The evaluation of the synthesized isoflavanones for aromatase
inhibitory activity was performed using a fluorometric substrate
(7-methoxy-trifluoromethylcoumarin) and human CYP19 aromatase
with ketoconazole as a positive control.33 All experiments
were performed at least in triplicate to determine the IC50 value
(Fig. 2). Since racemic compounds were synthesized, the activities
reported in this paper represent the lower limits of inhibitory potency.
Interestingly, the parent molecule 1a showed moderate
inhibition against aromatase with an IC50 value of 29 lM (Table 1).
Under the same conditions, no significant inhibition was found
with compounds 1i and 1j, in which the B ring was attached to a
large aromatic group. All other compounds showed moderate to
good inhibitory effects, with 2a being the most potent compound
in this investigation (Table 1). Both enantiomers of synthesized
isoflavanones were docked into the aromatase active site, and
the enantiomer with the higher docking score was used to identify
crucial enzyme/inhibitor interactions (Fig. 3).