ANTI-OBESITY PROPERTIES OF ETHANOLIC SEED EXTRACT OF SPHENOSTYLIS STENOCARPA ON HIGH FAT DIET-INDUCED OBESED RATS (RATTUS NORVEGICUS)
ABSTRACT
The anti-obesity properties of ethanolic extract of Sphenostylis stenocarpa on high fat diet-induced obese rats was investigated for a period of 28 days. A total of 72 adult albino rats were used for the study. The rats were divided into 6 groups, (A- F) comprising of 12 rats each and the groups were further replicated three times, with 4 rats each. Obesity was induced in rats of groups B to F, by feeding the rats daily with high fat diet comprising of 45% fat, 20% protein and 26% carbohydrate, for 5 weeks. Only rats with an abdominal circumference (AC) of 20 cm, thoracic circumference (TC) of 17 cm and body mass index (BMI) of 0.82 kg/m2 and above respectively were considered obese and used for the study. The extract which was obtained by standard methods was screened phytochemically. The rats in the normal control (group A) and negative control (group B) were given water and food only, while the rats in the positive control (group C) received 60 mg/kg of orlistat by oral inturbation. Furthermore, rats in groups D, E and F were administered graded doses 200 mg/kg, 400 mg/kg and 600 mg/kg of the extract, respectively. The anthropometrical parameters of the rats were determined before the commencement of treatment (week 0) and subsequently on a 7 days interval. Similarly, blood samples were obtained from the orbital sinus of each rat for the various biochemical and hormonal analyses before commencement of treatment (week 0) and subsequently on a weekly basis. The blood samples were used to ascertain the serum levels of total cholesterol level (CHO), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), serum triglyceride (TG), total antioxidant substance (TAS), aspartate aminotransferase (AST), alanine aminotransferase (ALT), fasting blood glucose (FBG), leptine and cortisol, respectively. There was no overall dose and time dependent significant difference observed in the mean weekly anthropometrical parameters of the treatment groups when compared with negative and positive control groups. However, it was observed that the thoracic circumference of the rats administered 200mg/kg of the extract was significantly reduced (P < 0.05) in the 4th week. Similarly, the abdominal circumference and the body weights of the rats that received 400mg/kg were significantly reduced (P < 0.05) in the 4th week respectively. It was equally noticed that the body mass index of the rats in the 400mg/kg treatment group significantly reduced in the 4th week. There was an overall significant decrease (P < 0.05) observed in the serum levels of CHO, LDL-C, TAG, ALT and FBGL of the rats in the treatment groups when compared with the positive and negative controls. Secondly, whereas no significant difference (P > 0.05) was observed in the serum levels of V-LDL and AST, a significant increase (P < 0.05) occurred in the HDL-C and total antioxidant levels. Whereas no overall significant difference (P > 0.05) was observed in the serum leptin and cortisol levels of the treated rats when compared with the negative control group, a significant increase (P < 0.05) was noticed in comparison with the positive control group. Conclusively, the ethanolic seed extract of Sphenostylis stenocarpa seems to possess some anti obesity potentiality which effect may become very evident with longer duration of treatment. Secondly, it possesses hypolipidaemic, hyypoglycemic and hepatoprotective effects.