Effects of ethanolic extracts of Nigerian Citrus peels on body weight, liver weight and serum fat contents in albino rats
Obesity is life threatening and an emerging serious health concern throughout all cultures, especially now in Africa, as diets tend towards western type. Several measures to reduce body weight include low fat diets, use of leptins and drugs to suppress appetite and induce thermogenesis as well as the use of herbs. Citrus peels have been used in certain cultures for weight control, among other pharmacological uses. As part of an on going search for local herbal drugs for weight control, this work investigated the comparative effects of ethanolic extracts of the peels of five locally grown citrus species on mean body and liver weight, serum fat content at a dose of 500mg/kg body weight in rats fed a high fat diet. The synergistic effects of equal combinations of these extracts (w/w) were also investigated. Rats were divided into eight groups (n=8 each). The first five groups were fed a high fat diet for seven days before a daily administration of the peel extracts of orange (OR), lemon (LE), lime (LI), tangerine (TA) and grape (GR) at a dose of 500mg/kg body weight for 14 days. The sixth group, in addition, received a synergistic combination (SY) of equal combinations of the 5 citrus peel extracts (w/w). The seventh (positive control) group received only the high fat diet (HFD), while the eighth (negative control) group received only a standard feed (STD). The weights of the animals were taken periodically and the animals were sacrificed after the 7th and 14th days of administration of extracts. Their liver weights were taken at necropsy and their sera tested for cholesterol and triglycerides using Randox Test kits. Whereas all the parameters increased in the positive control group (HFD) relative to the negative control (STD) group, there was a remarkable decrease in weight in all the test groups, but most significantly for SY and GR groups, at p<0.05. Suppression of appetite was observed in SY, OR, LI, and GR groups but not for LE and TA groups. Exfoliation of hairs was also observed for SY, OR and GR groups. Liver weight, serum cholesterol and triglycerides also decreased, but significantly mainly for the SY and GR groups (p<0.05). All extracts contained flavonoids and alkaloids as the main phytochemicals, while the grape peel extract had additional saponins. This could probably contribute to it being the most effective single extract in the reduction of both body weight and serum fat content. All statistical analyses were done using Graph Pad prism 4.
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