ANTIPLASMODIAL AND PATHOLOGICAL EFFECTS OF MORINDA LUCIDA (BENTH) AND ALSTONIA BOONEI (DE WILD) IN MICE INFECTED WITH PLASMODIUM BERGHEI.

Abstract

Malaria has become more difficult to control and treat with conventional drugs because of emergence and rapid spread of multidrug-resistant strains of malaria parasites. Thus, this study was carried out to evaluate the antiplasmodial and pathological effects of two medicinal plants, Morinda lucida and Alstonia boonei used by Nigerian folklore for the treatment of malaria infection. The in-vivo antiplasmodial activity against established Plasmodium berghei NK65 infection was evaluated in mice treated with extracts of Morinda lucida, Alstonia boonei, combined recipe of the plant extracts at graded doses of 400, 600, 800mg/kg and chloroquine (a standard drug) at 10mg/kg. On fifth day of treatment, there was no significant difference (P>0.05) in the percentage parasitaemia against P. berghei in mice treated at all doses of plant extracts including chloroquine at 10mg/kg. Chloroquine cleared the parasites by 100% compared to the percentage of clearance by the plant extracts. For the plant extracts, antiplasmodial activity was highest with the combined recipe of the plant extracts at 800mg/kg (92%) and 600 mg/kg (89%); 600 mg/kg of Alstonia boonei (85%); and 400 mg/kg of Morinda lucida (83%). The haematological analysis results obtained after 12 days post infection showed that the mean Packed Cell Volume, Red Blood Cell and Haemoglobin values of the negative control, infected mice treated with the plant extracts at different graded doses significantly (P>0.05) increased when compared to infected mice treated with chloroquine at 10mg/kg and the control group. This may be as a result of antiplasmodial activities of the plant extracts which only suppressed the parasites and not effective at these doses to totally clear the Plasmodial infection after five days of treatment. This study showed significant increase in mean level of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total protein and albumin of all the treatment groups when compared to the control group. Increase in the serum enzyme activity signifies damages to the liver membrane. Photomicrographs of the kidney sections of all the treatment groups showed no visible lesions except the kidney section of Plasmodium berghei infected mice treated with Alstonia boonei at 800 mg/kg and mice administered with only Alstonia boonei at 800 mg/kg body weight. Based on this result, high dose of A. boonei extract may possibly be nephrotoxic. Therefore, the isolation and identification of bioactive compounds from these medicinal plants is a approach which can be explored for obtaining less toxic and effective antimalarial drug especially against drug-resistant malaria infection.