Abstract

The effects of methanol extract of Vernonia amygdalina leaf (chosen from several extracts tested) on survival, parasitaemia, packed cell volume and some biochemical parameters were investigated in acute Trypanosoma brucei brucei infection. Results showed that the extract was relatively safe with median lethal dose, LD₅₀ ≥5000 mg/kg/day. Although none of the extracts tested cured infected mice, the methanol extract of V. amygdalina leaf at a dose of 300 mg/kg/day increased the maximum survival days of the mice to 24 days compared to 8 days for infected control, and also temporarily cleared the parasites from circulation for up to 72 h before relapse occurred. The active methanol extract significantly (p<0.05) reduced the parasitaemia and improved the packed cell volume of the extract-treated rats. Similarly, it significantly decreased (p < 0.05) the activities of alanine and aspartate aminotransferases, urea, triglycerides and malondialdehyde levels; increased the levels of reduced glutathione (p< 0.05), superoxide dismutase (p < 0.05) and catalase (p > 0.05) activities in serum, liver and kidney; but caused no change in total protein, albumin and creatinine levels. These suggest that the methanol extract of V. amygdalina leaf has ameliorative effects and may therefore be useful in the management of animal trypanosomiasis.

Key words: Vernonia amygdalina, Trypanosoma brucei brucei, oxidative stress, anti-trypanosomal, toxicity.