Inhibitory Effect of Bioassay-Guided Fractionation of Mushroom (Pleurotus ostreatus) Extract on Fructose-induced Glycated Hemoglobin and Aggregation in vitro

Background: Chronic hyperglycemia in diabetes mellitus is a prominent inducer for free radical production which results in non-enzymatic protein glycation that cause the pathogenesis of diabetic complications and deleterious health-related issues. Since ancient times, people have consumed mushrooms as food and as a form of folk medicine. Mushrooms are becoming more and more popular due to their medicinal and nutritional advantages. Pleurotus ostreatus has considerable antioxidant properties to scavenge free radicals and is helpful to offer antiglycation activity. Objectives: The purpose of this research was to determine the inhibitory effect of bioassay-guided fractionation of Pleurotus ostreatus on formation of glycated hemoglobin and aggregation of glycated protein in vitro. Materials and Methods: Total phenolic and flavonoids were determined from the crude extract of P. ostreatus. Antioxidant capability of methanolic crude extract was determined by DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, H₂O₂ (hydrogen peroxide) scavenging, and ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6 -sulfonic acid) radical cation scavenging activity. Inhibitory effect of bio-guided fractionations of crude P. ostreatus extract were measured using fructosamine formation, protein carbonyls, aggregation index, and fluorescence intensity. Results: Methanolic extract of P. ostreatus has significantly high levels of phenols (16.89 ± 1.44 mg GAE/g) and flavonoids (9.40 ± 0.86 mg QE/g). Methanolic extract was found to have excellent antioxidant capacity indicates from IC₅₀ values for DPPH radical scavenging (75.23 ± 2.32 μg/mL), H2O2 scavenging (96.54 ± 2.32 μg/mL), and ABTS radical cation (50.33± 1.82 μg/mL) scavenging activities. The analysis on fructose induced glycated hemoglobin model revealed that fraction F4 of methanolic extract of P. ostreatus is more potent to inhibit formation of glycated hemoglobin by (58.84 ± 2.36%), fructosamine (64.32 ± 3.74%) and protein carbonyls (51.35 ± 2.94%). It also showed an aggregation index of 46.32 ±1.05% and a decline in fluorescence intensity (52.04%) which are important factor in many pathological processes. Conclusion: The fraction F4 obtained from P. ostreatus can be used for the identification of bioactive compounds that can be further considered as therapeutic agents for AGE-associated pathogenesis.