Consumption of Mesona chinensis Attenuates Postprandial Glucose and Improves Antioxidant Status Induced by a High Carbohydrate Meal in Overweight Subjects

Edible plants constitute a potential source for controlling postprandial hyperglycemia and oxidative stress. The objective of this study was to investigate in vitro antioxidant and intestinal alpha-glucosidase inhibitory activities of Mesona chinensis (MC). In addition, the acute effect of MC on postprandial glucose and plasma antioxidant status after the consumption of a high carbohydrate (HC) meal by overweight subjects was also determined. The results showed that total phenolic and flavonoid contents in the extract were 212.37 +/- 5.64 mg gallic acid equivalents/g dried extract and 23.44 +/- 2.50 mg catechin equivalents/g dried extract, respectively. MC extract markedly inhibited the intestinal maltase and sucrose with the IC50 values of 4.66 +/- 0.22 mg/mL and 1.30 +/- 0.43 mg/mL, respectively. However, MC extract had no inhibitory activity against pancreatic alpha-amylase. In addition, MC extract had antioxidant properties including DPPH radical scavenging activity, superoxide radical scavenging activity (SRSA), hydroxyl radical scavenging activity (HRSA), trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and ferrous ion cheating activity (FICP). The significant decrease in postprandial plasma glucose, triglyceride and malondialdehyde levels, and the increase in plasma antioxidant capacity (FRAP and ORAC) were observed in overweight subjects receiving a HC meal together with MC extract (1 g). The finding supports that MC helps normalize and enhance antioxidant defense induced by a HC meal, suggesting that MC may have the potential for the prevention of chronic conditions and diseases associated with overweight and obesity.