(3)Lipid free radicals; The interaction of oxygen free radicals with polyunsaturated fatty acids in the phospholipids of cell membrane leads to the formation of lipid free radicals Types 1) Fatty acid radical (lL 2)Lipid peroxide (LOO) (4)Others: Cl, CH3 NO(3) Lipid free radicals： The interaction of oxygen free radicals with polyunsaturated fatty acids in the phospholipids of cell membrane leads to the formation of lipid free radicals. Types： 1) Fatty acid radical (L·) 2) Lipid peroxide（LOO·） (4) Others: Cl·, CH3·, NO·