Grapefruit (Citrus Paradise, family Rutaceae) is a citrus fruit that is low in calories and rich in dietary fibers. Sibutramine (Sibutramine hydrochloride monohydrate) is an anti-obesity drug that enhances satiety. The effect of grapefruit juice and sibutramine on body weight and neurotransmitters controlling appetite was investigated in obese rats. Rats were assigned to two dietary groups for 3 weeks; control group (n=6) was fed commercial standard pellets diet and obese group (n=24) was fed cafeteria diet (hypercaloric diet consisting of highly palatable food). The effect of sibutramine and grapefruit juice was studied on obese rats. Statistical difference and interactions were evaluated through one-way analysis of variance test (one-way ANOVA) followed by Dunnett's test was used for means of different groups. For all statistical tests done, a 0.05 level of probability was used as the criterion for significance. Grapefruit juice produced its weight reduction effect after 1 week of administration and lasted till the end of the experiment and did not affect brain neurotransmitters. Sibutramine produced its weight reduction effect after 1 week of administration and lasted for only 2 weeks and produced an increase in brain noradrenaline while grapefruit juice produced its effect from the first week till the end of the study. It can be concluded that grapefruit juice is better than sibutramine since its effect lasted till the end of the experiment and also did not affect brain noradrenaline.

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Metabolic syndrome is a cluster of cardiovascular and metabolic risk factors that include impaired glucose metabolism and obesity. The use of nutraceuticals is an ideal choice for controlling this disorder. The aim of the present study is to investigate the effect (-) hydroxycitric acid present in garcinia fruit rind and (+) hydroxycitric acid present in hibiscus calyx on metabolic syndrome and compare it to that of metformin. Metabolic syndrome was induced in rats by ingestion of high fat high fructose (HFHF) diet for 90 days. Metformin (500 mg/Kg animal b.wt.), garcinia (1000 mg/Kg animal b.wt.) and hibiscus (250 mg/Kg animal b.wt) were orally administered throughout the last 30 days of the HFHF diet regimen. Both garcinia and hibiscus were effective in reducing serum blood glucose and insulin levels. The effect of garcinia on blood glucose was comparable to that of metformin, while the effect of hibiscus on insulin and HOMA-IR was comparable to that of metformin. Both were able to reduce serum leptin level. All treated groups showed a significant decrease in total cholesterol level. Only hibiscus was able to normalize liver function while garcinia failed to reduce the elevated liver function. As a conclusion we would recommend the use of hibiscus over garcinia to overcome the adverse effects of metabolic syndrome.