The Effects of Ethanolic Extract of Ocimum gratissimum (Linn.) Leaves on Selected Reproductive Hormones and Insulin on Letrozole-Induced Polycystic Ovarian Syndrome in Wistar Rats

Abstract

Polycystic ovarian syndrome is a common endocrine disorder found mostly in women of reproductive age. It is characterized by menstrual irregularities, hyperandrogenism and polycystic ovaries and metabolic disorders such as hyperinsulinemia and dyslipidemia. Management options such as metformin and clomiphene citrate has been provided but these drugs have side effects which limit its acceptability. Thus the search for alternative options in plants like Ocimum gratissimum is desirable. Ocimum gratissimum is a plant that has been identified for its effectiveness in treating ailments. This study was designed to investigate the effect of the ethanolic extract of Ocimum gratissimum leaves on the oestrous cyclicity, hormones and lipid profile in letrozole induced PCOS. After the induction of letrozole (1mg/kg), normal (n=4) and PCOS (n=16; were distributed into 4 groups of 4 animals/group) were treated for 14 days orally with distilled water (1ml/kg), metformin (500mg/kg), clomiphene citrate (2mg/kg) and ethanolic extract of O.gratissimum (50 and 100mg/kg). The oestrous cycle, hormones, lipid profile, fasting blood glucose and body weight were measured. The letrozole induced PCOS was characterized by high triglycerides, low density lipoprotein (LDL), total cholesterol, insulin, testosterone, and luteinizing hormone (LH) concentrations. Low levels of high density lipoprotein (HDL), follicle stimulating hormone (FSH), progesterone and fasting blood glucose concentrations compared to the control group. The PCOS rats also had an altered oestrous cycle compared to the control group. Administration of the ethanolic extract of O.gratissimum at 50mg/kg increased the serum concentration of insulin, testosterone, FSH, total cholesterol and triglycerides and decreased the concentration of progesterone, LH, HDL and LDL. However, 100mg/kg of the ethanolic extract increased the serum concentration of testosterone, insulin, LH, HDL, LDL, and triglycerides and reduced the concentration of FSH, progesterone and total cholesterol. Ethanolic extracts of O.gratissimum however did not regulate the reproductive and oestrous acyclicity induced alterations of PCOS rats.