Jornal Europeu de Biologia Experimental Acesso livre

Abstrato

Antimicrobial and foam forming activities of extracts and purified saponins of leaves of Tephrosia vogelii

Inalegwu B. and Sodipo O. A.

The presence of saponins was detected by the formation of long-lasting foams. Foam-forming activities of crude aqueous extract(Phosphate Buffered Saline(PBS)) of the leaves were more pronounced than those of methanolic extract(Methanol/Phosphate Buffered Saline(M/PBS)). Crude PBS extract foamed with a height of 1.38+0.70mm and foaming time of 2.59+0.09 hr while crude M/PBS extracts possessed a foam height of 0.70+0.06 mm and foaming time of 1.51+ 0.02 hr. Generally, the foaming time was not proportional to the foam height. The foamforming activity of the purified saponins(PS) was also determined. The four fractions of purified saponins (PS₂, PS₃, PS₄ and PS₅) also possessed considerable and long-lasting foams with foaming activities ranging from 0.53+ 0.01 mm to 1.18+ 0.02 mm for foam heights and 1.08+0.08 hr to 1.25+ 0.09 hr for foaming times. Antimicrobial activity of crude aqueous and methanolic extracts as well as purified saponins of aqueous extract of leaves of the plant against four different bacteria(Streptococcus pneumonia, Staphylococcus epidermidis, Neisseria gonorrhoea and Escherichia coli) were determined. It was observed that with respect to all the bacteria using 100 mg/ml of extracts and 6.40 mg/ml of purified saponins there were no diameters of zones of inhibition while the diameters of zones of inhibition increased with increase in concentration of crude extracts from 200 mg/ml to 300mg/ml and purified saponins from 6.60 mg/ml to 7.02mg/ml.