Synthesis, Antiplatelet-Activity, and Cytotoxic Evaluation of Certain Phenyldicoumarol Derivatives

3,3'-(4-Substituted-benzylidene)-bis-4-hydroxycoumarins (3a-f and 5) and 3,3'-(4-substituted-benzylidene)-4,4'-epoxydicoumarins (4a-f and 6) were prepared by the condensation of 4-hydroxycoumarin and substituted benzaldehydes. These compounds were evaluated for antiplatelet aggregation and cytotoxicity to human cancer cells. Preliminary results indicated that bis-4-hydroxycoumarins 3a,b and 3d-f significantly exhibited Col- induced platelet aggregation. Compounds 3a,b and 3d were able to completely inhibited AA-induced platelet aggregation at a concentration of 100μg/mL. Although the α-methylene-γ-butyrolactone-bearing derivatives 5 and 6 were more cytotoxic than their respective carbonyl counterparts 3e and 4e, their cytotoxic profiles Were distinct. Compounds 3e and 4e strongly inhibited the growth of renal UO-31 cancer cells with a log GI50 of -7.30 and-7.21, respectively.