Antioxidant Activity and Inhibition Activity against α-Amylase and α-Glucosidase of Viola mandshurica Extracts
This study was performed to investigate the physiological activities of Viola mandshurica. Antioxidant activity was evaluated by measuring total phenolic contents, reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-di-2-ethyl-benzthiazoline sulphonate (ABTS) radical scavenging activity while anti-diabetic activity was measured by inhibition activities on α-amylase and α-glucosidase. V. mandshurica extracts were prepared by extracting with four different solvents (methanol, ethanol, acetone, and water). The methanol extract showed the highest total phenol content (34.49 mg/g gallic acid equivalents) among the extracts. The water extract showed the highest reducing power (0.454) at the concentration of 1,000 ㎍/mL. The acetone extract showed the most potent radical scavenging activity. DPPH and ABTS radical scavenging activity of the acetone extract at the concentration of 1,000 ㎍/mL were 21.13% and 43.53%, respectively. The inhibitory activity of acetone extracts against α-amylase and α-glucosidase showed more than 100% at the concentration of 1,000 ㎍/mL. The results indicate that V. mandshurica might have potential antioxidant and anti-diabetic activities.