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Bioactive Natural Compounds and Their Mechanisms of Action

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

Deadline for manuscript submissions: closed (31 December 2020) | Viewed by 68354

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Special Issue Editor

Dr. Karel Šmejkal

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Guest Editor

Department of Natural Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
Interests: phytochemistry; pharmacognosy; bioactivity; anti-inflammatory effect; animicrobial effect
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

I would like to invite you to submit a manuscript to the Special Issue “Bioactive Natural Compounds and Their Mechanisms of Action”.

As long as plants exist, phytochemicals exist, and the use of plants or their parts for the preparation of herbal remedies is as old as human history. Plants traditionally serve as a primary source of medicines for drug discovery, and although synthetic chemical molecules have an indisputable importance in therapy, an emphasis in natural product drug discovery has yielded numerous interesting results, such as the discovery of avermectins and artemisinin, which were awarded the Nobel Prize in 2015. In many countries, plant-based medicines are again integrated through regulation into the mainstream health system, such as in China, where the government announced the aim to integrate Traditional Chinese Medicine into their health system by 2020. This trend shows that there will be a tremendous demand for herbal-derived medicines in the coming years, and the critical evaluation of the phytochemical composition and biological activities of ethnomedicinal plants, followed by the process of finding the most promising plants content compounds for further possible semi-synthetic modifications, seems to be the right way for possible new drug approval as well as providing safe and effective therapy.

Therefore, this Special Issue is focused on both original research and review articles, which would cover all aspects of bioactive natural compounds (semisynthetic and nature-based substances included): from isolation of bioactive substances to elucidation of mechanisms of their action. Special attention will be given to plants or compounds with anti-inflammatory effects. If plant extracts are to be evaluated, only these with phytochemical profiling will be considered for evaluation. Reviews could focus on the most interesting groups of natural compounds, ethnobotanical evaluations, bioactive plants used in therapy or promising pharmacologic activities. Authors considering the submission of a review are kindly asked to provide in advance to the guest editor a brief outline of the subject matter of their work.

Prof. Karel Šmejkal
Guest Editor

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Keywords

Natural compounds
Plant phenolics
Alkaloids
Bioactivity
Mechanism of effect
Phytochemical profiling
Structural elucidation
Ethnobotany
Anti-inflammatory activity

Published Papers (14 papers)

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Research

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15 pages, 1671 KiB

Open AccessArticle

Direct and Indirect Antioxidant Effects of Selected Plant Phenolics in Cell-Based Assays

by Jakub Treml, Petra Večeřová, Petra Herczogová and Karel Šmejkal

Molecules 2021, 26(9), 2534; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26092534 - 26 Apr 2021

Cited by 17 | Viewed by 2207

Abstract

Background: Oxidative stress is a key factor in the pathophysiology of many diseases. This study aimed to verify the antioxidant activity of selected plant phenolics in cell-based assays and determine their direct or indirect effects. Methods: The cellular antioxidant assay (CAA) assay was employed for direct scavenging assays. In the indirect approach, the influence of each test substance on the gene and protein expression and activity of selected antioxidant enzymes was observed. One assay also dealt with activation of the Nrf2-ARE pathway. The overall effect of each compound was measured using a glucose oxidative stress protection assay. Results: Among the test compounds, acteoside showed the highest direct scavenging activity and no effect on the expression of antioxidant enzymes. It increased only the activity of catalase. Diplacone was less active in direct antioxidant assays but positively affected enzyme expression and catalase activity. Morusin showed no antioxidant activity in the CAA assay. Similarly, pomiferin had only mild antioxidant activity and proved rather cytotoxic. Conclusions: Of the four selected phenolics, only acteoside and diplacone demonstrated antioxidant effects in cell-based assays. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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10 pages, 2250 KiB

Open AccessCommunication

Morolic Acid 3-O-Caffeate Inhibits Adipogenesis by Regulating Epigenetic Gene Expression

by Sook In Chae, Sang Ah Yi, Ki Hong Nam, Kyoung Jin Park, Jihye Yun, Ki Hyun Kim, Jaecheol Lee and Jeung-Whan Han

Molecules 2020, 25(24), 5910; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25245910 - 13 Dec 2020

