Assessment of toxicity and anti trypanosomal activities of toad venom in rat models.

Abstract

African trypanosomiasis is considered one of the neglected diseases leading to the death of thousands of people. The case of drug resistance, coupled with adverse side effects of the available drugs, warrants urgent alternative. In this study, acute toxicity, and prophylactic and suppressive anti-trypanosomal activities were carried out followed by sub-acute toxicity of the toad venom in rats. In acute toxicity test a total of nine Wistar rats were distributed into three groups and administered 10, 100 and 1000 mg/kg body weight (bw.) of the venom, respectively. Doses of 5, 10 and 20 mg/kg bw. of the venom were administered to the rats in their respective groups in the suppressive and prophylactic and sub-acute tests respectively, and 5 mg/kg bw. of diminazene aceturate was administered to the rats in their respective groups while 2 mL/kg bw. of normal saline was administered to the control and untreated groups. The LD50 of the venom was calculated to be 31.62 mg/kg bw. No significant differences (p > 0.05) were observed between the % suppression in the prophylactic and suppressive anti-trypanosomal activities of diminazene aceturate (100 and 99.80%) and the venom at 5 mg/kg bw. (100 and 98.80%) and 10 mg/kg bw. (100 and 100%), respectively. Significant increases (p < 0.05) in the levels of ALT, AST, ALP, creatinine, urea and uric acid were observed at dose of 20 mg/kg bw. of the venom. It is shown from this study that toad venom exhibits suppressive and prophylactic anti-trypanosomal activities with no biochemical and histological alterations at lower doses.