Multiple cycles of repeated treatments with a Phaseolus vulgaris dry extract reduce food intake and body weight in obese rats

Previous lines of experimental evidence have suggested that Phaseolus vulgaris extracts reduce food intake, body weight, lipid accumulation, hedonic properties of food, carbohydrate absorption and metabolism, and glycemia in rats. The present study was designed to assess the effect of multiple cycles of repeated treatments with a standardized Phaseolus vulgaris dry extract on daily food intake and rat body weight in genetically obese Zucker fa/fa rats (Experiment 1). Additionally, this study tested the effect of acute treatment with Phaseolus vulgaris dry extract on post-prandial glycemia in Zucker fa/fa rats (Experiment 2). In Experiment 1, Phaseolus vulgaris dry extract was administered daily, at the doses of 50 and 500 mg/kg, in three 5-day treatment periods followed by three 20-day off-treatment periods. Administration of Phaseolus vulgaris dry extract resulted in dose-dependent decreases in daily food intake and body weight in each treatment phase. Reductions in food intake were of comparable magnitude in each treatment phase. In Experiment 2, food-deprived rats were acutely treated with 50 and 500 mg/kg Phaseolus vulgaris dry extract immediately before access to a fixed amount of a starch-enriched chow. Treatment with Phaseolus vulgaris dry extract resulted in a dose-dependent suppression of glycemia. These results extend previous data on the anorectic and hypoglycemic effects of the Phaseolus vulgaris dry extract to a validated animal model of obesity. Together with data published previously in literature, these results strengthen the hypothesis that potentially effective, novel pharmacotherapies for obesity and related disorders may originate from extracts and derivatives of Phaseolus vulgaris.