Characterization of the biological potential of the essential oils from five species of medicinal plants

Abstract

Essential oils from Mentha piperita, Cymbopogon citratus, Rosmarinus officinalis, Peumus boldus and Foeniculum vulgare were extracted by hydrodistillation, chemically characterized and quantified by GC/MS and GC/FID. The principal componentes in the essential oil of M. piperita (carvone and limonene), C. citratus (geranial, neral and myrcene), R. officinalis (1,8-cineole, camphor and α-pinene), P. boldus (α-terpinyl formate, p-cymene and 1,8- cineole) and F. vulgare (methyl chavicol, limonene and fenchone) were identified. The oils were tested for antioxidant activity employing the DPPH (2,2- diphenyl-1-picryl-hydrazyl) radical-capture method, the oxidation of the βcarotene/linoleic acid system, and the ABTS radical-capture method. The essential oils were not effective. The antioxidant activities of the oils were determined by the hydroxyl method, and the highest activity (62.80%) was observed with the essential oil from M. piperita. Activities of 1.54 and 1.82 μg μg−1 , respectively, were observed for the essential oils from C. citratus and P. Boldus using the phosphomolybdenum method. No activity was observed with respect to reducing power. The essential oil from C. citratus was effective in inhibiting the growth of L. monocytogenes (15.63 mg∙L−1 ), S. choleraesuis (15.63 mg∙L−1 ) and E. coli (31.25 mg∙L−1 ), and the essential oil from P. boldus inhibited the growth of S. aureus (62.5 mg∙L−1 ). No essential oil inhibited the growth of P. aeruginosa. A low antioxidant activity and a promising antibacterial activity were observed for these essential oils.