Antioxidant and antiproliferative activity of polyphenols in novel high-polyphenol grape lines

Health-beneficial effects of grape and wine consumption have been linked to the presence of various polyphenols including anthocyanins in these products. The anthocyanin levels of red grape varieties can vary significantly and there is an interest in developing grape varieties with high anthocyanin levels. In this study, antioxidant and antiproliferative effects of grape anthocyanins from a group of selected grape lines designated as V 72, V 83 and V 103 developed through traditional breeding of the parent lines Lomanto and Seibel 8357, were investigated. The total anthocyanin levels in the different “Vintinto” lines (V) ranged from 119 mg/100 g fresh weight to 963 mg/100 g fresh weight. HPLC–MS analysis of the anthocyanin fractions of grapes in three selected high-polyphenol lines showed predominantly the glucosides of delphinidin, cyanidin, peonidin, petunidin and malvidin with lesser amounts of acetoyl glucosides and coumaroyl glucosides. Anthocyanin fractionation based on hydrophobicity and subsequent evaluation of antioxidant activities showed varying efficiencies in scavenging superoxide, hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. However, antiproliferative activity of these fractions evaluated using the estrogen receptor positive MCF-7 cells were very similar. High polyphenol grapes and products derived from such grapes may be useful as a concentrated source of dietary polyphenols.