Toxicity assessment of 3-O-[6-deoxy-3-O-methyl-ß-D-allopyranosyl-(1 → 4)-ß-D-oleandropyranosyl]-17ß-marsdenin isolated from Gongronema latifolium leaf on selected brain and kidney function indices in mice.

The safety of bioactive compounds, especially those isolated from medicinal plants, is a major concern for health authorities, pharmaceutical industries, and the public. Of recent, anti-tumor pregnane glycosides were isolated from Gongronema latifolium leaf, of which the toxicity of one, 3-O-[6-deoxy-3-O-methyl-ß-D-allopyranosyl-(1 â†’ 4)-ß-D-oleandropyranosyl]-17ß-marsdenin (3DMAOM), has not been evaluated. This study, therefore, evaluated the effects of 3DMAOM on selected brain and kidney function indices in mice. Female Swiss albino mice were randomly administered 5% dimethyl sulphoxide and different doses of 3DMAOM (0.5, 1, 2, and 4 mg/kg body weight) for fourteen (14) days, and their blood, brains, and kidneys were collected for biochemical analysis. There was no significant alteration in the activities of alkaline phosphatase (ALP), acetylcholinesterase, creatine kinase, Na+/K+-ATPase, Ca2+/Mg2+-ATPase, and Mg2+-ATPase in the brain of the treated groups compared to control. Also, no significant changes in the activities of ALP, gamma-glutamyltransferase, Na+/K+-ATPase, Ca2+/Mg2+-ATPase, and Mg2+-ATPase in the kidney of the treated groups compared to control. The plasma concentrations of Na+, K+, Cl-, PO43-, creatinine, and urea of mice were not significantly altered at all doses of the 3DMAOM compared to controls. However, the plasma concentration of Ca2+ was significantly reduced (p < 0.05) at all doses of the 3DMAOM, and the plasma concentration of uric acid was significantly reduced (p < 0.05) at 2 mg/kg body weight of the 3DMAOM compared to controls. These findings suggest that 3DMAOM isolated from Gongronema latifolium leaf may not adversely affect brain function but may affect calcium ion homeostasis in subjects.

Exploring beetroot (Beta vulgaris L.) for diabetes mellitus and Alzheimer's disease dual therapy: in vitro and computational studies.

This study explored the flavonoid-rich extract of beetroot (Beta vulgaris L.) for type 2 diabetes mellitus (T2D) and Alzheimer's disease (AD) dual therapy by using in vitro and molecular simulation studies. Flavonoid-rich extracts of B. vulgaris fruit were evaluated for their antidiabetic and anti-alzheimic activities. Molecular docking and dynamic simulation were performed to identify potential bioactive flavonoids with dual therapeutic effects on T2D and AD. Flavonoid-rich extracts of B. vulgaris fruit (IC50 = 73.062 ± 0.480 µg mL-1) had moderate activity against α-amylase compared to the standard acarbose (IC50 = 27.104 ± 0.270 µg mL-1). Compared with acarbose, flavonoid-rich extracts of B. vulgaris fruit had appreciable activity against α-glucosidase (IC50 = 17.389 ± 0.436 µg mL-1) (IC50 = 37.564 ± 0.620 µg mL-1). For AChE inhibition, flavonoid-rich extracts of B. vulgaris fruit exhibited (p < 0.0001) inhibitory activity (IC50 = 723.260 ± 5.466 µg mL-1), albeit weaker than that of the standard control, galantamine (IC50 = 27.950 ± 0.122 µg mL-1). Similarly, flavonoid-rich extracts of B. vulgaris fruit showed considerable (p < 0.0001) inhibitory effects on BChE (IC50 = 649.112 ± 0.683 µg mL-1). In contrast, galantamine (IC50 = 23.126 ± 0.683 µg mL-1) is more potent than the extracts of B. vulgaris fruit. Monoamine oxidase (MAO) activity increased in FeSO4-induced brain damage. In contrast, flavonoid-rich extracts of B. vulgaris fruit protected against Fe2+-mediated brain damage by suppressing MAO activity in a concentration-dependent manner. HPLC-DAD profiling of the extracts identified quercetrin, apigenin, rutin, myricetin, iso-quercetrin, p-coumaric acid, ferulic acid, caffeic acid, and gallic acid. Molecular docking studies revealed quercetrin, apigenin, rutin, iso-queretrin, and myricetin were the top docked bioactive flavonoids against the five top target proteins (α-amylase, α-glucosidase AchE, BchE, and MAO). Molecular dynamic simulations revealed that the complexes formed remained stable over the course of the simulation. Collectively, the findings support the prospect of flavonoid-rich extracts of B. vulgaris root functioning as a dual therapy for T2D and AD.

