the rGO nanosheet, thus resulting in undesirable charge recombination formed at the photoanode in the DSSC device. Full article

(This article belongs to the Special Issue Dye-Sensitized Solar Cells: Opportunities and Challenges)

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11 pages, 3604 KiB

Open AccessArticle

Morusin Suppresses Cancer Cell Invasion and MMP-2 Expression through ERK Signaling in Human Nasopharyngeal Carcinoma

by Cheng-Chen Huang, Po-Hui Wang, Yen-Ting Lu, Jia-Sin Yang, Shun-Fa Yang, Yu-Ting Ho, Chiao-Wen Lin and Chung-Han Hsin

Molecules 2020, 25(20), 4851; https://doi.org/10.3390/molecules25204851 - 21 Oct 2020

Cited by 11 | Viewed by 2390

Abstract

The most important cause of treatment failure of nasopharyngeal carcinoma (NPC) patients is metastasis, including regional lymph nodes or distant metastasis, resulting in a poor prognosis and challenges for treatment. In the present study, we investigated the in vitro anti- tumoral properties of [...] Read more.

The most important cause of treatment failure of nasopharyngeal carcinoma (NPC) patients is metastasis, including regional lymph nodes or distant metastasis, resulting in a poor prognosis and challenges for treatment. In the present study, we investigated the in vitro anti- tumoral properties of morusin on human nasopharyngeal carcinoma HONE-1, NPC-39, and NPC-BM cells. Our study revealed that morusin suppressed the migration and invasion abilities of the three NPC cells. Gelatin zymography assay and Western blotting demonstrated that the enzyme activity and the level of matrix metalloproteinases-2 (MMP-2) protein were downregulated by the treatment of morusin. Mitogen-activated protein kinase proteins were examined to identify the signaling pathway, which showed that phosphorylation of ERK1/2 was inhibited after the treatment of morusin. In summary, our data showed that morusin inhibited the migration and invasion of NPC cells by suppressing the expression of MMP-2 by downregulating the ERK1/2 signaling pathway, suggesting that morusin may be a potential candidate for chemoprevention or adjuvant therapy of NPC. Full article

(This article belongs to the Special Issue Natural Product-Inspired Molecules: From Weed to Remedy)

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18 pages, 3173 KiB

Open AccessArticle

Engineering Stem Cell Factor Ligands with Different c-Kit Agonistic Potencies

by Tal Tilayov, Tal Hingaly, Yariv Greenshpan, Shira Cohen, Barak Akabayov, Roi Gazit and Niv Papo

Molecules 2020, 25(20), 4850; https://doi.org/10.3390/molecules25204850 - 21 Oct 2020

Cited by 11 | Viewed by 2742

Abstract

Receptor tyrosine kinases (RTKs) are major players in signal transduction, regulating cellular activities in both normal regeneration and malignancy. Thus, many RTKs, c-Kit among them, play key roles in the function of both normal and neoplastic cells, and as such constitute attractive targets [...] Read more.

Receptor tyrosine kinases (RTKs) are major players in signal transduction, regulating cellular activities in both normal regeneration and malignancy. Thus, many RTKs, c-Kit among them, play key roles in the function of both normal and neoplastic cells, and as such constitute attractive targets for therapeutic intervention. We thus sought to manipulate the self-association of stem cell factor (SCF), the cognate ligand of c-Kit, and hence its suboptimal affinity and activation potency for c-Kit. To this end, we used directed evolution to engineer SCF variants having different c-Kit activation potencies. Our yeast-displayed SCF mutant (SCF_M) library screens identified altered dimerization potential and increased affinity for c-Kit by specific SCF-variants. We demonstrated the delicate balance between SCF homo-dimerization, c-Kit binding, and agonistic potencies by structural studies, in vitro binding assays and a functional angiogenesis assay. Importantly, our findings showed that a monomeric SCF variant exhibited superior agonistic potency vs. the wild-type SCF protein and vs. other high-affinity dimeric SCF variants. Our data showed that action of the monomeric ligands in binding to the RTK monomers and inducing receptor dimerization and hence activation was superior to that of the wild-type dimeric ligand, which has a higher affinity to RTK dimers but a lower activation potential. The findings of this study on the binding and c-Kit activation of engineered SCF variants thus provides insights into the structure–function dynamics of ligands and RTKs. Full article

