【作者】 李红娟；

【导师】 樊金拴；

【作者基本信息】 西北农林科技大学 ， 野生动植物保护与利用， 2013， 硕士

【摘要】 核桃(Juglans regia L.)，又称胡桃，是核桃科(Juglandaccae）核桃属(Juglans linn)的一种落叶乔木，是集食用、药用、生态和用材于一体的优良植物，居世界四大干果之首，也是我国主要的木本油料植物之一。本文采用响应面法优化了核桃黄酮的提取工艺，分析了不同组织、不同处理方式下陕西12个主栽核桃品种(绿岭、香玲、鲁光、维纳、MK、温185、清香、岱香、辽1、辽3、辽4、辽6)黄酮种类和含量的差异，并采用DPPH清除法与普鲁士蓝法研究了各黄酮的抗氧化活性，取得以下结果：(1)核桃鲜叶黄酮热回流提取的最佳工艺条件为乙醇体积分数62%、液料比44.7:1、提取时间5.2h、提取温度61℃，黄酮得率为3.586%；鲜青皮黄酮的超声提取工艺最佳条件是乙醇体积分数62%、超声温度51℃、超声时间31min、静置时间6.5min，黄酮得率为1.077%。经用同一样品不同提取方法验证，结果显示，二者中热回流工艺更佳。(2)不同核桃品种及同一品种不同处理方式，对黄酮含量都有极显著的影响。经过阴干处理的样品，其黄酮含量显著高于烘干样及鲜样。黄酮含量随组织的变化存在极显著差异。对阴干样，4年生品种黄酮含量，温185>MK>维纳>鲁光>香玲>绿岭，后两者的差异不显著；2年生品种，清香>辽4>岱香>辽6>鲁光>辽3>辽1。对不同的组织，青皮>分心木>叶>叶柄>枝>仁(具膜)，枝和仁含量差异不显著。(3)抗氧化剂芦丁、槲皮素、VC、BHT的EC50分别为4.652μg/mL、3.709μg/mL、0.432μg/mL、6.552μg/mL。不同核桃组织清除DPPH自由基的能力由强到弱依次为：仁(具膜)>分心木>枝>叶>青皮，它们的EC50依次为0.0348、0.0496、0.182、0.212、0.307μg/mL。核桃黄酮清除DPPH自由基的能力显著高于这四种抗氧化剂。普鲁士蓝还原力测定显示：核桃黄酮的还原能力强于相同浓度的抗氧化剂。二者测定方法结果一致，均表明核桃黄酮具有较强的抗氧化活性。(4)化学显色，显示不同品种、组织中黄酮类化合物的种类基本相似，但也存在差异。核桃黄酮化合物以黄酮类、黄酮醇类、二氢黄酮类居多，青皮和仁中可能含有橙酮类化合物。更多还原

【Abstract】 Walnut (Juglans regia L.) is a kind of deciduous tree in the family of Juglandaccae. It is aexcellent plant with edible, medicinal, ecological, and material functions, and it is a rareeconomy resource plant in the world. Walnut, belongs to4great nuts, is also the majorspecies of woody oil-bearing plants in China. In this article, we analyse the contents and kindsof flavonoids in12cultivars in shaanxi. We use response surface analysis methodology (RSM)to optimize the extraction process of flavonoids, analyze the influences of different tissuesand treatments on the flavonoids contents. then we use DPPH free radical scavenging activityand Prussian blue method to research its antioxidant activities. The results are as follows:(1)Two RSM methods, CCD and BBD, are used to optimize the hot reflux and ultrasonicextraction process of flavonoids from walnut fresh leaves and green husk respectively. Thefront result shows that the ethanol volume fraction62%, liquid/solid ratio44.7:1, extractingtime5.2h, extraction temperature61℃, on this condition the yield of flavonoids is3.607%;the latter results shows that the ethanol volume fraction62%, ultrasonic temperature51℃,ultrasonic time31min, standing time6.5min, with this understanding the yield of flavonoidsis1.077%. By using different extracting methods with same sample, the result shows that thehot reflux process is better.(2)There are significant differences on flavonoids contents in different varieties and withdifferent treatments. To compare different treatments, the flavonoids contents of air-driedsamples are significantly higher than baked and fresh samples. The variability of flavonoidscontents are along with the changes of varieties and the tissues. Among air-dried samples inorder, the content of flavonoids for4-year old varities, the Wen185> MK>Vina> Luguang>Xiangling>Lvling. The difference between Lvling and Xiangling is not significant. For2-year old varities, Qingxiang>Liao4>Daixiang>Liao6>Luguang>Liao3>Liao1. Amongthe tissues in order, Green husk>diaphragma> leaves> petiole> branche> kernel, there isno significant difference between the content of branche and kernel.(3)The results of Favonoids antioxidant activity shows that the clearing DPPH activity ofdifferent tissues from strong to weak, in order: kernel>diaphragma>branch> leaf> greenhusk. The EC50of them in their proper order are:0.0348,0.0496,0.182,0.212,0.307μg/mL. And the EC50of VC, quercetin, rutin, BHT are0.432μg/mL,3.709μg/mL,4.652μg/mL,6.552μg/mL, the ability of walnut flavonoids scavenging DPPH· is stronger than the fourkinds of antioxidants. Prussian blue reduction measurement shows that the reduction abilitiesof flavonoids of walnut are stronger than the antioxidants at the same concentration. Bothresults are consistent, show that walnut flavonoids have stronger antioxidant activity.(4)Chemical color test according to the results of flavonoids in different varieties andtissues are similar, but there are also differences. The walnut flavonoids consist mostly offavone, flavonol and flavanone. Maybe there are ketone compounds in green husk and nuts.更多还原