硅胶柱色谱结合高速逆流色谱法分离纯化荷花中黄酮类化合物

采用硅胶柱色谱结合高速逆流色谱法分离纯化了荷花中3种黄酮类化合物。荷花粗提物先经过硅胶柱色谱初步分离,得到黄酮含量高的组分,再经过高速逆流色谱分离,以乙酸乙酯-乙醇-水-乙酸(4:1:5:0.025, v/v/v/v)为两相溶剂系统,上相为固定相,下相为流动相,在主机转速800 r/min、流速2.0 mL/min、检测波长254 nm条件下,从150 mg样品中一次性分离制备得到6.1 mg槲皮素-3-O-β-D-葡萄糖醛酸苷(I), 14.8 mg杨梅素-3-O-β-D-葡萄糖苷(II)和20.2 mg紫云英苷(III),经高效液相色谱检测其纯度分别为97.0%、95.4%、96.3%,并通过质谱和核磁共振氢谱、碳谱鉴定各化合物的结构。该方法简便、快速、节省溶剂,可以对荷花中的黄酮类化合物进行快速有效的分离纯化,具有较好的实用价值,为荷花资源的进一步开发应用提供了参考依据。     

Purification of coenzyme Q10 from fermentation extract: high-speed counter-current chromatography versus silica gel column chromatography

High-speed counter-current chromatography (HSCCC) is applied to the purification of coenzyme Q(10) (CoQ(10)) for the first time. CoQ(10) was obtained from a fermentation broth extract. A non-aqueous two-phase solvent system composed of heptane-acetonitrile-dichloromethane (12:7:3.5, v/v/v) was selected by analytical HSCCC and used for purification of CoQ(10) from 500 mg of the crude extract. The separation yielded 130 mg of CoQ(10) at an HPLC purity of over 99%. The overall results of the present studies show the advantages of HSCCC over an alternative of silica gel chromatography followed by recrystallization. These advantages extend to higher purity (97.8% versus 93.3%), recovery (88% versus 74.3%) and yield (26.4% versus 23.4%). An effort to avoid the toxic, expensive solvent CH(2)Cl(2) was unsuccessful, but at least its percentage is low in the solvent system.     

Endcapping of high performance liquid chromatography packings derived from silica gel

The effect of endcapping a reversed phase chromatographic packing material derived from silica gel depends on the degree of derivatization of the phase. The effect can be dramatic for phases with low loading. Whether an octadecylated silica gel has been endcapped or not can be ascertained by chromatographing the pair naphthalene/1-nitronaphthalene with a water/methanol eluent producing at least k' ≈ 10 for naphthalene. The ratio of the two k' values is 1.4 or higher for an endcapped material, while it is only 1.1 -1.2 for a non-endcapped phase. A similar approach fails to give conclusions of similar utility for octylated silica gels.     

One step purification of flavanone glycosides from Poncirus trifoliata by centrifugal partition chromatography

Flavanone glycosides were successfully separated from the crude extract of Poncirus trifoliata by preparative centrifugal partition chromatography with a two-phase solvent system composed of ethyl acetate-acetonitrile-water (3:2:5, v/v/v). Naringin (50.0 mg), neoponcirin (16.8 mg), and poncirin (71.9 mg) were purified from the 524 mg crude extract in only one step. The purities of the isolated compounds were determined to be over 90% by HPLC analysis and their structures were elucidated by (1)H NMR, (13)C NMR, and ESI-MS.     

Preparative isolation and purification of sinomenine from Sinomenium acutum by centrifugal partition chromatography

Preparative centrifugal partition chromatography (CPC) was successfully carried out for the separation of sinomenine from the methanolic extract of Sinomenium acutum stems and rhizomes. The optimum two-phase solvent system of CPC was composed of n-hexane/ethyl acetate/methanol/water at a volume ratio of 1:6:2:8 (v/v/v/v) with 0.1% triethylamine (TEA). Preparative CPC yielded 44.3 mg of sinomenine from 400 mg of MeOH extract with a purity of 96.9%.     

Thin-layer chromatography of 1,2,4-triazoles on silica gel

Summary The TLC behaviour of N-phenyl-1,2,4-triazoles and their derivatives on silica gel plates has been studied using simple solvents. Isomers were very well distinguished, resulting from different activities due to hydrogen bonding. A mixture of seven compounds has been resolved with diethylether-n-butylamine-pyridine (91.4:7.7:0.9).     

Separation of oligogalacturonic acids by high-performance gel filtration chromatography on silica gel with diol radical.

