Evaluation of the Antioxidant, Antidiabetic, and Antiplasmodial Activities of Xanthones Isolated from Garcinia forbesii and Their In Silico Studies

Ergostanes from the mushroom Trametes versicolor and their cancer cell inhibition: In vitro and in silico evaluation

In this study, five steroid compounds were isolated from the fruiting bodies mushroom Trametes versicolor. The compounds, 9,19-cyclolanostane-3,29-diol (3), ergosta-7,22-dien-3-acetate (4), and ergosta-8(14),22-dien-3β,5α,6β,7α-tetrol (5), were identified from T. versicolor for the first time. The five compounds were evaluated for their activity against cancer cell lines. Compound 5α,8α-epidioxyergosta-6,22-dien-3β-ol (1) was found to be the most effective against most of the cancer cell lines tested. In silico studies showed that compound 1 has good binding affinities to different cancer targets, namely cyclin-dependent kinase 2 (cdk2), human cyclin-dependent kinase 6 (cdk6), Human Topo IIa ATPase/AMP-PNP, anti-apoptotic protein Bcl-2, and Vegfr-2. It's also druglike based on Lipinski's rule of five and it's ADME/Tox properties. Therefore, compound 1 is a good candidate in the management of cancer. These results further show that T. versicolor is a potential source of drugs or drug leads for cancer treatment.

Development of an Antiviral Medicinal Plant and Natural Product Database (avMpNp Database) from Biodiversity

The construction of compound databases (DB) is a strategy for the rational search of bioactive compounds and drugs for new and old diseases. In order to bring greater impact to drug discovery, we propose the development of a DB of bioactive antiviral compounds. Several research groups have presented evidence of the antiviral activity of medicinal plants and compounds isolated from these plants. We believe that compiling these discoveries in a DB would benefit the scientific research community and increase the speed to discover new potential drugs and medicines. Thus, we present the Antiviral Medicinal Plant and Natural Product DB (avMpNp DB) as an important source for acquiring, organizing, and distributing knowledge related to natural products and antiviral drug discovery. The avMpNp DB contains a series of chemically diverse compounds with drug-like profiles. To test the potential of this DB, SARS-CoV-2 Mpro and PLpro enzymatic inhibition assays were performed for available compounds resulting in IC50 values ranging from 6.308±0.296 to 15.795±0.155 μM. As a perspective, artificial intelligence tools will be added to implement computational predictions, as well as other chemical functionalities that allow data validation.

GC-MS analysis, molecular docking, and pharmacokinetic studies on Dalbergia sissoo barks extracts for compounds with anti-diabetic potential

Diabetes is a metabolic condition defined by abnormal blood sugar levels. Targeting starch-hydrolyzing enzymes and Dipeptidyl Peptidase 4 (DPP-4) expressed on the surface of numerous cells is one of the key strategies to lower the risk of Type-2 diabetes mellitus (T2DM). Dalbergia sissoo Roxb. bark (DSB) extracts have been reported to have anti-diabetic properties. This study intended to scientifically validate use of alcoholic and hydro-alcoholic extracts of DSB for T2DM by conducting preliminary phytochemical investigations, characterising potential phytochemicals using Fourier transform infrared (FT-IR) spectroscopy and Gas chromatography-mass spectrometry (GC-MS) analysis followed by comprehensive in-silico analysis. A qualitative phytochemical evaluation indicated the presence of alkaloids, phenolics, glycosides, conjugated acids and flavonoids. Ethanolic extracts showed highest total phenolic content (TPC) (127.072 ± 14.08031 μg GAE/g dry extract) and total flavonoid content (106.911 ± 5.84516 μg QE /g dry extract). Further FT-IR spectroscopy also revealed typical band values associated with phenol, alcohol, alkene, alkane and conjugated acid functional groups. The GC-MS analysis identified 139 compounds, 18 of which had anti-diabetic potential. In-silico ADMET analysis of potential compounds revealed 15 compounds that followed Lipinski's rule and demonstrated drug-like properties, as well as good oral bioavailability. Molecular docking was utilised to analyse their potential to interact with three targets: α-amylase, α-glucosidase, and DPP-4, which are crucial in managing diabetes-related problems. Molecular Docking analysis and membrane permeability test utilising the PerMM platform revealed that compounds in the extracts, such as Soyasapogenol B and Corydine, had better interactions and permeability across the plasma membrane than standard drugs in use. Molecular dynamics simulations also showed that selected compounds remained stable upon interaction with α-amylase. Overall, using the in-silico approaches it was predicted that DSB extracts contain potential phytochemicals with diverse anti-diabetic properties. It further needs to be investigated for possible development as formulation or drug of choice for treating T2DM.

