Evaluation of phenolic contents and antioxidant activity of various solvent extracts of Sonchus asper (L.) Hill

Background: Sonchus asper (SA) is traditionally used for the treatment of various ailments associated with liver, lungs and kidneys. This study was aimed to investigate the therapeutic potential of nonpolar (hexane, SAHE; ethyl acetate, SAEE and chloroform, SACE) and polar (methanol, SAME) crude extracts of the whole plant. Methods: To achieve these goals, several parameters including free-radical (DPPH center dot, ABTS(center dot+), H2O2 and (OH)-O-center dot) scavenging, iron chelating activity, scavenging of superoxide radicals, total flavonoids and total phenolic content (TPC) were examined. Results: The SA extracts presented a remarkable capacity to scavenge all the tested reactive species with IC50 values being found at the mu g/ml level. The SAME was shown to have the highest TPCs while lowest IC50 values for the DPPH center dot, ABTS(center dot+) radical scavenging capacities and iron chelating scavenging efficiency, moreover, SAME had best activities in scavenging of superoxide radicals and hydrogen peroxide as well as potently scavenged the hydroxyl radicals. Conclusion: These results suggest the potential of S. asper as a medicine against free-radical-associated oxidative damage.