Antifatigue and increasing exercise performance of Actinidia arguta crude alkaloids in mice

Actinidia arguta (Siebold et Zucc.) Planch. ex. Miq. is one of the most recently domesticated fruit species with increasing commercial production worldwide. It is a well-known traditional Chinese medicine and is used to reduce blood glucose and treat atopic dermatitis. In addition, it possesses antioxidant, anticancer, and antiallergic properties. In this study, we investigated the physical antifatigue and exercise performance effects of A. arguta crude alkaloids (AACA) extracted with 70% ethanol. Four groups of male Kunming mice (n = 16) were orally administered AACA at doses of 0 mg/kg/d (vehicle), 50 mg/kg/d (AACA-50), 100 mg/kg/d (AACA-100), or 200 mg/kg/d (AACA-200) for 28 days. The effect of AACA treatment on exercise performance was studied using the forelimb grip strength experiment and by the measurement of the weight-loaded swimming time. The antifatigue effect is evaluated based on fatigue-associated biochemical parameters, hepatic and muscular glycogen levels, and changes in the morphology of transverse and longitudinal sections of skeletal muscle. The results showed that AACA could elevate the endurance and grip strength in mice. The exhaustive swimming time of the AACA-50, AACA-100, and AACA-200 groups was significantly (p < 0.05) increased compared with the vehicle. The swimming time of the AACA-100 group was the longest among all groups studied. Mice in the AACA-treated groups had decreased levels of lactate, ammonia, and creatine kinase after a physical challenge compared with the vehicle group. The tissue glycogen, an important energy source during exercise, significantly increased with AACA. The morphology of transverse and longitudinal sections of skeletal muscle did not change in the vehicle group. Overall, these findings suggest that AACA possesses antifatigue effects and increases exercise performance in mice. Therefore, A. arguta may be developed as an antifatigue dietary supplement in the category of functional foods.