Acne vulgaris, a prevalent dermatological condition, impacts a large proportion of adolescents globally, resulting in the development of comedones, inflamed papules, and pustules on the facial area, as well as the chest and back. Acne formation is a result of various factors including heightened sebum production, irregular keratinization of hair follicles, and the presence of the anaerobic bacteria C.acnes in the pilosebaceous unit[1].

The production of lipases, proteases, and inflammatory mediators by C.acnes is essential in the development of acne lesions, as they contribute to inflammation and tissue damage[2,3]. In the treatment of acne, antibiotics like erythromycin and tetracyclines are frequently employed to inhibit the growth of C.acnes. Nevertheless, the rise of antibiotic resistance in C.acnes strains has become a notable worry, leading to the necessity for alternative approaches to treatment[4,5].

The use of photodynamic therapy (PDT) has shown great potential in treating acne. The process includes the application of a photosensitive substance that specifically gathers in bacteria, and then subjecting it to particular light frequencies. The interaction triggers the generation of reactive oxygen species (ROS), leading to the demise of bacterial cells and the breakdown of biofilms. Promising outcomes have been demonstrated in recent studies that have investigated the potential of acne treatment using different photosensitizers in PDT [6], [7], [8], [9], [10].

The objective of this research is to assess the suppressive impacts of curcumin PDT on C.acnes in planktonic and biofilm states. Curcumin, an organic substance obtained from the spice turmeric, has exhibited properties that combat microbes and reduce inflammation[11], [12], [13], [14].Additionally, curcumin possesses favorable photophysical properties, making it an ideal candidate for PDT[15], [16], [17].Our hypothesis is that curcumin photodynamic therapy (PDT) has the potential to efficiently inhibit the viability of C.acnes and disturb the activity of biofilms, offering a new and innovative therapeutic choice for the treatment of acne.