Viewed by 2082

Abstract

Obesity causes a wide range of metabolic diseases including diabetes, cardiovascular disease, and kidney disease. Thus, plenty of studies have attempted to discover naturally derived compounds displaying anti-obesity effects. In this study, we evaluated the inhibitory effects of morolic acid 3-O-caffeate (MAOC), extracted from Betula schmidtii, on adipogenesis. Treatment of 3T3-L1 cells with MAOC during adipogenesis significantly reduced lipid accumulation and decreased the expression of adiponectin, a marker of mature adipocytes. Moreover, the treatment with MAOC only during the early phase (day 0–2) sufficiently inhibited adipogenesis, comparable with the inhibitory effects observed following MAOC treatment during the whole processes of adipogenesis. In the early phase of adipogenesis, the expression level of Wnt6, which inhibits adipogenesis, increased by MAOC treatment in 3T3-L1 cells. To identify the gene regulatory mechanism, we assessed alterations in histone modifications upon MAOC treatment. Both global and local levels on the Wnt6 promoter region of histone H3 lysine 4 trimethylation, an active transcriptional histone marker, increased markedly by MAOC treatment in 3T3-L1 cells. Our findings identified an epigenetic event associated with inhibition of adipocyte generation by MAOC, suggesting its potential as an efficient therapeutic compound to cure obesity and metabolic diseases. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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14 pages, 2764 KiB

Open AccessArticle

Diketoacetonylphenalenone, Derived from Hawaiian Volcanic Soil-Associated Fungus Penicillium herquei FT729, Regulates T Cell Activation via Nuclear Factor-κB and Mitogen-Activated Protein Kinase Pathway

by Hyun-Su Lee, Jae Sik Yu, Ki Hyun Kim and Gil-Saeng Jeong

Molecules 2020, 25(22), 5374; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25225374 - 17 Nov 2020

Cited by 5 | Viewed by 1839

Abstract

In immunological responses, controlling excessive T cell activity is critical for immunological homeostasis maintenance. Diketoacetonylphenalenone, derived from Hawaiian volcanic soil-associated fungus Penicillium herquei FT729, possesses moderate anti-inflammatory activity in RAW 264.7 cells but its immunosuppressive effect on T cell activation is unknown. In the present study, diketoacetonylphenalenone (up to 40 μM) did not show cytotoxicity in T cells. Western blot analysis showed treatment with diketoacetonylphenalenone did not alter the expression of anti-apoptotic proteins. Pretreatment with diketoacetonylphenalenone suppressed the interleukin-2 production in activated T cells induced by T cell receptor-mediated stimulation and PMA/A23187. The CFSE-proliferation assay revealed the inhibitory effect of diketoacetonylphenalenone on the proliferation of T cells. The expression of surface molecules on activated T cells was also reduced. We discovered the suppression of the TAK1-IKKα-NF-κB pathway by pretreatment with diketoacetonylphenalenone abrogated mitogen-activated protein kinase (MAPK) signaling in activated T cells. These results suggest that diketoacetonylphenalenone effectively downregulates T cell activity via the MAPK pathway and provides insight into the therapeutic potential of immunosuppressive reagents. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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20 pages, 7750 KiB

Open AccessArticle

The Grapefruit Effect: Interaction between Cytochrome P450 and Coumarin Food Components, Bergamottin, Fraxidin and Osthole. X-ray Crystal Structure and DFT Studies

by Miriam Rossi, Sandjida Aktar, Marissa Davis, Emily Hefter Feuss, Samara Roman-Holba, Kelly Wen, Christopher Gahn and Francesco Caruso

Molecules 2020, 25(14), 3158; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25143158 - 10 Jul 2020

Cited by 8 | Viewed by 3361

Abstract

Coumarins are plant-derived secondary metabolites. The crystal structure of three coumarins—bergamottin, osthole and fraxidin—are described and we analyze intermolecular interactions and their role in crystal formation. Bergamottin is a furanocoumarin found in citrus plants, which is a strong inhibitor of the principal human metabolizing enzyme, cytochrome P450 3A4 (CYP3A4). The crystal structure determinations of three coumarins give us the geometrical parameters and reveal the parallel-displaced π–π stacking and hydrogen bonding intermolecular interactions used for molecular assembly in the crystal structure. A quite strong (less than 3.4 Å) stacking interaction of bergamottin appears to be a determining feature that distinguishes it from other coumarins studied in this work. Our DFT computational studies on the three natural products of the same coumarin family docked into the active site of CYP3A4 (PDB 4D78) show different behavior for these coumarins at the active site. When the substrate is bergamottin, the importance of π-π stacking and hydrogen bonding, which can anchor the substrate in place, appears fundamental. In contrast, fraxidin and osthole show carbonyl coordination to iron. Our docking calculations show that the bergamottin tendency towards π–π stacking is important and likely influences its interactions with the heme group of CYP3A4. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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11 pages, 1083 KiB

