Photoprotective activity from Colombian Caribbean brown algae using HPLC-DAD metabolic profiling by MCR-ALS data analysis

Although synthetic UV filters are widely used for skin photoprotection, growing concerns about their environmental and health impacts underscore the need for new, effective photoprotective products. This study aimed to develop a screening methodology for selecting brown macroalgae extracts with potential photoprotective activity. The approach integrates in vitro photoprotection assays, antioxidant TLC-DPPH assays, and HPLC-DAD metabolic profiling of 17 algal samples from the Dictyota, Canistrocarpus, Stypopodium, Sargassum, Lobophora, Padina, and Turbinaria genera. The results revealed concentration-dependent sun protection factor (SPF) values ranging from 0.403 to 2.915, UVA ratios (UVAr) ranging from 0.167 to 3.623, critical wavelengths (λc) ranging from 335 to 393 nm, and antioxidant DPPH-TLC activity in 10 of the evaluated extracts. These findings were correlated with the HPLC-DAD metabolic profile using the Multivariate Curve Resolution- Alternating Least Squares (MCR-ALS) algorithm and multivariate data analysis tools. Extracts from Canistrocarpus cervicornis (CCe) and Stypopodium zonale (SS) presented the most promising photoprotective activity. Through NMR and MS analysis, 2,5,7-trihydroxy-2-pentadecylchroman-4-one (1), fucoxanthin, pheophytin a, and pheophorbide a were identified as the main contributors to this activity. This methodology was successfully implemented and could be further used to screen for photoprotective activity in algal species.