Enhance the flavonoids content and α-glucosidase inhibitor efficiency of mulberry leaves by fermented with Ganoderma lucidum

Abstract

Diabetes is a kind of chronic disease that seriously threatens human health. α-glucosidase inhibitors are an effective way to inhibit the increase of postprandial blood glucose. Mulberry leaf flavonoids can be used as highly effective α-glucosidase inhibitors, but usually in low concentrations. Microbial fermentation is an effective method to increase the content of flavonoids in plants. In this paper, the fermentation of mulberry leaves with Ganoderma lucidum was conducted to investigate the cell growth of microbial, the content and α-glucosidase inhibitory efficiency of flavonoids in mulberry leaves. The results indicated that mulberry leaves can satisfy the nutritional needs of G. lucidum, and the maximum cell dry weight of 393.32 mg was obtained after a 10 d of fermentation. The flavonoid content in mulberry leaves was increased significantly with the fermentation time. Compared to unfermented mulberry leaves, the flavonoid content in mulberry leaves fermented for 8 d increased by 56.5%. The inhibitory efficiency of the fermented flavonoids was also significantly improved. The IC50 of α-glucosidase of flavonoids extracted from 8 d fermented mulberry leaves and unfermented mulberry leaves were 0.041 mg/mL and 0.01 mg/mL, respectively. This article will provide a reference for the enrichment of functional active ingredients in plants through microbial fermentation technology.