Phytochemical Analysis of Local Spearmint (Mentha spicata) Leaves and Detection of the Antimicrobial Activity of its Oil

In the present study, the chemical composition of the spearmint leaves was determined as follows: moisture (76.01 ± 0.033)%, fiber (2.1 ± 0.03)%, ash (3.48 ± 0.001)%, protein (1.75 ± 01.)%, fat (3.20 ± 0.003)%, and carbohydrates (14.46 ± 0.15)%. On the other hand, the acid value, peroxide value, iodine value, free fatty acids, refractive index at 27Co and density at room temperature were 0.0614, 1.0, 0.564, 0.0305, 1.4572 and 0.8395, respectively. The inhibitory effect of spearmint oil was detected for the growth of four microorganisms, including Escherichia Coli, Bacillus subtilis, Aspergillus niger and Candida albicans. The result indicated that the spearmint oil has a potent antimicrobial activity against all tested organisms, the highest antibacterial effect was against E.coli while the highest inhibitory level among all tested organisms was found against the mould Asperrgillus niger where the inhibition zone (19mm) was at a higher oil concentration. The study pointed out the importance of spearmint and spearmint oil, as an antimicrobial, antiseptic and preservation agent.