Oligogalacturonic acids (OLGAs) ranging from two to nineteen residues in length were separated using high-performance gel filtration chromatography on a silica gel with diol radical. The optimum conditions (eluent, column temperature) for separation of OLGAs by high-performance gel filtration chromatography were investigated. The column used in this experiment allowed a high pressure of 4900 p.s.i. and a flow-rate of 2 ml/min. The stationary phase of silica gel stabilized the separation of OLGAs. The peaks of OLGAs separated using this column were assigned by comparing retention times with standards, and the molecular weights of the corresponding OLGAs were determined by fast atom bombardment mass spectrometry.     

Identification of alkylpyrocatechols by thin-layer chromatography on silica gel

Conclusions A method was developed for the chromatographic separation of the alkyl derivatives of pyrocatechol employing thin-layer chromatography on plates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2816–2817, December, 1971.     

Large scale bench-top synthesis of a nineteen unit ribonucleotide on silica gel.

The stepwise synthesis of a nonadecaribonucleotide corresponding to units 9 to 27 of the t·RNA^fmet from $\text{E.Coli}$ is described. The chlorophoshite condensation procedure and a silica gel support were used.     

Improvement purification of sulfated oligofucan by ion-exchange displacement centrifugal partition chromatography

Centrifugal partition chromatography in ion-exchange displacement mode was used to fractionate mixtures of sulfated oligofucans obtained by partial depolymerization of brown seaweed fucoidans. Diluted (10%, v/v) protonated LA2 (a lipophilic secondary amine) is used as a weak exchanger. In an attempt to improve this method, several solvents (methyl isobutyl ketone, methyl tert.-butyl ether, BuOH) were tested to dissolve LA2H+. MtBE produced less bleeding than MiBK, whereas BuOH proved unsuitable. The sample injected needs to be highly diluted in water to ensure participation in the chromatographic process. A comparison of data (NMR, composition, molecular mass) indicated the homogeneity of the fractions obtained as well as the differences between them.     

Preparative purification of plasmin activity stimulating phenolic derivatives from Gastrodia elata using centrifugal partition chromatography

Gastrodia rhizome, a dried and steamed tuber of Gastrodia elata Blume (Orchidaceae), has been traditionally used in Korea, China and Japan for the treatment of neurological and nervous disorders such as headaches, dizziness, vertigo and convulsive illnesses. The ethyl acetate and water extracts of G. elata stimulated plasmin activity. The active ethyl acetate fraction was subjected to centrifugal partition chromatography (CPC) with a two‐phase solvent system, composed of n‐hexane–ethyl acetate–methanol–water (3:7:4:6, v/v) followed by semi‐preparative HPLC purification to separate active compounds and the water fraction was purified by Diaion HP‐20 resin and semi‐preparative HPLC. In ethyl acetate extract, 4‐hydroxybenzyl alcohol (1), 4‐hydroxybenzoic acid (2), 4‐hydroxybenzaldehyde (3), 4‐ethoxymethylphenol (4), 4,4′‐oxybis(methylene)diphenol (5) and 4,4′‐methylenediphenol (6) were obtained with high purities. Parishin (7) and parishin B (8) were isolated from water extract. Among isolated compounds, 4‐hydroxybenzyl alcohol (1), 4‐hydroxybenzaldehyde (3) and 4‐ethoxymethylphenol (4) significantly stimulated plasmin activity. Copyright © 2015 John Wiley & Sons, Ltd.     

Separation of acidic and neutral lipids by aminopropyl-bonded silica gel column chromatography.

The separation of acidic and neutral lipids by aminopropyl-bonded silica gel column chromatography is presented. Total lipid extracts from Escherichia coli and human spermatozoa were loaded onto pre-packed aminopropyl-bonded silica gel columns and the lipids separated into four fractions. Non-polar lipids including cholesterol esters, triglycerides, diglycerides, monoglycerides and cholesterol, were eluted with 4 ml of isopropanol-chloroform (1:2, v/v) (fraction 1); free fatty acids were eluted with 4 ml of 2% acetic acid in diethyl ether (fraction 2); neutral polar lipids, including phosphophatidylethanolamine, phosphatidylcholine, sphingomyelin and neutral glycolipids, were eluted with 4 ml of methanol (fraction 3); and, finally, polar acidic lipids, including phosphatidylglycerol, cardiolipin, phosphatidylinositol, phosphatidylserine, seminolipid lipid A and acidic glycosphingolipids, were eluted with 4 ml of chloroform-methanol-0.8 M sodium acetate (60:30:4.5, v/V/V) (fraction 4). The recoveries for the different lipids ranged between 89 and 98% and the intra-assay variation, expressed as the standard deviation, was less than 5%.     

Thin-layer chromatography of steroids on microplates with fixed silica gel

Summary 1. A method for chromatographing steroids on microplates with silica gel of types KSK and KSM has been developed.2. The possibility of using a solution of iodine in potassium iodide to detect steroid compounds has been demonstrated and the sensitivity of this reaction has been determined.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 5, pp. 321–325, 1966