Profiling the antidiabetic potential of GC-MS compounds identified from the methanolic extract of Spilanthes filicaulis: experimental and computational insight.

This study examines the nutritional composition, phytochemical profiling, and antioxidant, antidiabetic, and anti-inflammatory potential of a methanolic extract of Spilanthes filicaulis leaves (MESFL) via in vitro, ex vivo, and in silico studies. In vitro antioxidant, antidiabetic, and anti-inflammatory activities were examined. In the ex vivo study, liver tissues were subjected to FeSO4-induced oxidative damage and treated with varying concentrations of MESFL. MESFL contains a reasonable amount of nitrogen-free extract, moisture, ash content, crude protein, and fat, with a lesser amount of crude fiber. According to GC-MS analysis, MESFL contains ten compounds, the most abundant of which are 13-octadecenal and Ar-tumerone. In this study, MESFL demonstrated anti-inflammatory activities via membrane stabilizing properties, proteinase inhibition, and inhibition of protein denaturation (IC50 = 72.75 ± 11.06 µg/mL). MESFL also strongly inhibited both α-amylase (IC50 = 307.02 ± 4.25 µg/mL) and α-glucosidase (IC50 = 215.51 ± 0.47 µg/mL) activities. Our findings also showed that FeSO4-induced tissue damage decreased the levels of GSH, SOD, and CAT activities while increasing the levels of MDA. In contrast, treatment with MESFL helped to restore these parameters to near-normal levels, which signifies that MESFL has great potential to address complications from oxidative stress. Furthermore, the in silico interaction of the GCMS-identified phytochemicals with the active sites of α-amylase and α-glucosidase via molecular and ensembled-based docking displayed strong binding affinities of Ar-tumerone and 4-hydroxy-3-methylacetophenone to α-amylase and α-glucosidase, respectively. Taken together, the biological activities of MESFL might be a result of the effects of these secondary metabolites.Communicated by Ramaswamy H. Sarma.

Elemental evaluation, nutritional analysis, GC-MS analysis and ameliorative effects of Artocarpus communis J.R.Forst. & G.Forst. seeds' phytoconstituents on metabolic syndrome via in silico approach.

The nutritional as well as beneficial effects of the Artocarpus communis seed on metabolic syndrome complications have not been studied. In this research, the aim was to investigate the nutritional composition and beneficial effects of Artocarpus communis seeds' phytoconstituents on the p53 core, fat mass and obesity-associated (FTO) protein and cytochrome P450 CYP11A1 domains. The elements and phytochemicals in the seed were determined through atomic absorption spectroscopy assay and gas chromatography-mass spectrometry (GC-MS) analysis, respectively. Also, the compounds detected were docked to the p53 core, FTO protein and cytochrome P450 CYP11A1 domains protein. Artocarpus communis seed contains sodium (7.824 ± 0.0134 ppm), magnesium (10.187 ± 0.0239 ppm) and iron (1.924 ± 0.0017), while zinc and cadmium were undetected. Phenolics and flavonoids were the most abundant phytochemicals in the seed. Phytoconstituents, such as pentadecanoic acid, hexadecanoic acid and methyl ester, possessing different therapeutic effects were identified via GC-MS analysis. In A. communis seed, 3-methyl-4-nitro-5-(1-pyrazolyl) pyrazole and phenanthrene were able to bind more peculiarly and specifically to the p53 core, FTO protein and cytochrome P450 CYP11A1 domains. One of the important processes that were hypothesized for the recovery of metabolic syndrome in affected victims is shown by the molecular dynamics analysis, which shows that the binding of these chemicals to the targeted structure stabilized the proteins. Therefore, Artocarpus communis seeds could be a new strategy for the management of metabolic syndrome.Communicated by Ramaswamy H. Sarma.

Therapeutic Study of Cinnamic Acid Derivative for Oxidative Stress Ablation: The Computational and Experimental Answers.

