Aromatase (CYP19) catalyzes the aromatization reaction of androgen substrates to estrogens, the last and
rate-limiting step in estrogen biosynthesis. Inhibition of aromatase is a new and promising approach to
treat hormone-dependent breast cancer. We present here the design and development of isoflavanone
derivatives as potential aromatase inhibitors. Structural modifications were performed on the A and B
rings of isoflavanones via microwave-assisted, gold-catalyzed annulation reactions of hydroxyaldehydes
and alkynes. The in vitro aromatase inhibition of these compounds was determined by fluorescence-based
assays utilizing recombinant human aromatase (baculovirus/insect cell-expressed). The compounds 3-(4-
phenoxyphenyl)chroman-4-one (1h), 6-methoxy-3-phenylchroman-4-one (2a) and 3-(pyridin-3-yl)chroman-
4-one (3b) exhibited potent inhibitory effects against aromatase with IC50 values of 2.4 lM, 0.26 lM
and 5.8 lM, respectively. Docking simulations were employed to investigate crucial enzyme/inhibitor
interactions such as hydrophobic interactions, hydrogen bonding and heme iron coordination. This report
provides useful information on aromatase inhibition and serves as a starting point for the development of
new flavonoid aromatase inhibitors.