Angelica acutiloba root attenuates insulin resistance induced by high-fructose diet in rats

Angelica acutiloba root (Japanese Dong Quai), used for treatment of gynecological disorders, is currently cultivated in Taiwan. The present study evaluated the preventative effect of Angelica acutiloba root (Japanese Dong Quai) on the induction of insulin resistance. Insulin resistance was induced in rats by feeding a high fructose diet for 6 weeks. Thereafter, the rats were maintained on the same diet and treated with oral A. acutiloba root extract or pioglitazone once daily for 8 weeks. At the end of treatment, the degree of basal insulin resistance was measured by homeostasis model assessment (HOMA-IR). Insulin sensitivity was calculated using the composite whole body insulin sensitivity index (ISIcomp). Protein expression was evaluated by immunoblotting. A. acutiloba (300 mg/kg/day) displayed similar characteristics to pioglitazone (20 mg/kg/day) in reducing HOMA-IR and elevating ISIcomp. Elevated glycosylated hemoglobin levels and hyperinsulinemia were ameliorated by A. acutiloba treatment without hepatotoxic or nephrotoxic effects. A. acutiloba treatment improved dyslipidemia, induced lipoprotein lipase activity and enhanced hepatic glycogen accumulation. Further, A. acutiloba treatment enhanced the action of insulin on muscle glucose transporter subtype 4 translocation and attenuated hepatic phosphoenolpyruvate carboxykinase expression. The findings suggest that A. acutiloba may be an effective ethnomedicine for improving insulin sensitivity.