This study aimed to examine the therapeutic activity of the cinnamic acid derivative KAD-7 (N'-(2,4-dichlorobenzylidene)-3-(4-methoxyphenyl) acrylohydrazide) on Fe2+-induced oxidative hepatic injury via experimental and computational models. In addition, the role of ATPase and ectonucleoside triphosphate diphosphohydrolase (ENTPDase) in the coordination of cellular signals is speculated upon to proffer suitable therapeutics for metabolic stress disorder upon their inhibition. While we know little about therapeutics with flexible dual inhibitors for these protein targets, this study was designed to screen KAD-7's (N'-(2,4-dichlorobenzylidene)-3-(4-methoxyphenyl) acrylohydrazide) inhibitory potential for both protein targets. We induced oxidative hepatic damage via the incubation of hepatic tissue supernatant with 0.1 mM FeSO4 for 30 min at 37 °C. We achieved the treatment by incubating the hepatic tissues with KAD-7 under the same conditions. The catalase (CAT), glutathione (GSH), malondialdehyde (MDA), ATPase, and ENTPDase activity were all measured in the tissues. We predicted how the drug candidate would work against ATPase and ENTPDase targets using molecular methods. When hepatic injury was induced, there was a significant decrease in the levels of the GSH, CAT, and ENTPDase (p < 0.05) activities. In contrast, we found a noticeable rise in the MDA levels and ATPase activity. KAD-7 therapy resulted in lower levels of these activities overall (p < 0.05), as compared to the control levels. We found the compound to have a strong affinity for ATPase (-7.1 kcal/mol) and ENTPDase (-7.4 kcal/mol), and a better chemical reactivity than quercetin. It also met all drug-likeness parameters. Our study shows that KAD-7 can protect the liver from damage caused by FeSO4 by reducing oxidative stress and purinergic actions. Our studies indicate that KAD-7 could be developed as a therapeutic option since it can flexibly inhibit both ATPase and ENTPDase.

Phytochemical analysis, in vitro and in silico effects from Alstonia boonei De Wild stem bark on selected digestive enzymes and adipogenesis in 3T3-L1 preadipocytes.

BACKGROUND: Obesity is a global health issue arising from the unhealthy accumulation of fat. Medicinal plants such as Alstonia boonei stem bark has been reported to possess body weight reducing effect in obese rats. Thus, this study sought to investigate the in vitro and in silico effects of fractions from Alstonia boonei stem bark on selected obesity-related digestive enzymes and adipogenesis in 3T3-L1 preadipocytes. METHOD: Two fractions were prepared from A. boonei: crude alkaloid fraction (CAF) and crude saponin fraction (CSF), and their phytochemical compounds were profiled using Liquid chromatography with tandem mass spectrometry (LCMS/MS). The fractions were assayed for inhibitory activity against lipase, α-amylase and α-glucosidase, likewise their antiadipogenic effect in 3T3-L1 adipocytes. The binding properties with the 3 enzymes were also assessed using in silico tools. RESULTS: Eleven alkaloids and six saponin phytochemical compounds were identified in the CAF and CSF using LCMS/MS. The CAF and CSF revealed good inhibitory activity against pancreatic lipase enzyme, but weak and good activity against amylase respectively while only CSF had inhibitory activity against α-glucosidase. Both fractions showed antiadipogenic effect in the clearance of adipocytes and reduction of lipid content in 3T3-L1 adipocytes. The LCMS/MS identified compounds (41) from both fractions demonstrated good binding properties with the 3 enzymes, with at least the top ten compounds having higher binding energies than the reference inhibitors (acarbose and orlistat). The best two docked compounds to the three enzymes were firmly anchored in the substrate binding pockets of the enzymes. In a similar binding pattern as the reference acarbose, Estradiol-17-phenylpropionate (-11.0 kcal/mol) and 3α-O-trans-Feruloyl-2 α -hydroxy-12-ursen-28-oic acid (-10.0 kcal/mol) interacted with Asp197 a catalytic nucleophile of pancreatic amylase. Estradiol-17-phenylpropionate (-10.8 kcal/mol) and 10-Hydroxyyohimbine (-10.4 kcal/mol) interacted with the catalytic triad (Ser152-Asp176-His263) of pancreatic lipase while Estradiol-17-phenylpropionate (-10.1 kcal/mol) and 10-Hydroxyyohimbine (-9.9 kcal/mol) interacted with Asp616 and Asp518 the acid/base and nucleophilic residues of modelled α-glucosidase. CONCLUSION: The antiobesity effect of A. boonei was displayed by both the alkaloid and saponin fractions of the plant via inhibition of pancreatic lipase and adipogenesis.

Atomistic simulations suggest dietary flavonoids from Beta vulgaris (beet) as promising inhibitors of human angiotensin-converting enzyme and 2-alpha-adrenergic receptors in hypertension.

