EVALUATION OF SUPEROXIDE SCAVENGING ACTIVITIES OF HAMAMELIS EXTRACT AND HAMAMELITANNIN

Hamamelitannin, which is a component of bark extract of hamamelis (Ham amelis virginior L.), was found to be a potent scavenger of superoxide anion radicals. Superoxide anion scavenging activity of the compound was evaluated by ESR-spin trap method using DMPO (5,5'-dimethyl-1-pyrr oline-N-oxide) as a spin trapping agent. The IC50 value (the concentra tion producing 50% inhibition of superoxide anion radicals) of hamamel itannin was found to be 1.38 +/- 0.06 muM much lower than that of asco rbic acid (23.31 +/- 2.23 muM). Supporting the superoxide scavenging a ctivity of hamamelitannin, the compound showed both suppresive ability against depolymelization of hyaluronic acid and protective ability ag ainst cytotoxicity induced by superoxide anion radicals. Hamamelitanni n increased the survival rate of fibroblast to 85.5 +/- 3.3%, compared with that of control (27.2 +/- 4.3%).