Syringic acid protective role: Combatting oxidative stress induced by UVB radiation in L-929 fibroblasts

Neglecting proper skin care and repeated exposure to ultraviolet (UV) radiation can have serious consequences, including skin burns, photoaging and even the development of skin cancer. UV radiation-induced damage is mediated by highly unstable and reactive molecules, named reactive oxygen species (ROS). To counteract ROS, the skin has an endogenous antioxidant system. Considering that, many sunscreens incorporate antioxidant substances to ensure additional photochemioprotective action in the formulation. Syringic acid (SA) is classified as a phenolic acid derived from hydroxybenzoic acid. It has antioxidant properties, which can reduce oxidative stress, and has shown potential to prevent skin cancer. The aim of this study was to assess the ability of SA to protect L-929 fibroblasts from UVB radiation by evaluating oxidative stress biomarkers. As a result, we demonstrated the antioxidant activity of SA through four methodologies, and confirmed the photochemioprotective activity of SA by attenuating the cytotoxicity of UVB radiation in L-929 fibroblasts. The mechanisms involved in the photoprotection of SA include a significant reduction in total ROS, maintenance of mitochondrial membrane potential, decrease in lipid peroxidation, preservation of endogenous antioxidant system enzymes and reduced glutathione (GSH) levels, thereby mitigating the ultrastructural damage caused by UVB. Additionally, SA showed promising results in wound healing. Considering such properties, SA emerges as a strong candidate for incorporation into photoprotective and multifunctional formulations.