Motivation: Beta vulgaris (beet) is extensively reported for its antihypertensive activity. However, the mechanismunderpinning its antihypertensive activity is not well understood. In this study, we evaluated the in silico interactionsof 70 compounds derived from beta vulgaris against the active sites of angiotensin-converting enzyme (ACE) and alpha-adrenergic receptor (AR). Results: Structure-based virtual screening against angiotensin-converting enzyme revealed that, Cochliophilin A (-9.0 Kcal/mol), Miraxanthin (-8.3 Kcal/mol), and quercimeritrin (-9.7 Kcal/mol) had lower docking scores than the reference lisinopril (-7.9 Kcal/mol). These compounds exhibited dual binding tendency as they also ranked top compounds upon screening against adrenergic receptor. The thermodynamic parameters computed from the resulting trajectories obtained from the 100 ns full atomistic molecular dynamics simulation revealed structural stability and conformational flexibility of the ligand-receptor complexes as indicated by the RMSD, RMSF, RoG, SASA, and H-bond calculations. The molecular mechanics with generalized Born and surface area solvation binding energy calculations revealed that the proteins exhibit considerable binding energy with the phytochemicals in a dynamic environment. Furthermore, the hit compounds possess good physicochemical properties and drug-likeness. Overall, cochliophilin and quercimeritrin are promising dual-target directed flavonoids from Beta vulgaris; and are suggested for further experimental and preclinical evaluation. Availability and implementation: All data was provided in the manuscript.

Antispasmodic Effect of Alstonia boonei De Wild. and Its Constituents: Ex Vivo and In Silico Approaches.

BACKGROUND: Alstonia boonei, belonging to the family Apocynaceae, is one of the best-known medicinal plants in Africa and Asia. Stem back preparations are traditionally used as muscle relaxants. This study investigated the antispasmodic properties of Alstonia boonei Stem back and its constituents. METHOD: The freeze-dried aqueous Stem back extract of A. boonei, as well as dichloromethane (DCM), ethyl acetate, and aqueous fractions, were evaluated for their antispasmodic effect via the ex vivo method. Two compounds were isolated from the DCM fraction using chromatographic techniques, and their antispasmodic activity was evaluated. An in silico study was conducted by evaluating the interaction of isolated compounds with human PPARgamma-LBD and human carbonic anhydrase isozyme. RESULTS: The Stem back crude extract, DCM, ethyl acetate, and aqueous fractions showed antispasmodic activity on high-potassium-induced (K+ 80 mM) contractions on isolated rat ileum with IC50 values of 0.03 ± 0.20, 0.02 ± 0.05, 0.03 ± 0.14, and 0.90 ± 0.06 mg/mL, respectively. The isolated compounds from the DCM fraction were ß-amyrin and boonein, with only boonein exhibiting antispasmodic activity on both high-potassium-induced (IC50 = 0.09 ± 0.01 µg/mL) and spontaneous (0.29 ± 0.05 µg/mL) contractions. However, ß-amyrin had a stronger interaction with the two proteins during the simulation. CONCLUSION: The isolated compounds boonein and ß-amyrin could serve as starting materials for the development of antispasmodic drugs.

GC-MS chemical profiling, antioxidant, anti-diabetic, and anti-inflammatory activities of ethyl acetate fraction of Spilanthes filicaulis (Schumach. and Thonn.) C.D. Adams leaves: experimental and computational studies.

Introduction: This study aimed to investigate the chemical profile of GC-MS, antioxidant, anti-diabetic, and anti-inflammatory activities of the ethyl acetate fraction of Spilanthes filicaulis leaves (EFSFL) via experimental and computational studies. Methods: After inducing oxidative damage with FeSO4, we treated the tissues with different concentrations of EFSFL. An in-vitro analysis of EFSFL was carried out to determine its potential for antioxidant, anti-diabetic, and anti-inflammatory activities. We also measured the levels of CAT, SOD, GSH, and MDA. Results and discussion: EFSFL exhibited anti-inflammatory properties through membrane stabilizing properties (IC50 = 572.79 µg/ml), proteinase inhibition (IC50 = 319.90 µg/ml), and inhibition of protein denaturation (IC50 = 409.88 µg/ml). Furthermore, EFSFL inhibited α-amylase (IC50 = 169.77 µg/ml), α-glucosidase (IC50 = 293.12 µg/ml) and DPP-IV (IC50 = 380.94 µg/ml) activities, respectively. Our results indicated that induction of tissue damage reduced the levels of GSH, SOD, and CAT activities, and increased MDA levels. However, EFSFL treatment restores these levels to near normal. GC-MS profiling shows that EFSFL contains 13 compounds, with piperine being the most abundant. In silico interaction of the phytoconstituents using molecular and ensembled-based docking revealed strong binding tendencies of two hit compounds to DPP IV (alpha-caryophyllene and piperine with a binding affinity of -7.8 and -7.8 Kcal/mol), α-glucosidase (alpha-caryophyllene and piperine with a binding affinity of -9.6 and -8.9 Kcal/mol), and to α-amylase (piperine and Benzocycloheptano[2,3,4-I,j]isoquinoline, 4,5,6,6a-tetrahydro-1,9-dihydroxy-2,10-dimethoxy-5-methyl with a binding affinity of -7.8 and -7.9 Kcal/mol), respectively. These compounds also presented druggable properties with favorable ADMET. Conclusively, the antioxidant, antidiabetic, and anti-inflammatory activities of EFSFL could be due to the presence of secondary metabolites.

