Phenolic Extract from L. Rhizomes Inhibits Cellular Oxidative Stresses.

UV-B and IR-A radiation are important inducers of biological changes in skin involving ROS generation. The overloading of antioxidant defense mechanisms by ROS production could lead to photoaging and photocarcinogenesis processes. Various traditional usages are reported for L. extracts, including treatment of dermatological disorders. Antioxidant and anti-inflammatory properties have already been reported for other species possibly due to the presence of phenolic compounds. However, the phenolic composition and the potential activity of rhizomes extract against oxidative stress and UV/IR damages have not been investigated. The main aims of this study were to prepare a fraction enriched in phenolic compounds (FEPC) from rhizomes, to identify its major phenolic compounds and to assess its potential for protective effects against oxidative stress induced by UV-B, IR-A or inflammation. A quantitative LC-MS study of FEPC shows that chlorogenic, caffeic and protocatechuic acids are the main phenolic compounds present, with concentrations of 15.6%, 15.3% and 4.8% of the total composition, respectively. With a validated analytical method, those compounds were quantified over different stages of the growing period. As for biological potential, first this extract demonstrates antioxidant and anti-inflammatory activities. Furthermore, ROS generation induced by IR-A and UV-B were strongly inhibited by extract, suggesting that L. rhizome extract could protect dermal cells against oxidative stress induced by UV-B and IR-A.