A new biphenyl from the stem bark of Garcinia macrantha A.C.Sm

In our continuation of exploring antidiabetic agents from Garcinia species, we found that the methanolic extract of G. macrantha A.C.Sm. exhibited considerable α-glucosidase inhibition of 58.20 ± 0.37% in sucrose substrate and 39.86 ± 2.07% in maltose substrate at 100 μg/mL. Phytochemical investigation on the extract revealed the presence of a new biphenyl, macrabiphenyl A, which was successfully elucidated by means of spectroscopic methods (HRESIMS and 1D and 2D NMR). The α-glucosidase inhibitory evaluation indicated that the new compound was weakly active against the enzyme.

Antiplasmodial and anticancer activities of xanthones isolated from Garcinia bancana Miq

This report describes the isolation and characterization of xanthones from Garcinia bancana Miq. and evaluates their antiplasmodial and anticancer activities. Macluraxanthone (1), isojacareubin (2), and gerontoxanthone C (3) were isolated from the stem bark of G. bancana Miq. for the first time. In silico molecular docking studies revealed the hydrogen bonding and steric interactions between xanthones (1-3) and PfLDH/VEGFR2. The in vitro antiplasmodial activity was assayed against the chloroquine-sensitive Plasmodium falciparum strain 3D7 by the lactate dehydrogenase (LDH) method. The anticancer evaluation was evaluated against the A549, MCF-7, HeLa, and B-16 cancer cell lines. Compounds (1) (IC50 8.45-16.71 μM) and (3) (IC50 9.69-14.86 μM) showed more potent anticancer activity than compound (2) (IC50 25.46-31.31 μM), as well for their antiplasmodial activity (4.28 μM, 5.52 μM, 11.45 μM). Our findings indicated the potential of G. bancana Miq. as a natural resource of antiplasmodial and anticancer compounds.

Garcinia dulcis and Garcinia forbesii King fruit peel extract: Secondary metabolite composition, antioxidant, and elastase inhibitory activity evaluation

Garcinia dulcis and Garcinia forbesii King are native plants from Indonesia and have tremendous potential as a source of raw medicines based on local wisdom. However, scientific data for strengthening pharmaceuticals are still limited. Therefore, it is necessary to conduct a study to strengthen and develop the potential of both plants using the approach of traditional medicine. This study aimed to explore the secondary metabolite composition and biological activity (antioxidant and antielastase) of both plants. Both samples were extracted using 70% ethanol and microwave-assisted extraction with a microwave power of 120 watts for 15 min. The extract obtained was then screened for phytochemicals using specific reagents. The total phenolic content (TPC) was determined using spectrophotometry with a 96-well microplate reader method. The total flavonoid content (TFC) was determined using the colorimetric method, whereas metabolite profiling analysis was conducted using the UPLC-QToF-MS/MS system. Meanwhile, biological activity was tested for antioxidant activity and antielastase as measured by a microplate reader 96-well spectrophotometry method at specific wavelengths. According to the results, G. dulcis and G. forbesii fruit peel extracts showed positive detection of particular secondary metabolites. TPC and TFC values were 13.98 ± 1.90 mg GAE/g and 10.33 ± 1.90 mg QE/g for G. dulcis and 11.98 ± 2.04 mgGAE/g and 1.96 ± 0.36 mgQE/g for G. forbesii. Metabolite profiling detected some compounds from G. dulcis, including ephedrannin B, hinokiflavone, mahuannin J, and candidate mass C9H12O8, and G. forbesii, including 5-Hydroxy-7,8,2'- trimethoxyflavone, lucialdehyde B, candidate mass C21H39NO4, candidate mass C14H10O6, and candidate mass C14H12O6. Meanwhile, the biological activities (antioxidant and antielastase) were 137.721 μg/mL and 108.893 μg/mL for G. dulcis and 481.948 μg/mL and 250.611 μg/mL for G. forbesii, respectively. Both plants showed different profiles of secondary metabolites and biological activities (antioxidant and antielastase) according to their respective characteristics.

