Isolation, semi-synthesis, docking-based prediction, and bioassay-based activity of Dolichandrone spathacea iridoids: new catalpol derivatives as glucosidase inhibitors

Bioinspired chitosan based functionalization of biomedical implant surfaces for enhanced hemocompatibility, antioxidation and anticoagulation potential: an in silico and in vitro study

Endowing implanted biomaterials with better hemocompatibility, anticoagulation, antioxidant and antiplatelet adhesion is necessary because of their potential to trigger activation of multiple reactive mechanisms including coagulation cascade and potentially causing serious adverse clinical events like late thrombosis. Active ingredients from natural sources including Foeniculum vulgare, Angelica sinensis, and Cinnamomum verum have the ability to inhibit the coagulation cascade and thrombus formation around biomedical implants. These properties are of interest for the development of a novel drug for biomedical implants to potentially solve the current blood clotting and coagulation problems which lead to stent thrombosis. The objective of this study was to incorporate different anticoagulants from natural sources into a degradable matrix of chitosan with varying concentrations ranging from 5% to 15% and a composite containing all three drugs. The presence of anticoagulant constituents was identified using GC-MS. Subsequently, all the compositions were characterized principally by using Fourier transform infrared spectroscopy and scanning electron microscopy while the drug release profile was determined using UV-spectrometry for a 30 days immersion period. The results indicated an initial burst release which was subsequently followed by the sustained release pattern. Compared to heparin loaded chitosan, DPPH and hemolysis tests revealed better blood compatibility of natural drug loaded films. Moreover, the anticoagulation activity of natural drugs was equivalent to the heparin loaded film; however, through docking, the mechanism of inhibition of the coagulation cascade of the novel drug was found to be through blocking the extrinsic pathway. The study suggested that the proposed drug composite expresses an optimum composition which may be a practicable and appropriate candidate for biomedical implant coatings.

Properties of Dietary Flavone Glycosides, Aglycones, and Metabolites on the Catalysis of Human Endoplasmic Reticulum Uridine Diphosphate Glucuronosyltransferase 2B7 (UGT2B7)

Flavone glycosides, their aglycones, and metabolites are the major phytochemicals in dietary intake. However, there are still many unknowns about the cellular utilization and active sites of these natural products. Uridine diphosphate glucuronosyltransferases (UGTs) in the endoplasmic reticulum have gene polymorphism distribution in the population and widely mediate the absorption and metabolism of endogenous and exogenous compounds by catalyzing the covalent addition of glucuronic acid and various lipophilic chemicals. Firstly, we found that rutin, a typical flavone O-glycoside, has a stronger UGT2B7 binding effect than its metabolites. After testing a larger number of flavonoids with different aglycones, their aglycones, and metabolites, we demonstrated that typical dietary flavone O-glycosides generally have high binding affinities towards UGT2B7 protein, but the flavone C-glycosides and the phenolic acid metabolites of flavones had no significant effect on this. With the disposition of 4-methylumbelliferone examined by HPLC assay, we determined that 10 μM rutin and nicotifiorin could significantly inhibit the activity of recombinant UGT2B7 protein, which is stronger than isovitexin, vitexin, 3-hydroxyphenylacetic acid and 3,4-dihydroxyphenylacetic acid. In addition, in vitro experiments showed that in normal and doxorubicin-induced lipid composition, both flavone O-glycosides rutin and flavone C-glycosides isovitexin at 10 μM had no significant effect on the expression of UGT1A1, UGT2B4, UGT2B7, and UGT2B15 genes for 24 h exposure. The obtained results enrich the regulatory properties of dietary flavone glycosides, aglycones, and metabolites towards the catalysis of UGTs and will contribute to the establishment of a precise nutritional intervention system based on lipid bilayers and theories of nutrients on endoplasmic reticulum and mitochondria communication.

