由許多文獻中已知葡萄皮與葡萄籽中含有豐富的植物性化學成份如多酚類等，具有良好的抗氧化效果；本研究以台灣本土栽種之巨峰葡萄為原料，比較不可食部位之巨峰葡萄皮與葡萄籽其甲醇與水萃取物的抗氧化成份與抗氧化活性。試驗結果，以水及甲醇萃取葡萄籽有較高之總多酚含量(以沒食子酸相對量表示，gallic acid equivalents; GAE)，分別為214.6 mg GAE/g及176.2 mg GAE/g。總黃酮含量(以兒茶素相對當量表示，catechin equivalents；CTE)以甲醇萃取葡萄籽(30.6 mg CTE / g)最高，其次為葡萄皮之甲醇萃取物(26.17 mg CTE / g)，而蒸餾水萃取葡萄籽(22.55 mg CTE / g)及葡萄皮(20.34 mg CTE / g)含量皆較低。比較葡萄皮與籽之抗氧化活性，在DPPH自由基(2,2-diphenyl-1-picrylhydrazyl radical)清除活性，葡萄籽甲醇與蒸餾水萃取物有最佳的抑制效果 (IC_(50)分別0.03與0.077 mg/mL)，而葡萄皮甲醇萃取物其IC_(50)為1.416 mg/mL表現最差。在ABTS( 2,2-azinobis(3-ethylbenz-thiazoline)-6-sulfonic acid)自由基清除活性，則以葡萄籽萃取物活性明顯高於葡萄皮萃取物，而其中甲醇萃取物活性明顯高於蒸餾水萃取物；在螯合亞鐵離子之能力，以蒸餾水萃取的效果明顯較甲醇萃取佳，其中以蒸餾水萃取之葡萄籽萃取物具有最佳的螯合亞鐵離子能力。綜合以上結果可知本土巨峰葡萄廢棄之部份的葡萄皮與葡萄籽皆具有抗氧化成份，且分別具有抗氧化活性，應可以此研究結果為基礎，進一步加以應用開發為機能性產品，促進廢棄農產品之利用。
Grape extracts is known as a powerful antioxidant that protects the body from premature aging, disease, and decay. Grape phenolics have antioxidant properties and ability to serve as free radical scavengers. The beneficial effects of grape polyphenols are due to their free radical scavenging capability. Extracts for grape skin and seed in grapevine fields of Kyoho grape by differential solvent extract were examined and compared for their antioxidant properties, including free radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH^.), ( 2,2-azinobis(3-ethylbenz-thiazoline)-6-sulfonic acid) radical (ABTS^.), Fe^(2+) chelating capacity and total phenolic content and total flavonoids content. The total phenolic content were distilled water extracts of grape seed＞methanolic extracts of grape seed＞distilled water and methanolic extracts of grape skin. The total flavonoids content were methanolic extracts of grape seed＞methanolic extracts of grape skin＞distilled water extracts of grape seed＞distilled water extracts of grape skin. Comparison of skin and seed antioxidant activity, distilled water and methanolic extracts of grape seed had the best inhibition in the DPPH free radical scavenging activity. The methanolic extracts of grape seed had the best inhibition in the ABTS free radical scavenging activity. The ferrous ion chelating capacity, the distilled water of seed extracts had the best of Fe^(2+)-chelating ability. These results demonstrated that the extracts of grape seed and skin have excellent antioxidant activities, indicating its potential applications are worthy of further investigations.
