微波辅助提取石蒜和虎杖中有效成分的动力学机理

以鳞茎药材石蒜(Lycoris radiata)和根茎药材虎杖(Rhizma Polygoni Cuspidati)作为研究对象,采用微波辅助提取(MAE)石蒜中的石蒜碱、力可拉敏和加兰他敏以及虎杖中的大黄素和白藜芦醇,研究了提取过程的动力学机理。分别对这5种组分在提取温度、提取时间、搅拌速度和颗粒度等因素影响下MAE过程的动力学行为和特征进行了探讨,并与常规的溶剂回流提取法(SRE)进行对比研究,采用扫描电镜观察了MAE和SRE提取后样品的表面细胞结构。结果表明,石蒜和虎杖的MAE提取过程具有明显不同的动力学特征,其机理分别基于内部扩散传质控制和细胞破壁引起的界面反应控制。与SRE相比,MAE能引起石蒜和虎杖的细胞结构发生显著变化,降低了表观活化能Ea,组分的表观速率常数明显增大。     

微波辅助提取石蒜和虎杖中有效成分的热力学机理研究

采用微波辅助提取(MAE)技术研究了石蒜和虎杖两种不同植物中石蒜碱、力可拉敏和加兰他敏以及白藜芦醇和大黄素提取过程的热力学机理. 以溶剂回流提取方法(SRE)作为对比, 采用一种简单的测定提取分配系数的方法, 计算了这些组分在两种提取过程中的热力学函数ΔH0, ΔS0和ΔG0, 对其化学结构与极性以及在MAE过程中的热力学行为进行了讨论, 并用扫描电镜法观察了MAE和SRE提取后样品的细胞结构. 结果表明, 石蒜和虎杖的提取是一个吸热熵增的过程, 微波的作用导致石蒜和虎杖细胞结构发生显著变化, 使MAE热力学函数变化较大, 其提取过程的热力学行为特征与SRE明显不同, 但提取效率提高.     

微波辅助提取石蒜和虎杖中有效成分的动力学模型

基于微波辅助提取(MAE)中药材中化学成分的非稳态扩散过程, 根据Fick第二定律建立了石蒜中石蒜碱、力可拉敏和加兰他敏以及虎杖中白藜芦醇和大黄素微波辅助提取过程的动力学模型. 研究了提取时间、提取温度及药材粒度等因素对石蒜中石蒜碱、力可拉敏和加兰他敏以及虎杖中大黄素和白藜芦醇的提取率的影响, 采用Matlab软件编程对动力学模型进行回归分析, 拟合的动力学模型与实验结果吻合. 根据模型计算了石蒜中石蒜碱、力可拉敏和加兰他敏以及虎杖中大黄素和白藜芦醇在MAE提取过程中的扩散系数D, 与溶剂加热回流法(SRE)比较, 引入增强因子γ, 表征了微波对溶质分子扩散传质的影响及其对不同基质药材作用的差异.     

离子液体微波辅助萃取石蒜中生物碱的研究

以离子液体溶液为溶剂,研究了离子液体微波辅助萃取石蒜中石蒜碱、力克拉敏和加兰他敏生物碱。考察了离子液体的种类和浓度对萃取石蒜生物碱的影响,并与传统有机溶剂和传统萃取技术进行了对比研究。结果表明,1.0mol/L[bmim]Cl溶液为溶剂,液固比(mL∶g)15∶1,80℃微波辅助萃取10min,石蒜碱、力可拉敏和加兰他敏生物碱的萃取率分别为2.730、0.857和0.179mg/g。与传统的萃取方法比较,本方法快速高效、环境友好。     

紫外分光光度法测定石蒜中石蒜碱含量

石蒜(Lycoris Herb.)属于单子叶植物纲石蒜科(Amaryllidaceae)植物,石蒜碱(Lycorien)是石蒜中具有显著生理活性的异喹啉类生物碱[1-2],具有很强的抗病毒活性和抗肿瘤作用[3-5],在临床上多用于小儿麻痹后遗症的治疗[1]。目前,石蒜碱的测定方法主要有高效液相色谱法(HPLC)[6],但由于该法操作复杂,不利于常规检测,因此建立石蒜碱的简便检测方法具有重要的现实意义。本工作用紫外分光光度法测定石蒜中石蒜碱含量。     

