Phytochemical screening, antioxidant and antimicrobial activities of grape (Vitis vinifera L.) seed extracts from red globe and Valenci Algerian varieties

Abstract

Until now, there is no documentation concerning the composition, biological and pharmaceutical activities of Algerian grape (Vitis vinifera L.) seeds. The present study aims to evaluate the phytochemical analysis, antioxidant and antimicrobial activities of grape seed extracts (GSEs) from the Algerian Red globe and Valenci varieties. The total polyphenols content (TPC) in the GSEs was evaluated by spectrophotometry, it was 398.01 ? 18.12 mg GAE/g GSEs and 335.11 ? 11.44 mg GAE/g GSEs for the Red globe and Valenci varieties respectively. The antioxidant activity of GSEs was also evaluated by spectrophotometry on stable free radicals of DPPH. The IC50 for the Red globe variety was 4 ? 0.2 ?g/ml, while for the Valenci variety it was 4.6 ? 0.36 ?g/ml. The antimicrobial activity was determined using the disk diffusion method. Both extracts showed antimicrobial activity against the eight studied strains: Escherichia coli, Pseudomonas aeruginosa, Pasteurella sp., Salmonella sp., Staphylococcus aureus, Streptococcus faecalis, Clostridium sp., and Candida albicans. The extracts produced a clear inhibition zone for all the tested strains. Inhibition diameters greater than 19 mm were registered. The obtained results in this study indicate the differences between the Red globe and Valenci varieties, in terms of polyphenol content, antioxidant and antimicrobial activities in Algerian GSEs.