沙苑子中酚类物质研究及其抗氧化成分的HPLC筛选

【作者】 张清安；

【导师】 张志琪；

【作者基本信息】 陕西师范大学 ， 应用化学， 2010， 博士

【摘要】 本论文以陕西地道特产沙苑子为研究对象,以沙苑子中酚类化合物的提取、纯化、抗氧化研究、成分鉴定和抗氧化活性成分的色谱法筛选为主要研究内容,以期通过深入系统研究为沙苑子的开发和深加工提供理论依据和工艺参数。论文共分九章,研究的主要内容及结果包括：1.在超声功率120W、40KHz条件下,采用响应面法对沙苑子中酚类化合物的提取工艺条件进行了优化,获得了如下结果：以60%甲醇做提取溶剂时,工艺参数为42℃、47min、液料比30：1和粒度120目。在此条件下提取率为10.66%。以60%乙醇做提取溶剂时,工艺参数为52℃、34min、液料比26：1和粒度100目。在此条件下提取率为7.08%。以60%丙酮做提取溶剂时,工艺参数为粒度120目、60min、50℃和液料比40：1。在此条件下提取率为16.19%。2.采用Folin-Ciocalteu比色法测定了沙苑子中酚类化合物含量,并对提取物的DPPH·自由基清除活性进行了测定。显色条件为：Folin-Ciocalteu显色剂(稀释10倍)1.00mL、7.50%Na2CO3溶液3.00mL、显色温度25℃、显色时间2h和测定波长647nm。酚类含量在10-100μg/mL范围内与吸光值呈良好线性关系。当提取物浓度在1.25%时,分别测得甲醇、乙醇和丙酮提取物溶液中酚类化合物含量为64.4、63.6和65.7μg gallic acid/mL。当DPPH·为10-4M时,反应时间30min,在波长515nm下测定,提取物浓度以2.00%为最佳,甲醇、乙醇、丙酮提取物的DPPH·自由基清除率可分别达到91.20%、91.79%和89.59%。3.采用D301和XDA-1树脂对沙苑子酚类粗提物进行了纯化。静态吸附等温线研究结果表明,D301树脂对沙苑子甲醇、乙醇提取物的吸附是吸热过程,而XDA-1树脂对丙酮提取物的吸附为放热过程；两种树脂均具有物理吸附特性且等温线略向上凸起属优惠吸附类型；吸附参数能用Freundlich方程较好拟和。静态吸附热力学性质研究表明,D301树脂对沙苑子甲醇、乙醇提取物的吸附过程中△H>0,△G<0,△S>0；而XDA-1树脂对丙酮提取物吸附过程中△H<0,△G<0,△S>0。动态吸附研究表明,在实验条件下,上样浓度在13.5mg/mL、流速为2.0mL/min左右时有利于吸附,能使吸附尽快达到平衡；用70%的乙醇作为洗脱剂可获得较高的解吸率。经所选树脂纯化后甲醇、乙醇、丙酮提取物的纯度分别为34.3%、39.6%和37.4%；分别比纯化前的10.2%、12.5%和14.2%提高了2倍左右。4.对提取物的体外抗氧化活性进行了实验。研究结果表明,沙苑子酚类各提取物均具有较强的还原能力、抑制Fe2+诱发的脂质过氧化反应和清除超氧阴离子自由基、羟基自由基的作用,部分指标的抑制效果甚至强于阳性对照物Vc和没食子酸。在实验浓度范围内,呈现一定的量效关系。5.采用高效液相色谱(HPLC)和UPLC-Q-Tof-MS对沙苑子酚类提取物进行了分析。HPLC分离沙苑子酚类提取物的条件为：0.1%甲酸-甲醇-水流动相体系,洗脱梯度为10%→40%→70%→100%→10%(0→10→45→50→60min)；根据Q-Tof-MS质谱图和PDA光谱图,参考相关文献报道推断了17种化合物。6.建立了HPLC-DPPH-UV/VIS在线筛选系统,并应用于沙苑子酚类提取物中抗氧化成分的在线筛选。在线筛选的最佳DPPH溶液浓度为50mg/L,流速为0.70mL/min。在线筛选结果表明：虽然提取溶剂不同,但提取物中具有明确清除DPPH自由基活性的化合物基本一致。这些化合物对应于色谱流出曲线峰1-8,分别鉴定为槲皮素-3-O-[2-O-(β-D-葡萄糖基)]-α-L-鼠李糖基、4’-O-(3’”-O-二氢红花菜豆酰-β-D-吡喃葡萄糖基)鼠李柠檬素、杨梅素-3-0-β-D-葡萄糖甙、杨梅素-5’-O-β-D-葡萄糖甙、二羟基黄烷的三聚体、沙苑子新苷[鼠李柠檬素-3-O-p-D(6”-乙酰化葡萄糖甙)]、沙苑子杨梅苷的二聚体和大豆皂甙Ⅰ甲脂。7.采用柱前反应法,通过比较色谱指纹图谱分别对三种不同沙苑子酚类提取物中的抗氧化成分进行了筛选。从沙苑子甲醇、乙醇提取物中均筛出11种有清除DPPH自由基活性的成分,其中9个化合物被鉴定。除在线法筛选的8个化合物(色谱1-8号峰对应于在线法筛选的8、1-7号峰)外,另一个鉴定为异鼠李素-3-O-[6-O-(a-L-鼠李糖基)]-β-D-葡萄糖甙。沙苑子丙酮提取物中共筛选出12个活性成分,其中10个化合物被鉴定。对应于色谱流出曲线峰1-12,其中峰1、2鉴定为毛蕊异黄酮的三聚体和山奈酚的三聚体,峰3-10与甲醇、乙醇提取物中的峰1-8相同。峰11、12未被鉴定。更多还原

