Abstract

This study reported the antiplasmodial and immunomodulatory activities of extracts of endophytic fungi isolated from Azadirachta indica. The extracts were evaluated for potential in-vivo and in-vitro antiplasmodial activity using murine malaria models and microtechnique methods respectively. Immunomodulatory potentials of the extracts were assessed using cyclophosphamide-immunomyelosuppression in mice and hypersensitivity and hemagglutination reactions in rats, using sheep red blood cells (SRBC) as the antigen. The extracts inhibited the growth of Plasmodium berghei in-vivo and Plasmodium falciparum in-vitro. At 100 and 200 mg/kg oral doses, extracts of AIL1, AIL3, AIS1 and AIS2 recorded parasite inhibition of 95.62-97.87, 73.47-85.71, 83.11-98.63 and 94.31-100% respectively. In vitro inhibition of schizont maturation was concentration-dependent; extract of AIS2 at 1 mg/ml gave the highest activity (86.67%). A dose-related increase in the mean total white blood cell (WBC) and a significant p < 0.001 increase in neutrophil counts compared to the positive control was shown by the extracts at 100 and 200 mg/kg with a significant p < 0.05 increase in the hypersensitivity reaction to the SRBC antigen and an increase in the antibody titer value, to SRBC in rats. Thus, extracts of the isolated fungi exhibited immunomodulatory activity in both the innate and adaptive immune components of the immune system which correlated positively with the antiplasmodial activity.

Key words: Azadirachta indica, endophytes, antiplasmodial, immunomodulatory activity.