Abstract

Crossopteryx febrifuga (Afzel.) Benth. (Rubiaceae) widely used in Northern Nigeria for management of trypanosomiasis, malaria and pain, has been previously shown to possess analgesic, anti-pyretic and anti-plasmodial effects. In the present study, acute and sub-acute toxicity studies of the methanolic stem bark extract of C. febrifuga were carried out in rats. Using modified lorkes (1983) method. In the sub acute toxicity study, 4 groups of 5 rats per group were used. Group 1 rats (control) received normal 10 ml normal saline/kg body weight while rats in groups 2, 3 and 4 were given daily doses of 250,500 and 1000 mg extract/kg body weight for 28 days. The effect of the extracts on feed intake, water intake and body weight changes, haematological and biochemical parameters as well as histological studies of vital organs (heart, lungs, kidneys, liver, brain, spleen and gonads) were assessed. Treatment related mortality was observed in the rats at a dose of 4000 mg/kg orally and 600 mg/kg intraperitoneally in the acute toxicity study. The oral and the intraperitoneal median lethal dose (LD₅₀) values of the extract were calculated to be 2828.48 and 471.17 mg/kg body weight respectively. The extract at 500 and 1000 mg extract\kg body weight doses produced significant (P < 0.05) decrease in fluid and feed intake, as well as body weight. The haematological parameters were normal except a significant (P < 0.05) increase in platelet counts observed at all dose levels used. At 1000 mg extract/ kg body weight dose, the extract exerted a significant (P < 0.05) decrease that lies within the normal range values of serum aspartate, alanine transaminase and creatinine levels for this animal species. Histological findings indicated possible toxicity in the Liver, Lungs, Kidney, Testes and Uterus At 1000 mg/kg. These results suggest that oral administration of C. Febrifuga may not produce severe toxic effects at doses lower than 500mg extract/kg body weight.

Key words: Crossopteryx febrifuga, sub-acute toxicity, haematology, biochemical and histopathology.