<i>Teucrium polium</i> L.: A natural source of antioxidants and a potential UV protector.

Teucrium polium L., commonly known as "El Kheyata," is a medicinal plant widely used in traditional Algerian medicine. In this study, we evaluated the total phenolic content (TPC) and biological activities of three extracts derived from its aerial parts: methanolic (MeOH), dichloromethane (DCM), and petroleum ether (EDP) extracts. The functional groups of these extracts were characterised using UV-VIS-NIR spectroscopy. Antioxidant potential was assessed through multiple assays, including 2,2-Diphenyl-1-picrylhydrazyl(DPPH), 2,20-Azinobis (3-ethylbenzothiazoline-6-sulfonic Acid) (ABTS), Reducing power assay (FRAP), and O-phenanthroline, while the sun protection factor (SPF) was measured to evaluate photoprotective effects. Our results demonstrated that T. polium contains significant concentrations of phenolic and flavonoid compounds, correlating with its notable biological activities. UV-VIS-NIR spectroscopy detected the presence of conjugated compounds, especially flavonoids and phenolic acids, in the MeOH and DCM extracts. The EDP extract, on the other hand, is rich in lipophilic compounds, such as terpenes. The results demonstrated that the MeOH extract stood out for its superior antioxidant activity compared with the DCM and EDP extracts. In line with this antioxidant richness, MeOH extract also demonstrated a powerful photoprotective effect, with SPF values ranging from 15.45 ± 0.45 to 32.96 ± 0.69, suggesting effective UV absorption. These results show that T. polium is a promising source for pharmaceutical applications (sunscreens, antioxidant supplements), pending further studies on its pharmacokinetic profile and potential drug interactions.