Chronic Oral Administration of Ocimum gratissimum Leaf Extract Induced Gastrointestinal Necrosis in Treated Albino Rats

Aim: This study was designed to investigate the effect on of Ocimum gratissimum leaves extract on the histology of the gastrointestinal tract in rats.

Study Design: Adult rats of both sexes were used for the work. The study was carried out at the Departments of Physiology and Histology, College of Veterinary Medicine, Michael Okpara University of Agriculture, Umudike, Nigeria between September 2014 and January, 2015.

Methodology: Fifty adult albino rats and 35 Mice were used for the study. The mice were used for acute toxicity study while the rats were divided into five groups of 10 rats each and were used for the histological study. Groups 2-5 were assigned different dose levels of OGLE in the order 100, 200, 400 and 800 mg/kg respectively while group 1 was given only feed and water. Treatment was given by the oral route and lasted for 28 days.

Results: Phytochemical compounds identified in the extract include protein and carbohydrate which occurred in high amounts, tannins, flavonoids and glycosides in moderate quantities, saponins, steroids and phenolic compounds in low amounts while tannins and alkaloids were absent. An LD50 and ED50 values of 2075 mg/kg and 850 mg/kg body weight respectively were obtained for the extract with a Therapeutic Index value of 2.44. Chronic oral administration of the extract also caused various degrees of histological changes in the gastrointestinal tract in all treated animals with significant erosions of the mucosa and submucosa. The gastrointesinal necrosis produced by Ocimum gratissimum leaf extract after long term treatment was dose dependent with 100 mg/kg inducing only mild necrosis of the villi, 200 mg/kg, a higher necrosis of the villi, while 400 mg/kg and 800 mg/kg induced severe necrosis of both the villi and the intestinal mucosa.

Conclusion: Results obtained from this study therefore suggest that Ocimum gratissimum leaf extract is rich in bioactive compounds and may be well tolerated at low to moderate doses during short term treatment but may cause gastrointestinal erosions when used continuously over a long period.