交联柚苷酶聚集体水解柚皮苷制备普鲁宁

为了提高普鲁宁的收率、简化分离提纯的工艺、得到较高纯度的普鲁宁,本实验采用交联柚苷酶聚集体水解柚皮苷制备普鲁宁,以普鲁宁浓度为优化指标,研究了底物浓度、p H、温度、加酶量、反应时间对制备普鲁宁的影响。利用正交设计对水解过程进行优化,确定最佳工艺条件为:柚皮苷浓度13.79 mmol/L、p H=8.0、温度65℃、加酶量18.0 mg/m L、反应时间12.0 h,优化后制备得到的普鲁宁浓度为13.36 mmol/L、收率达到96.87%。连续使用3个批次后,普鲁宁的收率可以达到91.29%,交联酶聚集体的稳定性较好。采用聚酰胺树脂对水解产物进行吸附,体积分数为40%~60%的异丙醇线性梯度洗脱,从0.36 g柚皮苷反应液中可以分离得到0.22 g普鲁宁。     

两步生物法转化柚皮苷制备L-鼠李糖

考察了利用柚苷酶和酵母静息细胞作为催化剂,两步生物法转化柚皮苷制备L-鼠李糖的工艺过程。柚苷酶水解柚皮苷的最佳工艺条件是ρ(柚皮苷)=14 g/L的水溶液为底物,加酶量10 mL/L(即每升底物中加入酶的体积,下同),pH=5.5,酶解时间22 h。酵母代谢葡萄糖的最佳工艺条件是酵母用量2.5 g/L(即每升水解液中加入酵母的质量,下同),温度32℃,pH=6.0,发酵时间120 min。在30 L发酵罐中进行了小试,最终获得了质量分数大于98.5%的鼠李糖结晶85.6 g,为理论得率的86.5%。     

柑橘皮柚皮苷提取工艺研究

采用乙醇-乙酸浸提法提取柑橘皮中的柚皮苷,通过单因素实验研究了不同因素对柚皮苷提取率的影响,并在此基础上进行正交实验,得出优化工艺条件为:料液比1∶25 g/m L,乙酸比例10%,提取温度80℃,提取时间3 h。在此工艺条件下,柚皮苷提取率为5.78%。此方法成本低、毒性低、重复性好,能够用于工业化生产。     

模拟移动床色谱制备纯化柚皮苷

通过四区模拟移动床色谱制备纯化柚皮苷。采用高效液相色谱测试单柱的相关参数,通过三角形方法,确定线性条件下的完全分离操作范围。在该范围中选取操作条件进行柚皮苷的制备纯化。实验结果表明,当选取的一至四区流速分别为2mL/min,1.35mL/min,1.69mL/min,0.69mL/min,切换时间为35.5min时,通过面积归一法计算出,该系统制备的柚皮苷纯度可从粗品的82%提升到98%左右,主要杂质峰基本消失,满足柚皮苷的高纯度制备要求。柚皮苷的回收率为97%,产率为0.33mg/min,溶剂耗量为4.85mL/mg。     

Pd/C催化剂对生物质基丁酮催化加氢制取仲丁醇

研究了生物质基丁酮经Pd/C催化加氢制备仲丁醇的工艺条件,考察了反应时间、反应温度、氢压和催化剂用量对仲丁醇收率的影响。结果表明,Pd/C可催化丁酮进行加氢反应,主要产物为仲丁醇。在一定温度条件下,仲丁醇收率随温度的升高而增大,但超过一定范围,继续增加反应温度,收率反而下降。加氢压力1 MPa,反应8 h后,90 ℃、120 ℃和150 ℃条件下仲丁醇收率分别为53.1%、52.8%和45.5%;增大氢压,仲丁醇收率反而明显降低。增加催化剂用量,反应速率加快,反应时间缩短,但对最终仲丁醇收率的影响不大。     

