Extraction, Antioxidant and Biological Activity of The Oil from Mentha spic ata.L (Spearmint) Leaves

Abstract

The aim of this study was to investigate the chemical composition, the antimicrobial and antioxidant activities of the essential oil from dried leaves of Mentha spicata (viridis). Moreover the antimicrobial activity of the oil against four bacterial species: Gram-positive bacteria, Bacillus subtilis (NCTC 8236) and Staphylococcus aureus (ATCC 25923) , Gram-negative bacterial strains Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853), and fungal strains, Candida albicans (ATCC 7596) using Agar plate diffusion method was also assessed. Antioxidant activity was performed using DPPH radical-scavenging method. The result of extraction shows that oil yield was 1.23% .From GC-MS analysis, 28 components were identified, accounting for 100.00% of the essential oil composition. The main constituents of the oil were D-carvone (57.20%) and D-Limonene (19.41%) .The essential oil exhibited moderate level of antibacterial activity against all test microorganisms, and didnot show antifungus activity. In general Gram-positive bacteria were more susceptible to Mentha spicata essential oil than Gram-negative bacteria. staphylococcus aureus was the most sensitive of the microorganisms to the antibacterial activity of Mentha spicata essential oil (inhibition zone = 13 mm). The results show this essential oil has clearly good antioxidant activity DPPH activity compared to Propyl gallate (as standard).