Antimalarial Effects of Ethanolic Leaf Extracts of Azadirachta indica and Ocimum gratissimum, and Their Histologic Effects on Some Organs (Liver, Kidney and Heart) of Plasmodium berghei Infected Albino Mice

Azadirachta indica (Neem) and Ociumum gratissimum (clove Basil) have long been employed locally for the management of malaria. The present study compared antimalaria activities of the ethanolic leaf extracts of the individual plants, and assessed their combined effects on some organs of malaria-infected mice, at the Parasitology and Histopathology units, Federal Medical Centre (FMC), Owerri, from January to March, 2021. The leaves of the different plants were extracted with absolute ethanol (BDL 95%) for the test. Clean albino mice were experimentally infected intraperitoneally with chloroquine-sensitive Plasmodium berghei NK65 strain. Parasitaemia level was determined before parasite inoculation and at 24 hours post treatment period. Histopathological study on the liver, kidney, and heart was carried out using the Paraffin Setions method. Extracts of the leaves were administered orally, while chloroquine administration was intramuscular. The efficacy of the leaf extracts was tested on the P. berghei infected albino mice using the 4-day curative test. The lethal median dose (LD50) recorded for neem and clove basil leaf extracts were 31.62 and 1246.9 mg/kg body weight, respectively. Significant activity against the parasite was produced by infected mice treated with extracts of A. indica and O. gratissimum, and their combinations throughout the treatment period (P<.05). Highest reduction of parasitaemia was observed on day 4. Maximum parasitaemia reduction (78.65%) was attained with 30mg/kg of the combined extracts on the 7th day. Mild pathological lesions were observed in mice treated with A. indica leaf extract. These observations indicate better anti-malaria activity of the combination therapy as compared with the individual extracts of A. indica and O. grassimum, and indicate good antimalarial and protective roles of the plant extracts on the parasitized mice at large, as it slows down development of resistance.