Magnoflorine, an natural alkaloid found in coptidis rhizoma, exerts an inhibitory effect against Cu2+-induced lipid peroxidation of high density lipoprotein (HDL), has beneficial properties on protecting human HDL against lipid peroxidation.. Magnoflorine possesses high activity as α-glucosidase inhibitor in vitro and in vivo, which indicates that the compound has antidiabetic potential activity.