(This article belongs to the Special Issue Anticancer Inhibitors)

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18 pages, 4644 KiB

Open AccessArticle

Tri-Herbal Medicine Divya Sarva-Kalp-Kwath (Livogrit) Regulates Fatty Acid-Induced Steatosis in Human HepG2 Cells through Inhibition of Intracellular Triglycerides and Extracellular Glycerol Levels

by Acharya Balkrishna, Vivek Gohel, Rani Singh, Monali Joshi, Yash Varshney, Jyotish Srivastava, Kunal Bhattacharya and Anurag Varshney

Molecules 2020, 25(20), 4849; https://doi.org/10.3390/molecules25204849 - 21 Oct 2020

Cited by 10 | Viewed by 5504

Abstract

Steatosis is characterized by excessive triglycerides accumulation in liver cells. Recently, application of herbal formulations has gained importance in treating complex diseases. Therefore, this study explores the efficacy of tri-herbal medicine Divya Sarva-Kalp-Kwath (SKK; brand name, Livogrit) in treating free fatty acid (FFA)-induced [...] Read more.

Steatosis is characterized by excessive triglycerides accumulation in liver cells. Recently, application of herbal formulations has gained importance in treating complex diseases. Therefore, this study explores the efficacy of tri-herbal medicine Divya Sarva-Kalp-Kwath (SKK; brand name, Livogrit) in treating free fatty acid (FFA)-induced steatosis in human liver (HepG2) cells and rat primary hepatocytes. Previously, we demonstrated that cytosafe SKK ameliorated CCl₄-induced hepatotoxicity. In this study, we evaluated the role of SKK in reducing FFA-induced cell-death, and steatosis in HepG2 through analysis of cell viability, intracellular lipid and triglyceride accumulation, extracellular free glycerol levels, and mRNA expression changes. Plant metabolic components fingerprinting in SKK was performed via High Performance Thin Layer Chromatography (HPTLC). Treatment with SKK significantly reduced the loss of cell viability induced by 2 mM-FFA in a dose-dependent manner. SKK also reduced intracellular lipid, triglyceride accumulation, secreted AST levels, and increased extracellular free glycerol presence in the FFA-exposed cells. SKK normalized the FFA-stimulated overexpression of SREBP1c, FAS, C/EBPα, and CPT1A genes associated with the induction of steatosis. In addition, treatment of rat primary hepatocytes with FFA and SKK concurrently, reduced intracellular lipid accumulation. Thus, SKK showed efficacy in reducing intracellular triglyceride accumulation and increasing extracellular glycerol release, along with downregulation of related key genetic factors for FFA-associated steatosis. Full article

(This article belongs to the Special Issue Phytotherapy: Medicinal Plants and Natural Products in Healthcare)

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10 pages, 2571 KiB

Open AccessArticle

Total Synthesis of Phorbazole B

by Yngve Guttormsen, Magnus E. Fairhurst, Sunil K. Pandey, Johan Isaksson, Bengt Erik Haug and Annette Bayer

Molecules 2020, 25(20), 4848; https://doi.org/10.3390/molecules25204848 - 21 Oct 2020

Cited by 5 | Viewed by 3324

Abstract

Phorbazoles are polychlorinated heterocyclic secondary metabolites isolated from a marine sponge and several of these natural products have shown inhibitory activity against cancer cells. In this work, a synthesis of the trichlorinated phorbazole B using late stage electrophilic chlorination was developed. The synthesis [...] Read more.

Phorbazoles are polychlorinated heterocyclic secondary metabolites isolated from a marine sponge and several of these natural products have shown inhibitory activity against cancer cells. In this work, a synthesis of the trichlorinated phorbazole B using late stage electrophilic chlorination was developed. The synthesis relied on the use of an oxazole precursor, which was protected with an iodine in the reactive 4-position, followed by complete chlorination of all pyrrole positions. Attempts to prepare phorbazole A and C, which contain a 3,4-dichlorinated pyrrole, were unsuccessful as the desired chlorination pattern on the pyrrole could not be obtained. The identities of the dichlorinated intermediates and products were determined using NMR techniques including NOESY/ROESY, 1,1-ADEQUATE and high-resolution CLIP-HSQMBC. Full article

(This article belongs to the Special Issue Total Synthesis of Natural Products)

