Dioscorea oppositifolia is a well-known edible and traditional medicine for the treatment of gastrointestinal diseases. In our previous study, D. oppositifolia exhibited both pancreatic lipase inhibition and an anti-adipogenesis effect in vitro. This study was performed to investigate the anti-obesity effect of D. oppositifolia on high-fat diet-induced obese mice. Female ICR mice were fed a high-fat diet with the 100 mg/ kg of D. oppositifolia n-BuOH extract for 8 weeks. The high-fat diet mice received the 15 mg/kg Orlistat orally as a positive control. The body weight, parametrial adipose tissue weight, and the levels of triglyceride (TG), total cholesterol (TC), and low density lipoprotein (LDL)-cholesterol in blood serum of female ICR mice were significantly decreased by feeding a high-fat diet with the n-BuOH extract of D. oppositifolia. An inhibitory effect of D. oppositifolia extract on dietary fat absorption was also clearly shown. The D. oppositifolia sample was found to contain 3,5-dimethoxy-2,7-phenanthrenediol and (3R,5R)-3,5-dihydroxy-1,7-bis(4-hydroxyphenyl)-3,5-heptanediol as main components based on its phytochemical analysis. The present study is the first report of the anti-obesity effect by D. oppositifolia n-BuOH extract using an established disease model. The increase in fecal fat excretion by treatment of D. oppositifolia may be an effective approach for treating obesity and related diseases.Key words Dioscorea oppositifolia; anti-obesity; high-fat diet-induced obese mouse; fecal fat excretion; phytochemical analysis Obesity is the disease associated with accumulation of excessive body fat resulting from energy imbalance.1) The obesity epidemic has become a public health problem, leading to secondary chronic diseases like dyslipidemia, cardiovascular disease, and type 2 diabetes.2,3) Furthermore, obese persons experience a number of physical problems such as sleep apnoea and joint pain, which shortens the life expectancy and impacts on the quality of life. 4) Natural phytochemicals have become more attractive as sources of industrial and medicinal materials in overweight and obese patients due to potential anti-obesity properties.5) Numerous trials have been conducted to discover pharmacological features of crude plant extracts, isolates, and phytochemical combinations against obesity.
6,7)Nevertheless, attention has continuously focused on new anti-obesity agents from herbal resources to minimize adverse effects associated with the present anti-obesity drugs.
6)Dioscorea oppositifolia L. (Dioscoreaceae, synonym: D. opposita THUNB.) has been cultivated in China, Japan, and Korea as a food and widely used as a traditional medicine for a long time. Our current pharmacological studies showed that D. oppositifolia possesses significant inhibitory activity against porcine pancreatic lipase in vitro. 8) In addition, the anti-adipogenesis effect of D. oppositifolia n-BuOH soluble extract has been detected in cultured 3T3-L1 adipocyte.
9)Biological activities of Dioscorea species against diverse met...