三(3,6-二氧杂庚基)胺(TDA-1)相转移催化合成异甘草苷

以TDA-1为相转移催化剂,碳酸氢钠/氯化钾体系为碱性介质,就对羟基苯甲醛与1-溴-2,3,4,6-O-四乙酰基--αD-吡喃葡萄糖的糖苷化反应条件进行了探讨,着重考察了反应时间、反应温度和催化剂用量对-βD-甲乙酰基葡萄糖对甲酰苯基苷合成收率的影响;并利用硼酸/哌啶/二甘醇二乙醚催化体系,通过-βD-四乙酰基葡萄糖对甲酰苯基苷与2,4-二羟基苯乙酮的羟醛缩合反应,对异甘草苷的合成工艺进行了研究,其结果经红外光谱和核磁共振氢谱确证,总收率为27%。     

新橙皮苷二氢查耳酮工艺研究

以新橙皮苷为起始原料,制备新橙皮苷二氢查耳酮,通过对碱(氢氧化钠)用量、催化剂用量、反应温度、氢气压力、搅拌速度、反应时间等关键因素的单因素实验,对制备工艺进行了研究,建立了适用于工业化生产的方法,最佳合成的工艺为:新橙皮苷与氢氧化钠的质量比为1∶0.3,新橙皮苷与催化剂(阮尼镍)的质量比为1∶0.1,搅拌速度为150转/分钟,反应温度为25℃,反应时间为10小时。     

负载型Ni-Cr-B非晶态合金催化对氯硝基苯加氢制备对氯苯胺

提出一种以负载型Ni-Cr-B非晶态合金催化对氯硝基苯加氢制备对氯苯胺的工艺。通过正交实验考察反应温度、反应时间、反应压力和催化剂用量对对氯苯胺收率的影响。最优工艺条件为:反应温度60℃,反应时间4 h,反应压力1.2 MPa,催化剂用量占对氯硝基苯质量的8%。在此优化条件下,催化剂重复使用4次,对氯硝基苯转化率为99.9%,对氯苯胺选择性为99.9%,对氯苯胺平均收率为99.8%。     

MnSalophen/Al_2O_3高压催化环己烯合成环己烯酮

介绍了催化剂MnSalophen/Al2O3的制备方法,并对其结构进行了表征。然后以自制的MnSalophen/Al2O3为催化剂,以分子氧为氧化剂,研究了催化剂用量、反应时间、反应温度以及反应压力对环己烯转化率和环己烯酮收率的影响。结果表明,在催化剂用量:50 mg,反应时间:8 h,反应温度:100℃,反应压力:1.5 MPa的条件下,环己烯酮的收率可达50.3%。     

醛加氢法制备三羟甲基丙烷加氢工艺的研究

介绍了高压反应釜中2,2-二羟甲基丁醛在自制Cu-Zn-Mn/γ-Al2O3催化剂作用下,在不同催化剂用量、反应温度、反应压力和反应时间加氢制备三羟甲基丙烷的研究,从2,2-二羟甲基丁醛转化率和三羟甲基丙烷收率两方面进行优化。通过实验,得到了2,2-二羟甲基丁醛加氢制三羟甲基丙烷的最佳工艺条件:催化剂用量为正丁醛质量的2.0%,反应温度120℃,反应压力5.5 MPa,反应时间3.5 h,2,2-二羟甲基丁醛转化率和三羟甲基丙烷的收率最好,分别为96.53%和86.58%。     

Effect of β-Cyclodextrin Complexation on Solubility and Enzymatic Conversion of Naringin

