Bioactivity guided fractionation of Icacina trichantha Oliv. (Icacinaceae) tuber for antimalarial activity against Plasmodium berghei infected mice and GC-MS profile of bioactive fraction

Abstract

Aqueous methanol extract of the tuber of Icacina trichantha was prepared using cold maceration and dried in vacuo at 40°C. The extract was purified using solvent-solvent partitioning with n-hexane, dichloromethane, ethyl acetate, n-butanol. n-Hexane fraction was purified using Vacuum Liquid Chromatography, eluting with a gradient of dichloromethane in methanol (9:1, 7:3, 5:5, 0:10, each 500 mL) to obtain four sub-fractions. Acute toxicity study was done using Lorke’s method while in vivo anti-malarial study was carried out using suppressive model. Phytochemical analysis was carried out using standard procedure and most active sub-fraction was subjected to gas chromatography-mass spectroscopy. The extract at doses of 100, 200 and 400 mg/kg caused a significant (p<0.001) increase in percentage suppression of Plasmodium: 91.54 %, 94.48 % and 94.58% respectively. Phytochemical analysis of the extract revealed the presence of alkaloids, tannins, flavonoids saponin, glycoside, terpenoids, phenols, steroids, carbohydrates, reducing sugars. The GC-MS analysis showed the presence of eighteen compounds, the most abundant compound includes 9- octadecenoic acid (Z)-, methyl ester (oleic acid, 15.30%), 9, 12-octadecadienoic acid (Z, Z), methyl ester (linoleic acid, 14.34%). These findings suggest scientific evidence in support to the use of I. trichantha tuber for the management of malaria.