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18 pages, 5020 KiB

Open AccessArticle

Structural Evolution and Magnetic Properties of Gd₂Hf₂O₇ Nanocrystals: Computational and Experimental Investigations

by Madhab Pokhrel, Nicholas Dimakis, Chamath Dannangoda, Santosh K. Gupta, Karen S. Martirosyan and Yuanbing Mao

Molecules 2020, 25(20), 4847; https://doi.org/10.3390/molecules25204847 - 21 Oct 2020

Cited by 4 | Viewed by 2565

Abstract

Structural evolution in functional materials is a physicochemical phenomenon, which is important from a fundamental study point of view and for its applications in magnetism, catalysis, and nuclear waste immobilization. In this study, we used x-ray diffraction and Raman spectroscopy to examine the [...] Read more.

Structural evolution in functional materials is a physicochemical phenomenon, which is important from a fundamental study point of view and for its applications in magnetism, catalysis, and nuclear waste immobilization. In this study, we used x-ray diffraction and Raman spectroscopy to examine the Gd₂Hf₂O₇ (GHO) pyrochlore, and we showed that it underwent a thermally induced crystalline phase evolution. Superconducting quantum interference device measurements were carried out on both the weakly ordered pyrochlore and the fully ordered phases. These measurements suggest a weak magnetism for both pyrochlore phases. Spin density calculations showed that the Gd³⁺ ion has a major contribution to the fully ordered pyrochlore magnetic behavior and its cation antisite. The origin of the Gd magnetism is due to the concomitant shift of its spin-up 4f orbital states above the Fermi energy and its spin-down states below the Fermi energy. This picture is in contrast to the familiar Stoner model used in magnetism. The ordered pyrochlore GHO is antiferromagnetic, whereas its antisite is ferromagnetic. The localization of the Gd-4f orbitals is also indicative of weak magnetism. Chemical bonding was analyzed via overlap population calculations: These analyses indicate that Hf-Gd and Gd-O covalent interactions are destabilizing, and thus, the stabilities of these bonds are due to ionic interactions. Our combined experimental and computational analyses on the technologically important pyrochlore materials provide a basic understanding of their structure, bonding properties, and magnetic behaviors. Full article

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17 pages, 958 KiB

Open AccessArticle

Micro-Fibrillated Cellulose in Adhesive Systems for the Production of Wood-Based Panels

by Emmanouil Karagiannidis, Charles Markessini and Eleftheria Athanassiadou

Molecules 2020, 25(20), 4846; https://doi.org/10.3390/molecules25204846 - 21 Oct 2020

Cited by 17 | Viewed by 2827

Abstract

Micro-Fibrillated Cellulose (MFC) is a new type of bio-based additive, coming from wood cellulose. It can compete and substitute oil derived chemicals in several application fields. In the present work, the use of micro-fibrillated cellulose, in waterborne adhesive systems applied in the manufacture [...] Read more.

Micro-Fibrillated Cellulose (MFC) is a new type of bio-based additive, coming from wood cellulose. It can compete and substitute oil derived chemicals in several application fields. In the present work, the use of micro-fibrillated cellulose, in waterborne adhesive systems applied in the manufacture of composite wood-based panels was evaluated. Research was conducted to test the potential of improving the performance of wood-based panel types such as particleboard, waferboard or randomly-oriented strand board and plywood, by the application of MFC and the substitution of conventional and non-renewable chemical compounds. The approaches followed to introduce MFC into the adhesive systems were three, i.e., MFC 2% suspension added during the adhesive resin synthesis, MFC 10% paste admixed with the already prepared adhesive resin and MFC 2% suspension admixed with the already prepared resin. It was found that MFC improves not only the performance of the final wood panel products but also the behaviour of the applied adhesive polymer colloids (e.g., rheology improvement), especially when admixed with the already prepared resins. Moreover, it was proven that when MFC is introduced into the adhesive resin system, there is a possibility of decreasing the resin consumption, by maintaining the board performance. MFC’s robustness to pH, shear and temperature makes it a highly interesting new additive for adhesive producers. In addition, its natural origin can give adhesive producers the opportunity to move over to more environmentally friendly product solutions. Full article

(This article belongs to the Special Issue Lignocellulosic Biomass)

