Biochemical Investigation of Inhibitory Activities of Plant-Derived Bioactive Compounds Against Carbohydrate and Glucagon-Like Peptide-1 Metabolizing Enzymes

Combination of plant metabolites hinders starch digestion and glucose absorption while facilitating insulin sensitivity to diabetes

Introduction

Diabetes mellitus (DM) is a common endocrine disease resulting from interactions between genetic and environmental factors. Type II DM (T2DM) accounts for approximately 90% of all DM cases. Current medicines used in the treatment of DM have some adverse or undesirable effects on patients, necessitating the use of alternative medications.

Methods

To overcome the low bioavailability of plant metabolites, all entities were first screened through pharmacokinetic, network pharmacology, and molecular docking predictions. Experiments were further conducted on a combination of antidiabetic phytoactive molecules (rosmarinic acid, RA; luteolin, Lut; resveratrol, RS), along with in vitro evaluation (α-amylase inhibition assay) and diabetic mice tests (oral glucose tolerance test, OGTT; oral starch tolerance test, OSTT) for maximal responses to validate starch digestion and glucose absorption while facilitating insulin sensitivity.

Results

The results revealed that the combination of metabolites achieved all required criteria, including ADMET, drug likeness, and Lipinski rule. To determine the mechanisms underlying diabetic hyperglycemia and T2DM treatments, network pharmacology was used for regulatory network, PPI network, GO, and KEGG enrichment analyses. Furthermore, the combined metabolites showed adequate in silico predictions (α-amylase, α-glucosidase, and pancreatic lipase for improving starch digestion; SGLT-2, AMPK, glucokinase, aldose reductase, acetylcholinesterase, and acetylcholine M2 receptor for mediating glucose absorption; GLP-1R, DPP-IV, and PPAR-γ for regulating insulin sensitivity), in vitro α-amylase inhibition, and in vivo efficacy (OSTT versus acarbose; OGTT versus metformin and insulin) as nutraceuticals against T2DM.

Discussion

The results demonstrate that the combination of RA, Lut, and RS could be exploited for multitarget therapy as prospective antihyperglycemic phytopharmaceuticals that hinder starch digestion and glucose absorption while facilitating insulin sensitivity.

Biosynthesis and Multifaceted Characterization of Breynia nivosa-Derived Silver Nanoparticles: An Eco-Friendly Approach for Biomedical Applications

This study presents an environmentally friendly synthesis of stable silver nanoparticles (Ag-NPs) using the methanolic extract of Breynia nivosa. Initial phytochemical analysis of the extract revealed the presence of alkaloids, flavonoids, glycosides, saponins, and tannins. Further characterization through high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) analyses identified a diverse array of bioactive compounds, including hydroquinone, stearic acid, neophytadiene, 9,12-octadecadienoic acid (Z,Z), methyl ester, and others. The addition of B. nivosa methanolic extract to an AgNO3 solution resulted in a color change, confirming the green synthesis of Ag-NPs through the reduction of AgNO3, as made evident by ultraviolet-visible (UV-vis) spectroscopy. X-ray diffraction (XRD) analysis provided valuable insights into the crystal structure, and scanning electron microscopy (SEM) analysis visualized the predominantly spherical shape of the Ag-NPs. However, the zeta (ζ)-potential and dynamic light scattering (DLS) analyses confirmed the stability and nanoscale dimensions of the synthesized Ag-NPs. Meanwhile, Fourier transform infrared (FT-IR) spectra exhibited peaks indicative of various functional groups, including carboxylic acids, phenols, alkanes, and isocyanates. These functional groups played a crucial role in both the reduction and capping processes of the Ag-NPs. The study further explored the antioxidant activity, cytotoxicity, acetylcholinesterase inhibition, and α-amylase inhibition activities of the Ag-NPs of the B. nivosa extract, demonstrating their potential for biomedical and therapeutic applications. In conclusion, this environmentally sustainable synthesis of Ag-NPs from the B. nivosa extract, enriched with bioactive secondary metabolites detected through HPLC and GC-MS analysis, holds promise for diverse applications in the burgeoning field of green nanotechnology.

Integrated computational approaches for designing potent pyrimidine-based CDK9 inhibitors: 3D-QSAR, docking, and molecular dynamics simulations

CDK9 is an emerging target for the development of anticancer drugs. The development of CDK9 inhibitors with significant potency had consistently posed a formidable challenge. In the current research, a number of computational methodologies, such as, 3D-QSAR, molecular docking, fingerprint analysis, molecular dynamic (MD) simulations followed by MMGB/PBSA and ADMET studies were used systemically to uncover the binding mechanism of pyrimidine derivatives against CDK9. The CoMFA and CoMSIA models having high q2 (0.53, 0.54) and r2 values (0.96, 0.93) respectively indicating that model could accurately predict the bioactivities of CDK9 inhibitors. Using the R-group exploration technique implemented by the Spark™ by Cresset group, the structural requirements revealed by the contour maps of model were utilized strategically to create an in-house library of 100 new CDK9 inhibitors. Additionally, the compounds from the in-house library were mapped into 3D-QSAR model which predicted pIC50 values comparable to the experimental values. A comparison between 3D-QSAR generated contours and molecular docking conformation of ligands was performed to elucidate the essentials of CDK9 inhibitor design. MD simulations (100 ns) were performed on the selected docked complexes A21, A14 and D98 which contributed in validating the binding interactions. According to the findings of binding free energy analysis (MMGB/PBSA), It was observed that residues CYS106 and GLU107 had a considerable tendency to facilitate ligand-protein interactions via H-bond interactions. The aforementioned findings have the potential to enhance researchers comprehension of the mechanism underlying CDK9 inhibition and may be utilized in the development of innovative and efficacious CDK9 inhibitors.

