Toxicological Evaluation of the Anti-Malarial Herb Cryptolepis sanguinolenta in Rodents

In this study, we evaluated the aqueous extract of the roots of Cryptolepis sanguinolenta (Periplocaceae), an anti-malarial herb in the West African sub-region for possible toxicity in rodents. Administration of cryptolepis (10-1000 mg kg super(-1)) daily for two weeks did not cause significant changes in most of the haematological parameters assessed. However, the MCV reduced from a vehicle-treated value of 63.1 plus or minus 0.6 to 58.1 plus or minus 0.9 g dL super(-1) at a dose of 10 mg kg super(-1), which reflected in an increased MCHC (27.8 plus or minus 0.3 to 30.5 plus or minus 0.3 g dL super(-1)), since the Hb concentration remained unchanged. Serum transaminase levels did not change significantly suggesting a limited effect on the liver. Administration of the extract (50-1000 mg kg super(-1), p.o.) 30 min before pentobarbitone (50 mg kg super(-1), i.p.) caused a dose-dependent prolongation of the rat sleeping time from 66.6 plus or minus 8.1 min (vehicle-treated control) to 266.5 plus or minus 7.0 min (1000 mg kg super(-1)). Similarly, daily treatment with the extract (50-1000 mg kg super(-1)) for 2 weeks prolonged the sleeping time from 155 plus or minus 28.4 to 292.8 plus or minus 28.7 min. This effect appeared to be CNS-related rather than an enzymatic as reflected in a decreased locomotor activity (19.4 plus or minus 1.5 to 1.8 plus or minus 0.8 min super(-1)) at a dose of 500 mg kg super(-1) body weight. All together, our results suggest that Cryptolepis could synergize with hypno-sedatives or other CNS depressants and therefore caution needs to be taken in the concomitant administration of Cryptolepis and other CNS depressants.