Inhibition on α-Glucosidase Activity and Non-Enzymatic Glycation by an Anti-Oxidative Proteoglycan from Ganoderma lucidum

Albadri A, Patel H, Kadri A, Aouadi K. Identification of dual-target isoxazolidine-isatin hybrids with antidiabetic potential: Design, synthesis, in vitro and multiscale molecular modeling approaches

In the development of novel antidiabetic agents, a novel series of isoxazolidine-isatin hybrids were designed, synthesized, and evaluated as dual α-amylase and α-glucosidase inhibitors. The precise structures of the synthesized scaffolds were characterized using different spectroscopic techniques and elemental analysis. The obtained results were compared to those of the reference drug, acarbose (IC50 = 296.6 ± 0.825 μM for α-amylase & IC50 = 780.4 ± 0.346 μM for α-glucosidase). Among the title compounds, 5d exhibited impressive α-amylase and α-glucosidase inhibitory activity with IC50 values of 30.39 ± 1.52 μM and 65.1 ± 3.11 μM, respectively, followed by 5h (IC50 = 46.65 ± 2.3 μM; IC50 = 85.16 ± 4.25 μM) and 5f (IC50 = 55.71 ± 2.78 μM; IC50 = 106.77 ± 5.31 μM). Mechanistic studies revealed that the most potent derivative 5d bearing the chloro substituent attached to the oxoindolin-3-ylidene core, and acarbose, are a competitive inhibitors of α-amylase and α-glucosidase, respectively. Structure activity relationship (SAR) was examined to guide further structural optimization of the most appropriate substituent(s). Moreover, drug-likeness qualities and ADMET prediction of the most active analogue, 5d was also performed. Subsequently, 5d was subjected to molecular docking and dynamic simulation during the progression of 120 ns analysis to check the essential ligand-receptor patterns, and to estimate its stability. In silico studies were found in good agreement with the in vitro enzymatic inhibitions results. In conclusion, we demonstrated that most potent compound 5d could be exploited as dual potential inhibitor of α-amylase and α-glucosidase for possible management of diabetes.

Balancing adipocyte production and lipid metabolism to treat obesity-induced diabetes with a novel proteoglycan from Ganoderma lucidum

Obesity is often accompanied by metabolic disorder and insulin resistance, resulting in type 2 diabetes. Based on previous findings, FYGL, a natural hyperbranched proteoglycan extracted from the G. lucidum fruiting body, can decrease blood glucose and reduce body weight in diabetic mice. In this article, the underlying mechanism of FYGL in ameliorating obesity-induced diabetes was further investigated both in vivo and in vitro. FYGL upregulated expression of metabolic genes related to fatty acid biosynthesis, fatty acid β-oxidation and thermogenesis; downregulated the expression of insulin resistance-related genes; and significantly increased the number of beige adipocytes in db/db mice. In addition, FYGL inhibited preadipocyte differentiation of 3T3-L1 cells by increasing the expression of FABP-4. FYGL not only promoted fatty acid synthesis but also more significantly promoted triglyceride degradation and metabolism by activating the AMPK signalling pathway, therefore preventing fat accumulation, balancing adipocyte production and lipid metabolism, and regulating metabolic disorders and unhealthy obesity. FYGL could be used as a promising pharmacological agent for the treatment of metabolic disorder-related obesity.

Recent Updates on Phytoconstituent Alpha-Glucosidase Inhibitors: An Approach towards the Treatment of Type Two Diabetes

Diabetes is a common metabolic disorder marked by unusually high plasma glucose levels, which can lead to serious consequences such as retinopathy, diabetic neuropathy and cardiovascular disease. One of the most efficient ways to reduce postprandial hyperglycemia (PPHG) in diabetes mellitus, especially insulin-independent diabetes mellitus, is to lower the amount of glucose that is absorbed by inhibiting carbohydrate hydrolyzing enzymes in the digestive system, such as α-glucosidase and α-amylase. α-Glucosidase is a crucial enzyme that catalyzes the final stage of carbohydrate digestion. As a result, α-glucosidase inhibitors can slow D-glucose release from complex carbohydrates and delay glucose absorption, resulting in lower postprandial plasma glucose levels and control of PPHG. Many attempts have been made in recent years to uncover efficient α-glucosidase inhibitors from natural sources to build a physiologic functional diet or lead compound for diabetes treatment. Many phytoconstituent α-glucosidase inhibitors have been identified from plants, including alkaloids, flavonoids, anthocyanins, terpenoids, phenolic compounds, glycosides and others. The current review focuses on the most recent updates on different traditional/medicinal plant extracts and isolated compounds' biological activity that can help in the development of potent therapeutic medications with greater efficacy and safety for the treatment of type 2 diabetes or to avoid PPHG. For this purpose, we provide a summary of the latest scientific literature findings on plant extracts as well as plant-derived bioactive compounds as potential α-glucosidase inhibitors with hypoglycemic effects. Moreover, the review elucidates structural insights of the key drug target, α-glucosidase enzymes, and its interaction with different inhibitors.

Antioxidant, Hypoglycemic and Molecular Docking Studies of Methanolic Extract, Fractions and Isolated Compounds from Aerial Parts of Cymbopogon citratus (DC.) Stapf

Traditionally, Cymbopogon citratus is used to treat a variety of ailments, including cough, indigestion, fever, and diabetes. The previous chemical and bioactive research on C. citratus mainly focused on its volatile oil. In this study, 20 non-volatile known compounds were isolated from the dried aerial part of C. citratus, and their structures were elucidated by MS, NMR spectroscopy, and comparison with the published spectroscopic data. Among them, 16 compounds were reported for the first time from this plant. The screening results for antioxidant and α-glucosidase inhibitory activities indicated that compounds caffeic acid (5), 1-O-p-coumaroyl-3-O-caffeoylglycerol (8), 1,3-O-dicaffeoylglycerol (9) and luteolin-7-O-β-D-glucopyranoside (12) had potent antioxidant capacities, with IC₅₀ values from 7.28 to 14.81 μM, 1.70 to 2.15 mol Trolox/mol and 1.31 to 2.42 mol Trolox/mol for DPPH, ABTS, and FRAP, respectively. Meanwhile, compounds 8 and 9 also exhibited significant inhibitory activities against α-glucosidase, with IC₅₀ values of 11.45 ± 1.82 μM and 5.46 ± 0.25 μM, respectively, which were reported for the first time for their α-glucosidase inhibitory activities. The molecular docking result provided a molecular comprehension of the interaction between compounds (8 and 9) and α-glucosidase. The significant antioxidant and α-glucosidase inhibitory activities of compounds 8 and 9 suggested that they could be developed into antidiabetic drugs because of their potential regulatory roles on oxidative stress and digestive enzyme.