TITLE:
A Comparative Study on Antiradical and Antimicrobial Properties of Red Grapes Extracts Obtained from Different Vitis vinifera Varieties
AUTHORS:
Nada El Darra, Joanna Tannous, Paulette Bou Mouncef, James Palge, Joseph Yaghi, Eugène Vorobiev, Nicolas Louka, Richard G. Maroun
KEYWORDS:
Phenolic Compounds; DPPH; HPLC-DAD; Antimicrobial; Antiradical; Grapevines; and Synergistic Effect
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.3 No.10,
October
15,
2012
ABSTRACT: The present work is devoted to the study of antiradical and antimicrobial activities of phenolic compounds extracted from different grapevine varieties grown in the Bekaa plane-Lebanon. The amount of phenolic compounds in selected grape extracts was determined by the Folin-Ciocalteau method. Phenolic composition was specified by high performance liquid chromatography. Free radical scavenging activity was examined by using the (2,2’-diphenyl-1-picrylhy-drazyl) DPPH assay. The potential antimicrobial activity was studied using a new quantitative method developed during this work. This activity was tested against several microbial pathogens, including a Gram-positive strain (Listeria monocytogenes), two Gram-negative strains (Escherichia coli and Salmonella arizonae) and a fungal strain (Candida albicans). According to the results of the present screening study, a great variability in the composition of phenolic com-pounds in red grape extracts was detected. All phenolic compounds extracts, demonstrated important scavenging properties and antimicrobial effect against bacterial and fungal strains. Yet, a different response degree was noticed depending on the tested microorganism and the phenolic composition of grape extracts. Antimicrobial activity was more effective against Gram-positive than Gram-negative and yeast strains. Furthermore, our results highlighted a significant role of synergistic effect between various phenolic compounds in the free radical scavenging and antimicrobial activities.