Free radical scavenging capacity and protective effect of natural substances in peloids from the thermal spring pool Bagnaccio (Viterbo, Italy).

Natural peloids from sulfurous thermal springs are largely used in cosmetic and pelotherapy for the treatment of different dermatological conditions, including skin aging, dermatitis, and other eczemas. The beneficial effects are correlated to mineralogical and other thermal properties, as well as to the presence of natural substances with specific antioxidant activity. Few data are available for the comparison between natural peloids and synthetic (i.e., artificially maturated) muds. In this context, the natural substances and antioxidant activity of natural white mud (WM) and dark mud (DM) peloids from the sulfurous thermal spring pool Bagnaccio (Viterbo, Italy) have been studied in detail to evaluate possible relationships between physicochemical properties and therapeutic effect. A large panel of natural substances in WM and DM were characterized for the first time by ³¹P-nuclear magnetic resonance and gas chromatography associated to mass spectrometry analysis. Polar fractions of WM and DM peloids were characterized by the presence of several bioactive natural compounds, showing high antioxidant activity and DNA protective effect, as evaluated by 2,2-diphenyl-1-picrylhydrazyl assay, and hydrogen peroxide–induced DNA breakage in the alkaline comet assay. The antioxidant activity and DNA protective effect could be attributed to radical scavenging rather than a modulatory effect on the induced DNA repair, and are of order of intensity higher than that reported for synthetic muds.