Novel α-Glucosidase Inhibitory Peptides Identified In Silico from Dry-Cured Pork Loins with Probiotics through Peptidomic and Molecular Docking Analysis

Diabetes mellitus is a serious metabolic disorder characterized by abnormal blood glucose levels in the body. The development of therapeutic strategies for restoring and maintaining blood glucose homeostasis is still in progress. Synthetic alpha-amylase and alpha-glucosidase inhibitors can improve blood glucose control in diabetic patients by effectively reducing the risk of postprandial hyperglycemia. Peptides of natural origin are promising compounds that can serve as alpha-glucosidase inhibitors in the treatment of type 2 diabetes. Potential alpha-glucosidase-inhibiting peptides obtained from aqueous and saline extracts from dry-cured pork loins inoculated with probiotic LAB were evaluated using in vitro and in silico methods. To identify the peptide sequences, liquid chromatography-mass spectrometry was used. For this purpose, in silico calculation methods were used, and the occurrence of bioactive fragments in the protein followed the ADMET approach. The most promising sequences were molecularly docked to test their interaction with the human alpha-glycosidase molecule (PDB ID: 5NN8). The docking studies proved that oligopeptides VATPPPPPPPK, DIPPPPM, TPPPPPPG, and TPPPPPPPK obtained by hydrolysis of proteins from ripening dry-cured pork loins showed the potential to bind to the human alpha-glucosidase molecule and may act effectively as a potential antidiabetic agent.

Drug Repurposing of FDA Compounds against α-Glucosidase for the Treatment of Type 2 Diabetes: Insights from Molecular Docking and Molecular Dynamics Simulations

Type 2 diabetes mellitus is a chronic health problem that can be controlled by slowing one's carbohydrate metabolism by inhibiting α-glucosidase, an enzyme responsible for carbohydrate degradation. Currently, drugs for type 2 diabetes have limitations in terms of safety, efficiency, and potency, while cases are rapidly increasing. For this reason, the study planned and moved towards drug repurposing by utilizing food and drug administration (FDA)-approved drugs against α-glucosidase, and investigated the molecular mechanisms. The target protein was refined and optimized by introducing missing residues, and minimized to remove clashes to find the potential inhibitor against α-glucosidase. The most active compounds were selected after the docking study to generate a pharmacophore query for the virtual screening of FDA-approved drug molecules based on shape similarity. The analysis was performed using Autodock Vina (ADV)-based on binding affinities (-8.8 kcal/mol and -8.6 kcal/mol) and root-mean-square-deviation (RMSD) values (0.4 Å and 0.6 Å). Two of the most potent lead compounds were selected for a molecular dynamics (MD) simulation to determine the stability and specific interactions between receptor and ligand. The docking score, RMSD values, pharmacophore studies, and MD simulations revealed that two compounds, namely Trabectedin (ZINC000150338708) and Demeclocycline (ZINC000100036924), are potential inhibitors for α-glucosidase compared to standard inhibitors. These predictions showed that the FDA-approved molecules Trabectedin and Demeclocycline are potential suitable candidates for repurposing against type 2 diabetes. The in vitro studies showed that trabectedin was significantly effective with an IC₅₀ of 1.263 ± 0.7 μM. Further investigation in the laboratory is needed to justify the safety of the drug to be used in vivo.