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14 pages, 2802 KiB

Open AccessArticle

Phenolic Acids-Rich Fractions from Agaricus bitorguis (Quél.) Sacc. Chaidam ZJU-CDMA-12 Mycelia Modulate Hypoxic Stress on Hypoxia-Damaged PC12 Cells

by Hongyun Lu, Zhihua Jiao, Yingchun Jiao, Wei Wang and Qihe Chen

Molecules 2020, 25(20), 4845; https://doi.org/10.3390/molecules25204845 - 21 Oct 2020

Cited by 5 | Viewed by 2678

Abstract

Hypoxia is a common pathological process in various clinical diseases. However, there is still a lack of effective anti-hypoxia active substances. Agaricus bitorguis (Quél.) Sacc Chaidam (ABSC) is a rare wild edible macrofungus that grows underground at high altitudes. Herein, intracellular phenolic acids-rich [...] Read more.

Hypoxia is a common pathological process in various clinical diseases. However, there is still a lack of effective anti-hypoxia active substances. Agaricus bitorguis (Quél.) Sacc Chaidam (ABSC) is a rare wild edible macrofungus that grows underground at high altitudes. Herein, intracellular phenolic acids-rich fractions (IPA) were extracted from ABSC ZJU-CDMA-12, and the structural characterization and anti-hypoxia activity of IPA on PC12 cells were elucidated as well. The results of HPLC-Q-TOF-MS illustrated that five kinds of IPA were isolated from ABSC, including (−)-epicatechin gallate, arabelline, yunnaneic acid D, 2′-O-p-hydroxybenzoyl-6′-O-trans-caffeoylgardoside,4′-O-methylgallocatechin-(4->8)-4′-O-methylepigallocatechin. IPA extracted from ABSC proved to show anti-hypoxia activity on hypoxia-damaged PC12 cells. Hypoxia enhanced reactive oxygen species (ROS) generation and reduced the mitochondrial membrane potential (ΔΨm) in PC12 cells, resulting in the inhibition of survival and induction of apoptosis in PC12 cells. Measurements of 100 μg/mL and 250 μg/mL IPA could significantly reduce hypoxia-induced damage in PC12 cells by decreasing overproduced intracellular ROS, improving ΔΨm, and reducing cell apoptosis rate. Our findings indicated that the IPA from ABSC potentially could be used as novel bioactive components applied to anti-hypoxia functional foods or medicines. Full article

(This article belongs to the Special Issue Synthesis and Evaluation of Antioxidant and Antiproliferative Activity of Plant Natural Compounds)

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16 pages, 1488 KiB

Open AccessReview

The Circular Life of Human CD38: From Basic Science to Clinics and Back

by Alberto L. Horenstein, Angelo C. Faini, Fabio Morandi, Cristiano Bracci, Francesco Lanza, Nicola Giuliani, Aneel Paulus and Fabio Malavasi

Molecules 2020, 25(20), 4844; https://doi.org/10.3390/molecules25204844 - 21 Oct 2020

Cited by 25 | Viewed by 4314

Abstract

Monoclonal antibodies (mAbs) were initially considered as a possible “magic bullet” for in vivo elimination of tumor cells. mAbs represented the first step: however, as they were murine in nature (the earliest experience on the field), they were considered unfit for human applications. [...] Read more.

Monoclonal antibodies (mAbs) were initially considered as a possible “magic bullet” for in vivo elimination of tumor cells. mAbs represented the first step: however, as they were murine in nature (the earliest experience on the field), they were considered unfit for human applications. This prompted the development of techniques for cloning the variable regions of conventional murine antibodies, genetically mounted on human IgG. The last step in this years-long process was the design for the preparation of fully human reagents. The choice of the target molecule was also problematic, since cancer-specific targets are quite limited in number. To overcome this obstacle in the planning phases of antibody-mediated therapy, attention was focused on a set of normal molecules, whose quantitative distribution may balance a tissue-dependent generalized expression. The results and clinical success obtained with anti-CD20 mAbs revived interest in this type of strategy. Using multiple myeloma (MM) as a tumor model was challenging first of all because the plasma cells and their neoplastic counterpart eluded the efforts of the Workshop on Differentiation Antigens to find a target molecule exclusively expressed by these cells. For this reason, attention was turned to surface molecules which fulfill the requisites of being reasonably good targets, even if not specifically restricted to tumor cells. In 2009, we proposed CD38 as a MM target in virtue of its expression: it is absent on early hematological progenitors, has variable but generalized limited expression by normal cells, but is extremely high in plasma cells and in myeloma. Further, regulation of its expression appeared to be dependent on a variety of factors, including exposure to all-trans retinoic acid (ATRA), a potent and highly specific inducer of CD38 expression in human promyelocytic leukemia cells that are now approved for in vivo use. This review discusses the history of human CD38, from its initial characterization to its targeting in antibody-mediated therapy of human myeloma. Full article

