In vitro Antiplasmodial and Cytotoxicity Evaluation of Ethanol Leaf Extract of Erythrina senegalensis DC

This study evaluates in vitro antiplasmodial and cytotoxicity activity of an ornamental plant commonly employed in Northern part of Nigeria for curing malaria infection. Fresh mature leaves of Erythrina senegalensis were collected, air dried, ground, percolated in ethanol for two weeks and evaporated to dryness at room temperature. The dried ethanol crude extract was fractionated with pet-ether, chloroform, ethyl acetate and methanol in order of increasing polarity. These were screened for phytochemicals, in vitro antiplasmodial and cytotoxicity test using standard procedures. The results of the phytoconstituents revealed the presence of alkaloids, tannins, flavonoids and terpenoids which could be responsible for the medicinal properties of the extract. Ethanol crude extract, pet-ether and ethyl acetate fractions were discovered to be non-cytotoxic exhibiting LC50 > 1000 µg/ml respectively. Only methanol fraction showed slight toxicity with LC50 value of 630 µg/ml. The highest activity of the extract and its fractions against Artemia salina larvae was recorded at 1000 µg/ml dose whereas lowest larvicidal activities and lethalities occurred at 10 µg/ml dose. The ethanol extract and its fractions were significantly active against Plasmodium falciparum strain (K1) with percentage elimination of the parasites were in the range of 77% - 83% at 5000 µg/ml. Ethyl acetate (71%) and methanol fraction (71%) were found to be the most active fractions at the lowest concentration of 625 µg/ml. This finding justifies the usage of the plant in traditional medicine by traditional healers and local populace against malaria disease. The observed value for cytotoxicity assay of LC50>1000 µg/ml recorded for the ethanolic extract suggested that oral intake of the extract could be deemed safe and would not be lethal at low/moderate dose as lethality is directly proportional to dosage and oral consumption of the extract as over dosage could lead to lethality and subsequently, mortality over a long period of time due to bioaccumulation. The isolation of antiplasmodial compounds from the leaves of the plant is necessary as it could be a potential candidate for novel antimalarial drugs. Continuous utilization of the leaves as antimalarial and the wide range of its safety at low and moderate dosages further supports its use among the less privileged and vulnerable people in malaria endemic areas in lieu of existing expensive modern antimalarial drugs.