ABSTRACT
Structure-activity relationship of cinnamic acid derivatives as inhibitors of the human neutrophil elastase is reported. Comparison of the inhibitory concentrations (IC50 values) with the results of the ligand docking calculations revealed that the structure element of the aromatic ortho-dihydroxy groups combined with a lipophilic residue seems to be a prerequisite for an optimal binding within the active site.
Subject(s)
Cinnamates/pharmacology , Enzyme Inhibitors/pharmacology , Leukocyte Elastase/antagonists & inhibitors , Cimicifuga/chemistry , Cinnamates/chemical synthesis , Crystallography, X-Ray , Enzyme Inhibitors/chemical synthesis , Humans , Indicators and Reagents , Ligands , Structure-Activity Relationship , Verbesina/chemistryABSTRACT
Human neutrophil elastase (HNE) is a serine protease that has been implicated in the abnormal turnover of connective tissue proteins and has been described as an important pathogenic factor in several inflammatory diseases such as rheumatoid arthritis or cystic fibrosis. Here we investigated 17 sesquiterpene lactones (SLs) for their ability to inhibit human neutrophil elastase in an in vitro assay. Podachaenin was the most active compound with an IC(50) value of 7 microM. SLs do not covalently bind to the amino acids of the catalytic triad, thus differing from other elastase inhibitors with a lactone moiety. In contrast to most other biological activities of SLs HNE inhibition is not mediated by alpha,beta-unsaturated carbonyl functions. Ligand binding calculations using the X-ray structure of HNE and the program FlexX revealed structural elements which are a prerequisite for their inhibitory activity.
