The In Vitro Antioxidant and Antidiabetic Activity of Various Fractions from Monascus-Fermented Ginger Extract

Abstract

This study investigated the potential antioxidant and antidiabetic activity of Monascus-fermented ginger extract (MGE). Gingers was fermented with Monascus pilosus KCCM 60084 for 2 weeks at 30°C and extracted with 95% ethanol. The antioxidant activity of the ethyl acetate fraction of the MGE was measured through DPPH, ABTS, and FRAP. The antioxidant activity of MGE increased 2.36 to 3.76-fold compared with those of raw ginger extracts (CGE) (P<0.05). The ethyl acetate fraction of MGE had a higher potential to inhibit the key digestive enzymes linked to type 2 diabetes (α-amylase, α-glucosidase) as compared to CGE (P<0.05). The IC50 for the α-amylase inhibitory activity (3.40±0.88 mg/mL) of MGE showed a higher potency than acarbose (7.01±0.23 mg/mL), which is currently used as a diabetes treatment. Moreover, the ethyl acetate fraction of MGE increased the expression of glucose transporter type 4 (GLUT4), glucokinase (GCK), and AMP-activated protein kinase (AMPK) in HepG2 cells. These findings demonstrate that the ethyl acetate fraction of MGE significantly improved glucose uptake in HepG2 cells by activating both PI3K/Akt and AMPK phosphorylation pathways. Our results suggest that MGE show the potential to be developed as a antidiabetic nutraceuticals.