Seaweeds have been identified as promising sources of bioactive substances for the cosmeceutical industry, especially by their photoprotection capacity. Accordingly, this study aimed to evaluate the photoprotective properties of extracts from macroalgae and one marine lichen. Samples of 22 species of macroalgae and one marine lichen, were collected along the southern Iberian Peninsula. Hydroethanolic extracts were prepared from algal and marine lichen lyophilized biomass. Ultraviolet (UV) and visible absorption spectra, polyphenol content, antioxidant activity, mycosporine-like amino acid content and composition were analyzed. In order to quantify the photoprotection capacity of the extracts against different biological effects, two new indices were used, i.e., effective solar absorption radiation (%ESAR) and extract photoprotection index (EPI), considering the radiation absorbed and transmitted by the extract, respectively. In the ultraviolet spectrum, Porphyra umbilicalis and Pyropia elongata presented the highest absorbance values at 330 nm, while Ulva lactuca showed a prominent peak at 290 nm. In the visible spectrum, a fucoxanthin peak (450 nm) was strongly evident in extracts from the brown algal species, while green algal extracts presented characteristic chlorophyll a and b peaks at 447, 620 and 664 nm. Polyphenol content and antioxidant activity were much higher in Sargassum vulgare, Carpodesmia tamariscifolia, P. umbilicalis and Lichina pygmaea in comparison to the other species. P. umbilicalis and Bangia atropurpurea showed the highest amount of mycosporine-like amino acids. S. vulgare and P. umbilicalis extracts presented the highest values of potential photoprotection against all analyzed biological response according to the different action spectra. S. vulgare and P. umbilicalis showed an increase in %ESAR values associated with an increase in the concentration of their extracts. Considering the analyzed species, our results suggest that S. vulgare and P. umbilicalis could be potential sources of photoprotective extracts. The potential use of these species in cosmeceutical products is discussed.

海藻尤其是通过其光保护能力，已被确定为药妆业有希望的生物活性物质来源。因此，本研究旨在评估大型藻类和一种海洋地衣的提取物的光防护性能。在伊比利亚半岛南部采集了22种大型藻类和一种海洋地衣的样品。从藻类和海洋地衣冻干的生物质制备氢乙醇提取物。分析了紫外线（UV）和可见吸收光谱，多酚含量，抗氧化活性，霉菌素样氨基酸含量和组成。为了量化提取物对不同生物效应的光保护能力，使用了两个新指标，即有效太阳吸收辐射（％ESAR）和提取物光保护指数（EPI），分别考虑提取物吸收和透射的辐射。在紫外线光谱中脐带紫菜和延性Pyropia elongata在330 nm处显示出最高的吸光度值，而Ulva lactuca在290 nm处显示出突出的峰。在可见光谱中，在褐藻物种的提取物中有明显的岩藻黄质峰（450 nm），而绿藻提取物在447、620和664 nm处呈现特征性的叶绿素a和b峰。与其他物种相比，马尾藻（Sargassum vulgare），小叶锦鸡儿（Carpodesmia tamariscifolia），脐带假单胞菌（P. umbilicalis）和栗china（Lichina pygmaea）的多酚含量和抗氧化活性要高得多。P. umbilicalis和Bangia atropurpurea显示出最高的霉菌素样氨基酸含量。根据不同的作用谱，S。vulgare和P. umbilicalis提取物对所有分析的生物反应均表现出最高的潜在光保护作用。寻常葡萄球菌和脐带假单胞菌显示出％ESAR值的增加与其提取物浓度的增加有关。考虑到所分析的物种，我们的结果表明，S。vulgare和P. umbilicalis可能是光保护提取物的潜在来源。讨论了这些物种在药妆产品中的潜在用途。