Effect of Eurotium cristatum fermentation on the α-glucosidase inhibitory activity of mulberry leaves alkaloids

Abstract

Eurotium cristatum CY-1 was used for the solid-stated fermentation of mulberry leaves (ML) with the purpose of enhancing the alkaloids content and α-glucosidase inhibitory activity of ML through microbial fermentation. The results indicated that Eurotium cristatum CY-1 grown well when cultivated with MLs as substrate. The maximum cell dry weight of 393.32 mg was reached on the 10 d of fermentation. The alkaloids content of ML was increased with the fermentation time, and the maximum value of 8.711 mg/g was obtained at 8 d of fermentation, which was increased by171.96% compared to that extracted from unfermented ML. The α-glucosidase inhibitory efficiency was also improved along with the fermentation time. The IC50 values of alkaloid extracted from 8d-fermented mulberry leaves was 3.94 μg/mL, but 6.82 μg/mL of the alkaloid extracted from the unfermented ML. Therefore, the fermentation of Eurotium cristatum could benefit for enhancing the alkaloid content and α-glucosidase inhibitory efficiency of ML. It would provide a valuable strategy for obtain safe and low-cost α-glucosidase inhibitors from natural herbal medicines.