58-6 |
Antioxidant and antiproliferative activities of grapes |
R. H. LIU1, M. Eberhardt1, and C. Y. Lee2. (1) Dept. of Food Science, Cornell Univ., 410 Stocking Hall, Ithaca, NY 14853-7201, (2) Dept. of Food Science & Technology, Cornell Univ., W. North St., NYSAES, Geneva, NY 14456 Fruits contain numerous phytochemicals which are capable of scavenging free radicals, thereby decreasing free radical-induced cell damage. This study was designed to: 1) measure the total antioxidant activity of grapes by the total oxyradical scavenging capacity (TOSC) assay; 2) determine the ability of grape extract to inhibit tumor cell growth in vitro. Grapes were extracted using 80% acetone. Total phenolics and flavonoids were measured by spectrophotometer. Total antioxidant activity was determined using the TOSC assay. Inhibition of tumor cell growth was determined in colon cancer cell models. Proliferation was assessed using the MTT assay. The red grape varieties, Concord and Pinot Noir, had a higher total phenolic content and flavonoid content than the white grape varieties, Niagara and Chardonnay. Grape skins, regardless of variety, had higher total phenolic and flavonoid contents than the whole grapes. Grape extracts possessed a strong antioxidant activity. The red grape varieties had greater antioxidant activities than the white grape varieties. There was a positive and significant relationship between total phenolic and flavonoid content and antioxidant activity in grapes. The grape extract inhibited colon cancer cell growth in vitro in a dose-dependent manner. Cell proliferation inhibition occurred from 1 to 20 mg/ml with a saturation of inhibition occurring at approximately 30 mg/ml. The inhibition of cell proliferation was greater for skin only fractions when compared to whole grapes. These results suggest that the combination of natural antioxidants in grapes is critical to powerful antioxidant activity and antiproliferative activity. The balanced antioxidants in grapes are efficient oxyradical scavengers and tumor cell inhibitors. Therefore, phytochemicals in fruits may help to reduce the incidence of cancers and other degenerative diseases if consumed as part of a balanced diet.
Session 58, Food Chemistry: Lipids, Emulsions and Antioxidants
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