Abstract
Chardonnay and Tinta Cao grape pomaces were generated by the winemaking process. The pomaces were extracted with 50% acetone and tested for antioxidant capacities using the oxygen radical absorbance capacity (ORAC) assay, DPPH□EC50 , and ABTS.+ scavenging capacity tests. Cytotoxicity and antiproliferative activities against Caco-2 and HT-29 human colon cancer cell lines were also analyzed. The quantitative detection of caspase-3 activity during the early apoptotic process was evaluated by fluorometric immunosorbent enzyme assay (FIENA). Induction of late stage apoptosis was analyzed by DNA fragmentation. Total phenolic content (TPC), individual phenolic acids, total oil, and fatty acid profile were also analyzed. The Tinta Cao pomace had the highest antioxidant capacity in all tests with an ORAC value of 386.5 μmol trolox equivalents (TE) per g pomace (μmol TE/g), its DPPH□EC50 value was 94.6 mg equivalents/L, and its ABTS.+ value was 806.7 μmol TE/g, which was more than twice as high as the Chardonnay. Both Tinta Cao and Chardonnay grape pomace extracts appear to contain components that inhibit the proliferation of Caco-2 and HT-29 cancer cells, at least in part, by triggering apoptosis. Expression of caspase-3 was induced by Tinta Cao and Chardonnay pomace extracts at 3 g/L after 4 hours of treatment with a 308% and 229% increase compared to control, respectively. An increase in DNA fragmentation was also observed with both grape pomace treatments. This study demonstrated that these tested grape pomaces were potent scavengers of free radicals and may provide some level of protection against certain cancers.
Highlights
Over 7 million tons of grapes were harvested in the U.S in 2009, and more than 60% were used to make wine or juice
We investigated 2 grape species (Vitis vinifera) Tinta Cao and Chardonnay grape pomaces for antioxidant activities, inhibition of the proliferation of HT-29 and Caco-2 colon cancer cells, and phytochemical compositions
Chardonnay grape seed flour was compared to several other flour sources using the Oxygen Radical Absorbance Capacity (ORAC) method extracted with 50% acetone including Pinot Noir grape seed flour, which is a red grape seed flour
Summary
Over 7 million tons of grapes were harvested in the U.S in 2009 (http://usda.mannlib.cornell.edu/usda/), and more than 60% were used to make wine or juice. These biological free radicals may damage DNA, protein, and lipids [1,2,3], and it is currently believed that they are among the underlying pathophysiological causes of the development of cancer, heart disease, aging, and other chronic health afflictions [4,5,6]. Antioxidants are free radical scavengers that can decrease radical induced detrimental effects [7,8,9]
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