Anti‐hyperglycemic Activities of Korean Red Ginseng (Panax ginseng Meyer) and Arginyl‐fructose‐enriched Red Ginseng Extracts In‐vitro and In‐vivo Animal Models

Maillard reaction that occurs during the manufacturing processes of red ginseng produces a large amount of Amadori rearrangement compounds (ARCs), such as arginyl-fructose (AF). The antioxidant, anti-hyperglycemic immune enhancing effects of AF have been reported. Amino acid derivatives such as AF are formed through amadori rearrangement, the early step of maillard reaction from arginine and glucose in heat processed foods. Heat processed red ginseng have high content of AF and saponins. In this study inhibitory activities of red ginseng extract (RG) and AF-enriched red ginseng extract (ARG) against rat intestinal α-glucosidases (sucrase, maltase, and glucoamylase) and α-amylase were evaluated using in-vitro and Sprague Dawley (SD) rat models. The in-vitro results showed that ARG have higher α-glucosidase inhibitory activities than those of RG in a dose-dependent manner. In SD rat model, postprandial blood glucose levels were measured for 3 hours after oral administration of 0.1 and 0.5 g/kg-body weight of ARG or RG along with sucrose or starch. The postprandial blood glucose lowering effects of ARG and RG were compared to a known type 2 diabetes medicine (Acarbose®), a strong α-glucosidase inhibitor in the SD rat model. In rats fed on sucrose, ARG significantly reduced the blood glucose spike after sucrose loading (p < 0.01). The maximum blood glucose concentration (Cmax) in ARG-treated SD rats (0.1 g-ARG/kg) was significantly lower than in RG-treated SD rats (p < 0.01). These results suggest that AF-enriched red ginseng could have a beneficial effect for blood glucose management relevant to diabetes prevention in normal and pre-diabetic individuals via inhibition of the carbohydrate hydrolysis enzymes in the colon. AF, ARCs may have high potential as a material for the development of products, nutritious foods with antidiabetic activity. Our findings provide a pharmacological rationale and the basis for further clinical study for AF-enriched natural products such as ginseng and red ginseng.