(This article belongs to the Special Issue From Cell Signalling to Anticancer Drug Discovery: A Theme Issue in Honor of Professor Barry Potter)

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2 pages, 163 KiB

Open AccessEditorial

Special Issue: Frontiers in RNA Structure

by Quentin Vicens

Molecules 2020, 25(20), 4843; https://doi.org/10.3390/molecules25204843 - 21 Oct 2020

Viewed by 2125

Abstract

The frontiers of our knowledge about RNA structure are rapidly moving [...] Full article

(This article belongs to the Special Issue Frontiers in RNA Structure)

11 pages, 2060 KiB

Open AccessArticle

Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable Enterotoxin

by Shigeru Shimamoto, Mayu Fukutsuji, Toi Osumi, Masaya Goto, Hiroshi Toyoda and Yuji Hidaka

Molecules 2020, 25(20), 4798; https://doi.org/10.3390/molecules25204798 - 21 Oct 2020

Cited by 6 | Viewed by 2643

Abstract

Heat-stable enterotoxin (ST_a) produced by enterotoxigenic E. coli causes acute diarrhea and also can be used as a specific probe for colorectal cancer cells. ST_a contains three intra-molecular disulfide bonds (C1–C4, C2–C5, and C3–C6 connectivity). The chemical synthesis of ST [...] Read more.

Heat-stable enterotoxin (ST_a) produced by enterotoxigenic E. coli causes acute diarrhea and also can be used as a specific probe for colorectal cancer cells. ST_a contains three intra-molecular disulfide bonds (C1–C4, C2–C5, and C3–C6 connectivity). The chemical synthesis of ST_a provided not only the native type of ST_a but also a topological isomer that had the native disulfide pairings. Interestingly, the activity of the topological isomer was approximately 1/10–1/2 that of the native ST_a. To further investigate the bioactive conformation of this molecule and the regulation of disulfide-coupled folding during its chemical syntheses, we examined the folding mechanism of ST_a that occurs during its chemical synthesis. The folding intermediate of ST_a with two disulfide bonds (C1–C4 and C3–C6) and two Cys(Acm) residues, the precursor peptide, was treated with iodine to produce a third disulfide bond under several conditions. The topological isomer was predominantly produced under all conditions tested, along with trace amounts of the native type of ST_a. In addition, NMR measurements indicated that the topological isomer has a left-handed spiral structure similar to that of the precursor peptide, while the native type of ST_a had a right-handed spiral structure. These results indicate that the order of the regioselective formation of disulfide bonds is important for the regulation of the final conformation of disulfide-rich peptides in chemical synthesis. Full article

(This article belongs to the Special Issue Oxidative Folding of Proteins and Peptides)

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14 pages, 5794 KiB

Open AccessArticle

New Insights into The Photoactivity of Shape-Tailored BiVO₄ Semiconductors via Photocatalytic Degradation Reactions and Classical Reduction Processes

by Zsolt Kása, Enikő Eszter Almási, Klára Hernádi, Tamás Gyulavári, Lucian Baia, Gábor Veréb, Zsuzsanna László and Zsolt Pap

Molecules 2020, 25(20), 4842; https://doi.org/10.3390/molecules25204842 - 20 Oct 2020

Cited by 9 | Viewed by 2606

Abstract

In the present study, additive-free, pH-driven, hydrothermal crystallization was used to obtain shape-tailored monoclinic BiVO₄ photocatalysts. The as-prepared BiVO₄ products were systematically characterized, uncovering their crystallographic, morphologic and optical properties, while their applicability was verified in the visible light-driven photodegradation of [...] Read more.

