The Antifungal Activity of <i>Litsea cubeba</i> Essential Oil against <i>Trametes hirsuta</i> and <i>Laetiporus sulphureus</i> is Mediated by Plasma Membrane Damage

Trametes and Laetiporus are globally recognized as major wood-decaying fungi. To explore safe and environmentally friendly alternatives, the antifungal activity of 37 plant essential oils (EOs) against Trametes hirsuta and Laetiporus sulphureus was assessed using the mycelial growth rate method. The results revealed that Litsea cubeba EO exhibited the strongest inhibitory effects, with 50% effective concentration values of 72.3 and 40.2 µg/mL. Subsequent mechanistic studies were conducted. Gas chromatograph-mass spectrometry analysis identified geranial (32.12%) and neral (29.43%) as the primary bioactive compounds. Optical microscopy of the treated mycelia revealed morphological abnormalities, including surface wrinkling, and confirmed membrane damage via propidium iodide fluorescence. Further biochemical analysis revealed increased levels of nucleic acids, proteins, soluble sugars, and ergosterol. These findings collectively demonstrate that L. cubeba EO disrupts plasma membrane integrity in both fungi, effectively inhibiting mycelial growth. These results highlight the significant potential of L. cubeba EO as a natural wood preservative.