Effects of verbascoside and martynoside on muscle contractility were investigated. Bufo gastrocnemius muscle was electrically stimulated in vitro, the amplitude and duration of the contraction were mechanically recorded and used as indices of muscle contractility. After 30 min pretreatment of muscle, verbascoside at 20.0 μmol·L -1 resisted muscle fatigue greatly. The duration at which the contraction kept at the level of 90%, 50% and 10% of its maximal amplitude(T 0.9 , T 0.5 and T 0.1 ) were prolonged by (23±10)%,(23±8)% and(31±15)%, respectively, while the maximal amplitude of contraction was not affected. Martynoside even at 80.0 μmol·L -1 improved muscle contractility slightly 〔only T 0.1 was prolonged by (14±5)%〕. The results suggest that verbascoside exhibits stronger antifatigue capacity, which may be due to its higher antioxidation activity than that of martynoside.
