PHYTOCHEMICAL AND BIOLOGICAL STUDIES OF THE COMPOUNDS OF AERIAL PARTS OF SENECIO LYRATUS (ASTERACEAE)

Abstract

Extracts of the aerial parts of Senecio lyratus were phytochemically and biologically studied. The extracts exhibited biological activity against bacterial and fungi. The aerial parts of S. lyratus were collected from Kericho District in Kenya. Brine shrimps (Artemia salina) lethal toxicity tests were done on n- hexane, dichloromethane and methanol extracts. Their LD50 were 506.11, 553.21 and 689.44 ppm, respectively. The n-hexane extract was found to be more potent and its column chromatographed fractions were subjected to anti-bacterial and anti-fungal tests in vitro. Two fractions RSL9 and RSL5 had equal inhibition diameters of 9.00 mm against Staphylococcus aureas and 8.33 mm against Bacillus subtilis at 1000 ppm. The isolated pure compounds were also subjected to anti-bacterial and anti-fungal assay test and proved to be relatively active. Compounds Rsle and Rslb had inhibition diameters of 10.00 and 11.67 mm against Candidas albicans fungi, respectively. The highest inhibition diameters for Rsle and Rslb against Pseudomonas aureginosa bacteria were 8.33 and 7.33 mm, respectively at 1000 ppm. Three compounds were characterized from the n-hexane extract by use of physical and spectroscopic data. The isolated compounds were -amyrin (24), -sitosterol (25) and stigmasterol (26). A fourth compound is yet to be characterized.