Flavonoids as dual-target inhibitors against α-glucosidase and α-amylase: a systematic review of in vitro studies

Diabetes mellitus remains a major global health issue, and great attention is directed at natural therapeutics. This systematic review aimed to assess the potential of flavonoids as antidiabetic agents by investigating their inhibitory effects on α-glucosidase and α-amylase, two key enzymes involved in starch digestion. Six scientific databases (PubMed, Virtual Health Library, EMBASE, SCOPUS, Web of Science, and WHO Global Index Medicus) were searched until August 21, 2022, for in vitro studies reporting IC50 values of purified flavonoids on α-amylase and α-glucosidase, along with corresponding data for acarbose as a positive control. A total of 339 eligible articles were analyzed, resulting in the retrieval of 1643 flavonoid structures. These structures were rigorously standardized and curated, yielding 974 unique compounds, among which 177 flavonoids exhibited inhibition of both α-glucosidase and α-amylase are presented. Quality assessment utilizing a modified CONSORT checklist and structure-activity relationship (SAR) analysis were performed, revealing crucial features for the simultaneous inhibition of flavonoids against both enzymes. Moreover, the review also addressed several limitations in the current research landscape and proposed potential solutions. The curated datasets are available online at https://github.com/MedChemUMP/FDIGA .

Vitisin B, a resveratrol tetramer from Vitis thunbergii var. taiwaniana, ameliorates impaired glucose regulations in nicotinamide/streptozotocin-induced type 2 diabetic mice

Background and aim

In Taiwan, Vitis thunbergii var. taiwaniana (VTT) is used in traditional medicine and as a local tea. VTT rich in resveratrol and resveratrol oligomers have been reported to exhibit anti-obesity and anti-hypertensive activities in animal models; however, no studies have investigated type 2 diabetes mellitus (T2DM) treatments. This study aimed to investigate the anti-T2DM effects of resveratrol tetramers isolated from the VTT in nicotinamide/streptozotocin (STZ)-induced Institute of Cancer Research (ICR) mice.

Experimental procedure

The oral glucose tolerance test (OGTT) was used to imitate postprandial blood glucose (BG) regulations in mice by pre-treatment with VTT extracts, resveratrol tetramers of vitisin A, vitisin B, and hopeaphenol 30 min before glucose loads. Vitisin B (50 mg/kg) was administered to treat T2DM-ICR mice once daily for 28 days to investigate its hypoglycemic activity.

Results and conclusion

Mice pre-treated with VTT-S-95EE, or vitisin B (100 mg/kg) 30-min before glucose loading showed significant reductions (P < 0.001) in the area under the curve at 120-min (BG-AUC0-120) than those without pre-treatment with VTT-S-95 E E or vitisin B. Vitisin B-treated T2DM mice showed hypoglycemic activities via a reduction in plasma dipeptidyl peptidase (DPP)-IV activities to maintain insulin actions and differed significantly than those of untreated T2DM mice (P < 0.05), and also reduced BG-AUC0-120 and insulin-AUC0-120 in the OGTT.These in vivo results showed that VTT containing vitisin B would be beneficial for developing nutraceuticals and/or functional foods for glycemic control in patients with T2DM, which should be investigated further.

Biochemical Investigation of Therapeutic Potentials of Plant-Based Bioactive Compounds as Stimulators of Glucagon like peptide-1 Secretion

This study was aimed to investigate the therapeutic potentials of plant-based bioactive compounds; lutein and resveratrol alone and/or in combination with DPP-4 enzyme inhibitor; sitagliptin on the secretion and bioavailability of Glucagon like peptide-1(GLP). For this, experimental rats were divided into seven groups. Group 1 was marked as control, while other six groups received streptozotocin (60 mg/kg I.P.). Later, group 2 was kept disease-control. While group 3 received 10 mg/kg/day sitagliptin (DDP-4i). Group 4 received 40 mg/kg/day lutein (LUT) and group 5 received 30 mg/kg/day resveratrol (RES). While group 6 and 7 were received combination of DPP-4i+LUT and DPP-4i+RES, respectively. Combined administration of DPP-4i+LUT or DPP-4i+RES showed expected therapeutic effects by lowering the fasting blood glucose and maintaining the serum insulin concentrations with improved glucose sensitivity and reduced insulin resistance. Further, co-administration of LUT and RES with DPP-4i revealed beneficial effects on measures of insulin resistance, circulating lipids, glycemic index, oxidative stress, and inflammatory status along with restoration of histological morphology of pancreatic cells and enterocytes that seemed to improve the level of GLP-1. Hence, substantial verdicts of this study showing therapeutic potentials of LUT and RES would surely help to recognize the potential effects in combination with DPP-4i as stimulators of GLP-1 secretion.