Determination of in vitro antioxidant and UV-protecting activity of aqueous and ethanolic extracts from Galinsoga parviflora and Galinsoga quadriradiata herb.

Galinsoga species are used in folk medicine as anti-inflammatory agents and accelerators for wound healing. They also have reported antioxidant activity. We examined aqueous and ethanolic extracts derived from the Galinsoga herb as potential photoprotectors, as the role of reactive oxygen species (ROS) has implicated in skin damage. The extracts used in the study were standardized by determining the sum of flavonoids, and the amount of caffeic acid and its derivatives. The antioxidant activity of the extracts was evaluated by examining the scavenging of two radicals (O2(-) and H2O2) generated in cell-free systems. We also examined the effect on ROS generation by human skin fibroblasts after UV irradiation. In addition we determined the cytotoxicity of the extracts and their protective effect against damage caused by UV irradiation (MTT test, LDH release test and staining with annexine V-FITC/PI). Our findings show that the ethanolic extracts from the herb have cytotoxic effects, while the aqueous extracts from Galinsoga herb have protective activity, in part due to their ability to inhibit ROS generation. In the conclusion the aqueous extracts from the both tested species may be effective as photoprotectors.