In the present paper, the effect of β-cyclodextrin (β-CD) inclusion complexation on the solubility and enzymatic hydrolysis of naringin was investigated. The inclusion complex of naringin/β-CD at the molar ratio of 1:1 was obtained by the dropping method and was characterized by differential scanning calorimetry. The solubility of naringin complexes in water at 37 ± 0.1 °C was 15 times greater than that of free naringin. Snailase-involved hydrolysis conditions were tested for the bioconversion of naringin into naringenin using the univariate experimental design. Naringin can be transformed into naringenin by snailase-involved hydrolysis. The optimum conditions for enzymatic hydrolysis were determined as follows: pH 5.0, temperature 37 °C, ratio of snailase/substrate 0.8, substrate concentration 20 mg·mL⁻¹, and reaction time 12 h. Under the optimum conditions, the transforming rate of naringenin from naringin for inclusion complexes and free naringin was 98.7% and 56.2% respectively, suggesting that β-CD complexation can improve the aqueous solubility and consequently the enzymatic hydrolysis rate of naringin.     

超微粉体技术对枳实药材中黄酮类成分溶出率的影响

探讨了超微粉碎对枳实药材中有效成分溶出率的影响。以0.05%磷酸水-甲醇-乙腈为流动相,采用高效液相色谱法（high performance liquid chromatography,HPLC）测定枳实超微粉与药材60目细粉中橙皮苷、柚皮苷和芸香柚皮苷的溶出率。结果表明,枳实超微粉中的橙皮苷、柚皮苷和芸香柚皮苷的溶出率明显高于其60目细粉中三者的溶出率,超微粉碎可增强枳实药材有效成分的溶出。     

Surface Functionalization of PVDF Membrane with a Naringin-Imprinted Polymer Layer Using Photo-Polymerization Method

The aim of this work was the preparation of molecularly imprinted membranes by surface modification of microfiltration polyvinylidene fluoride membranes with a thin layer of molecular imprinted polymer by UV irradiation. The flavonoid naringin (4,5,7-trihydroxyflavanone-7-rhamnoglucoside) was used as template molecule. The compound 4-vinylpyridine was used as functional monomer. Benzoin ethyl ether and ethylene glycol dimethacrylate were used as photo-initiator and cross-linker, respectively. Membranes were also modified in the absence of naringin and used as reference (blank). Imprinted membranes prepared in this work could be applied as new separation devices in affinity filtrations aimed to reduce the naringin content in grapefruit and improve its benefit properties. The method used to prepare them offers the advantage of combining the mechanical integrity of the membrane support with the selective recognition properties of the imprinted polymer layer. The recognition properties of all prepared membranes were evaluated by their capability to retain naringin in aqueous solution during filtration tests. Results showed that imprinted membranes exhibited specific binding properties for template molecules. Blank membranes only showed non-specific binding. The selectivity of the naringin-imprinted membranes was tested evaluating their bound property toward the rutin, a structural analogue of naringin.     

Hydrolysis of citrus peel naringin by recombinant α‐L‐rhamnosidase from Clostridium stercorarium

The citrus fruit processing industry generates substantial quantities of waste rich in glycosylated phenolic substances such as naringin, which are a valuable natural source of polyphenols as well as L‐rhamnopyranose. Naringin is the major polyphenol in bitter orange peel and its hydrolysis by α‐L ‐rhamnosidase (EC 3.2.1.40) catalyzes the cleavage of the terminal rhamnosyl groups to form prunin and rhamnose. In this work, a recombinant α‐L ‐rhamnosidase from C. stercorarium was shown to be suitable for narigin hydrolysis. The recombinant rhamnosidase was found to be relatively stable at 60 °C, and a residual activity close to 50% after 180 min of incubation was demonstrated. The purified enzyme established hydrolysis of naringin extracted from citrus peel waste (CPW). The result indicated that recombinant α‐L ‐rhamnosidase has industrial applicability and is an interesting candidate for producing rhamnose from citrus peel. Copyright © 2010 Society of Chemical Industry     

