Anti-obesity effects of the methanolic extract and chakasaponins from the flower buds of Camellia sinensis in mice.

The methanolic extract from the flower buds of Camellia sinensis cultivated in Fujian Province showed inhibitory effects on body weight gain and the weight of visceral fats in high-fat diet-fed mice and/or Tsumura Suzuki Obese Diabetic (TSOD) mice. A suppressive effect of the extract on food intake was suggested to contribute to the anti-obesity effect. The n-butanol (BuOH)-soluble fraction also reduced food intake in normal diet-fed mice. A principal constituent, chakasaponin II, inhibited gastric emptying (GE) as well as food intake. These inhibitory effects were partly reduced by pretreatment with a high dose of capsaicin. The n-BuOH-soluble fraction and chakasaponin II suppressed mRNA levels of neuropeptide Y (NPY), an important regulator of body weight through its effects on food intake and energy expenditure, in the hypothalamus. Furthermore, chakasaponin II enhanced the release of serotonin (5-HT) from the isolated ilea of mice in vitro. These findings suggested that the active saponins suppressed the appetite signals in the hypothalamus through stimulation of the capsaicin-sensitive sensory nerves, probably vagal afferent nerves, or enhancement of 5-HT release from the ilea, leading to reduced food intake and body weight gain.