Identification of potential inhibitors of cholinergic and ß-secretase enzymes from phytochemicals derived from Gongronema latifolium Benth leaf: an integrated computational analysis.

Neurodegenerative disorders (NDDs) are associated with increased activities of the brain acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and ß-secretase enzyme (BACE1). Inhibition of these enzymes affords therapeutic option for managing NDDs such as Alzheimer's disease (AD) and Parkinson's disease (PD). Although, Gongronema latifolium Benth (GL) has been widely documented in ethnopharmacological and scientific reports for the management of NDDs, there is paucity of information on its underlying mechanism and neurotherapeutic constituents. Herein, 152 previously reported Gongronema latifolium derived-phytochemicals (GLDP) were screened against hAChE, hBChE and hBACE-1 using molecular docking, molecular dynamics (MD) simulations, free energy of binding calculations and cluster analysis. The result of the computational analysis identified silymarin, alpha-amyrin and teraxeron with the highest binding energies (-12.3, -11.2, -10.5 Kcal/mol) for hAChE, hBChE and hBACE-1 respectively as compared with those of the reference inhibitors (-12.3, -9.8 and - 9.4 for donepezil, propidium and aminoquinoline compound respectively). These best docked phytochemicals were found to be orientated in the hydrophobic gorge where they interacted with the choline-binding pocket in the A-site and P-site of the cholinesterase and subsites S1, S3, S3' and flip (67-75) residues of the pocket of the BACE-1. The best docked phytochemicals complexed with the target proteins were stable in a 100 ns molecular dynamic simulation. The interactions with the catalytic residues were preserved during the simulation as observed from the MMGBSA decomposition and cluster analyses. The presence of these phytocompounds most notably silymarin, which demonstrated dual high binding tendencies to both cholinesterases, were identified as potential neurotherapeutics subject to further investigation.

Evaluation of Antimalarial Activity of Ethanolic Extract of Annona muricata L.: An in vivo and an in silico Approach.

In Nigeria, Annona muricata L. has been used to treat a variety of ailments. The mechanism of the antimalarial activity of ethanolic leaf extract of Annona muricata (EEAML) was investigated using both an in vivo and an in silico approach. The experimental mice were divided into five groups: A-F. The mice in groups B-F were inoculated with Plasmodium berghei NK-65 and treated accordingly. Groups A and B are the negative and positive controls (infected and untreated), respectively. Group C received 10 mg/kg chloroquine (standard drug), whereas groups D-F received 100, 200, and 300 mg/kg body weight of the extract orally respectively. The mice were euthanized eight days after infection, and their liver and blood were collected and used in biochemical tests. Molecular docking was performed using the extract's HPLC compounds and Plasmodium falciparum proteins. In the suppressive, prophylactic, and curative tests, there was a significant decrease (p < 0.05) in parasitemia levels in groups treated with the extract compared to the positive control and standard drug. When compared to the positive control, there was a significant (p < 0.05) reduction in liver MDA, total cholesterol, and total triglyceride levels. The binding energies of luteolin and apigenin-pfprotein complexes were significantly (p < 0.05) higher compared to their respective references. The anti-plasmodial activity of the extract may result from its hypolipidemic effect, which deprives the parasite of essential lipid molecules needed for parasite growth, as well as from the inhibitory effects of apigenin and luteolin on specific proteins required for the Plasmodium metabolic pathway.

In silico prediction of the possible antidiabetic and anti-inflammatory targets of Nymphaea lotus-derived phytochemicals and mechanistic insights by molecular dynamics simulations.

