THE STRUCTURAL FEATURES AND ANTIOXIDATIVEACTIVITIES ON TANSHINONE COMPOUNDS I
丹参醌化合物结构特征与抗氧化活性

The antioxidation effect of dihydrotanshinone I and tanshinone II on fat and the relationship between the structures and antioxidative activities of the two tanshinones were studied by quantum chemical calculation in this paper. The results show that the formation of stable radical AH-R· between the antioxidants and the carbon-centred free radical R·in fat may be a main mechanism of the antioxidation to retard lipid rancid, and dihydrotanshinone I can also react by donating a hydrogen atom to R·,becoming itself a stable radical A·. The chemical activities of tanshinone molecule and the stabilities of AH-R· and A· have important effects on the antioxidation. The distribution of spin populations in AH-R· and A·, specially the spin population of C atom at donating H, may be a valuable parameter of electric structure to compare the relative activity of antioxidants.