Antibacterial, cytotoxicity and GC-MS analysis of Psidium Guajava extracts

Abstract

Leaves of Psidium guajava was extracted with water, ethanol and chloroform using percolation technique. The extracts were subjected to thin layer chromatography, bioactivity and toxicity studies as well as GC-MS analysis. The TLC chromatogram revealed 3, 4 and 6 bands respectively for the water, ethanolic and chloroform extracts. Contact bio-autographic assay conducted on the extracts against the tested bacteria showed that, out of the thirteen (13) fractions tested only one (1) showed activity on the test bacteria (Rf3).The fraction was active against all the tested bacteria with strong zones of inhibition against S. Paratyphi B, moderate against S. Paratyphi A and weak against S. Typhi. S. typhi showed slight sensitivity, S. paratyphi moderately sensitive, while S. paratyphi B showed strong sensitivity. Result of the brine shrimp lethality assay showed that all the extracts were toxic in the order of chloroform extracts (31.112µg/mL) more toxic, and then ethanolic extracts (39.903µg/mL) and lastly water extracts (49.534µg/mL). The GC-MS analysis was conducted on the most active fraction (Rf3).In the total ion chromatograms (TIC), constituents including fatty acids, heterocyclic compounds and esters among others were found. The major constituents successfully matched and identified were Oleic acid (Peak 6, 35.56% peak area), Palmitic acid (Peak 2, 20.26% peak area)and were all reported to be active principles.

Keywords: bacteria, Bioactivity, GC-MS analysis, Psidium guajava, thin layer chromatography, toxicity