ABSTRACT
To explore new biflavones, 7-hydroxy-8-hydroxymethyl-4'-methoxyisoflavone (1), (5, 7-dihydroxyflavone-8-yl)-(7'-hydroxy-4"-methoxyisoflavone-8'-yl)methane (2), bis(7-hydroxy-4'-methoxyflavone-8-yl) methane (3), bis(3', 5'-diisopropyl-7, 4'-dihydroxy-isoflavone-8-yl)methane (4), and bis(7-hydroxy-isoflavone-8-yl) methane (5) were designed and synthesized from chrysin, formononetin, 7, 4'-dihydroxy-3', 5'-diisopropyl-isoflavone and 7-hydroxy-isoflavone. Their structures were identified with IR, 1H NMR, 13C NMR and elemental analysis. The binding of 1-5 with DNA was studied with fluorescent spectroscopy. Compounds 2-5 showed higher binding affinity with DNA than 1. According to the Stern-Volmer equation, the binding constants of 2, 3 were determined at 35 degrees C and 25 degrees C respectively, they were Kq2 (25 degrees C) = 1.95 x 10(4) Lx mol(-1) and Kq2 (35 degrees C) = 1.67 x 10(4) L x mol(-1); Kq3 (25 degrees C) = 1.89 x 10(4) L x mol(-1) and Kq3 (35 degrees C) = 1.58 x 10(4) L x mol(-1). The quenching mechanism of 2, 3 was suggested as static quenching.
