Inhibition of neutrophil elastase activity by phenolic compounds from plants.

The influence of 40 phenolic compounds from plants were tested on the enzymatic activity of neutrophil elastase (EC 3.4.21.37). Among the flavonoids especially the compounds with a catecholic structure showed a strong inhibitory activity in the range of mumol/l, hyperosid was the strongest inhibitor with an IC50 of about 0.3 mumol/l. Lipophilic caffeic acid esters and phenolic compounds with catecholic structure elements in general inhibited the enzyme. Because of the specific role of neutrophil elastase in the inflammatory process its inhibition by phenolic natural compounds might be one explanation for the use of medicinal plants containing phenolic compounds in the treatment of inflammation.