【Abstract】 In this dissertation, the phenolics in Semen Astragali Complanati, a native medicinal seed in Shaanxi province, were studied for its extraction, purification, antioxidant capacity, components identification, and screening of antioxidants by high performance liquid chromatography (HPLC). This systematical research was expected to provide theoretical basis and technology parameters for the development and deep-processing of Semen Astragali Complanati.Nine chapters are included in the dissertation. The contents and results are following:1. The optimum extraction conditions of phenolcs from Semen Astragali Complanati under the ultrasonic condition of 120 W and 40.0 kHz were as follows:With the.60%(v/v) methanol as extractant, the optimized conditions were extraction temperature of 42℃, extraction time of 47min, solvent-to-sample ratio,30:1 and particle size,120mesh. Under the optimized conditions, the extraction yield was 10.66%.With the 60%(v/v) ethanol as extractant, the optimized conditions were extraction temperature of 52 C, extraction time of 34min, solvent-to-sample ratio,26:1 and particle size, 100mesh. Under the optimized conditions, the extraction yield was 7.08%.With the 60% (v/v) acetone as extractant, the optimized conditions were particle size,120mesh; extraction time of 60min, extraction temperature of 50 C, solvent-to-sample ratio,40:1. Under the optimized conditions, and the extraction yield was 16.19%.2. The determining conditions of Folin-Ciocalteu method were optimized: the volume of Folin-Ciocalteu, 1.00mL; 7.5g/100mL Na2CO3 solution,3.00mL; the reaction temperature,25℃; the reaction time,120 min; and the determination wavelength,647nm. There is a good relationship between the content of gallic acid and the absorbance value within the range of 10-100μg/mL(y=0.0081x-0.0249, R2=0.9996). The suitable concentrations for determining of the methanol, ethanol, and acetone extracts are all 1.25g/100mL. The contents of phenol were 64.4,63.6, and 65.7μg gallic acid/mL, respectively.The optimum conditions for determining the scavenging DPPH·free radical were:515nm,30min. At the concentration of 2.00% for methanol, ethanol, and acetone extracts, the highest free radical scavenging activity were 91.20%、91.79%%、89.59%, respectively.3. The results for purifying of extracts by resins of D301 and XDA-1 were as follows:The results for Static equilibrium adsorption isotherms showed: the adsorptions by D301 resin for methanol, and ethanol extracts are all endothermic process, while an exothermic adsorption process for acetone extracts by XDA-1 resin. The properties of adsorptions by D301 and XDA-1 are all favorable and physical adsorptions. The Freundlich adsorption law is applicable to the adsorptions of extracts on D301 and XDA-1 adsorbents within the concentration in our study.The results for thermodynamics of the adsorptions showed:the adsorption enthalpy change and entropy change of methanol, ethanol extracts on D301 resin