高效液相色谱法测定石蒜中加兰他敏、力可拉敏及石蒜碱3种生物碱

以石蒜鳞茎为材料,建立了石蒜生物碱的反相高效液相色谱(HPLC)分析方法。探讨了流动相中乙腈含量、三乙胺含量、pH值、流速等对生物碱分离的影响,结果表明在ZORBAX ODS-C18(150 mm×4.6mm,5μm)反相色谱柱上,以0.9%三乙胺水溶液(pH 8.0)-乙腈-甲醇为流动相,梯度洗脱,流速为1mL/min,检测波长为234 nm时,石蒜样品可有效分离出14种石蒜生物碱,分离度良好。加兰他敏、力可拉敏和石蒜碱的检出限分别为3.375、0.475、0.495 mg/L,平均加标回收率均为98%。运用此法测定了石蒜不同部位中3种生物碱的含量,结果表明石蒜不同部位的3种生物碱含量差异较大,叶子中的含量最高;同一部位中,石蒜碱的含量最高,力可拉敏次之,加兰他敏最低。     

超临界二氧化碳流体萃取中药苦参的生物总碱

超临界ＣＯ2流体萃取(ＣＯ2 ＳｕｐｅｒｃｒｉｔｉｃａｌＦｌｕｉｄＥｘｔｒａｃｔｉｏｎ,ＳＦＥ ＣＯ2)技术是一种新型分离提取技术,其选择分离效果好,提取率高,产物没有有机溶剂残留,有利于热敏性物质和易氧化物质的萃取[1]。苦参为豆科植物,是传统的清热燥湿类中药,其有效成分主要为生物碱。苦参生物碱具有抗肿瘤、平喘、升白、抗菌、抗病毒、抗原虫等多种功能[2]。由于生物碱在植物中多数以盐的形式存在,若直接用极性较弱的溶剂提取往往提取不完全,故在提取前需碱化,使之成为游离碱[3]。本实验用氨水作碱化剂,选用无水甲醇为夹带剂,…     

毛细管电泳-电化学发光法测定石蒜鳞茎中的石蒜碱

建立了毛细管电泳-电化学发光(CE-ECL)检测石蒜碱的方法。探讨了检测电位、分离缓冲液pH和浓度、分离电压、进样电压及进样时间等因素对石蒜碱分离检测的影响。在最佳实验条件下,石蒜碱含量在0.03~2μg/mL范围内与其峰面积呈良好的线性关系,相关系数为0.9995,检出限为0.005μg/mL(S/N=3)。对0.8μg/mL石蒜碱进行7次平行实验,其迁移时间、峰高和峰面积的RSD分别为1.7%,5.2%和5.6%。方法应用于石蒜鳞茎中石蒜碱的测定,加标回收率为92.2%~98.6%。     

HPLC法同时测定石蒜中加兰他敏和石蒜碱

建立了高效液相色谱同时测定石蒜中加兰他敏和石蒜碱含量的方法。 采用phenomenex-C18色谱柱,以乙腈(A)-0.1%TFA水溶液(B)为流动相梯度洗脱,检测波长289 nm。 结果表明,加兰他敏和石蒜碱均在0.5～10 mg/L(r=0.9999)呈现良好的线性关系,最低检测限(S/N=3)分别为0.09和0.15 mg/L,平均加样回收率分别为99.53%和96.82%。 该方法简单、快速、准确,适合于石蒜中加兰他敏和石蒜碱的测定。     

石蒜科类生物碱Gracilamine的全合成

正Angew.Chem.Int.Ed.2014,53,9539~9543Gracilamine是2005年由土耳其学者ünver等从纤细雪花莲(Galanthus gracilis)中分离得到的一种石蒜科类生物碱.Gracilamine与传统石蒜科类生物碱相比其结构更为复杂,具有五环体系和7个连续手性中心,其中包括1个全碳季碳和1个杂季碳.由于自然含量较少所以其生物活性尚未报道.最近,华东师范大学化学系高栓虎课题组报道了Gracilamine的全合成工作.该小组在对光促进的Nazarov环化进行系统研究的基础上,成功地应用该策略完成了     

Pressurized liquid extraction and anticholinesterase activity-based thin-layer chromatography with bioautography of Amaryllidaceae alkaloids