Inhibition Kinetics and Theoretical Studies on Zanthoxylum chalybeum Engl. Dual Inhibitors of α-Glucosidase and α-Amylase

Compounds from Zanthoxylum chalybeum Engl. were previously reported for inhibitory activities of amylase and glucosidase enzymatic action on starch as a preliminary study toward the establishment of a management strategy against postprandial hyperglycemia, however, the inhibitory kinetics and molecular interaction of these compounds were never established. A study was thus designed to establish the inhibitory kinetics and in silico molecular interaction of α-glucosidase and α-amylase with Z. chalybeum metabolites based on Lineweaver–Burk/Dixon plot analyses and using Molecular Operating Environment (MOE) software, respectively. Skimmianine (5), Norchelerythrine (6), 6-Acetonyldihydrochelerythrine (7), and 6-Hydroxy-N-methyldecarine (8) alkaloids showed mixed inhibition against both α-glucosidase and α-amylase with comparable Ki to the reference acarbose (p > 0.05) on amylase but significantly higher activity than acarbose on α-glucosidase. One phenolic 2,3-Epoxy-6,7-methylenedioxyconiferol (10) showed a competitive mode of inhibition both on amylase and glucosidase which were comparable (p > 0.05) to the activity of acarbose. The other compounds analyzed and displayed varied modes of inhibition between noncompetitive and uncompetitive with moderate inhibition constants included chaylbemide A (1), chalybeate B (2) and chalybemide C (3), fagaramide (4), ailanthoidol (9), and sesame (11). The important residues of the proteins α-glucosidase and α-amylase were found to have exceptional binding affinities and significant interactions through molecular docking studies. The binding affinities were observed in the range of −9.4 to −13.8 and −8.0 to −12.6 relative to the acarbose affinities at −17.6 and −20.5 kcal/mol on α-amylase and α-glucosidase residue, respectively. H-bonding, π-H, and ionic interactions were noted on variable amino acid residues on both enzymes. The study thus provides the basic information validating the application of extracts of Z. chalybeum in the management of postprandial hyperglycemia. Additionally, the molecular binding mechanism discovered in this study could be useful for optimizing and designing new molecular analogs as pharmacological agents against diabetes.

Antioxidant and antibacterial activities of two xanthones derivatives isolated from the leaves extract of Anthocleista schweinfurthii Gilg (Loganiaceae)

Phytochemical investigations on the dechlorophyllated extract of Anthocleista schweinfurthii Gilg (Loganiaceae) leaves have enabled the isolation of two xanthones derivatives: 1,8-dihydroxy-2,6-dimethoxyxanthone (1) and 1-hydroxy-3,7,8-trimethoxyxanthone (2) known, respectively, as swertiaperenin (1) and decussatin (2), but isolated here for the first time from this plant. The structures of these compounds were investigated by rigorous analysis of their one- and two-dimensional NMR spectral data. Compounds (1) and (2) were evaluated for their antioxidant activities using the 1,1-diphenyl-2-picrylhydrazyl method (DPPH°); the reducing power of iron III (FRAP) and antibacterial activity by the solid diffusion method on three bacteria strains (Escherichia coli, Staphylococcus aureus, and Bacillus cereus). The results obtained show that the two compounds have good antioxidant and antibacterial activities. Obviously, swertiaperenin and decussatin are among the active secondary’s metabolites responsible for the biological activity of A. schweinfurthii Gild recognized by the Cameroonian populations.

Alpha glucosidase inhibitory properties of a few bioactive compounds isolated from black rice bran: combined in vitro and in silico evidence supporting the antidiabetic effect of black rice

Alpha glucosidase inhibitors reduce post prandial hyperglycemia and are the drugs of choice for the treatment of type 2 diabetes. As synthetic α-glucosidase inhibitors often produce undesirable side effects, less toxic inhibitors from natural sources are in high demand.

Protective Effect of Flavonoids from a Deep-Sea-Derived Arthrinium sp. against ox-LDL-Induced Oxidative Injury through Activating the AKT/Nrf2/HO-1 Pathway in Vascular Endothelial Cells