are positive, and the free energy change is negative. While the adsorption enthalpy change and free energy change of acetone extracts on XDA-1 resin are negative, and the entropy change is positive.The results for dynamic adsorptions showed 70% ethanol was the suitable de-adsorption solvent, it was good for attaining the adsorption equilibrium at the concentration of 13.5mg/mL, and flow of 2.0mL/min.With the resins of D301, and XDA-1, the purity degrees of methanol, ethanol, and acetone extracts were increased from 10.2%,12.5%, and 14.2% to 34.3%,39.6%, and 37.4%, respectively.4. Experimental values for antioxidant capacity suggested that the extracts possess stronger reduced capacities, inhibition rate on lipid peroxidation reaction induced by Fe2+, and scavenging rate for O2-·and·OH radicals. There is a good relationship between concentrations and effects in the range of experimental concentrations.5. The conditions of HPLC for extracts were:mobile phase,0.1% formic acid-methanol-water; elution gradient,10%→40%→70%→100%→10%(0→10→45→50→60min). The extracts were studied by UPLC/Q-Tof & Mass Spectrometry, and 17 compounds were characterized according to their mass spectrometry, UV/VIS spectrometry, and related literature reports.6. The on-line HPLC screening system was constructed and applied to search for antioxidants from phenolics in Semen Astragali Complanati. The optimized concentration and flow of DPPH were 50mg/L, and 0.70mL/min.There are eight compounds with scavenging DPPH radical activity, whether in methanol extracts, ethanol extracts or acetone extracts. which are 3-O-[2-O-(β-D-glucosyl)-α-L-rhamnosyl] quercetin, 4’-O-(3"’-O-dihydrophaseoyl-β-D-glucopyranosyl) rhamnocitrin, myricetin-3-O-β-D-glucoside, myricetin-5’-O-β-D-glucoside, trimer of flavan with two hydroxyl groups, neocomplanoside, dimer of myricomplanoside, and soyasaponinⅠmethyl ester, and are corresponding to the peaks of chromatogram from number 1 to 8, respectively.7. The off-line HPLC screening results suggested that there are 11 compounds with scavenging DPPH radical activity, either in methanol or ethanol extracts. The compounds for peaks from number 1 to 8 in chromatogram are corresponding to that of 8,1-7 in chromatogram of on-line HPLC screening. One was identified for 3-O-[6-O-(α-L-rhamnosyl)-β-D-glucosyl] isorhamnocitrin in peaks of number 9,10, and 11, and the others were unidentified.There are 12 active peaks in chromatogram of acetone extracts, to which 10 compounds were identified. Peak 1and peak 2 are corresponding to trimer of calycosin, and trimer of kaempferol, respectively. The compounds for the 8 peaks from number 3 to 10 are corresponding to soyasaponin I methyl ester,3-O-[2-O-(β-D-glucosyl)-a-L-rhamnosyl] quercetin,4’-O-(3’"-O-dihydrophaseoyl-β-D-glucopyranosyl) rhamnocitrin, myricetin-3-O-β-D-glucoside, myricetin-5’-O-β-D-glucoside, trimer of flavan with two hydroxyl groups, neocomplanoside, and dimer of myricomplanoside, respectively.更多还原