AN IN-VIVO EVALUATION OF ANTIPLASMODIAL ACTIVITY OF AQUEOUS AND ETHANOLIC LEAF EXTRACTS OF AZADIRACHTA INDICA IN PLASMODIUM BERGHEI INFECTED BALB/c MICE

Abstract

Malaria remains one of the most prevalent infections in the tropical regions of the world. The increased resistance of the parasite to many available antimalarials backs the need to develop novel antimalarial drugs with effective mode of action. Several plants with antiplasmodial properties have been proved as sources for novel antiplasmodial compounds. Azadirachta indica has widely been reported for its medicinal properties. The leaf extract is used in folklore medicine to treat malaria. Previous in vitro studies has shown that the leaf extract of A. indica possess antiplasmodial properties. In the current research, the antiplasmodial activity of both aqueous and ethanolic leaf extracts of A. indica (ALEAI and ELEAI respectively) were studied in vivo using Plasmodium berghei infected BALB/c mice at 50, 100 and 200mg/kg/day dosages. The extracts were also screened for phytochemicals using standard methods. Preliminary phytochemical screening revealed the presence of alkaloids, saponins, tannins, reducing sugars, flavonoids and polyphenols in both extracts. Both ELEAI and ALEAI demonstrated significant antiplasmodial activity in vivo against plasmodium berghei in a dose-dependent manner. During early infection, oral administration of 50, 100 and 200mg/kg/day dosages of ELEAI caused chemosuppression of 56.96, 63.15 and 69.60% respectively on day four and a chemosuppression of 69.65, 75.76 and 78.32 % respectively on day six. Similar dosages of ALEAI respectively caused chemosuppression of 56.96, 59.89, 69.49% on day four and 64.42, 70.23 and 77.41% on the sixth day. These values were statistically significant (P < 0.001) as compared to negative control. The LD50 of the ELEAI was found to be greater than 1g/kg body weight of naive mice. Results from the present study therefore confirm that A. indica leaf contains active antiplasmodial compounds and therefore can be very useful in the search for new antimalarial drugs.