Oxidized low-density lipoprotein (ox-LDL)-induced oxidative injury in vascular endothelial cells is crucial for the progression of cardiovascular diseases, including atherosclerosis. Several flavonoids have been shown cardiovascular protective effects. Recently, our research group confirmed that the novel flavonoids isolated from the deep-sea-derived fungus Arthrinium sp., 2,3,4,6,8-pentahydroxy-1-methylxanthone (compound 1) and arthone C (compound 2) effectively scavenged ROS in vitro. In this study, we further investigated whether these compounds could protect against ox-LDL-induced oxidative injury in endothelial cells and the underlying mechanisms. Our results showed that compounds 1 and 2 inhibited ox-LDL-induced apoptosis and adhesion factors expression in human umbilical vein vascular endothelial cells (HUVECs). Mechanistic studies showed that these compounds significantly inhibited the ROS level increase and the NF-κB nuclear translocation induced by ox-LDL. Moreover, compounds 1 and 2 activated the Nrf2 to transfer into nuclei and increased the expression of its downstream antioxidant gene HO-1 by inducing the phosphorylation of AKT in HUVECs. Importantly, the AKT inhibitor MK-2206 2HCl or knockdown of Nrf2 by RNA interference attenuated the inhibition effects of these compounds on ox-LDL-induced apoptosis in HUVECs. Meanwhile, knockdown of Nrf2 abolished the effects of the compounds on ox-LDL-induced ROS level increase and the translocation of NF-κB to nuclei. Collectively, the data showed that compounds 1 and 2 protected endothelial cells against ox-LDL-induced oxidative stress through activating the AKT/Nrf2/HO-1 pathway. Our study provides new strategies for the design of lead compounds for related cardiovascular diseases treatment.

Chemical Constituents, In Vitro Antioxidant Activity and In Silico Study on NADPH Oxidase of Allium sativum L. (Garlic) Essential Oil

Allium sativum L., also known as garlic, is a perennial plant widely used as a spice and also considered a medicinal herb since antiquity. The aim of this study was to determine by gas chromatography-mass spectrometry (GC-MS) the chemical profile fingerprint of the essential oil (EO) of one accession of Peruvian A. sativum (garlic), to evaluate its antioxidant activity and an in- silico study on NADPH oxidase activity of the volatile phytoconstituents. The antioxidant activity was tested using DPPH and β-carotene assays. An in-silico study was carried out on NADPH oxidase (PDB ID: 2CDU), as was ADMET prediction. The results indicated that diallyl trisulfide (44.21%) is the major component of the EO, followed by diallyl disulfide (22.08%), allyl methyl trisulfide (9.72%), 2-vinyl-4H-1,3-dithiine (4.78%), and α-bisabolol (3.32%). Furthermore, the EO showed antioxidant activity against DPPH radical (IC50 = 124.60 ± 2.3 µg/mL) and β-carotene bleaching (IC50 = 328.51 ± 2.0). The best docking score on NADPH oxidase corresponds to α-bisabolol (ΔG = -10.62 kcal/mol), followed by 5-methyl-1,2,3,4-tetrathiane (ΔG = -9.33 kcal/mol). Additionally, the volatile components could be linked to the observed antioxidant activity, leading to potential inhibitors of NADPH oxidase.

Biological Activity Evaluation and In Silico Studies of Polyprenylated Benzophenones from Garcinia celebica

This study aimed to isolate polyprenylated benzophenones from the rootbark of Garcinia celebica and assess their activities in vitro and in silico. The antioxidant activity was evaluated by the DPPH, ABTS, and FRAP methods. The cytotoxicity was evaluated against HeLa, MCF-7, A549, and B16 cancer cell lines. The antiplasmodial activity was performed against the chloroquine-sensitive Plasmodium falciparum strain 3D7. Molecular docking was analyzed on alpha-estrogen receptor (3ERT) and P. falciparum lactate dehydrogenase enzyme (1CET). The prediction of ADMET for the compounds was also studied. For the first time, (-)-cycloxanthochymol, isoxanthochymol, and xanthochymol were isolated from the root bark of Garcinia celebica. The antioxidant and cytotoxicity evaluation showed that all benzophenones exhibited antioxidant activity compared to gallic acid and quercetin as positive controls and also exhibited strong activity against HeLa, MCF-7, A549, and B16 cell lines compared to cisplatin as the positive control. The antiplasmodial evaluation showed that isoxanthochymol exhibited activity against the chloroquine-sensitive P. falciparum strain 3D7. In addition, the in silico molecular docking study supported in vitro activities. The ADMET analysis also indicated the isolated benzophenones are potential oral drug candidates.