Completed preparative separation of alkaloids from Cephaltaxus fortunine by step-pH-gradient high-speed counter-current chromatography

Cephalotaxine-type alkaloids are the anti-cancer components in twigs, leaves, roots and seeds of Cephalotaxus fortunine. It is very important to use the limited resource by finding an efficient purification technology of the alkaloids. Separation of cephalotaxine-type alkaloids in Cephalotaxus fortunine by step-pH-gradient high-speed counter-current chromatography (step-pH-gradient HSCCC) was studied in this paper. The step-pH-gradient HSCCC was performed on a HSCCC instrument equipped with a 400-mL column, using the upper phase of ethyl acetate–n-hexane–water, with added 0.01% trifluoroacetic acid (TFA) as stationary phase, and the lower phase of ethyl acetate–n-hexane–water, with added 2% NH₄OH, 0.2% NH₄OH and 0.05% TFA as mobile phase. For each separation, 800 mg of extract of cephalotaxine-type alkaloids was separated to yield 9.3 mg of drupacine, 15.9 mg of wilsonine, 130.4 mg of cephalotaxine, 64.8 mg of epi-wilsonine, 12.8 mg of fortunine and 35.6 mg of acetylcephalotaxine with purities 81.2%, 85.7%, 95.3%, 97.5%, 89.1% and 96.2%, respectively. The recovery of each alkaloid was more than 90%. The structures of the six alkaloids were identified by electrospray ionization mass spectrum (ESI-MS) and ¹H and ¹³C NMR.     

Isolation of chavibetol from essential oil of Pimenta pseudocaryophyllus leaf by high-speed counter-current chromatography

Counter-current chromatography (CCC) was used to isolate chavibetol from the essential oil of leaves of Pimenta pseudocaryophyllus (Gomes) Landrum. Chavibetol was obtained in high purity (98%) and mass recovery (94.4%). Methyleugenol was also isolated. The CCC biphasic solvent system used was composed of hexane:n-butanol:methanol:water (12:4:4:3, v/v/v/v).     

Separation of epigallocatechin and flavonoids from Hypericum perforatum L. by high-speed counter-current chromatography and preparative high-performance liquid chromatography

High-speed counter-current chromatography (HSCCC) and preparative high-performance liquid chromatography (prep-HPLC) were successively used for the separation of epigallocatechin and flavonoids from Hypericum perforatum L. The two-phase solvent system composed of ethyl acetate–methanol–water (10:1:10, v/v) was used for HSCCC. About 900 mg of the crude extract was separated by HSCCC, yielding 7.8 mg of quercitrin at a purity of over 97%, 12.6 mg of quercetin at a purity of over 93%, and 38.9 mg of a mixture of hyperoside, isoquercitrin and miquelianin constituting over 97% of the fraction. A mixture of epigallocatechin and avicularin pooled from three HSCCC runs, a total amount of 54.3 mg, was further separated by prep-HPLC yielding 23.4 mg of epigallocatechin and 15.3 mg of avicularin each at a purity of over 97%.     

Isolation of the new minor constituents dihydropyranochromone and furanocoumarin from fruits of Peucedanum alsaticum L. by high-speed counter-current chromatography

A preparative high-speed counter-current chromatography (HSCCC) method was successfully used for isolation of two new minor compounds – alsaticol and alsaticocoumarin A. A two-phase solvent system composed of n-hexane–ethyl acetate–methanol–water (1:1:1:1) was developed. Compounds were obtained from the dichloromethane extract of Peucedanum alsaticum fruits and their identification was performed with NMR and MS methods. Optimized HSCCC offers a rapid method of obtaining new natural compounds.     

高速逆流色谱法从蝙蝠蛾拟青霉中快速分离制备麦角甾醇纯品

建立了用高速逆流色谱从蝙蝠蛾拟青霉中高效、快速分离制备高纯度麦角甾醇的方法。将蝙蝠蛾拟青霉的乙酸乙酯提取物直接进行高速逆流色谱分离,考察了不同溶剂系统的分离效果。结果表明,最佳的溶剂系统为正己烷-乙酸乙酯-甲醇-水(体积比为6:1.7:6:0.3),以上相为固定相,下相为流动相,转速为850 r/min,流速为2 mL/min,检测波长为280 nm。制备所得的麦角甾醇经紫外光谱(UV)和高分辨质谱(HRMS)鉴定及与标准品对照定性;纯度经高效液相色谱(HPLC)分析为99.2%(峰面积归一化法)。该方法制备麦角甾醇简便、快速,所得产物的纯度高,适合于麦角甾醇对照品的制备。     

