Synergistic antifungal mechanism of eugenol and citral against Aspergillus niger: Molecular Level

Previous studies have demonstrated that the combination of eugenol and citral (CEC) synergistically damages the Aspergillus niger cell membrane, yet the mechanism remains elusive. This study investigated the molecular perspective of the synergistic damage mechanism of CEC on A. niger cell membrane. Both eugenol and citral are highly lipophilic, with eugenol exhibiting higher lipophilicity. Analysis of glycerophospholipids, ergosterol, fatty acid content, as well as intracellular pH and potassium ions leakage, suggested that eugenol plays a leading role in CEC. In contrast, citral had a greater effect on cell membrane potential and energy metabolism than eugenol. Furthermore, CEC regulated the expression of proteins and genes related to cell membrane synthesis, with eugenol exerting a more pronounced regulatory effect on ergosterol synthesis-related proteins than citral. These results provided new insights for future investigations into the synergistic mechanism of essential oil small molecules or antifungal agents.