Nymphaea lotus is used traditionally for the treatment of diabetes and its complications. However, the mode of action and the likely bioactive phytochemicals involved are not yet fully explored. GC-MS analysis was employed to identify the inherent compounds in N. lotus leaves. To gain an insight into the antidiabetic mode of action of this plant, the identified phytochemicals were subjected to computational studies against four molecular targets of diabetes, dipeptidyl peptidase-4, glycogen synthase kinase 3, NADPH oxidase (NOX), sodium-glucose co-transporter-2, and one target of inflammation, cyclooxygenase-2. Compounds with notable binding affinity were subjected to druggability test. Results from molecular docking showed that seven of the compounds investigated exhibited druggability properties and had outstanding binding affinity values for these targets relative to values obtained for the respective standards of each of the targets. Analysis of the MD trajectories from a 100 ns atomistic run shows that the integrities of the complex systems were more stable and preserved throughout the simulation than the unbound protein. These results indicated that the antidiabetic and anti-inflammatory effects of these compounds might be via the inhibition of these targets, laying the foundation for further studies, such as in vitro and in vivo studies to fully validate the anti-diabetic agents from this plant.Communicated by Ramaswamy H. Sarma.

Nutritional benefits, ethnomedicinal uses, phytochemistry, pharmacological properties and toxicity of Spondias mombin Linn: a comprehensive review.

OBJECTIVES: Spondias mombin is traditionally used as an herbal medicine for several human diseases and ailments in the tropical regions across the globe including the African countries. This study aimed to provide comprehensive information on nutritional benefits, ethnomedicinal uses, phytochemical constituents, pharmacological properties and toxicology study of S. mombin. Information was gathered from documented literatures in scientific database. KEY FINDINGS: The study revealed that S. mombin has nutritional values; with the leaf, fruit, flower, seed, and stem bark possessing a wide range of ethnomedicinal uses across several regions, with documented pharmacological properties. S. mombin has a frequent rate of ethnomedicinal utility in cases of abortion, constipation, fever, gonorrhea, postpartum hemorrhage, digestive pain, diarrhoea, dysentery and wounds. Ethnopharmacological studies showed that crude extracts and chemical compounds from S. mombin manifested in vivo and in vitro biological and pharmacological activities. About 102 isolated compounds from the leaf, fruit, or stem bark of S. mombin have been reported. SUMMARY: Overall, S. mombin has several nutritive and ethnomedicinal benefits owing to its chemical constituents, which are linkable to the several pharmacological activities. There remains however, the need for dosage intake caution, upon the advice of medical professionals.

Identification of promising multi-targeting inhibitors of obesity from Vernonia amygdalina through computational analysis.

Vernonia amygdalina, a widely consumed West African food herb, can be a boon in the discovery of safe anti-obesity agents given the extensive reports on its anti-obesity and antidiabetic potentials. The main aim of this study was to screen 78 Vernonia-Derived Phytocompounds (VDPs) against the active site regions of Human Pancreatic Lipase (HPL), Human Pancreatic Amylase and Human Glucosidase (HG) as drug targets associated with obesity in silico. Structure-based virtual screening helped to identify Luteolin 7-O-glucuronoside and Andrographidoid D2 as hit compounds with dual targeting tendency towards the HPL and HG. Analysis of the molecular dynamic simulation trajectory files of the ligand-receptor complexes as computed from the thermodynamic parameters plots showed not only increased flexibility and greater interaction potential of the active site residues of the receptor towards the VDPs as indicated by the root mean square fluctuation but also higher stability as indicated by the root mean square deviation, radius of gyration and number of hydrogen bonds. The cluster analysis further showed that the interactions with important residues were preserved in the dynamic environment. These observations were further verified from Molecular Mechanics Generalized Born Surface Area Analysis, which also showed that residual contributions to the binding free energies were mainly from catalytic residues at the active sites of the enzymes. The hit compounds also feature desirable physicochemical properties and drug-likeness. This study provides in silico evidence for the inhibitory potential of phytochemicals from Vernonia amygdalina against two target enzymes in obesity.

Computational studies on the cholinesterase, beta-secretase 1 (BACE1) and monoamine oxidase (MAO) inhibitory activities of endophytes-derived compounds: towards discovery of novel neurotherapeutics.

