Naphthoquinolinone Derivative with Anti- Plasmodial Activity from Vitex doniana [Sweet] Stem Bark Extracts

Abstract

In an effort to identify promising phytotherapeutical substances from plants, the bark of Vitex doniana was collected, air dried and pounded. The powder was extracted with ethanol. The crude ethanol (VD1) was macerated sequentially. Four fractions obtained namely petroleum ether (VD1-01), ethyl acetate (VD1-02), chloroform (VD1-03) and methanol (VD1-04). These fractions were assayed at various concentrations (250Dg/ml, 500Dg/ml and 1000Dg/ml) for anti-malaria activity against Plasmodium falciparum and were also screened for the presence of secondary metabolites. The ethanol extract (VD1) and methanol soluble fraction (VD1-04) exhibited the highest activity against the test organism with 68.0% and 78.0% elimination at 500Dg/ml after 72 hours respectively. The VD1-04 was subjected to activity guided column chromatography that lead to isolation of pure compound VD1-04-198 named as 3-ethyl-3,4,4a,5,6,6a,10a,11,12,12a-decahydro-1H-naphtho[2,3,-g]quinolin-2-one. This was active against the malaria parasite with 89.0% elimination at 500Dg/ml after 48 hours. The phytochemical analysis showed that the plant contain flavonoids, tannins, alkaloid, reducing sugar and steroids.

Keywords: anti-malaria, Vitex doniana, Naphthoquinolinone, phytotherapy, extract