Bioassay-guided purification, GC-MS characterization and quantification of phyto-components in an antibacterial extract of <i>Searsia lancea</i> leaves

Abstract

Phytocompounds in an aqueous methanol (70% MeOH) leaf extract of <i>Searsia lancea</i> were separated using liquid-liquid partitioning techniques and gravity-assisted column chromatography. The resultant fractions were screened for antibacterial properties (minimum inhibitory concentration, MIC) against four bacterial strains (<i>Enterococcus faecalis, Klebsiella pneumoniae, Neisseria gonorrhoeae and Staphylococcus aureus</i>). Bioactive fractions were purified using preparative thin layer chromatography (TLC) and subjected to further antibacterial screening. Phytocompounds in antibacterial sub-fractions were characterized and quantified using Gas Chromatography-Mass Spectrometry (GC-MS). An ethyl acetate sub-fraction purified from the aqueous methanol extracts of the leaves demonstrated potent antibacterial properties (MIC range: 31-61 µg/ml against <i>E. faecalis and S. aureus</i>). Based on GC-MS analysis, 81.5% of the sub-fraction consisted of broad-spectrum antibacterial compounds namely tetracosanol (43.98%) and nonadecanol (37.5%). Current research findings support the traditional use of <i>S. lancea</i> leaves to manage gastro-intestinal disorders and gonorrhoea.