Antifungal and Insecticidal Activities of Essential Oils of Four Mentha Species

Background: Mentha species are commonly used in traditional medicine for their several pharmacological properties. Mentha species are also used as spice and are known for their bactericidal, antiviral and fungicidal properties. Objectives: The main objective of this work was to evaluate the antifungal activity and fumigation toxicity of essential oils of Mentha spicata, M. pulegium, M. piperita and M. rotundifulias against fungi and Bactrocera oleae insect responsible for olive rot. Methods: Essential oils of the four Mentha species were extracted by a Clevenger-type apparatus. Their antifungal activity was tested using radial growth technique, and their insecticidal activity was examined by fumigant test. Results: Oxygenated monoterpenes were the main components of the four Mentha essential oils. All the essential oils presented antifungal activity against Aspergillus flavus, A. niger, Alternaria spp. and Penicillium spp. At the highest concentration (15 mu L/mL air), essential oil of M. pulegium caused 100% mortality after 1.5 h of exposure. However, for M. piperita and M. rotundifulia essential oils, 25 mu L/mL air was required to have mortality of 100%. Conclusions: The essential oils could act as antifungal agents and fumigants against B. oleae.