Synthesis of B-ring substituted flavones and evaluation of their antitumor and antioxidant activities

A series of flavones, substituted at the ring B, were synthesized using either Claisen–Schimdt Condensation or Baker–Venkataraman rearrangement. The synthesized compounds were tested for in vitro cytotoxic activity by sulforhodamine B assay against three cell lines of different origin, viz. HepG2, MCF-7, and MOLT-4. The compounds were also tested for a possible antioxidant activity by determination of inhibition of lipid peroxidation. Quercetin was taken as a standard for antioxidant activity. Compound 1c showed the highest cytotoxic activity against MCF-7 (GI50 < 0.1 μM) and MOLT-4 (GI50 < 0.1 μM) cell lines and was comparable to adriamycin, the standard used. Compounds 1b, 1g, and 1h also showed promising activity against MCF-7 and MOLT-4 cell lines. In the absence of a hydroxyl group, one or more methoxy groups present on the B-ring (compounds 1c–1e) were major determinants of inhibition of lipid peroxidation.