Anti-Plasmodial And Ifn-y Immunosuppressive Activities of an Aqueous Crude Extract from Aerial Parts of Tephrosia Purpurea

Plasmodium infections present a high risk that lead to high mortality and mobidity among human populations globally.Cellular and humoral mmune responses during inate and adaptive stages of malaria have been recorded. The most effective malaria medications are plant-derived but are costly and remain a challenge in the developing world, which is curretly focused on ethnomedicines for malaria management. Many medications contain immunomodulatory components which exhibit diverse action such as downregulation or upregulation of the immune responses. An earlier study confirmed that Tephrosia purpurea, a herb growing in arid and semi-arid regions of the world contains terpurinflavones, which were anti-plasmodial in vitro. In this study, effects of an orally administered aqueous crude extract from T. purpurea aerial parts and Chloroquine on peripheral IFN-γ and parasitemia in P. berghei infected BALB/C mice were compared. Groups of mice peritoneally inoculated with 1 × 10⁷  parasitized RBC were treated orally daily for four days with aqueous crude extract (200 mg / kg mouse body weight) or with Chloroquine (5 mg / kg mouse body weight)or normal saline. Blood samples for parasitemia and mouse IFN-γ assays were collected through the tail tip and cardiac punctures respectively. There was a significant (P< 0.05) curative activity of the extract against the established infection of P. berghei in the mice. Activities of the crude extract and chloroquine against the infection were not significantly (P< 0.05) different. The extract also significantly (P< 0.05) limited the potentially dangerous inflammatory response of IFN-γ in the infected mice. Comparatively, chloroquine significantly (P< 0.05) lowered concentration of the cytokine in infected mice more than the extract. This study has thus revealed that T. purpurea aerial parts possess potent in vivo antiplasmodial characteristics and also contains components that are immunosuppressive.