Protective activity of components of an edible plant, Mallotus japonicus, against oxidative modification of proteins and lipids

Protective activities of components of Mallotus japonicus leaves, namely mallotinic acid, mallotusinic acid, corilagin, and geraniin, against oxidation of both intracellular and extracellular proteins including lipoproteins and lipids were evaluated. These four components dose-dependently protected bovine serum albumin (BSA) against protein degradation by ClO, one of the reactive oxygen species (ROS) generated in the human body, in a manner similar to epigallocatechin gallate (EGCG), a strong antioxidant in green tea. Lipid peroxidation assay indicates they also inhibit lipid peroxidation suggesting they may protect elements of the human body against oxidation induced diseases. As a model element, low-density lipoprotein (LDL) was chosen and the anti-LDL oxidation activity of the four tannin components were evaluated. All four showed strong protective activity against LDL oxidation at levels greater than EGCG. These observations suggest that the leaves of the edible plant, M. japonicus, containing mallotinic acid, mallotusinic acid, corilagin, and geraniin, may be useful in controlling oxidative stress in the human body.