Chemical composition and antimicrobial activity of the essential oil from Chrysocoma ciliata L. leaves

Chrysocoma ciliata L. is one of the South African medicinal plants used for the management of pains, stomach and menstrual disorders by the people of the Eastern Cape. The essential oil extracted from the leaves of the plant through hydrodistillation yielded 1.20% (volume/fresh weight). A total of 37 compounds were identified, constituting 85.28% of the total oil composition. The major components of the oil were the monoterpenes (alpha-pinene, 7.87%; beta-pinene, 42.94%; myrcene, 6.13%, cis-ocimene, 7.23%; allo-ocimene, 1.18%) and sesquiterpenes (trans-beta farnesene, 1.49%; germacrene D, 1.82%; bicyclogermacrene, 2.52%; viridiflorol, 7.70%). The oil inhibited both bacteria and fungi species at relatively low concentrations. The 10 bacteria (five gram-positive and five gram-negative) used were inhibited at minimum inhibitory concentration (MIC) range of 0.08-10.00 mg/ml. Also, the oil suppressed the growth of four fungi species with inhibition zone ranging from 14.50-51.24 mm. The presence of monoterpenes as the major constituents of the essential oil from this herb could be responsible for the notable antimicrobial activity observed in this study. Therefore, the essential oil from C. ciliata could be promising natural product for the development of antimicrobial agents.