Unsymmetrical 1,3-disubstituted urea derivatives as α-chymotrypsin inhibitors

Abstract

The objective of this study was to synthesize potent and/or novel inhibitors for α-chymotrypsin activity. Eighteen derivatives of N-methylphenyl-N′-(alkyl/aryl) urea (1–18) were synthesized, and their inhibitory effects on α-chymotrypsin enzyme were evaluated. Two compounds exhibited potent inhibitory activities. The most potent, N-(2-methylphenyl)-2-oxo-1-pyrrolidinecarboxamide (15) having a methyl group at ortho position was the most active inhibitor with an IC50 value of 8.10 ± 0.14 μM, which was comparable to standard chymostatin (IC50 = 8.24 ± 0.11 μM). A slightly less potent, N-(2-acetylphenyl)-N′-(3-methylphenyl) urea (10), exhibited an IC50 of 13.6 ± 0.23 μM. Compounds 3, 4, 7, 11, and 13 exhibited moderate activities. The results demonstrated that α-chymotrypsin inhibition is related to the position of the methyl group and the presence of substituent at the nitrogen of the urea bridge. The inhibitory trend suggests that α-chymotrypsin inhibitory activity declines with ortho > meta > para substitution order. In conclusion, our data suggest that the compound 15 may serve as a lead compound for further designing of other potent or novel α-chymotrypsin inhibitors.