Antifungal activity and mechanism of the essential oils from Litsea (Litsea cubeba), Melissa (Melissa officinalis), Palmarosa (Cymbopogon martini) and Verbena (Verbena officinalis) and their major active constituents against Trametes hirsuta and Laetiporus sulphureus

Abstract Antifungal activities of 37 essential oils (EOs) against two wood-decaying fungi, Trametes hirsuta and Laetiporus sulphureus were screened in vitro, and investigated the underlying mechanism. Of the 37 EOs, litsea (Litsea cubeba), melissa (Melissa officinalis), palmarosa (Cymbopogon martini), and verbena (Verbena officinalis) demonstrated strong antifungal activity, in which litsea oil exhibited the strongest antifungal property against T. hirsuta and L. sulphureus, with IC50 values of 72.3 and 40.2 µg/ml, respectively. The compositions of litsea, melissa, palmarosa, and verbena EOs were analyzed using a gas chromatography-mass spectrometry method and demonstrated geranial, geraniol, neral, and citral as their major active constituents. Among of them geranial exhibited the strongest antifungal activity against T. hirsuta and L. sulphureus, with IC50 values of 56.6 and 33.3 µg/ml, respectively. These EOs and their major active constituents increased the plasma membrane permeability of T. hirsuta and L. sulphureus, resulting in the leakage of nucleic acid, protein, and soluble sugar. Results indicate that the EOs of litsea, melissa, palmarosa, and verbena and its major constituents inhibited T. hirsuta and L. sulphureus growth by targeting its plasma membrane.