Effect of Curcumin Pretreatment on the Susceptibility of to Photodynamic Therapy Mediated by Aluminum Phthalocyanine in Nanoemulsion.

Curcumin has antimicrobial activity, and its mechanism of action involves changing histone acetylation. Our group has shown that histone deacetylases (HDACs) inhibitors increase the sensibility of to certain antifungal treatments. Therefore, the aim of this work was to investigate whether curcumin pretreatment increases the effect of photodynamic therapy (PDT) mediated by aluminum phthalocyanine in nanoemulsion (AlPc-NE) against . The minimum inhibitory concentrations (MIC) of AlPc-NE and curcumin, along with the 72-h growth curve of cells exposed to the combined treatments, were evaluated in the reference strain H99. Additionally, further analysis was performed using HDAC gene deletion mutant strains, Δ and Δ. Curcumin reduces the effect of PDT on reference strain H99, likely due to its antioxidant properties. In the strain, 50% MIC of curcumin reduced the effect of PDT, but this effect was not observed in response to 75% MIC of curcumin. Conversely, in the Δ strain, pretreatment with curcumin at 75% MIC enhanced the efficacy of PDT in combination with 50% MIC of AlPc-NE. These results indicate that curcumin inhibits . Moreover, at lower concentrations, curcumin protects cells against oxidant damage, while at higher concentrations, it may trigger epigenetic mechanisms that compromise cell viability. In conclusion, both curcumin and PDT are active against , with HDACs affecting their efficacy, and the effectiveness of the combined treatment depends on the concentration of both curcumin and AlPc-NE.