Phytochemical and in-vitro antibacterial potential of Struchium spargnophora (Linn). (Compositae)

Abstract

The petroleum ether, chloroform, methanol and water extracts of the whole plant of Struchium sparganophora [Linn.] were screened phytochemically for the presence of secondary metabolites and for in-vitro antibacterial activity.  The Phytochemical screenings showed the presence of alkaloids, cardiac glycosides, traces of saponins, flavonoids and hydrolysable tannins but absence of anthraquinone glycosides.  Extracts of the plant material were screened for antibacterial properties using seven Gram positive and eight Gram – negative human pathogenic bacteria.  All the crude extracts except aqueous extract at a concentration of 100mg/ml showed various degree but broad-spectrum activity against most Gram-positive and Gram-negative bacteria.

     Of the four extracting solvents, the chloroform extracts gave the highest level of anti bacterial potency followed by the methanol extract and then petroleum ether extract in the agar cup diffusion technique.  The aqueous extract showed no activity against all the tested organisms.  Some ampicillin resistant strains of Staphylococcus aureus were sensitive to some of the extracts.  Ampicillin, gentamicin and streptomycin were used as standard reference drug.  Diameters of zones of inhibition were in the range of 10 – 25 mm for the extracts and drug.  The antimicrobial activities observed are discussed in relation to the chemical constituents reportedly isolated from this plant and the traditional use.