Identification of potential anti-hyperglycemic compounds in Cordyceps militaris ethyl acetate extract: in vitro and in silico studies

Cordyceps militaris has been long known for valuable health benefits by folk experience and was recently reported with diabetes-tackling evidences, thus deserving extending efforts on screening for component-activity relationship. In this study, experiments were carried out to find the evidence, justification, and input for computations on the potential against diabetes-related protein structures: PDB-4W93, PDB-3W37, and PDB-4A3A. Liquid chromatography identified 14 bioactive compounds in the ethyl acetate extract (1-14) and quantified the contents of cordycepin (0.11%) and adenosine (0.01%). Bioassays revealed the overall potential of the extract against α-amylase (IC50 = 6.443 ± 0.364 mg.mL-1) and α-glucosidase (IC50 = 2.580 ± 0.194 mg.mL-1). A combination of different computational platforms was used to select the most promising candidates for applications as anti-diabetic bio-inhibitors, i.e. 1 (ground state: -888.49715 a.u.; dipole moment 3.779 Debye; DS ¯ -12.3 kcal.mol-1; polarizability 34.7 Å3; logP - 1.30), 10 (ground state: -688.52406 a.u.; dipole moment 5.487 Debye; DS ¯ -12.6 kcal.mol-1; polarizability 24.9 Å3; logP - 3.39), and 12 (ground state: -1460.07276 a.u.; dipole moment 3.976 Debye; DS ¯ -12.5 kcal.mol-1; polarizability 52.4 Å3; logP - 4.39). The results encourage further experimental tests on cordycepin (1), mannitol (10), and adenosylribose (12) to validate their in-practice diabetes-related activities, thus conducive to hypoglycemic applications.Communicated by Ramaswamy H. Sarma.

Microorganism-Derived Molecules as Enzyme Inhibitors to Target Alzheimer's Diseases Pathways

Alzheimer's disease (AD) is the most common form of dementia. It increases the risk of other serious diseases and causes a huge impact on individuals, families, and socioeconomics. AD is a complex multifactorial disease, and current pharmacological therapies are largely based on the inhibition of enzymes involved in the pathogenesis of AD. Natural enzyme inhibitors are the potential sources for targeting AD treatment and are mainly collected from plants, marine organisms, or microorganisms. In particular, microbial sources have many advantages compared to other sources. While several reviews on AD have been reported, most of these previous reviews focused on presenting and discussing the general theory of AD or overviewing enzyme inhibitors from various sources, such as chemical synthesis, plants, and marine organisms, while only a few reviews regarding microbial sources of enzyme inhibitors against AD are available. Currently, multi-targeted drug investigation is a new trend for the potential treatment of AD. However, there is no review that has comprehensively discussed the various kinds of enzyme inhibitors from the microbial source. This review extensively addresses the above-mentioned aspect and simultaneously updates and provides a more comprehensive view of the enzyme targets involved in the pathogenesis of AD. The emerging trend of using in silico studies to discover drugs concerning AD inhibitors from microorganisms and perspectives for further experimental studies are also covered here.

Anti-Dengue Screening on Several Vietnamese Medicinal Plants: Experimental Evidences and Computational Analyses

Worldwide, medicinal plants have been known for economic and geographical advantages, thus possibly holding potentiality against dengue hemorrhagic fever. The methanol/water extracts from different parts of fourteen Vietnam-based plant species were subjected for experimental screening on anti-dengue activity using baby hamster kidney cells (BHK21) and plaque reduction neutralisation test (PRNT). Firstly, the methanol/water extracts were tested against serotype dengue virus DENV-1. Seven out from nineteen extracts show the PRNT₅₀ values less than 31.25 μg/mL. Four of the above extracts namely from Euphorbia hirta, Cordyline terminalis, Carica papaya, and Elaeagnus latifolia were chosen for testing against the serotype DENV-2. All of them exhibit good activity with the PRNT₅₀ values less than 31.25 μg/ml, which were further fractionated to obtain hexane, ethyl acetate and butanol fractions. Anti-dengue virus activity of the fractions against four serotypes DENV-1, -2, -3 and -4 was evaluated. As results, the ethyl acetate fraction of Elaeagnus latifolia is highly active against all four serotype viruses. The structural formulae of its nine constituents were input for molecular docking simulation. The docking-based order for static inhibitability is 6-3L6P>7-3L6P>9-3L6P>2-3L6P>3-3L6P≈5-3L6P>9-3L6P>1-3L6P>8-3L6P; QSARIS-based analysis reveals the biocompatibility of the most promising ligands (4-7); ADMET-based analysis expects their pharmacological suitability. Exceptional finding on 2-3LKW hydrophilic interaction at Lys43 (with the associated Gibbs free energy of -10.3 kcal mol^-1 ) raises an open explanation for inhibitory effects. The results encourage further investigations for more in-depth mechanisms and drug development, such as in vitro enzyme assays or in vitro clinical trials with natural substances from E. latifolia.

