Photodynamic and Sonodynamic Antibacterial Activity of Grape Leaf Extracts

Food spoilage and contamination are major global challenges, reducing food quality, safety, and availability, causing significant economic losses. This study evaluates the photodynamic and sonodynamic antibacterial activities of grape leaf extracts from Beer and Hanut Orcha varieties. The extracts were tested against Staphylococcus aureus and Escherichia coli under illumination and ultrasonic activation. The results demonstrated that the photodynamic and sonodynamic treatments significantly enhanced the antibacterial efficacy of the extracts when higher concentrations of the extracts and prolonged exposure led to complete bacterial eradication. Separation of the extracts using RP-18 cartridges (Yicozoo Energy Technology Co., Ltd., Xi’an, China) enabled us to get an active fraction containing components responsible for antimicrobial effects. Singlet oxygen generation measurements confirmed the involvement of reactive oxygen species in bacterial inactivation under illumination. Using HPLC/MS, the active components responsible for the photodynamic properties of the extracts were identified as quercetin 3’-O-glucuronide and pheophorbide a. The findings suggest that these natural extracts, in combination with photodynamic and sonodynamic activation, represent promising alternatives to conventional antibiotics. Further studies should focus on the isolation of active individual compounds, the improvement of treatment parameters, and the investigation of molecular mechanisms to facilitate the development of practical applications in medicine and food preservation.