The effects of ethanolic extracts of five different citrus peels on mean body and liver weight and serum lipid content were investigated in albino rats. Six groups (n=8 each) were fed with a high fat diet for seven days ad libitum before oral daily administration of the peel extracts of orange (OR), lemon (LE), lime (LI), tangerine (TA), grapefruit (GR) and synergistic combination of equal ratios (w/w), that is, (SY), respectively at a dose of 500 mg / kg body weight for 14 days. The positive control group received only the high fat diet (HFD), while the negative control group received only a standard diet (STD). The body weights of the animals were monitored every two days and the animals were sacrificed after the 7th and 14th days of or following the administration of the extracts. All the parameters increased in the positive control group (HFD) compared to the negative control (STD) group. Body and liver weights decreased in all treated groups, as well as serum cholesterol and triglycerides, which decreased significantly in SY and GR groups, p < 0.05. All extracts contained mainly flavonoids and alkaloids while the grapefruit peel extract contained additional saponins that could contribute to the reduction in both body weight and serum lipid content. Conclusively, peel extract from different types of Nigerian citrus which ordinarily serve as waste may synergistically be used to control and manage obesity and associated pathologies.
Key words: Citrus peel, high fat diet, obesity, serum lipids, liver and body weight.