Involvement of a Multidrug Efflux Pump and Alterations in Cell Surface Structure in the Synergistic Antifungal Activity of Nagilactone E and Anethole against Budding Yeast Saccharomyces cerevisiae

Abstract

Nagilactone E, an antifungal agent derived from the root bark of Podocarpus nagi, inhibits 1,3-β glucan synthesis; however, its inhibitory activity is weak. Anethole, the principal component of anise oil, enhances the antifungal activity of nagilactone E. We aimed to determine the combinatorial effect and underlying mechanisms of action of nagilactone E and anethole against the budding yeast Saccharomyces cerevisiae. Analyses using gene-deficient strains showed that the multidrug efflux pump PDR5 is associated with nagilactone E resistance; its transcription was gradually restricted in cells treated with the drug combination for a prolonged duration but not in nagilactone-E-treated cells. Green-fluorescent-protein-tagged Pdr5p was intensively expressed and localized on the plasma membrane of nagilactone-E-treated cells but not in drug-combination-treated cells. Quick-freeze deep-etch electron microscopy revealed the smoothening of intertwined fiber structures on the cell surface of drug-combination-treated cells and spheroplasts, indicating a decline in cell wall components and loss of cell wall strength. Anethole enhanced the antifungal activity of nagilactone E by enabling its retention within cells, thereby accelerating cell wall damage. The combination of nagilactone E and anethole can be employed in clinical settings as an antifungal, as well as a food preservative to restrict food spoilage.

Effect of anethole and anethole+itraconazole assiciantion on experimental arthritis induced by Paracoccidioides brasiliensis

“…The treatment with AN+IT association showed similar efficacy to treatment with IT, but at lower doses (62.5 + 12.5 mg/kg). Fujita et al (2017) and Ueda et al (2021) reported a synergism of AN+dodecanol association and AN+naglinactone E, respectively, changing the expression of efflux pumps in yeast, and potentiating antifungals effects. As it was already mentioned above, the Grocott staining technique showed fungus presence in the joint of an infected animal, and with the histological analysis using the HE staining technique, it was observed that this fungus causes an inflammatory response with intense cell recruitment and change in synovial membrane and cartilage degradation, as demonstrated by Loth et al (2014).…”

In Saccharomyces cerevisiae ρ0 Cells, UME6 Contributes to the Activation of ABC Transporter Genes and Pleiotropic Drug Resistance via RPD3 and PDR3

“…Plasma membrane ABC transporters, such as Pdr5, Snq2, and Yor1, export a variety of functionally and structurally unrelated compounds from cells [13,16,17]. PDR5 encodes a major efflux pump of structurally and functionally unrelated drugs and xenobiotics, such as fluconazole and cycloheximide [18,19].…”

Fungal Biofilms as a Valuable Target for the Discovery of Natural Products That Cope with the Resistance of Medically Important Fungi—Latest Findings

“…Although the different types of discovered antifungal drugs have enabled progress in the management of fungal infections, serious problems regarding side effects, limited options of antifungals and mainly the development of drug resistance [ 30 , 31 , 32 , 33 ], highlight the urgent need of exploring new therapeutic approaches that overpass the unmet clinical needs [ 34 , 35 , 36 ].…”