Design and discovery of novel antifungal inhibitors targeting 14α-demethylase: F11 as a promising antifungal candidate

Matrine, as a natural product with antifungal activity, has been proven to be safe and exhibit certain biological activity in inhibiting fungi. Due to its low toxicity, it holds significant advantages as a natural product. However, its relatively high minimum inhibitory concentration (MIC) necessitates structural modification to enhance antifungal potency. The enzyme 14α-demethylase (CYP51) is a well-established target in antifungal therapy. Many CYP51 inhibitors have successfully entered the market, such as fluconazole and itraconazole. However, these azole drugs still face issues of drug resistance due to single-target mechanisms. Therefore, developing a new structural class of antifungal agents is essential. In this study, for the first time, matrine was used as the parent scaffold to design various types of ligands targeting CYP51. In the structural studies of these compounds, derivative F11 showed the highest binding affinity when binding to CYP51. The benzimidazole and fluorene moieties of F11 formed significant interactions with CYP51, and their incorporation markedly enhanced antifungal efficacy. In vitro assays confirmed that compound F11 possessed superior antifungal activity compared to fluconazole. In summary, this study aims to explore the potential of matrine derivatives as CYP51 inhibitors, representing chemical entities with significant antifungal activity. This approach expands the limited chemical space of existing azole drugs and offers a promising strategy to overcome azole resistance. • F11 demonstrated superior antifungal activity compared to fluconazole in vitro. • Single-fluorene compounds show stronger affinity for proteins than double-fluorene compounds. • Compounds without linkers exhibit stronger protein affinity than those with linkers. • F11 inhibits CYP51 to prevent fungal cell membrane synthesis, potentially serving as a CYP51 inhibitor.