Open AccessArticle

Relaxant Effect of Monoterpene (−)-Carveol on Isolated Human Umbilical Cord Arteries and the Involvement of Ion Channels

by Renata Evaristo Rodrigues da Silva, Andressa de Alencar Silva, Luís Pereira-de-Morais, Nayane de Sousa Almeida, Marcello Iriti, Marta Regina Kerntopf, Irwin Rose Alencar de Menezes, Henrique Douglas Melo Coutinho and Roseli Barbosa

Molecules 2020, 25(11), 2681; https://doi.org/10.3390/molecules25112681 - 09 Jun 2020

Cited by 14 | Viewed by 2670

Abstract

Carveol is a monoterpene present in the structure of many plant products. It has a variety of biological activities: antioxidant, anticancer and vasorelaxation. However, studies investigating the effect of monoterpenoids on human vessels have not yet been described. Thus, the present study aimed to characterize the effect of (−)-carveol on human umbilical arteries (HUAs). HUA ring preparations were isolated and subjected to isometric tension recordings of umbilical artery smooth muscle contractions. (−)-Carveol exhibited a significant vasorelaxant effect on KCl and 5-HT-induced contractions, obtaining EC₅₀ values of 344.25 ± 8.4 and 175.82 ± 4.05 µM, respectively. The participation of calcium channels in the relaxation produced by (−)-carveol was analyzed using vessels pre-incubated with (−)-carveol (2000 µM) in a calcium-free medium, where the induction of contractions was abolished. The vasorelaxant effect of (−)-carveol on HUAs was reduced by tetraethylammonium (TEA), which increased the (−)-carveol EC₅₀ to 484.87 ± 6.55 µM. The present study revealed that (−)-carveol possesses a vasorelaxant activity in HUAs, which was dependent on the opening of calcium and potassium channels. These results pave the way for further studies involving the use of monoterpenoids for the vasodilatation of HUAs. These molecules have the potential to treat diseases such as pre-eclampsia, which is characterized by resistance in umbilical arteries. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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12 pages, 2550 KiB

Open AccessFeature PaperArticle

Virtual Screening of Natural Products against Type II Transmembrane Serine Protease (TMPRSS2), the Priming Agent of Coronavirus 2 (SARS-CoV-2)

by Noor Rahman, Zarrin Basharat, Muhammad Yousuf, Giuseppe Castaldo, Luca Rastrelli and Haroon Khan

Molecules 2020, 25(10), 2271; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25102271 - 12 May 2020

Cited by 138 | Viewed by 14978

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused about 2 million infections and is responsible for more than 100,000 deaths worldwide. To date, there is no specific drug registered to combat the disease it causes, named coronavirus disease 2019 (COVID-19). In the current study, we used an in silico approach to screen natural compounds to find potent inhibitors of the host enzyme transmembrane protease serine 2 (TMPRSS2). This enzyme facilitates viral particle entry into host cells, and its inhibition blocks virus fusion with angiotensin-converting enzyme 2 (ACE2). This, in turn, restricts SARS-CoV-2 pathogenesis. A three-dimensional structure of TMPRSS2 was built using SWISS-MODEL and validated by RAMPAGE. The natural compounds library Natural Product Activity and Species Source (NPASS), containing 30,927 compounds, was screened against the target protein. Two techniques were used in the Molecular Operating Environment (MOE) for this purpose, i.e., a ligand-based pharmacophore approach and a molecular docking-based screening. In total, 2140 compounds with pharmacophoric features were retained using the first approach. Using the second approach, 85 compounds with molecular docking comparable to or greater than that of the standard inhibitor (camostat mesylate) were identified. The top 12 compounds with the most favorable structural features were studied for physicochemical and ADMET (absorption, distribution, metabolism, excretion, toxicity) properties. The low-molecular-weight compound NPC306344 showed significant interaction with the active site residues of TMPRSS2, with a binding energy score of −14.69. Further in vitro and in vivo validation is needed to study and develop an anti-COVID-19 drug based on the structures of the most promising compounds identified in this study. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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15 pages, 1986 KiB

Open AccessArticle

Serjanic Acid Improves Immunometabolic Markers in a Diet-Induced Obesity Mouse Model

by Gustavo Gutiérrez, Deisy Giraldo-Dávila, Marianny Y. Combariza, Ulrike Holzgrabe, Jorge Humberto Tabares-Guevara, José Robinson Ramírez-Pineda, Sergio Acín, Diana Lorena Muñoz, Guillermo Montoya and Norman Balcazar

