Fractionation of Methanolic Crude Extract of Root of Senna siamea Decreases Antimicrobial Activity

The effect of different fractions of methanolic crude extract of root of Senna siamea on Escherichia coli, Salmonella typhi, and Staphilococcus aureus was investigated. Phytochemical analysis of root of Senna siamea revealed the presence of tannins, saponins, flavonoids, steroids,cardiac glycosides, and anthraquinone.The methanolic crude extract of the root of the plant exhibited highest activity on Escherichia coli and Salmonella typhi both with zone of inhibitions of 30.00 mm and least activity on Staphilococcus aureus with a value of 23.00 mm. The extract was further separated chromatographically using different solvents, four fractions were collectedand designated: I, II, III and IV which were eluted using methanol/water (1:1), ethylacetate/methanol (19:1), benzene/methanol (9:1) and acetic acid/methanol (1:1). Among the four fractions, fraction IV had least effect on the test organisms ranging from 0.00 mm to 20.00 mm while fraction I had highest effect on the test organisms ranging from 13.00 mm to 20.00 mm. This study revealed that fractionation of the methanolic crude extract of the root of Senna siamea resulted in the decrease of activity on the test organisms.