Antimicrobial and anticancer applications and related mechanisms of curcumin-mediated photodynamic treatments

Curcumin has gained increasing attention in recent years due to its biological properties and photosensitivity. Curcumin-mediated photodynamic therapy has been used in antibacterial and anticancer applications. Considering the importance and rapid advances in curcumin-mediated photodynamic treatments and its related beneficial functions, a comprehensive and up-to-date review is timely to summarize the state-of-art in this area and to suggest directions for future progress. In this review, photodynamic therapies (PDT) with curcumin as photosensitizers are discussed, with particular emphasis on their application in anticancer and antibacterial therapies. Through photodynamic activation, enhanced therapeutic effect of curcumin is readily exhibited towards cancer and bacterial treatments. In addition, modification of curcumin with metal complexes and encapsulation of curcumin in nano delivery systems to enhance the PDT effect are discussed. Special emphasis is given to the mechanisms of curcumin-related PDT and to suggest future directions for progress. The key finding of this review is that curcumin in combination with PDT can enhance the therapeutic effects of native curcumin against microbiota and cancer cell lines. However, there is still a lack of curcumin-PDT in vivo studies, and targeted delivery of curcumin has not yet been studied sufficiently, despite clear evidence for its potential. For future studies, more in vivo studies are needed, and the nano-delivery systems for curcumin can be modified with aptamers to realize targeted delivery and to enhance the PDT effect.