红心火龙果果肉中活性成分与其抗氧化能力的相关性研究

为探讨红心火龙果活性成分与抗氧化能力相关性,以8种红火龙果肉为材料,测定甜菜红素、总酚及黄酮含量,测定总抗氧化、清除DPPH·、ABTS+·、·OH及NO-2·自由基能力,并进行相关性分析,HPLC和HPLC-MS分离鉴定甜菜红素组分,PLSR研究色素组分含量与抗氧化活性的相关性。结果表明:8个火龙果样品中甜菜红素、总酚和黄酮含量存在差异,"海南金都1号"火龙果甜菜红素和黄酮含量均最高,分别为76.77和9.00 mg/L,"广西大红龙"中总酚含量最高达53.01 mg/L。除·OH清除能力外,甜菜红素与其他4种抗氧化能力呈极显著正相关(r=0.936~0.955)。黄酮与抗氧化能力较显著相关(r=0.717~0.956),而总酚与抗氧化能力无显著相关性(P>0.05)。液质鉴定甜菜红素组分有Betanin、Isobetanin、Phyllocactin和Isophyllocactin,Betanin是抗氧化的重要成分,Phyllocactin其次,可能是Phyllocactin的丙二酰基与苯环邻位酚羟基产生分子内氢键,抑制酚羟基的氧化性。

Study on the Correlation Between Active Components and Antioxidant Capacities in Red Dragon Fruits

This study aimed to explore the correlation between the active components and antioxidant capacities in red dragon fruits. Eight common red dragon fruits were used as materials,the contents of betalanin,total phenolic and flavonoid were measured,the antioxidant capacities were evaluated by total reducing capacity,scavenging DPPH,ABTS,hydroxyl and nitrite free radical abilities,and the correlation between the two had been analyzed. The compositions of betanin were isolated and identified by HPLC and HPLC-MS,and the correlation between the contents of betanin compositions and antioxidant capacities was investigated by PLSR. It was shown that there were differences in the contents of betanin, total phenolic and flavonoid in eight dragon fruit samples,the highest contents of betanin and flavonoid were 76.77 and 9.00 mg/L in "Hainan Jindu No.1",respectively and "Guangxi Dahonglong" had the highest total phenolic content which reached 53.01 mg/L. With the exception of hydroxy free radical scavenging capacity,antioxidant activity of pitaya extractive had a significant positive correlation with betalanin content(r=0.936~0.955). There also was a strong correlation between flavonoid and antioxidant capacity(r=0.717~0.956),but there was no such phenomenon in total phenol. Betalain included betanin,isobetanin,phyllocactin and isophyllocactin identified by HPLC-MS. Betanin was the dominant antioxidant component in betalanin,followed by phyllocactin which intramolecular hydrogen bonds between malonyl group and the ortho-phenolic hydroxyl group might hinder the oxidation of phenolic hydroxyl group.