Concurrent administration of aqueous extract of Cryptolepis sanguinolenta reduces the effectiveness of Artesunate against Plasmodium berghei in Rats

Concurrent administration of aqueous extract of C. sanguinolenta was earlier reported to alter the pharmacokinetics of artesunate consequently resulting in an increase in the clearance rate, which could cause sub-therapeutic levels of dihydroartemisinin of artesunate leading to reduced efficacy. In the present study, the effect of aqueous extract of C. sanguinolenta (Cryp) on the effectiveness of artesunate (Art) against Plasmodium berghei in male Sprague-Dawley rats was investigated. Twenty (20) female Sprague-Dawley rats were divided into four (4) treatment groups (1 to 4). Groups 2 (Cryp) and 3 (Cryp/Art) served as test groups, which were pre-treated with aqueous extract of C. sanguinolenta for two weeks whilst groups 1 (no drug) and 4 (Art) served as negative and positive controls, respectively and were given water. The rats were inoculated with P. berghei after the two weeks pretreatment period and were either not treated (no drug) or treated with artesunate (Art) or C. sanguinolenta (Cryp and Cryp/Art) 2 days post-inoculation. Parasitemia and chemosuppression were then determined in 4 and 6-day suppressive tests. The parasitemia in group 3 rats (Cryp/Art) was significantly (p < 0.05) higher (270%) than in group 4 (Art) on day 8. Consequently, the chemosuppression of artesunate only group was significantly (p < 0.05) higher (133%) than that of the concurrently administered Cryp/Art group. The findings show that concurrent usage of C. sanguinolenta and artesunate reduces the effectiveness of artesunate as an antimalarial. Therefore, patients should be advised on the implication of the practice of taking C. sanguinolenta and artesunate concurrently.