In vitro inhibition of purified human carbonic anhydrase I and II by novel fluorene derivatives

In this study, 9-benzylidene-9H-fluorene-substituted urea (5a–p) and thiourea derivatives (5q–v) were synthesized and their inhibitory effects on the activity of human carbonic anhydrase (hCA) I and II were evaluated. hCA I and II were purified from human erythrocytes using a Sepharose 4B-L-tyrosine-sulphanilamide affinity column. All the synthesized compounds inhibited the activity of the hCA I and II isoenzymes. Among the synthesized compounds, 5f was found to be the most active (IC50 = 21.4 μM) for inhibition of hCA I and 5s was the most active (IC50 = 25.3 μM) for inhibition of hCA II.