Anti-fatigue activity of Hovenia dulcis on a swimming mouse model through the inhibition of stress hormone expression and antioxidation.

Hovenia dulcis (H. dulcis) Thunb., which is distributed in Korea, China, and Japan, has been known to show hepatoprotective and free radical scavenging effects and enhance physical activity. Therefore, the objectives of this present study were to determine the anti-fatigue activity of hot-water extract from H. dulcis peduncle, and to find the reason why H. dulcis extract (HDE)-ingested mice had enhanced physical activity against swimming performance. The mice orally administrated with HDE (HDE-mice) dramatically enhanced their swimming time compared to the control mice. HDE significantly decreased serum levels of stress hormones, such as cortisol and adrenocorticotropic hormone (ACTH) in mice. The levels of thiobarbituric acid reactive substances (TBARS) were dramatically decreased in gastrocnemius muscle from both 100 mg/kg of HDE (LHDE) and 200 mg/kg of HDE (HHDE)-ingested mice compared to the control mice. The liver activities of superoxide dismutase (SOD) were significantly increased in HHDE-mice with increasing tendency in LHDE-mice. In addition, HHDE-mice significantly decreased the levels of blood glucose, total cholesterol (T-Chol), and triglyceride (TG). These results suggest that HDE had a significant anti-fatigue effect via its anti-stress and antioxidant activities, and thereby enhanced physical activity in swimming performance.