Acute and chronic toxicity evaluation of methanol leaf extract of Psidium guajava (Myrtaceae)

The medicinal value of herbal plants have been widely described in a number of studies, this has resulted in their increased usage. This study aimed to evaluate the safety of methanolic leaf extract of Psidium guajava extract in albino rats using biochemical, hematological and histological parameters. In acute toxicity, the extract was administered orally up to 5,000 mg/kg body weight once to male albino mice. While in chronic toxicity, twenty four adult male albino rats were randomly divided into four groups of six rats for each group. The control group received 10 ml/kg body weight distilled water daily. The other groups received 50, 200 and 400 mg/kg body weight of extract daily for 90 days. All the rats were observed daily for signs of toxicity and mortality. At the end of the treatment period, biochemical and hematological tests were carried out on prepared sera. Histology of vital organs was evaluated. Acute toxicology showed the LD50 of the extract to be less than 5000 mg/kg. Chronic toxicological study revealed that at 200 mg/kg, there was no significant (P > 0.05) differences in hematological and biochemical parameters, and there was no alterations in the histology of the organs. However, at 400 mg/kg body weight, the concentrations of the liver biomarkers were increased, with distorted liver. Since no alterations was observed at 200 mg/kg, the extract may be considered to be relatively safe at this dose and could be used for long term treatment of infections.