The aim of the study was to determine the scavenging capacity of aqueous and ethanolic extracts derived from the herb of two species of Galinsoga against NO and ONOO-. In both tests the aqueous extracts of both Galinsoga species were more active than the ethanolic extracts. The highest scavenging activity against NO, and also against ONOO- was shown by G. quadriradiata aqueous extract (SC50 ± SD = 1.54 ± 0.32, and 2.10 ± 1.98, respectively). The study showed that the activity of the extracts from both Galinsoga species is related not only to the presence of flavonoids but also to caffeic acid derivatives and caffeic acid. The results of this study partly explain the beneficial effects of Galinsoga herb extracts in the treatment of skin diseases.
