Microwave-Assisted Hydrodistillation of Essential Oil from Plectranthus amboinicus: Evaluation of Its Antifungal Effect and Chemical Composition

Abstract

Fusarium wilt, a vascular syndrome in a wide range of plants, is caused by the pathogen Fusarium Oxysporum. The objective of this investigation was to evaluate the antifungal effect of four essential oils (EOs) (Plectranthus amboinicus, Syzygium aromaticum, Lippia alba, and Rosmarinus officinalis), which were obtained by using microwave-assisted hydrodistillation (MAH), against F. oxysporum. The yield obtained from P. amboinicus with the use of MAH was 0.2%, which was higher than that of a conventional extraction; its extraction time was also shorter. For concentrations of 100 and 300 μL/L, P. amboinicus caused an inhibition rate of 27.2 and 55.7%, respectively, while S. aromaticum caused an inhibition rate of 23.1 and 87.3%, respectively. It was observed that increasing the concentration also increased the % inhibition rate. The extracts of L. alba and R. officinalis caused an inhibition rate of 14.5 and 14.7% at 500 µL/L, respectively, at 10 days of incubation, while at this concentration, P. amboinicus and S. aromaticum achieved 100%. The major chemical compounds of P. amboinicus were carvacrol (41.20%), o-cymene (11.61%), caryophyllene (11.45%), α-bergamotene (7.71%), and caryophyllene oxide (4.62%), and these monoterpene hydrocarbons were responsible for the biological activity. The essential oil of P. amboinicus in appropriate concentrations is a potent antifungal agent that could be used for the control of F. oxysporum.

The Fungicidal Effect of Essential Oils of Fennel and Hops against Fusarium Disease of Pea

“…The essential oils studied also significantly reduced the concentrations of fungal mycotoxins, zearalenone and group B trichothecenes, in wheat grains [71]. The inhibitory effect of The antifungal activity of essential oils extracted from other plant species has been investigated in numerous studies [49,[70][71][72][73][74][75]. Different ways of applying essential oils to plants are also used, e.g., dipping the seeds in the tested essential oils for 24 h reduces the Fusarium wilt and seedling rot and improved the survival of pea plants [76].…”

“…The antifungal activity of essential oils extracted from other plant species has been investigated in numerous studies [49,[70][71][72][73][74][75]. Different ways of applying essential oils to plants are also used, e.g., dipping the seeds in the tested essential oils for 24 h reduces the Fusarium wilt and seedling rot and improved the survival of pea plants [76].…”

Chemical Composition and Biological Activities of Essential Oil from Plectranthus amboinicus Collected in Dak Lak, Vietnam

“…This work is licensed under the Creative Commons Attribution 4.0 International License grown in Mexico via microwave and GC-MS analysis. 23 In comparison, the content of carvacrol (41.20%) is lower but those of ocymene (11.61%) and caryophyllene (11.45%) are higher in the essential oil from Mexico than in the oil from Buon Ma Thuot.…”