To investigate the relationship between the antioxidant capacity and structure of daidzein, a series of derivatives were synthesised. The results from DPPH and ABTS radical scavenging assays indicated that 4'-hydroxy modified daidzein derivatives exhibited no free radical scavenging ability. In contrast, the daidzein derivative with 7-hydroxy modification retained or enhanced its free radical scavenging rate. Notably, derivatives 3-(4-hydroxyphenyl)-7-((4-(trifluoromethyl)benzyl)oxy)-4H-chromen-4-one (3s) and 7-((2,6-dimethylbenzyl)oxy)-3-(4-hydroxyphenyl)-4H-chromen-4-one (4h) demonstrated exceptional DPPH and ABTS radical scavenging capabilities, achieving rates exceeding 80% in both assays. Furthermore, quantitative structure-activity relationships (QSAR) for daidzein derivatives have been explored, providing valuable insights for future research endeavours.
