Abstract

A major problem besetting the chemotherapy of African Trypanosomiasis is parasite resistance to the few available drugs, and a known strategy is to use combination of drugs to overcome parasite drug resistance. An attempt has been made in this study to explore the potential of Tridax procumbens and Morinda lucida individually as single therapy and as combination therapy in the treatment of trypanosomiasis. The effective dosage of the T. procumbens and M. lucida extracts were combined at ratio 1:1, 1:2 and 2:1(w/w) respectively. All treatments were by intraperitoneal and commenced after the establishment of infection. The methanol extract of M. lucida stem bark and leaves gave significant mean survival of 7.0 ± 3.3 and 9.7 ± 3.7 days respectively when compared to the untreated control (P<0.05). The ethyl acetate and methanol extracts of T. procumbens gave a mean survival of 11.7 ± 5.4 and 14.3 ± 10.2 days respectively (P<0.05). The combination of Tridax procumbens and leaves of Morinda lucida methanol extracts at 1:2 gave significant mean survival of 10±2.2 days (P<0.05) at 200 mg/kg body weight, while the least was when combined in ratio 1:1. Phytochemical screening revealed the presence of steroids, saponins, tannins, alkaloids, flavonoids, phenols and carbohydrate in the crude methanol extract and phenols, flavonoids and steroids in the crude ethyl acetate extract of T. procumbens while M. lucida showed the presence of alkaloids, tannins and saponins. The methanol extracts of the two plants exhibited significant anti-trypanosomal activity and when combined, the plant extracts showed synergy in their activity. The plant extracts therefore have the potential for use as antitrypanosomal phytomedicine which could provide antitrypanosomal drug leads.

Key words: Tridax procumbens, Morinda lucida, antitrypanosomal activity, combination therapy, Rubiaceae, Asteraceae.