Synthesis and antiproliferative in-vitro activity of natural flavans and related compounds

The total synthesis of natural flavan racemates (+/-) 1, (+/-) 2 and natural flavones 3, 4 had thus been achieved. A straightforward synthetic procedure of flavans via the Pd-C catalyzed hydrogenation/hydrogenolysis of corresponding flavones was developed. Furthermore, the antiproliferative activities of racemic flavans (+/-) 1, (+/-) 2, flavones 3, 4, and five synthetic intermediates toward human SGC-7901, BEL-7402, HeLa, and HL-60 cell lines in vitro were evaluated by MTT assay, and the racemic flavans (+/-) 1 were found to have significant antiproliferative activity against all four cell lines.