Cholinesterases, beta-secretase 1 (BACE1) and monoamine oxidase (MAO) are significant in the etiology of neurodegenerative diseases. Inhibition of these enzymes is therefore a major strategy for the development of neurotherapeutics. Even though, this strategy has birthed some approved synthetic drugs, they are characterized by adverse effects. It is therefore, imperative to explore promising alternatives. Consequently, we assessed the inhibitory activities of some endophytes-derived compounds against selected targets towards discovery of novel neurotherapeutics. Standard inhibitors and 83 endophytes-derived compounds were docked against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), BACE 1 and MAO using AutodockVina while the molecular interactions between the selected targets and the compounds with notable binding affinity were viewed through Discovery Studio Visualizer. Druglikeness and Absorption-Distribution-Metabolism-Excretion-Toxicity (ADMET) and blood brain barrier (BBB) properties of the top 4 compounds were evaluated using the Swiss online ADME web tool and OSIRIS server; ligands-enzymes complex stability was assessed through molecular dynamics (MD) simulation. From the 83 compounds, asperflavin, ascomfurans C, camptothecine and corynesidone A exhibited remarkable inhibitory activity against all the four target enzymes compared to the respective standard inhibitors. However, only corynesidone A could transverse the BBB and predicted to be safe. MD simulation of the unbound and complexed enzymes with corynesidone A showed that the complexes were stable throughout the simulation time. Given the exceptional inhibitory activity of endophytes-derived corynesidone A against the four selected targets, its ability to permeate the BBB, excellent drugability properties as well as its stability when complexed with the enzymes, it is a good candidate for further studies towards development of new neurotherapeutics.Communicated by Ramaswamy H. Sarma.

Antimalarial phytochemicals as potential inhibitors of SARS-CoV-2 guanine N7-methyltransferase (nsp 14): an integrated computational approach.

The inhibition of capping enzymes such as guanine-N7-methyltransferase (GMT) is an attractive target for regulating viral replication, transcription, virulence, and pathogenesis. Thus, compounds that target the Severe Acute Respiratory Syndrome Corona Virus 2 GMT (S2GMT) will enhance drug development against COVID-19. In this study, an in-house library of 249 phytochemicals from African medicinal plants was screened using computational approaches including homology modeling, molecular docking, molecular dynamic simulations, binding free energy calculations based on molecular mechanics/Poisson-Boltzmann surface area (MMPBSA) and Absorption-Distribution-Metabolism-Excretion-Toxicity (ADMET) analysis for inhibitors of S2GMT. The top-ten ranked phytochemicals (TTRP) obtained from the docking analysis to S2GMT were further docked to SARS-COV N7-MTase. Among the TTRP, the top-four ranked phytocompounds (TFRP) viz: 3 alkaloids (Isocryptolepine, 10'-Hydroxyusambarensine and Isostrychnopentamine) and a flavonoid (Mulberrofuran F) interacted strongly with critical catalytic residues whose interference either reduce or completely abolish N7-MTase activity, indicating their potential as capping machinery disruptors. The interactions of TFRP with the catalytic residues of S2GMT were preserved in a 100 ns simulated dynamic environment, thereby, demonstrating high degree of structural stability. The MMPBSA binding free energy calculations corroborated the docking scores with biscryptolepine having the highest binding free energy to S2GMT. The TFRP showed favourable drug-likeness and ADMET properties over a wide range of molecular descriptors. Therefore, the TFRP can be further explored as potential S2GMT inhibitors in in vitro and in vivo experiments.Communicated by Ramaswamy H. Sarma.

Inhibition mechanism of alpha-amylase, a diabetes target, by a steroidal pregnane and pregnane glycosides derived from Gongronema latifolium Benth.

Alpha-amylase is widely exploited as a drug target for preventing postprandial hyperglycemia in diabetes and other metabolic diseases. Inhibition of this enzyme by plant-derived pregnanes is not fully understood. Herein, we used in vitro, in silico, and in vivo studies to provide further insights into the alpha-amylase inhibitory potential of selected pregnane-rich chromatographic fractions and four steroidal pregnane phytochemicals (SPPs), viz: marsectohexol (P1), 3-O-[6-deoxy-3-O-methyl-ß-D-allopyranosyl-(1→14)-ß-D-oleandropyranosyl]-11,12-di-O-tigloyl-17ß-marsdenin (P2), 3-O-[6-deoxy-3-O-methyl-ß-D-allopyranosyl-(1→4)-ß-D-oleandropyranosyl]-17ß-marsdenin (P3), and 3-O-[6-deoxy-3-O-methyl-ß-D-allopyranosyl-(1→4)-ß-D-canaropyranosyl]-17ß-marsdenin (P4) derived from Gongronema latifolium Benth. The results revealed that the SPPs source pregnane-rich chromatographic fractions and the SPPs (P1-P4) exhibited inhibitory potential against porcine pancreatic alpha-amylase in vitro. Compounds P1 and P2 with IC50 values 10.01 and 12.10 µM, respectively, showed greater inhibitory potential than the reference acarbose (IC50 = 13.47 µM). Molecular docking analysis suggests that the SPPs had a strong binding affinity to porcine pancreatic alpha-amylase (PPA), human pancreatic alpha-amylase (HPA), and human salivary alpha-amylase (HSA), interacting with the key active site residues through an array of hydrophobic interactions and hydrogen bonds. The strong interactions of the SPPs with Glu233 and Asp300 residues may disrupt their roles in the acid-base catalytic mechanism and proper orientation of the polymeric substrates, respectively. The interactions with human pancreatic amylase were maintained in a dynamic environment as indicated by the root mean square deviation, radius of gyration, surface accessible surface area, and number of hydrogen bonds computed from the trajectories obtained from a 100-ns molecular dynamics simulation. Key loop regions of HPA that contribute to substrate binding exhibited flexibility and interaction potential toward the compounds as indicated by the root mean square fluctuation. Furthermore, P1 significantly reduced blood glucose levels and area under the curve in albino rats which were orally challenged with starch. Therefore, Gongronema latifolium and its constituent SPPs may be exploited as inhibitors of pancreatic alpha-amylase as an oral policy for impeding postprandial blood glucose rise.

