核桃分心木黄酮物质的组分及其抗氧化性分析

Flavonoid Composition and Antioxidant Activity of Diaphragma juglandis Fructus

采用超声波辅助乙醇提取核桃分心木黄酮,利用AB-8大孔树脂对黄酮粗提物进行分离纯化,利用自动收集器收集到6管样液。分别对6管样品的2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)(2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid),ABTS)阳离子自由基、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基、羟自由基、超氧阴离子自由基、活性氧(reactiveoxygenspecies,ROS)自由基清除率以及铁离子还原力6个抗氧化指标进行测定。利用超高效液相色谱-三重四极杆串联质谱仪联用进样,对6管样品进行组分以及含量分析。结果表明:6管样品中的ABTS阳离子自由基清除率、羟自由基清除率以及ROS自由基清除率显著高于VC阳性对照。6管样品中槲皮苷含量最多,质量浓度高达2 426.9 ng/mL,芦丁和没食子酸几乎不存在。组分分析结果除了文献已报道的黄酮类物质柚皮素、金丝桃苷、二氢槲皮素、儿茶素、槲皮苷、芦丁、异槲皮素、没食子酸(属多酚)外,还含有槲皮素、黄芪苷、表儿茶素没食子酸酯。黄酮物质含量与抗氧化能力的相关性分析发现,柚皮素含量与DPPH自由基清除能力和ABTS阳离子自由基清除能力呈显著负相关,而儿茶素含量与ROS清除率呈正相关。验证实验的结果表明:槲皮苷的ABTS阳离子自由基清除能力显著高于VC阳性对照以及混合样品。本研究为槲皮苷、柚皮素和儿茶素的抗氧化能力及其构效关系的研究提供一定理论基础。

In this study,ultrasonic-assisted ethanol extraction was used to extract flavonoids from Diaphragma juglandis fructus,the dry wooden diaphragm inside walnuts,and AB-8 macroporous resin was used to separate and purify the crude flavonoids,yielding six fractions.Their antioxidant properties including 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical,2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid(ABTS)cation radical,hydroxyl radical,superoxide anion radical and reactive oxygen species(ROS)scavenging capacity,and iron ion reducing power were determined.The composition and content of flavonoids in the six fractions were analyzed by ultra-high performance liquid chromatography-triple quadruple tandem mass spectrometry(UPLC-QQQ-MS/MS).The results showed that the ABTS cation radical,hydroxyl radical and ROS scavenging capacity of all six samples were significantly higher than those of vitamin C(VC).Quercetin was the most abundant flavonoid with the highest concentration of 2426.9 ng/mL,and rutin and gallic acid were hardly detectable.In addition to the reported flavonoids naringin,rutin,isoquercetin,hyperoside,dihydroquercetin,catechin,quercetin and gallic acid(a member of the polyphenol family),quercetin,astragaloside and epicatechin gallate were also detected.The correlation analysis between flavonoid content and antioxidant capacity showed that naringin content was significantly negatively correlated with DPPH radical and ABTS cation radical scavenging capacity,while catechin content was positively correlated with ROS scavenging capacity.The results of validation experiment showed that the ABTS cation radical scavenging capacity of quercetin was significantly higher than that of VC and mixed samples.This study lays a foundation for the study of the antioxidant capacity and structure-activity relationship of quercetin,naringin and catechin.