| 摘要: | 葡萄是一種已知的抗氧化劑，可預防疾病的產生，且對於保護人體避免提早衰老有很大的貢獻，而葡萄的抗氧化能力來自於多酚類、花青素以及類黃酮三大種類，其中又以多酚類的含量較為豐富。本實驗使用乙酸乙酯與甲醇萃取葡萄皮、葡萄籽與葡萄葉，進行抗氧化能力與抗氧化成分實驗，並進一步藉由管柱分離其有效之抗氧化物質。實驗結果顯示，粗萃取物抗氧化成分方面，總酚類含量以甲醇葡萄籽粗萃取物含有2.8896 GAE mg/ g最多；總黃酮含量則為乙酸乙酯葡萄籽粗萃取物含有24.1219 CTE mg/ g最豐富；而花青素含量方面亦是乙酸乙酯葡萄皮粗萃取物花青素含量11.4482 μmole/ g最豐富。而粗萃取物抗氧化能力方面，DPPH自由基清除能力皆以甲醇葡萄各部位粗萃取物有較佳的表現，而其葡萄皮、葡萄籽與葡萄葉之EC50分別為0.1932 mg/ mL、0.0292 mg/ mL與0.0693 mg/ mL，以甲醇葡萄籽粗萃取物有較佳的表現；而ABTS自由基清除能力實驗中，甲醇葡萄各部位粗萃取物有良好的表現，而其葡萄皮、葡萄籽與葡萄葉之EC50分別為0.600 mg/ mL、0.0542 mg/ mL與0.0967 mg/ mL；還原力實驗中，甲醇葡萄各部位粗萃取物之K值皆比乙酸乙酯葡萄各部位粗萃取物之K值表現好，而葡萄籽甲醇粗萃取物其K值1.0861亦為最高，其次依序為葡萄葉與葡萄皮，K值分別為0.3755與0.3204；過氧化氫清除實驗中，則是以乙酸乙酯葡萄粗萃取物表現較好，其中又以葡萄籽之EC50為0.0176 mg/ mL最佳；TBARS實驗中，甲醇粗萃取物皆比乙酸乙酯粗萃取物有較佳的表現，其EC50順序依序為葡萄籽0.4078 mg/ mL、葡萄葉1.1175 mg/ mL以及葡萄皮6.2540 mg/ mL。經由管柱分離後，DPPH自由基清除能力以甲醇籽EA15:MeOH85可溶部有最好的效果，其EC50為0.0811 mg/ mL；而ABTS自由基清除能力以甲醇籽EA15:MeOH85可溶部有最好的效果，其EC50為0.2514 mg/ mL；過氧化氫清除實驗中，則是以甲醇皮EA25:MeOH75可溶部與甲醇葉EA25:MeOH75可溶部有最好的效果，其EC50分別為14.1324 mg/ mL與15.9661 mg/ mL；在還原力實驗中，則是以甲醇籽EA25:MeOH75可溶部表現最好，其K值為0.6927；在TBARS實驗方面，以甲醇籽EA15:MeOH85與EA0:M100表現最佳，EC50分別為0.0982 mg/ mL與0.1088 mg/ mL。綜合上述實驗結果得知，葡萄具有極佳的抗氧化能力，極具開發應用之潛力。
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 objective of this study is to assess the antioxidant activity of ethyl acetate and methanol and its soluble fractions from grape skin, seed and leaf. The antioxidant activities were carried out using various antioxidant assays, including DPPH and ABTS free radical scavenging assays, reducing power assay, hydrogen peroxide scavenging assay and thiobarbituric acid reactive substances(TBARS) scavenging assay. In addition, total phenolic contents, total flavonoids contents and anthocyanin contents of these extracts were also determined. Results revealed that, among the various fractions, the methanol soluble fraction of grape seed crude extracts which contains the highest percentage of phenolic compounds exhibited the strongest antioxidant composition; the ethyl acetate soluble fraction of grape seed crude extracts which contains the highest percentage of flavonoids compounds exhibited the strongest antioxidant composition; the ethyl acetate soluble fraction of grape skin crude extracts which contains the highest percentage of anthocyanin compounds exhibited the strongest antioxidant composition.
In DPPH free radical scavenging capacity, the EC50 value of grape skin, seed and leaf crude methanolic extracts exhibited 0.1932, 0.0292 and 0.0693 mg/mL, respectively; In ABTS free radical scavenging capacity, the EC50 value of grape skin, seed and leaf crude methanolic extracts exhibited 0.600, 0.0542 and 0.0967 mg/mL, respectively; In hydrogen peroxide scavenging capacity, the EC50 value of grape seed ethyl acetate extracts exhibited 0.0176 mg/mL; In reducing power capacity, the K value of grape skin, seed and leaf crude methanolic extracts exhibited 0.3204, 1.0861 and 0.3755 K value, respectively; In TBARS scavenging capacity, the EC50 value of grape skin, seed and leaf methanol extracts exhibited 0.600, 0.0542 and 0.0967 mg/mL, respectively.
On column chromatography assay, in DPPH free radical scavenging capacity, the EC50 value of the strongest of methanolic grape seed EA15:MeOH85 soluble fraction exhibited 0.0811 mg/mL;In ABTS free radical scavenging capacity, the EC50 value of the strongest of methanolic grape seed EA15:MeOH85 soluble fraction exhibited 0.2514 mg/mL; In hydrogen peroxide scavenging capacity, the EC50 value of the strongest of methanolic grape skin EA25:MeOH75 soluble fraction exhibited 14.1324 mg/mL; In reducing power capacity, the K value of the strongest of methanolic grape seed EA25:MeOH75 soluble fraction exhibited 0.6927 K value on reducing power; In TBARS scavenging capacity, the EC50 value of methanolic grape seed EA15:MeOH85 soluble fraction exhibited 0.0982 mg/mL. These results demonstrated that the extracts of grape have excellent antioxidant activities, indicating its potential applications are worthy of further investigations. |