Molecules 2020, 25(7), 1486; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25071486 - 25 Mar 2020

Cited by 5 | Viewed by 3669

Abstract

Plant extracts from Cecropia genus have been used by Latin-American traditional medicine to treat metabolic disorders and diabetes. Previous reports have shown that roots of Cecropia telenitida that contains serjanic acid as one of the most prominent and representative pentacyclic triterpenes. The study aimed to isolate serjanic acid and evaluate its effect in a prediabetic murine model by oral administration. A semi-pilot scale extraction was established and serjanic acid purification was followed using direct MALDI-TOF analysis. A diet induced obesity mouse model was used to determine the impact of serjanic acid over selected immunometabolic markers. Mice treated with serjanic acid showed decreased levels of cholesterol and triacylglycerols, increased blood insulin levels, decreased fasting blood glucose and improved glucose tolerance, and insulin sensitivity. At transcriptional level, the reduction of inflammation markers related to adipocyte differentiation is reported. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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18 pages, 351 KiB

Open AccessArticle

Antimicrobial and Antioxidant Properties of Four Lycopus Taxa and an Interaction Study of Their Major Compounds

by Eva Trajčíková, Elena Kurin, Lívia Slobodníková, Marek Straka, Aneta Lichváriková, Svetlana Dokupilová, Iveta Čičová, Milan Nagy, Pavel Mučaji and Silvia Bittner Fialová

Molecules 2020, 25(6), 1422; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25061422 - 20 Mar 2020

Cited by 4 | Viewed by 2635

Abstract

The compositions of leaf infusions of three genotypes of Lycopus europaeus L. with origins in central Europe, namely L. europaeus A (LeuA), L. europaeus B (LeuB), and L. europaeus C (LeuC), and one genotype of L. exaltatus (Lex), were examined by LC-MS-DAD (Liquid Chromatography Mass Spectrometry and Diode Array Detection) analysis. This revealed the presence of thirteen compounds belonging to the groups of phenolic acids and flavonoids, with a predominance of rosmarinic acid (RA) and luteolin-7-O-glucuronide (LGlr). The antimicrobial activity of leaf infusions was tested on the collection strains of Gram-positive and Gram-negative bacteria, and on the clinical Staphylococcus aureus strains. We detected higher activity against Gram-positive bacteria, of which the most susceptible strains were those of Staphylococcus aureus, including methicillin-resistant and poly-resistant strains. Furthermore, we examined the antioxidant activity of leaf infusions using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) methods, and on NIH/3T3 cell lines using dichlorodihydrofluorescein diacetate (DCFH-DA). We also studied the mutual interactions between selected infusions, namely RA and/or LGlr. In the mixtures of leaf infusion and RA or LGlr, we observed slight synergism and a high dose reduction index in most cases. This leads to the beneficial dose reduction at a given antioxidant effect level in mixtures compared to the doses of the parts used alone. Therefore, our study draws attention to further applications of the Lycopus leaves as a valuable alternative source of natural antioxidants and as a promising topical antibacterial agent for medicinal use. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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12 pages, 2776 KiB

Open AccessArticle

Enhancement of Macarpine Production in Eschscholzia Californica Suspension Cultures under Salicylic Acid Elicitation and Precursor Supplementation

by Andrea Balažová, Júlia Urdová, Vladimír Forman and Pavel Mučaji

Molecules 2020, 25(6), 1261; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25061261 - 11 Mar 2020

Cited by 4 | Viewed by 2613

Abstract

Macarpine is a minor benzophenanthridine alkaloid with interesting biological activities, which is produced in only a few species of the Papaveraceae family, including Eschscholzia californica. Our present study was focused on the enhancement of macarpine production in E. californica suspension cultures using three elicitation models: salicylic acid (SA) (4; 6; 8 mg/L) elicitation, and simultaneous or sequential combinations of SA and L-tyrosine (1 mmol/L). Sanguinarine production was assessed along with macarpine formation in elicited suspension cultures. Alkaloid production was evaluated after 24, 48 and 72 h of elicitation. Among the tested elicitation models, the SA (4 mg/L), supported by L-tyrosine, stimulated sanguinarine and macarpine production the most efficiently. While sequential treatment led to a peak accumulation of sanguinarine at 24 h and macarpine at 48 h, simultaneous treatment resulted in maximum sanguinarine accumulation at 48 h and macarpine at 72 h. The effect of SA elicitation and precursor supplementation was evaluated also based on the gene expression of 4′-OMT, CYP719A2, and CYP719A3. The gene expression of investigated enzymes was increased at all used elicitation models and their changes correlated with sanguinarine but not macarpine accumulation. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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16 pages, 3014 KiB

