Trans chalcone

Trichophyton rubrum CBS 118892 was cultured on Sabouraud dextrose agar (Oxoid, Hampshire, England) at 28 °C, as described previously [28 (link)]. Conidial suspensions were obtained from 15-day-old plates. The conidial concentration was determined in a Neubauer chamber and approximately 1.6 × 10⁶ conidia were added to 20 mL of liquid Sabouraud and incubated for 72 h at 28 °C under shaking at 150 rpm. The resulting mycelia were incubated under six different conditions: i) control medium (MMNG): Cove’s minimal medium [29 (link)] containing 70 mM nitrate (Sigma Aldrich, St. Louis, MO, USA) and 50 mM glucose (Sigma Aldrich); ii) keratin medium (MMK): Cove’s minimal medium supplemented with 0.5% bovine keratin; iii) elastin medium (MME): Cove’s medium supplemented with 0.25% elastin (Sigma Aldrich); iv) MMNG+TChal: MMNG medium containing 0.24 μg/mL of trans-chalcone (Sigma Aldrich); v) MMK + TChal: MMK containing 0.24 μg/mL of trans-chalcone, and vi) MME + TChal: MME containing 0.24 μg/mL of trans-chalcone. The pH of the medium was 5.0 in all conditions and the cultures were incubated for 3, 7, and 14 days at 28 °C under shaking (130 rpm). The concentration of trans-chalcone was based on its minimal inhibitory concentration as reported previously [9 (link)].

4′‐Hydroxychalcone was obtained from the internal compound collection of RBG, Kew. Purity and structure were verified using LC–MS and NMR. trans‐Chalcone was purchased from Sigma‐Aldrich, Gillingham, UK.