4-Methyl-8-hydroxylpsoralen (MXan) and 4, 9-dimethyl-8-hydroxylpsoralen (DMXan) were synthesized in order to clarify the effect of methyl on the antioxidant effectiveness of xanthotoxol (8-hydroxylpsoralen, Xan), which were assessed by bleaching β-carotene in linoleic acid–Triton emulsion, by interacting with 2, 2′-azinobis (3-ethylbenzothiazoline-6- sulfonate) cationic radical (ABTS+), 2, 2′-diphenyl-1-picrylhydrazyl radical (DPPH), and ...