In vitro effect of novel β-lactam compounds on xanthine oxidase enzyme activity.

Carbazole substituted imines (2a-l) were prepared from N-methyl-3-amino carbazole with different aldehydes. The imines compounds undergo (2+2) cycloaddition reactions with in situ ketenes to produce β-lactam compounds (3a-l). The β-lactam compounds were tested as inhibitors of the xanthine oxidase (XO) purified from bovine milk. The results show that these compounds exhibit inhibitory effects on XO at low concentrations with IC(50) values ranging from 21.65 to 58.04 µM. The most effective compound for XO was 4-(4-chlorophenyl)-1-(9-ethyl-9H-carbazol-3-yl)-3-phenylazetidin-2-one with IC(50) of 21.65 μM. The lactams investigated here showed effective XO inhibitory effects, in the same range as the clinically used allopurinol.