In the present study, additive-free, pH-driven, hydrothermal crystallization was used to obtain shape-tailored monoclinic BiVO₄ photocatalysts. The as-prepared BiVO₄ products were systematically characterized, uncovering their crystallographic, morphologic and optical properties, while their applicability was verified in the visible light-driven photodegradation of oxalic acid and rhodamine B. Monoclinic clinobisvanite was obtained in most cases, with their band gap values located between 2.1 and 2.4 eV. The morphology varied from large, aggregated crystals, individual microcrystals to hierarchical microstructures. It was found that the degradation efficiency values obtained in the case of oxalic acid were directly related to the presence of (040) crystallographic plane, while the degradation of rhodamine B was partially independent by the presence of this structural feature. The importance of (040) crystallographic plane was also demonstrated via the reduction of Cu²⁺ to Cu, by analyzing the Raman spectra of the Cu containing samples, the mean primary crystallite size of Cu and Cu content. Furthermore, the presence of (040) crystallographic plane was directly proportional with the hydrodynamic properties of the powders as well. Full article

(This article belongs to the Special Issue Research on Nanostructured Materials)

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17 pages, 2458 KiB

Open AccessArticle

Pimpinella anisum Essential Oil Nanoemulsion Toxicity against Tribolium castaneum? Shedding Light on Its Interactions with Aspartate Aminotransferase and Alanine Aminotransferase by Molecular Docking

by Ahmed S. Hashem, Marwa M. Ramadan, Amira A. A. Abdel-Hady, Stefania Sut, Filippo Maggi and Stefano Dall’Acqua

Molecules 2020, 25(20), 4841; https://doi.org/10.3390/molecules25204841 - 20 Oct 2020

Cited by 17 | Viewed by 5164

Abstract

The insecticidal activity is the result of a series of complex interactions between toxic substances as ligands and insect’s enzymes as targets. Actually, synthetic insecticides used in pest control programs are harmful to the environment and may affect non-target organisms; thus, the use [...] Read more.

The insecticidal activity is the result of a series of complex interactions between toxic substances as ligands and insect’s enzymes as targets. Actually, synthetic insecticides used in pest control programs are harmful to the environment and may affect non-target organisms; thus, the use of natural products as pest control agents can be very attractive. In the present work, the toxic effect of aniseed (Pimpinella anisum L.) essential oil (EO) and its nanoemulsion (NE) against the red flour beetle Tribolium castaneum, has been evaluated. To assess the EO mode of action, the impact of sub-lethal concentrations of aniseed EO and NE was evaluated on enzymatic and macromolecular parameters of the beetles, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), total protein, total lipids and glucose. Finally, a molecular docking study was conducted to predict the mode of action of the major EO and NE components namely E-anethole, Limonene, alpha-himalachalene, trans-Verbenol and Linalool at binding site of the enzymes AST and ALT. Herein, the binding location of the main compounds in both proteins are discussed suggesting the possible interactions between the considered enzymes and ligands. The obtained results open new horizons to understand the evolution and response of insect-plant compounds interactions and their effect predicted at the molecular levels and side effects of both animal and human. Full article

(This article belongs to the Special Issue Natural Product-Inspired Molecules: From Weed to Remedy)

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24 pages, 3582 KiB

Open AccessReview

Transformations of Monoterpenes with the p-Menthane Skeleton in the Enzymatic System of Bacteria, Fungi and Insects

by Małgorzata Grabarczyk, Wanda Mączka, Anna K. Żołnierczyk and Katarzyna Wińska

Molecules 2020, 25(20), 4840; https://doi.org/10.3390/molecules25204840 - 20 Oct 2020

Cited by 6 | Viewed by 5480

Abstract

The main objective of this article was to present the possibilities of using the enzymatic system of microorganisms and insects to transform small molecules, such as monoterpenes. The most important advantage of this type of reaction is the possibility of obtaining derivatives that [...] Read more.

The main objective of this article was to present the possibilities of using the enzymatic system of microorganisms and insects to transform small molecules, such as monoterpenes. The most important advantage of this type of reaction is the possibility of obtaining derivatives that are not possible to obtain with standard methods of organic synthesis or are very expensive to obtain. The interest of industrial centers focuses mainly on obtaining particles of high optical purity, which have the desired biological properties. The cost of obtaining such a compound and the elimination of toxic or undesirable chemical waste is important. Enzymatic reactions based on enzymes alone or whole microorganisms enable obtaining products with a specific structure and purity in accordance with the rules of Green Chemistry. Full article

(This article belongs to the Special Issue Microbial Biotransformation of Natural Products)

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