VALUATION OF THE OIL EXTRACT FROM MENTHA SPICATA AND ITS CHEMICAL CONSTITUENTS

Abstract

Response surface methodology (RSM) has been employed to model and optimize the extraction of oil from Mentha spicata a local leaf used for several microbial and insect activities. The detailed effects of the solvents, weight of leaf (X1) and time of extraction (X2) have been studied. The interaction effects of these two (2) variables on the oil yield (X3) have been investigated using Central Composite Design of experiments. The results were analyzed using MINITAB 17 software. Soxhlet extraction method was used with three (3) different solvents hexane, ethanol and petroleum ether. Petroleum ether gave the highest yield of oil using Response Surface Methodology. The oil extract of the leaf was analyzed using Gas Chromatography-Mass Spectrometry [GC-MS], about 15 components were discovered with Carvone as the most abundant [27.68%.]. The antimicrobial activities of the oil extract against some fungi and bacteria viz., Pseudomonas aeruginosa, Bacillus Subtilis, Staphylococcus aureus, Aspergillus niger, Escherichia coli and Saccharomyces cerevisiae was evaluated. From the microbial analysis the zone of inhibitions indicated that the extract had strong activity against bacteria and fungi. Mentha spicata oil is rich in compounds with therapeutic activities and several substances of industrial interest. Carvone, Neophytadiene, methyl ester, palmitic acid and Linolenic were also discovered by the GC/MS analysis, presenting good microbial activity performance. The aim of this work was to establish the antimicrobial claim of the Mentha spicata oil extract.