Potent antiperoxidation activity of the bisbenzylisoquinoline alkaloid cepharanthine : the amine moiety is responsible for its pH-dependent radical scavenge activity - Kogure,K.; Goto,S.; Abe,K.; Ohiwa,C.; Akasu,M.; Terada,H. (Biochimica et Biophysica Acta, 1999)