以Liposomes模式探討五種含氧類胡蘿蔔素之抗氧化功能

在非酵素微脂粒系統中分別以高濃度葡萄糖及比較不同pH值的條件下，Fe2+誘發脂質過氧化，β-carotene和五種帶類胡蘿蔔素 ( astaxanthin、β-cryptoxanthin、capsanthin、lutein和zeaxanthin )的抗氧化能力。實驗結果發現，濃度為17.6μM的類胡蘿蔔素對於高濃度葡萄糖與還原力有顯著的表現( p<0.05)，而可以延緩脂質氧化現象產生，達到抗氧化性的作用。在pH7.2環境中，類胡蘿蔔素有抑制脂質氧化效果，可能是類胡蘿蔔素可以清除Fe2+所引起的自由基，或是可以穩定脂質膜的構型，而減少自由基氧化傷害。在pH4.5環境中，類部份胡蘿蔔素有促氧化效果，或許是因為氫離子影響類胡蘿蔔素結構的穩定性，進而降低了抗氧化能力，增加脂質氧化現象。本研究結果也表示，五種帶氧類胡蘿蔔素在高濃度葡萄糖中，以astaxanthin、zeaxanthin和lutein比β-carotene有更好的顯著表現，能夠延緩脂質氧化，進一步達到抗氧化效果。未來可能針對帶氧類胡蘿蔔素發展成機能性食品，應用於平日保健或對治療氧化相關疾病有所幫助。 關鍵字：β-carotene、含氧類胡蘿蔔素、脂質氧化

Abstract The non-enzymatic antioxidant activity of β-carotene, astaxanthin, β-cryptoxanthin, capsanthin, lutein and zeaxanthin was studied in liposomal system, in which high glucose or Fe2+ was used to induced oxidation. The influence of pH upon the antioxidant effects of these carotenoids was also evaluated. The result showed β-carotene and oxycarotenoids at 17.6μM significantly delayed lipid oxidation (p<0.05) in high glucose. β-carotene and oxycarotenoids were had the effect of the induced oxidation in acid (pH 4.5). It was suggested that the hydrogen atom was neutralized the hydroxyl atom of the oxycarotenoids and then lowed the antioxidant ability, increase lipid oxidation. It would be benefit for preventing or controlling diabetes mellitus and oxidation-related disease. Keywords: β-carotene, oxycarotenoids, lipid oxidant.