Open AccessArticle

Sanguinarine Induces Apoptosis in Papillary Thyroid Cancer Cells via Generation of Reactive Oxygen Species

by Abdul Q. Khan, Elham A. N. Mohamed, Ishrat Hakeem, Aneeza Nazeer, Shilpa Kuttikrishnan, Kirti S. Prabhu, Kodappully S. Siveen, Zafar Nawaz, Aamir Ahmad, Hatem Zayed and Shahab Uddin

Molecules 2020, 25(5), 1229; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25051229 - 09 Mar 2020

Cited by 26 | Viewed by 5446

Abstract

Sanguinarine (SNG), a natural compound with an array of pharmacological activities, has promising therapeutic potential against a number of pathological conditions, including malignancies. In the present study, we have investigated the antiproliferative potential of SNG against two well-characterized papillary thyroid cancer (PTC) cell lines, BCPAP and TPC-1. SNG significantly inhibited cell proliferation of PTC cells in a dose and time-dependent manner. Western blot analysis revealed that SNG markedly attenuated deregulated expression of p-STAT3, without affecting total STAT3, and inhibited growth of PTC via activation of apoptotic and autophagy signaling cascade, as SNG treatment of PTC cells led to the activation of caspase-3 and caspase-8; cleavage of PARP and activation of autophagy markers. Further, SNG-mediated anticancer effects in PTC cells involved the generation of reactive oxygen species (ROS) as N-acetyl cysteine (NAC), an inhibitor of ROS, prevented SNG-mediated antiproliferative, apoptosis and autophagy inducing action. Interestingly, SNG also sensitized PTC cells to chemotherapeutic drug cisplatin, which was inhibited by NAC. Finally, SNG suppressed the growth of PTC thyrospheres and downregulated stemness markers ALDH2 and SOX2. Altogether, the findings of the current study suggest that SNG has anticancer potential against PTC cells as well its derived cancer stem-like cells, most likely via inactivation of STAT3 and its associated signaling molecules. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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11 pages, 919 KiB

Open AccessCommunication

Structural Study on Hypochlorous Acid-Mediated Chlorination of Betanin and Its Decarboxylated Derivatives from an Anti-Inflammatory Beta vulgaris L. Extract

by Agnieszka Kumorkiewicz-Jamro, Karolina Starzak, Katarzyna Sutor, Boris Nemzer, Zbigniew Pietrzkowski, Łukasz Popenda and Sławomir Wybraniec

Molecules 2020, 25(2), 378; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25020378 - 16 Jan 2020

Cited by 4 | Viewed by 3225

Abstract

Hypochlorous acid (HOCl) produced by neutrophils is a part of the natural innate immune response system in the human body, but excessive levels of HOCl can ultimately be detrimental to health. Recent reports suggest that betacyanin plant pigments can act as potent scavengers of inflammatory factors and are notably effective against HOCl. In this contribution, chlorination mechanism and position of the electrophilic substitution in betacyanins was studied by high-resolution mass spectrometry and further structural analyses by NMR techniques, which completed the identification of the chlorinated betacyanins. For the study on the influence of the position of decarboxylation on the chlorination mechanism, a comparison of the chlorination position between betanin as well as 17-, and 2,17-decarboxylated betanins was performed. The structural study confirmed that the chlorination position in betanin occurs within the dihydropyridinic moiety at carbon C-18. Therefore, out of the aqueous free chlorine equilibrium species: HOCl, OCl⁻, Cl₂, and Cl₂O, the most potent chlorinating agents are HOCl and Cl₂O postulated previously and the attack of the Cl^⁺ ion on the carbon C-18 with a cyclic intermediate version is considered. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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16 pages, 1961 KiB

Open AccessArticle

Evaluation Procoagulant Activity and Mechanism of Astragalin

by Changqin Li, Miyun Hu, Shengjun Jiang, Zhenhua Liang, Jinmei Wang, Zhenhua Liu, Hui-Min David Wang and Wenyi Kang

Molecules 2020, 25(1), 177; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25010177 - 01 Jan 2020

