Biosafety evaluation of Carica papaya aqueous leaf extract on haematological parameters and organ/body weight ratio in Wistar rats.

Abstract

Carica papaya L. (Caricaceae) is an herbaceous perennial tree crop commonly cultivated for its ripe edible fruit. Locally, the leaf decoction is used for treatment of malaria. This study investigated acute toxicity and sub-acute biosafety of C. papaya aqueous leaf extract on haematological and organ/body weight indices. Matured fresh C. papaya leaves were collected, dried and pulverized before extraction using aqueous decoction technique. The liquid extract was further concentrated to dryness and kept in an air tight bottle until further use. Acute toxicity in mice was appraised according to the method of Lorke, while sub-acute toxicity was determined by assessing haematological and organ/body weight parameters in four groups of Wistar rats pre-treated as follows: Group I (control) received distilled water (ml/kg body weight), while groups II, III and IV were administered single daily doses of 200 mg/kg, 400 mg/kg and 800 mg/kg of the extract for 28 consecutive days. The result from the acute toxicity studies was assessed to be above 5000 mg/kg, while the 28 days sub-acute test revealed that there was no significant difference, P> 0.05, in all haematological parameters and organ/body weight ratios evaluated when compared with the control. This study revealed that orally administered C. papaya aqueous leaf extract was tolerated at a single high dose, LD50 above 5000 mg/kg. Also, repeated administration of the test doses did not adversely interfere with any haematological parameter as well as organ/body weight profiles evaluated. The data obtained tend to support the biosafety of the plant extract as reportedly used in herbal home remedies.