荔枝生理落果中A型原花青素提取纯化鉴定及抗氧化活性研究

Extraction,Purification,Identification of A-type Procyanidine from Litchi Fruitlet and Its Antioxidant Activity

本文以荔枝生理落果为原料,采用乙醇提取、AB-8大孔树脂纯化和Sephadex LH-20葡聚糖凝胶分离得到多酚组分,采用DPPH·、ABTS^(+)·清除法及FRAP法测定各多酚组分体外抗氧化活性后,使用电喷雾液质联用四级杆飞行时间质谱(LC-ESI-Q-TOF)对多酚进行鉴定。结果表明,荔枝生理落果总酚及总原花青素含量分别为(49.96±2.66)mg GAE/g DW和(27.25±0.44)mg EPE/g DW;而体外抗氧化活性结果表明,第4个多酚组分(P4)具有较强ABTS^(+)·和DPPH·清除能力,当100μg/mL时,清除率分别为92.52%和46.98%,总抗氧化能力显著高于抗坏血酸(P<0.05);经LC-ESI-Q-TOF分析发现,荔枝生理落果多酚纯化物含有10种A型原花青素,其中P4组分由纯A型原花青素组成,分别为原花青素A_(4)、原花青素A_(2)及A型原花青素二聚体和四聚体。从荔枝生理落果中分离纯化的A型原花青素具有优秀的抗氧化活性,可作为新的A型原花青素来源。

In this study,polyphenol fractions were extracted from litchi fruitlet which drop naturally,then purified by AB-8 macroporous resin and separated by Sephadex LH-20.After comparing the antioxidant activities of each sample in vitro,the polyphenol components were identified by LC-ESI-Q-TOF.The results showed that the content of total phenols and total procyanidines in litchi fruitlet were(49.96±2.66)mg GAE/g DW and(27.25±0.44)mg EPE/g DW,respectively.In vitro antioxidant activity text indicated that the fourth polyphenol component(P4)had strong ABTS^(+)·and DPPH·scavenging ability,and its free radical scavenging rate could reach 92.52% and 46.98% in 100μg/mL respectively.According to LCESI-Q-TOF analysis,PLFE contained 10 types of A procyanidines,which were much more than B procyanidines.P4 was composed of pure A-type procyanidine,which were procyanidine A_(4),procyanidine A_(2),A-type procyanidine dimer and tetramer.Therefore,A-type procyanidine isolated and purified from litchi fruitlet have remarkable antioxidant activity,which can be used as an excellent source of new A-type procyanidine.