Phytochemical and in-vivo antimalarial investigations of Dichrostachys cinerea (L.) Wight & Arn. (Fabaceae) Root bark.

Abstract

The various parts of Dichrostachys cinerea (L.) are ethnomedicinally useful in the management of malaria. This study investigates the in-vivo antimalarial potentials of the ethanol extract of D. cinerea root bark and its fractions, as well as, the isolation and characterization of a phytoconstituent from one of the active fractions. Phytochemical, acute toxicity and antimalarial potentials of the crude ethanol extract of D. cinerea (ED) its chloroform- (EDC), ethyl acetate- (EDE) and butanol- (EDB) fractions were evaluated. The extract, ED and its fractions revealed no toxicity in mice, up to 2000 mg/kg. In-vivo antimalarial testing of extract and fractions against P. berghei using the 4-day suppressive testing revealed that fractions EDC and EDB at 600 mg/kg significantly (p < 0.05) suppressed the level of parasitemia, prolonged the mean survival time (p < 0.05) and protected infected mice against reductions in rectal temperature (p > 0.05), body weights (p > 0.05) and packed cell volume (p < 0.05); all in comparison with Chloroquine at 25 mg/kg/day. Application of different chromatographic and spectroscopic techniques to fraction EDB led to the isolation and characterization of Methyl 2, 3-dihydroxy-4-methoxybenzoate (a derivative of methyl gallate). These findings revealed that the strong presence of phenolic constituents, either acting singly or synergistically with other bioactive compounds probably contributed to the antimalarial activity of factions EDC and EDB and hence, the folkloric use of D. cinerea root bark as an antimalarial agent; an indication that the plant might be a potential source of novel antimalarial agent(s).