Effect of different solvents on polyphenolic content, antioxidant capacity and antibacterial activity of irish york cabbage

Cabbage is a rich source of a number of bioactive compounds such as flavonoids, glucosinolates and their breakdown products, which may have antibacterial, antioxidant and anticancer properties. This investigation was undertaken to estimate the effect of using water and different organic solvents such as ethanol, acetone and methanol at various concentrations on the total polyphenols, antibacterial activity and antioxidant capacity of Irish York cabbage. Water has the highest extraction yield of 3.85%, whereas 60% methanolic extract has the highest content of total polyphenols (33.5mg gallic acid equivalents per gram [dried weight, dw] of extract) and flavonoid (21.9mg quercetin equivalents per gram [dw] of extract). A concentration-dependent antioxidative capacity was confirmed for different reactive oxygen species, including hydrogen peroxide, metal chelating capacity, reducing power and lipid peroxidation. The crude extracts showed a broad spectrum of antibacterial activity for the different extraction solvents applied; however, 60% methanolic extract (1.4%) exhibited higher antibacterial activity against Listeria monocytogenes (100%).