Antifungal activity and chemical composition of essential oils from Smyrnium olusatrum L. (Apiaceae) from Italy and Portugal

Abstract

The essential oils and supercritical CO₂ extracts of wild Smyrnium olusatrum L. growing in Sardinia (Italy) and in Portugal were investigated. For the study, oils were isolated from total plant aerial part (umbels containing seeds). The content of β-phellandrene (67.3% vs. 42.7%) and α-pinene (31.9% vs. 1.2%), respectively, the main components of Portuguese and Italian essential oils, declined during the maturation stage of the umbels. Contrarily, some other important components, particularly curzerene, germacrene B, germacrone, alexandrofuran, 1-β-acetoxyfurano-4(15)-eudesmene and 1-β-acetoxyfurano-3-eudesmene, increased in fruiting umbels. The chemical composition of the Sardinian oil is rather different from those of other origin. The composition of the supercritical extracts and the essential oils is markedly different, particularly due to the high amount of furanosesquiterpenoids in the supercritical fluid extraction. The minimal inhibitory concentration (MIC) and the minimal lethal concentration were used to evaluate the antifungal activity of the oils against Candida albicans, Candida tropicalis, Candida krusei, Candida guillermondii, Candida parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus. The oils were particularly active against dermatophyte strains and C. neoformans, with MIC values in the range of 0.32–0.64 µL mL⁻¹.

Keywords:

• Smyrnium olusatrum L.
• essential oil
• supercritical carbon dioxide
• antifungal activity

Acknowledgements

The authors thank Regione Autonoma della Sardegna (RAS), Italy, and Center of Pharmaceutical Studies (POC12010FEDER), Portugal, for providing financial support. Maria Assunta Frau is RAS Research Fellow in the Department of Botanical Sciences, University of Cagliari, Italy – POR Sardegna, FSE 2007-2013, L.R. 7/2007, Research and IT in Sardinia.