Antibiofilm effect of Curcuma longa L. extract in antimicrobial photodynamic therapy against Enterococcus faecalis

Cullash Luza A.C.H.; Salazar Salvatierra M.E.; Luza Montero S.C.; Castro Yanahida J.E.; Gutierrez Leiva A.C.; Temoche Rosales C.A.; Colchado Carhuavilca J.R. · Photodiagnosis and Photodynamic Therapy (2026) · DOI: 10.1016/j.pdpdt.2026.105515

Resumen

Background: Enterococcus faecalis is associated with persistent endodontic infections due to its ability to form resistant biofilms. Antimicrobial photodynamic therapy (aPDT) has emerged as a promising alternative approach. This study evaluated the antibiofilm activity of an ethanolic extract of Curcuma longa L. against E. faecalis ATCC 29,212, with and without aPDT. Methods: An in vitro biofilm model was used. The minimum biofilm inhibitory concentration (MBIC) was determined. Biofilms were treated with the C. longa extract (7.81–2000 µg/mL) under LED irradiation (aPDT) and without light activation. Chlorhexidine (2%) served as a positive control while untreated biofilms served as negative control. Biofilm biomass was quantified by optical density, and statistical analysis was performed using ANOVA and Tukey’s test (p < 0.05). Results: The MBIC was 62.5 µg/mL. aPDT significantly reduced biofilm formation compared to the negative control (p < 0.001). The highest inhibitory effects were observed at 31.25 and 62.5 µg/mL, with effects comparable to those of 2% chlorhexidine under in vitro conditions. The highest concentration (2000 µg/mL) showed reduced activity and a potential paradoxical, concentration-dependent effect. Without light activation, the extract also showed antibiofilm activity, but to a lesser extent. Conclusion: Curcuma longa L. exhibits concentration-dependent antibiofilm activity against E. faecalis, enhanced by aPDT. Reduced efficacy at higher concentrations may be related to aggregation and self-quenching of curcumin. Despite chlorhexidine remaining the clinical reference, C. longa showed comparable effects at optimal concentrations. Limitations include the absence of a light-only control, lack of CFU confirmation, and potential staining risk.

Instituciones: Universidad Nacional Mayor de San Marcos; Universidad de San Martín de Porres