柠檬酸修饰柚皮对铅离子的吸附研究

以柚皮为原料,制备了四种吸附剂,结果表明同一条件下柠檬酸修饰的柚皮吸附剂(SOP)对Pb2+的吸附效果最好,对SOP进行单因素实验,研究了吸附时间、Pb2+初始浓度、吸附剂用量对吸附性能的影响,分析了吸附过程的动力学和等温吸附规律,结果表明,SOP对铅离子的吸附符合二级吸附动力学模型,吸附等温线与Langmuir方程具有很好的拟合性。     

柚皮黄酮抑制硝化和氧化作用的研究

以抑制过氧亚硝酸根硝化酪氨酸生成3－硝基酪氨酸评价了柚皮黄酮的抗硝化作用;以Fenton反应产生羟基自由基体系和邻苯三酚自氧化产生超氧阴离子自由基体系,用紫外可见分光光度法测定了柚皮黄酮对羟基自由基和超氧阴离子自由基的清除效果。结果表明．柚皮苷的抗硝化作用较强,而芦丁和橙皮苷没有明显的抗硝化作用;3种柚皮黄酮清除羟基自由基的效果在μg·mL^-1水平就已经比较显著（超过50％）．且显示出浓度依赖性．作用大小依次为;柚皮苷〉橙皮苷〉芦丁13种柚皮黄酮在μg·mL^-1水平清除超氧阴离子自由基的作用大小依次为：芦丁〉柚皮苷〉橙皮苷。     

Imprinted β‐cyclodextrin polymers using naringin as template

The objective of this study was to identify a kind of molecular imprinting polymer (MIP) which was suitable for recognizing naringin (NG) in aqueous medium. Based on two crosslinkers (hexamethylene diisocyanate and epichlorohydrin) and two polymerization methods (solution polymerization and emulsion polymerization), four non‐covalent naringin‐β‐cyclodextrine (NG‐β‐CD) imprinted polymers were prepared by using β‐CD as a functional monomer and NG as a template molecule. The binding property and selectivity were evaluated by equilibrium binding experiments. These demonstrated that all the sites in the MIPs show good selective binding ability for NG from naringin dihydrochalcone, a structurally similar molecule. Of the four MIPs, rod‐like 3# MIP which was prepared by emulsion polymerization using hexamethylene diisocyanate as crosslinker exhibited the highest selectivity, its imprinting factor α being 1.53. Scatchard analysis of 3# MIP suggests that there are two classes of binding sites during the MIP's recognition of NG. Additionally, the 3# MIP could be used at least five times without any loss in sorption capacity. Copyright © 2011 Society of Chemical Industry     

Regioselective acylation of flavonoids catalyzed by lipase in low toxicity media

Flavonoid fatty esters were prepared by acylation of flavonoids (rutin and naringin) by fatty acids (C8, C10, C12), catalyzed by immobilized lipase from Candida antarctica in various solvent systems. The reaction parameters affecting the conversion of the enzymatic process, such as the nature of the organic solvent and acyl donor used, the water activity (a_w) of the system, as well as the acyl donor concentration have been investigated. At optimum reaction conditions, the conversion of flavonoids was 50—60% in tert‐butanol at a_w less than 0.11. In all cases studied, only flavonoid monoester was identified, which indicates that this lipase‐catalyzed esterification is regioselective.     

Kinetic studies of adsorption of bitter principles and titratable acid from grapefruit juice

Measurement of the initial rates of removal of limonin and naringin from grapefruit juices by several polystyrene and polyacrylic adsorbents has allowed these adsorbents, in the forms as supplied, to be ranked in their order of kinetic effectiveness for removal of the two bitter principles. Partition coefficients of bitter principles between juice and polystyrene adsorbent resins show that the capacity of such resins for naringin increases with specific surface area, but the capacity for limonin appears to increase with specific pore volume. With respect to titratable acid, the two weak base resins, Amberlite IRA-93 and Duolite A378, were equally effective both kinetically and in their capacity for titratable acid; both adsorbed somewhat less than 1 mol of titratable acid from grapefruit juice per equivaient of weak base resin.