Evaluation of Phytochemical and Antimicrobial Constituents of the Aerial Parts of Mentha spicata Lam

Abstract

Mentha spicata Lam has a sub-cosmopolitan distribution across Europe, Africa, Asia, Australia and North America. The aerial parts of   Mentha spicata Lam was studied to evaluate its chemical constituents as well as its antimicrobial efficacy. The result of the qualitative  phytochemical screening of the aerial parts of this plant revealed the presence of alkaloids, flavonoids and saponins in different  concentrations. The result of the quantitative phytochemical screening shows that the ethyl acetate of Mentha spicata revealed the  highest percentage yield of alkaloids to be 12.5 % w/w. The percentage yield of flavonoids in the ethyl acetate fraction was 0.57 %, tannins  was 0.93 % while phenol was 1.28 % using 0.1 g of the extracts. The result of the antimicrobial susceptibility test of Mentha  spicata shows the highest zone of inhibition of 24 mm for Candida albican while the ethyl acetate fraction and hexane fraction show no inhibition. The methanol fraction of the plant shows a Minimum Inhibitory Concentration (MIC) value of 20 mg/ml for Bacillus subtillis,  Pseudomonas aeruginosa, Escherichia coli and Trichophyton rubrum. These results on the phytochemicals and antimicrobial activity of  this plant justify the traditional use by local populations. The findings, therefore, suggest that there is an indication that the aerial parts of  Mentha spicata Lam contain phytochemicals that may be linked to its beneficial effects on health.