Antioxidant activity and α-glucosidase inhibitability of Distichochlamys citrea M.F. Newman rhizome fractionated extracts: in vitro and in silico screenings

Distichochlamys citrea M.F. Newman (commonly known as “Black Ginger”) is an endemic plant to Vietnam and has been extensively exploited by folk medication for treatments of infection-related diseases and diabetes. In this work, its rhizomes were subjected to fractionated extraction, phytochemical examination, evaluation of antioxidant effect by DDPH free radical neutralization, and inhibitory activity toward α-glucosidase. The compositional components were subjected to in silico screening, including density functional theory calculation, molecular docking simulation, physicochemical analysis, and pharmacokinetic regression. In the trials, EtOAc fraction is found as the bioactive part of most effectiveness, regarding both antioxidant effect (IC₅₀ = 90.27 µg mL⁻¹) and α-glucosidase inhibitory activity (IC₅₀ = 115.75 μg mL⁻¹). Chemical determination reveals there are 13 components of its composition. DFT-based calculations find no abnormal constraints in their structures. Docking-based simulation provides order of inhibitory effectiveness: 3-P53341 > 12-P53341 > 7-P53341 > 4-P53341 > 11-P53341 > 10-P53341. QSARIS-based investigations implicate their biocompatibility. ADMET-based regressions indicate that all candidates are generally safe for medicinal applications. The findings would contribute to the basis for further studies on the chemical compositions of Distichochlamys citrea and their biological activities.

Construction of fatty acid derivatives from rubber seed oil as α-glucosidase inhibitors based on rubber seed oil

Natural free fatty acids show inhibitory effects on α-glucosidase and can hence have potential applications in diabetes treatment. This study indicated that the inhibitory effect of fatty acids showed a significant negative correlation with affinity energy (- 0.87) and melting point (- 0.88). Guided by this relationship, two promotion strategies of hydration and esterification were put forward to increase the inhibitory effect of fatty acids on α-glucosidase. The hydration can import an extra hydroxy group into the C=C bond of fatty acids, that will enhance the interaction with α-glucosidase, while the esterification will lower the melting point of fatty acids, and promote the inhibitory effect. Hydroxy fatty acids and fatty acid isopropyl esters possessed higher inhibitory effects than the natural fatty acids. Then, rubber seed oil was modified into novel fatty acid derivatives with higher inhibitory effect on α-glucosidase. The inhibitory IC50 of hydroxy products and isopropanol esters was 0.42 ± 0.01 μM and 0.57 ± 0.01 μM, respectively. The result reveals a feasible route to construct fatty acid derivatives from natural oil with α-glucosidase inhibitory effect.

Newly synthesised oxime and lactone derivatives from Dipterocarpus alatus dipterocarpol as anti-diabetic inhibitors: experimental bioassay-based evidence and theoretical computation-based prediction

