Synthesis and Antioxidant Properties of Psoralen Derivatives

Abstract Five psoralen derivatives were synthesized and the structures of them were characterized by 1 H‐NMR, 13 C‐NMR, and IR. The antioxidant properties of the compounds were tested by inhibiting the free radical‐initiated DNA oxidation and scavenging the radical reaction. The results showed that the effective stoichiometric factors ( n ) of the compounds V and IV could reach 2.00 and 2.11 in the system of inhibiting the DNA oxidation reaction initiated by 2,2′‐Azobis(2‐methylpropionamidine) dihydrochloride (AAPH). In the inhibition of ⋅OH‐oxidation of the DNA system, compounds I ~ V showed antioxidant properties. The thiobarbituric acid absorbance (TBARS) percentages of compounds IV and V were 76.19 % and 78.84 %. Compounds I ~ V could also inhibit Cu 2+ /GSH‐oxidation of DNA, and all compounds exhibited good antioxidant properties except compound II (94.00 %). All the five compounds were able to trap diammonium 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonate) salt radical (ABTS + ⋅), 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH⋅) and 2,6‐di‐tert‐butyl‐alpha‐(3,5‐di‐tert‐butyl‐4‐oxo‐2,5‐cyclohexadien‐ p‐ tolylox radical (galvinoxyl⋅). The ability of compounds I ~ V to scavenge those free radicals can be measured by the k values. The k values ranged from 0.07 to 0.82 in scavenging ABTS + ⋅, galvinoxyl, and DPPH radicals, respectively.