Computer-Aided Identification of Cholinergic and Monoaminergic Inhibitory Flavonoids from Hibiscus sabdariffa L.

BACKGROUND: The reduced levels of acetylcholine and dopamine lead to Alzheimer's disease (AD) and Parkinson's disease PD, respectively, due to the action of cholinesterase and monoamine oxidase B. METHODS: Therapeutic options for AD and PD involve respective cholinergic and monoaminergic inhibitors, and considering the adverse outcomes of cholinergic- and monoaminergic- inhibitory therapeutics, phytoconstituents may be promising alternatives. Reports have shown that different extracts of the calyx of Hibiscus sabdariffa exhibit anticholinesterase and monoamine oxidase B inhibitory properties with the potential to delay and prevent the development of AD and PD. However, there is limited knowledge on the multitarget cholinergic and monoaminergic inhibitory activities of individual compounds in this plant. Computational methods were used to identify the specific compounds responsible for the observed cholinergic and monoaminergic inhibitory activities of the H. sabdariffa calyx extracts. RESULTS: Results confirm that three flavonoids: delphinidin-3-sambubioside, kaempferol-3-O-rutinoside and quercetin-3-rutinoside showed strong binding affinity with acetylcholinesterase, butyrylcholinesterase and monoamine oxidase B while the observed stability of the ligands-enzymes complexes over the MD simulation time suggests their cholinergic and monoaminergic inhibitory properties. CONCLUSION: The three flavonoids may be responsible for the reported anticholinergic and monoaminergic inhibitory potentials of H. sabdariffa extracts and could be enlisted as multi-target inhibitory agents for cholinesterases and monoamine oxidase B.

African derived phytocompounds may interfere with SARS-CoV-2 RNA capping machinery via inhibition of 2'-O-ribose methyltransferase: An in silico perspective.

Despite the ongoing vaccination against the life-threatening COVID-19, there is need for viable therapeutic interventions. The S-adenosyl-l-Methionine (SAM) dependent 2-O'-ribose methyltransferase (2'-O-MTase) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents a therapeutic target against COVID-19 infection. In a bid to profile bioactive principles from natural sources, a custom-made library of 226 phytochemicals from African medicinal plants with especially anti-malarial activity was screened for direct interactions with SARS-CoV-2 2'-O-MTase (S2RMT) using molecular docking and molecular dynamics (MD) simulations as well as binding free energies methods. Based on minimal binding energy lower than sinefungin (a reference methyl-transferase inhibitor) and binding mode analysis at the catalytic site of S2RMT, a list of 26 hit phytocompounds was defined. The interaction of these phytocompounds was compared with the 2'-O-MTase of SARS-CoV and MERS-CoV. Among these compounds, the lead phytocompounds (LPs) viz: mulberrofuran F, 24-methylene cycloartenol, ferulate, 3-benzoylhosloppone and 10-hydroxyusambarensine interacted strongly with the conserved KDKE tetrad within the substrate binding pocket of the 2'-O-MTase of the coronavirus strains which is critical for substrate binding. The thermodynamic parameters analyzed from the MD simulation trajectories of the LPs-S2RMT complexes presented an eminent structural stability and compactness. These LPs demonstrated favorable druggability and in silico ADMET properties over a diverse array of molecular computing descriptors. The LPs show promising prospects in the disruption of S2RMT capping machinery in silico. However, these LPs should be validated via in vitro and in vivo experimental models.