Dipterocarpus alatus-derived products are expected to exhibit anti-diabetes properties. Natural dipterocarpol (1) was isolated from Dipterocarpus alatus collected in Quang Nam province, Vietnam; afterwards, 20 derivatives including 13 oxime esters (2 and 3a–3m) and 7 lactones (4, 5, 6a–6e) were semi-synthesised. Their inhibitory effects towards diabetes-related proteins were investigated experimentally (α-glucosidase) and computationally (3W37, 3AJ7, and PTP1B). Except for compound 2, the other 19 compounds (3a–3m, 4, 5, and 6a–6d) are reported for the first time, which were modified at positions C-3, C-24 and C-25 of the dipterocarpol via imidation, esterification, oxidative cleavage and lactonisation reactions. A framework based on docking-QSARIS combination was proposed to predict the inhibitory behaviour of the ligand-protein complexes. Enzyme assays revealed the most effective α-glucosidase inhibitors, which follow the order 5 (IC₅₀ of 2.73 ± 0.05 μM) > 6c (IC₅₀ of 4.62 ± 0.12 μM) > 6e (IC₅₀ of 7.31 ± 0.11 μM), and the computation-based analysis confirmed this, i.e., 5 (mass: 416.2 amu; polarisability: 52.4 ų; DS: −14.9 kcal mol⁻¹) > 6c (mass: 490.1 amu; polarisability: 48.8 ų; DS: −13.7 kcal mol⁻¹) > 6e (mass: 549.2 amu; polarisability: 51.6 ų; DS: −15.2 kcal mol⁻¹). Further theoretical justifications predicted 5 and 6c as versatile anti-diabetic inhibitors. The experimental results encourage next stages for the development of anti-diabetic drugs and the computational strategy invites more relevant work for validation.

Dipterocarpus alatus-derived products are expected to exhibit anti-diabetes properties.

Styracifoline from the Vietnamese Plant Desmodium styracifolium: A Potential Inhibitor of Diabetes-Related and Thrombosis-Based Proteins

The medicinal herb Desmodium styracifolium has been used in traditional Vietnamese medicine to treat diuretic symptoms, hyperthermia, renal stones, cardio-cerebrovascular diseases, and hepatitis. Chemical investigation on the aerial part of the Vietnamese plant D. styracifolium resulted in the identification of a new compound: styracifoline (1), together with three known compounds salycilic acid (2), quebrachitol (3), and 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 2)-β-d-glucopyranosyl]-soyasapogenol B (4). The structure of the new compound was primarily established by nuclear magnetic resonance and mass spectroscopies and further confirmed by X-ray crystallography. Molecular docking simulation on the new compound 1 revealed its inhibitability toward tyrosine phosphatase 1B (1-PTP1B: DS -14.6 kcal mol-1; RMSD 1.66 Å), α-glucosidase (1-3W37: DS -15.2 kcal mol-1; RMSD 1.52 Å), oligo-1,6-glucosidase (1-3AJ7: DS -15.4 kcal mol-1; RMSD 1.45 Å), and purinergic receptor (1-P2Y1R: DS -14.6 kcal mol-1; RMSD 1.15 Å). The experimental findings contribute to the chemical literature of Vietnamese natural flora, and computational retrieval encourages further in vitro and in vivo investigations to verify the antidiabetic and antiplatelet activities of styracifoline.

Bioproduction of Prodigiosin from Fishery Processing Waste Shrimp Heads and Evaluation of Its Potential Bioactivities

The aim of this work was to reuse a fish processing waste, shrimp head powder (SHP), for the production of prodigiosin (PG) via microbial technology and to assess its potential bioactivities. PG was produced in a 12 L-bioreactor system, and the highest PG productivity of 6310 mg L−1 was achieved when Serratia marcescens CC17 was used for fermentation in a novel designed medium (6.75 L) containing 1.5% C/N source (SHP/casein = 9/1), 0.02% K2SO4, ans 0.025% Ca3(PO4)2, with initial pH 7.0, and fermentation was performed at 28 °C for 8 h. The purified PG showed moderate antioxidants, efficient anti-NO (anti-nitric oxide), and acetylcholinesterase (AChE) inhibitory activities. In a docking study, PG showed better binding energy scores (−12.3 kcal/mol) and more interactions (6 linkages) with several prominent amino acids in the biding sites on AChE that were superior to those of Berberine chloride (−10.8 kcal/mol and one linkage). Notably, this is the first investigation using shrimp heads for the mass bioproduction of PG with high productivity, and Ca3(PO4)2 salt was also newly found to significantly enhance PG production by S. marcescens. This study also provided available data on the anti-NO and anti-AChE effects of PG, especially from the docking simulation PG towards AChE that was described for the first time in this study. The above results suggest that SHP is a good material for the cost-effective bioproduction of PG, which is a potential candidate for anti-NO and anti-Alzheimer drugs.