Investigations on the Toxicological Effects of Aqueous Extract of Ocimum Gratissimum Leaves on Biochemical, Haematological, and Histopathological Parameters in Wistar Albino Rats

An ethnobotanical survey found over 50,000 flowering plants used to treat ailments. The medicinal properties of these plants are due to the bioactive compounds they contain. However, these bioactive components can potentially be harmful when taken at certain concentrations. Ocimum gratissimum is commonly used in Africa to treat various diseases, but its toxicity level is often overlooked. An investigation was conducted into the adverse impacts of the aqueous extract derived from Ocimum gratissimum leaves (AEOGL) on rats at varying concentrations. The acute toxicity of AEOGL was evaluated using Lorke’s method with minor modifications. The animals were exposed to AEOGL at 100, 200, 300, and 400 mg/kg doses for 4 weeks to evaluate sub-acute toxicity effects on rats. The acute toxicity analysis revealed the death of one animal following a decrease in appetite and activity. The LD50 was determined to be 6245 mg/kg of body weight. In the subacute toxicity investigation, there was a significant decrease (p<0.05) in the percentage of weight gain with rising AEOGL concentration. Kidney function parameters revealed changes in serum urea (control: 6.23±1.02; 400 mg/kg: 10.40±1.18 mmol/L), BUN (control: 3.40±0.60; 400 mg/kg: 5.86±0.55 mmol/L), and creatinine (control: 41.79±2.68; 400 mg/kg: 61.63±1.00 μmol/L). Liver function parameters also varied: AST (control: 125.94±12.39; 400 mg/kg: 165.65±8.79 U/L), ALT (control: 46.61±2.66; 400 mg/kg: 48.05±4.09 U/L), direct bilirubin (control: 0.37±0.05; 400 mg/kg: 1.15±0.06 mg/dL), and GGT (control: 0.39±0.01; 400 mg/kg: 1.03±0.05 U/L). The cardiac function parameters exhibited changes in LDH (control: 1334.68±87.20; 400 mg/kg: 1684.35±73.13 U/L), CK (control: 20.64±1.95; 400 mg/kg: 31.92±3.73 U/L), and troponin (control: 0.32±0.02; 400 mg/kg: 0.45±0.02 ng/mL). The histopathological results showed heart with myocardial vascular congestion and lungs with tissue inflammation in rats treated with high doses (400 mg/kg). The investigation concludes that high doses and prolonged oral use of AEOGL may pose health risks. Caution is advised, especially in herbal medicine.