In an attempt to determine the antioxidant/prooxidant, antibacterial/probacterial action of flavan-3-ols and procyanidins from\ngrape seeds, pure catechin (CS), and an aqueous grape seed extract (PE), were applied in the absence and presence of pure\nlipoxygenase (LS) or in extract (LE) to leucocyte culture, Escherichia coli B41 and Brevibacterium linens, and observed whether there\nwas any effect on lipid peroxidation, cytotoxicity, or growth rate. Short time periods of coincubation of cells with the polyphenols,\nfollowed by the exposure to LS and LE, revealed a high level of lipid peroxidation and a prooxidative effect. Longer coincubation\nand addition of LS and LE resulted in the reversal of the prooxidant action either to antioxidant activity for CS + LS and PE + LS or\nto the control level for CS + LE and PE + LE. Lipid peroxidation was significantly reduced when cells were exposed to polyphenols\nover a longer period. Longer exposure of E. coli to CS or PE followed by addition of LS for 3 h resulted in bactericidal activity.\nSignificant stimulatory effect on microbial growth was observed for PE + LS and PE + LE treatments in B. linens, illustrating the\npotential probacterial activity in B. linens cultures. Lipoxygenase-polyphenols complex formation was found to be responsible for\nthe observed effects.
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