Abstract

Euphorbia hirta powdered plant material was extracted using 3 solvents methanol, hexane and distilled water. The water extracts provided the higher yield and also more antibacterial effectiveness than when organic solvents were used. Phytochemical screening of the crude extracts revealed the presence of tannins, saponins, phenolics, flavonoids, cardiac glycosides, anthroquinones and alkaloids. This presence of these bioactive constituents have been linked to the antimicrobial activity of the plant material, the agar well diffusion method was used to determine the antimicrobial activity against Escherichia coli, Klebsiella pneumoniae. Shigella dysentriae, Salmonella typhi and Proteus mirabilis, a group of gram-negative bacteria that frequently cause enteric infections in humans. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranged from 25 to 100 mg/ml. The growth of all the bacteria were inhibited though to varying degrees, thus justifying the use of the herb in traditional medicine in treating enteric infections, with E. coli and S. typhibeing more susceptible, the antibacterial activity of the plant material is enhanced under acidic conditions and at elevated temperatures. The herb E.hirta can be used as source of oral drugs to fight infections caused by susceptible bacteria.

Key words: Euphorbia hirta, phytochemical, methanolic extract, hexane extract, aqueous extract, enteric infections, antimicrobial activity.