Antimicrobial activities of grape ( Vitis vinifera L.) pomace polyphenols as a source of naturally occurring bioactive components

Grape pomace is a potential source of winery by-products having useful bioactive components. Antimicrobial activities of enzyme-assisted grape pomace polyphenols (GPP) were assessed against Escherichia coli IFO 3301 and Staphylococcus aureus IFO 12732 using plate count and spectrophotometry assays. GPP have shown credential growth inhibition against E. coli and S. aureus , respectively. The higher growth inhibition was mediated by the higher GPP concentrations against both E. coli and S. aureus , which implies dose dependency. GPP also exhibited bactericidal effects against both the Gram-positive and Gram-negative bacteria, whereas, Gram-positive bacteria have shown more susceptibility than Gram-negative bacteria. It is revealed that GPP is a potential source of natural antimicrobial agents. Keywords: Grape pomace, polyphenols, antimicrobial activity.