Antioxidant and UV photoprotective activity of lichenized fungi from Paramo de Sumapaz (Colombia)

Abstract Lichenized fungi are particularly abundant in harsh environments. Paramos are unique neotropical mountain environments located in the northern Andes which face several treats due to human activities. The preset study evaluated the antioxidant and photoprotective activities of four paramo lichen extracts. Antioxidant activity was assessed using DPPH and FRAP assays. While photoprotective parameters (Sun protection factor - SPF, critical wavelength and spectral amplitude) were determined spectrophotometrically. Rock-inhabiting lichens such as Thamnolia performed better than phorophyte or soil-growing lichens, such as Lobariella, Everniastrum and Peltigera. All extracts showed DPPH inhibition higher than 70% at 200 µg mL⁻ ¹ and exhibited significant differences with BHT (92% at 20 µg mL⁻ ¹). Furthermore, the extracts had moderate ferric ion reducing power and were statistically different from BHT. For protection against UV-B, the in vitro SPF were above 10 at 100 µg mL⁻ ¹ for all extracts except extract from Peltigera older thalli, with Lobariella proving to be the most active. Thamnolia and Lobariella can be identified as potential broad-spectrum filters (λcrit = 367.9 and 355.8 nm), while Everniastrum can be proposed as UV-B and UVA-2 filter and Peltigera presented the least photoprotective activity. Either younger or older Peltigera thalli were distinguished, obtaining differences in composition, antioxidant and photoprotective activity, which coincided with the optimal defense theory (ODT). Consequently, it is feasible to propose paramo lichen extracts, especially those growing on UV-exposed habitats, as sources of new photoprotective compounds. Indeed, they presented antioxidant capability as a remarkable improvement upon synthetic sunscreens.