Modern extraction technique-pressurized liquid extraction (PLE) was optimised for extraction of lycorine and galanthamine (Amaryllidaceae alkaloids) from Narcissus jonquilla ‘Pipit’. Crude extracts were purified on Oasis MCX cartridges, and the alkaloids eluted with 80-100% recoveries using methanol-10% ammonia solution (3:1, v/v). Quantitative results were obtained by both HPTLC-densitometry on silica gel plates and RP-HPLC with diode array (DAD) on XTerra C₁₈ stationary phase. Both methods were fully validated in terms of specificity, precision (including intra- and inter-day measurements), LOD and LOQ values, correlation of UV spectra and linearity of calibration curves. The methods were also well correlated each other with correlation coefficients (r) 0.98823 and 0.99081, respectively, for the mean values of galanthamine and lycorine.Among the investigated solvents methanol and 1% tartaric acid methanolic solution at default conditions (120 °C, p = 60 bar, time: 10 min, one static cycle) permit the highest yields of the total sum of the alkaloids, whereas for toluene the lowest amounts were measured. Lycorine to galanthamine mean ratios were dependant on the type of solvent used, and in toluene galanthamine and related alkaloids were preferably extracted.In temperature experiments for galanthamine, the levels of this compound increased from the temperature of 20 till 150 °C in the investigated solvent systems, then decreased with slight increase from the temperature of 175 to 200 °C in 1% tartaric acid methanolic solution. When lycorine was analysed, similar trends were observed, however the maximum of the concentration was measured at a temperature about 125 °C. The ratios of the mean values of these two compounds differed in temperature-dependant experiments in both solvent systems.Further more, two TLC with bioautography approaches were used in screening for anticholinesterese properties of the extracts. No qualitative differences were found among the different solvent extracts, and AChE inhibition was correlated with galanthamine and related compounds.In conclusion, optimised PLE was much more effective than previously applied hot-solvent extraction, microwave-assisted extraction (MAE) or ultrasound-assisted extraction (USAE).     

Nonaqueous CE ESI‐IT‐MS analysis of Amaryllidaceae alkaloids

The Amaryllidaceae are widely distributed medical plants. Lycorine, lycoramine, lycoremine, and lycobetaine are the major active alkaloids in Amaryllidaceae plants. A nonaqueous CE ESI‐IT‐MS method for separation, identification, and quantification of the Amaryllidaceae alkaloids has been developed. The MS^1–3 behavior has been studied and the fragmentation pathways of main fragment ions have been proposed. The effects of several factors such as composition and concentration of buffer, applied voltage, composition, and flow rate of the sheath liquid, nebulizing gas pressure, flow rate, and temperature of drying gas were investigated. Under the optimal conditions, the linear concentration range of these compounds was wide with the correlation coefficient (R²) >0.99. RSDs of migration time and peak areas were <10%. The LODs were <240 ng/mL. The proposed method can be successfully applied to the determination of the related alkaloids in the Lycoris radiata roots.     

Microwave-assisted extraction of tanshinones from Salvia miltiorrhiza bunge with analysis by high-performance liquid chromatography

A novel microwave-assisted extraction (MAE) method has been developed for the extraction and determination of tanshinones (tanshinone IIA, cryptotanshinone and tanshinone I) from the root of Salvia miltiorrhiza bunge with analysis by HPLC. Various experimental conditions were investigated to optimize the percentage extraction. Under appropriate MAE conditions, such as ethanol concentrations of 95% (v/v), MAE for 2 min, liquid/solid ratio of 10:1 (ml/g), the percentage extraction can reach high in a short time. The percentage extraction (tanshinone IIA: 0.29%; cryptotanshinone: 0.23%; tanshinone I: 0.11%) by MAE was the same or even higher than conventional extraction methods. MAE only needs 2 min, but extraction at room temperature, heat reflux extraction, ultrasonic extraction and Soxhlet extraction need 24 h, 45 min, 75 min and 90 min, respectively. MAE was also available in pilot plant form for larger scale extraction.     

Simultaneous determination of galanthamine and lycorine in Lycoris radiata by a capillary electrophoresis with an electrochemiluminescence method

A novel capillary electrophoresis with electrochemiluminescence determination method was developed for the determination of two alkaloids based on the electrochemiluminescence signal enhancement effect of the tertiary amine group on tris(2,2′‐bipyridyl)ruthenium(II). A linear relationship between the electrochemiluminescence peak area and concentrations of galanthamine and lycorine in the range of 0.07 ～ 17 μg/mL and 0.07 ～ 18 μg/mL was obtained and the detection limit was 0.008 and 0.002 μg/mL, respectively. The method is selective, simple, and convenient. It had been successfully applied to the analysis of galanthamine and lycorine in Lycoris radiata samples purchased from a local market.     

加兰他敏的半合成研究

加兰他敏提取工艺中的主要副产品——力可拉敏的药用价值明显低于加兰他敏, 为提高力可拉敏的利用价值, 在催化剂存在下脱氢制取加兰他敏. 以力可拉敏为原料, 分别考察了反应时间、温度和催化剂用量对反应的影响, 得出在9%镧镍稀土合金催化剂存在下, 240 ℃时选择性脱氢, 半合成加兰他敏, 收率达45.9%, 光学纯度为97%. 计算该反应在反应前10 min内的表观活化能为77.25 kJ/mol, 属化学反应控制过程. 产物用HPLC, IR, MS, ¹H NMR和¹³C NMR进行定性及结构表征.