Long-term administration of an aqueous extract of dried, immature fruit of Poncirus trifoliata (L.) Raf. suppresses body weight gain in rats

Aim of study: The purpose of the present study was to examine the effects of daily administration of an aqueous extract of the dried, immature fruit of Poncirus trifoliata Raf. (Rutaceae) (PF-W) on body weight in rats. Materials and methods: PF-W was used in following experiments: 10-week-long measurement of body weight and food intake, in vitro pancreatic lipase activity assay, in vivo triglyceride concentration study, and measurement of intestinal transit rate. Results: A high dose of PF-W (200 mg/2 mL/animal/day, in aqueous solution) was administered intragastrically to rats for 10 weeks. PF-W suppressed body weight gain by 6%. However, administration of PF-W at a lower dose (20 mg/animal/day) did not reduce weight gain. Administration of low- or high-dose PF-W had no effect on food intake throughout the experimental period. Additional experiments revealed that the suppressive effect of PF-W on body weight gain was not related to pancreatic lipase activity. Moreover, co-administration of PF-W with a lipid emulsion did not reduce plasma triglyceride concentration. Of interest, the high dose of PF-W significantly increased the rate of intestinal transit, whereas oral administration of the lower dose did not. Control and PF-W-treated groups did not differ in hematological and serum biochemical parameters, or in relative organ weights after 10 weeks of high-dose PF-W administration. Conclusion: PF-W does not suppress body weight gain by interfering with fat absorption in a pancreatic lipase-dependent manner. The suppressive effect of PF-W on weight gain is likely due to the increased rate of intestinal transit, and the consequent reduction in nutrient absorption. Moreover, it appears that PF-W is relatively safe for long-term use. Taken together, the results of the present study suggest that long-term, daily administration of PF-W successfully suppressed body weight gain-apparently due to accelerated intestinal transit and not to interference with pancreatic lipase activity. Due to its apparent long-term safety, PF-W is a potential therapeutic agent for reduction of body weight in humans.