Collagenase and elastase inhibitory activity of white grape pomace extracts
To investigate the inhibition exerted by the grape pomace extract on ChC and PPE, the respective enzymes were incubated with the extract and the appropriate substrates. The assays were performed with synthetic peptides as substrate molecules, and enzyme preparations isolated from C. histolyticum and porcine pancreas, respectively. As reported in literature, PPE is topologically very similar to human neutrophil elastase and inhibition mechanisms for some phenolic substances were found to be equal [17] and [18]. Therefore, it can be assumed that the in vitro assays performed with the ChC and PPE and synthetic peptides are a reliable tool to get first indications of the capability of grape pomace polyphenols to prevent extracellular matrix degradation as a skin aging phenomenon. The inhibitory potential of the grape pomace extract was examined for increasing dilutions, in order to establish dose-dependent relationships, and to calculate the half maximal inhibitory concentrations (IC50).