Cited by 18 | Viewed by 4871

Abstract

Astragalin, isolated from flowers of Rosa chinensis Jacq., is a kind of flavonoid, with anti-inflammatory, antioxidant, antiviral, analgesic, antibacterial, antiallergic, and antihepatotoxic effects. However, no studieson the procoagulant effect of astragalin have been reported. This study aimed to investigate the procoagulant activity of astragalin and its mechanism. Its procoagulant effect was investigated by activated partial thromboplastin time (APTT), thrombin time (TT), prothrombin time (PT), and fibrinogen (FIB) in vitro, and a rat model established by heparin sodium was used to evaluate the mechanism for the procoagulant effect in vivo. The results showed that astragalin had good procoagulant effects compared with the control group in vitro. Compared with the model group in vivo, astragalin could shorten the coagulation time and significantly increase the number of platelets. Meanwhile, astragalin could significantly reduce the effectual time of PT and APTT and increase the content of FIB. The contents of 6-keto-PGF_1α and eNOS significantly decreased. Astragalin could increase whole blood viscosity (WBV), plasma viscosity (PV), erythrocyte sedimentation rate (ESR) and packedcell volume (PCV). All of the above revealed that astragalin had good procoagulant effects by promoting the intrinsic and extrinsic coagulation system. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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Review

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23 pages, 1265 KiB

Open AccessReview

Chili Pepper Carotenoids: Nutraceutical Properties and Mechanisms of Action

by Maria Guadalupe Villa-Rivera and Neftalí Ochoa-Alejo

Molecules 2020, 25(23), 5573; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25235573 - 27 Nov 2020

Cited by 43 | Viewed by 6330

Abstract

Chili pepper is a prominent cultivated horticultural crop that is traditionally used for food seasoning and is applied for the treatment and prevention of multiple diseases. Its beneficial health properties are due to its abundance and variety of bioactive components, such as carotenoids, capsaicinoids, and vitamins. In particular, carotenoids have important nutraceutical properties, and several studies have focused on their potential in the prevention and treatment of human diseases. In this article, we reviewed the state of knowledge of general aspects of chili pepper carotenoids (biosynthesis pathway, types and content in Capsicum spp., and the effects of processing on carotenoid content) and recent findings on the effects of carotenoid nutraceuticals, such as antioxidant, cancer preventive, anti-inflammatory, cardiovascular disorder preventive, and anti-obesity effects. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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29 pages, 3731 KiB

Open AccessFeature PaperReview

Molecular Insight into the Therapeutic Promise of Flavonoids against Alzheimer’s Disease

by Md. Sahab Uddin, Md. Tanvir Kabir, Kamal Niaz, Philippe Jeandet, Christophe Clément, Bijo Mathew, Abdur Rauf, Kannan R.R. Rengasamy, Eduardo Sobarzo-Sánchez, Ghulam Md Ashraf and Lotfi Aleya

Molecules 2020, 25(6), 1267; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25061267 - 11 Mar 2020

Cited by 86 | Viewed by 11336

Abstract

Alzheimer’s disease (AD) is one of the utmost chronic neurodegenerative disorders, which is characterized from a neuropathological point of view by the aggregates of amyloid beta (Aβ) peptides that are deposited as senile plaques and tau proteins which form neurofibrillary tangles (NFTs). Even though advancement has been observed in order to understand AD pathogenesis, currently available therapeutic methods can only deliver modest symptomatic relief. Interestingly, naturally occurring dietary flavonoids have gained substantial attention due to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties as alternative candidates for AD therapy. Experimental proof provides support to the idea that some flavonoids might protect AD by interfering with the production and aggregation of Aβ peptides and/or decreasing the aggregation of tau. Flavonoids have the ability to promote clearance of Aβ peptides and inhibit tau phosphorylation by the mTOR/autophagy signaling pathway. Moreover, due to their cholinesterase inhibitory potential, flavonoids can represent promising symptomatic anti-Alzheimer agents. Several processes have been suggested for the aptitude of flavonoids to slow down the advancement or to avert the onset of Alzheimer’s pathogenesis. To enhance cognitive performance and to prevent the onset and progress of AD, the interaction of flavonoids with various signaling pathways is proposed to exert their therapeutic potential. Therefore, this review elaborates on the probable therapeutic approaches of flavonoids aimed at averting or slowing the progression of the AD pathogenesis. Full article

(This article belongs to the Special Issue Bioactive Natural Compounds and Their Mechanisms of Action)

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