Abstract

Acute and sub-acute oral toxicity assessment of the aqueous root extract ofCryptolepis sanguinolenta was studied in Sprague Dawley rats for possible use as animal medication. The extract (250 - 3000 mg/kg, p.o) was administered daily for a period of 72 h and (500 - 2000 mg/kg, p.o) for 14 days for acute and sub-acute studies respectively.  Acute administration of the extract did not produce any physiological and behavioural changes. In the subacute toxicity studies however, a dose-dependent increase in the number of platelets (from a vehicle-treated control value of 353.00 ± 49.40 - 958.00 ± 42.50 in animals treated with 2000 mg/kg) was observed.  Granulocyte number also increased dose-dependently (0.77±0.15 - 3.70±0.20) from the vehicle-treated control to the group that received 2000 mg/kg, indicating possible inflammation.  Central nervous system toxicity and marginal enlargement of liver and kidney were evident in the 2000 mg/kg treated group. These findings however did not correlate with the biochemical and histopathological studies as no pathological changes occurred in the renal or hepato-biliary systems. The present results suggest that the aqueous root extract of C. sanguinolenta < 500 mg/kg orally is generally safe. However, caution should be taken with doses > 500 mg/kg as these may induce thrombocytosis, inflammation and central nervous system toxicity.

Key words:  Sub-acute toxicity, rats, Cryptolepis sanguinolenta extract.