Phytochemical components, antimalarial activity and toxicity profile of methanol leaf extract of Polyalthia longifolia (masquaerade)

Abstract

Malaria continues to be a life-threatening disease worldwide, causing the deaths of over eight thousand individuals each year. A major obstacle in the fight against malaria is the emergence and spread of parasites that are resistant to existing drugs. Because of this problem, researchers are now focusing on discovering new, natural compounds that can fight malaria more effectively and safely. Medicinal plants have been used since ancient times in different communities for treating many illnesses. This study investigated the phytochemical components, antimalarial activity, and toxicity profile of methanol leaf extract of Polyalthia longifolia. Fresh leaves were collected, authenticated, dried, powdered, and extracted with 80% methanol using the cold maceration technique. Phytochemical screening was conducted by standard procedures while in vitro antiplasmodial activity was tested against Plasmodium falciparum–infected red blood cells at different extract concentrations. Toxicity evaluation involved acute and sub-chronic studies in rats. The extract contained alkaloids, flavonoids, saponins, tannins, steroids, triterpenes, and cardiac glycosides whereas anthraquinones was absent. Quantitative analysis showed saponins as the most abundant compound (120 mg/g). Antimalarial testing revealed 53.4% parasite inhibition at the highest concentration. The LD₅₀ was estimated above 5000 mg/kg, indicating safety at high doses, although sub-chronic administration produced dose-related changes in hematological and biochemical parameters. Overall, the methanol extract of Polyalthia longifolia leaves demonstrated promising antimalarial activity, and was relatively safe, but should be administered with caution at elevated doses.