Antifungal potential of naphthoquinone derivatives: screening of shikonin-based compounds and mechanistic insights into 5,8-dihydroxy-1,4-naphthoquinone againstand.

Abstract

Invasive fungal infections (IFIs), predominantly caused by, are a significant threat to immunocompromised individuals. The emergence of drug-resistant strains has intensified the need for novel antifungal agents. Natural naphthoquinones, including 5,8-dihydroxy-1,4-naphthoquinone (DHNQ, also as PNP-02), have broad-spectrum antimicrobial properties, but their antifungal potential againstremains underexplored. This study evaluates the antifungal activity of DHNQ derivatives and elucidates their mechanisms of action. The antifungal properties of these compounds were evaluated using the Kirby-Bauer disk diffusion method, broth microdilution assays, and phenotypic screening. DHNQ was identified as the most effective compound, and further investigation focused on its effects ongrowth, biofilm formation, hyphal development, and underlying mechanisms, including oxidative stress induction and mitochondrial dysfunction. In a murine candidiasis model, DHNQ significantly reduced the fungal burden in both the kidneys and the skin, with a minimum inhibitory concentration (MIC) ranging from 2 to 8 μg/mL, exceeding the activity of fluconazole against clinical isolates of fluconazole-resistantstrains by over 32 times. Mechanistic investigations revealed that DHNQ exerts its antifungal effects through a multi-pronged approach: inhibiting glycolysis, disrupting biofilm and hyphal formation, and inducing oxidative stress-mediated mitochondrial dysfunction. Notably, DHNQ exhibited low cytotoxicityand no observable toxicity. These properties make it a promising lead molecule for future optimization and development of treatments forinfections, pending crucial evaluations of its selectivity and safety in host environments.IMPORTANCEIn summary, this study demonstrated that DHNQ exhibits potent and broad-spectrum antifungal activity, showing significant efficacy againstbothand. Unlike conventional antifungals, DHNQ disrupted the virulence ofby inhibiting glycolysis, suppressing biofilm formation, and inducing oxidative stress-mediated mitochondrial dysfunction. These findings not only highlight the promising potential of DHNQ as a treatment forinfections but also provide critical insights that may facilitate the development of new antifungal agents.