高速逆流色谱分离纯化蔓荆子中的活性成分

应用高速逆流色谱法(HSCCC)分离纯化蔓荆子中的活性成分。以石油醚-乙酸乙酯-甲醇-水(体积比为3:6:3.6:3)为两相溶剂体系,在转速为800 r/min、流速为1.5 mL/min、检测波长为254 nm的条件下进行分离,所得馏分经高效液相色谱法(HPLC)检测,并经电喷雾电离(ESI)质谱和核磁共振谱(NMR)鉴定化合物的结构。从250 mg蔓荆子粗提物中一次性分离得到4个化合物,分别为23 mg对羟基苯甲酸、15 mg 3,6,7-三甲基槲皮万寿菊素、24 mg蔓荆子黄素和5 mg蒿黄素,其纯度约为93.1%、 97.3%、 98.7%和98.5%。该法具有简便、快速、重复性好的优点,为分离蔓荆子中的活性成分提供了新的方法。     

高速逆流色谱分离制备陈皮中的黄酮类化合物

应用高速逆流色谱法分离制备了陈皮中3种黄酮类化合物。以石油醚-乙酸乙酯-甲醇-水(体积比为2∶4∶3∶3)为两相溶剂系统,在主机转速850 r/min、流动相流速1.7 mL/min、检测波长280 nm条件下进行分离制备,6 h内从4.0 g陈皮粗提物中一步分离制备得到橙皮苷10.1 mg、桔皮素49.8 mg和5-羟基-6,7,8,3′,4′-五甲氧基黄酮50.6 mg,纯度均达97.0%以上,各化合物结构经质谱和核磁共振氢谱、碳谱鉴定。利用该方法可以对陈皮中的黄酮类化合物进行快速的分离和纯化。     

高速逆流色谱与硅胶柱层析联用分离岩黄连中的2种原小檗碱型季胺生物碱

建立了分离岩黄连2种生物碱的方法。岩黄连醇提物经溶剂萃取后的水相提取物,经过硅胶柱层析粗分离,对其中一个流分采用高速逆流色谱法,以正己烷-乙酸乙酯-正丁醇-乙醇-水-氨水(体积比为0.4:1.5:4:0.4:5:0.11)为两相溶剂系统,下相为固定相,上相为流动相,通过一次高速逆流色谱,即可从64.81 mg样品中分离得到9.28 mg纯度为97.0%的去氢碎叶紫堇碱(dehydrocheilanthifoline)和4.38 mg纯度为90.7%的脱氢异阿朴卡维汀(dehydroisoapocavidine),并通过与对照品HPLC保留时间的比较,以及ESI-MS测定分子量,确认了化合物的结构。该方法降低了反复的柱层析导致的样品损失,也为上述两种化合物的药理研究提供了物质基础。     

Isolation of antioxidants from Psoralea corylifolia fruits using high-speed counter-current chromatography guided by thin layer chromatography-antioxidant autographic assay

A combinative method using high-speed counter-current chromatography (HSCCC) and thin layer chromatography (TLC) as an antioxidant autographic assay was developed to separate antioxidant components from the fruits of Psoralea corylifolia. Under the guidance of TLC bioautography, eight compounds including five flavonoids and three coumarins were successfully separated from the fruits of P. corylifolia by HSCCC with an optimized two-phase solvent system, n-hexane–ethyl acetate–methanol–water (1:1.1:1.3:1, v/v/v/v). The separation produced 5.91 mg psoralen, 6.26 mg isopsoralen, 3.19 mg psoralidin, 0.92 mg corylifol A, and 2.43 mg bavachinin with corresponding purities of 99.5, 99.8, 99.4, 96.4, and 99.0%, as well as three sub-fractions, in a single run from 250 mg ethyl acetate fraction of P. corylifolia extract. Following an additional clean-up step by preparative TLC, 0.4 mg 8-prenyldaidzein (purity 91.7%), 4.18 mg neobavaisoflavone (purity 97.4%) and 4.36 mg isobavachalcone (purity 96.8%) were separated from the three individual sub-fractions. The structures of the isolated compounds were identified by ¹H NMR and ¹³C NMR. The results of antioxidant activity estimation by electron spin resonance (ESR) method showed that psoralidin was the most active antioxidant with an IC₅₀ value of 44.7 μM. This is the first report on simultaneous separation of eight compounds from P. corylifolia by HSCCC.     

Preparative isolation and purification of cuminaldehyde and p-menta-1,4-dien-7-al from the essential oil of Cuminum cyminum L. by high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) technique in semi-preparative scale was successfully used in isolation and purification of cuminaldehyde and p-menta-1,4-dien-7-al from the essential oil of Cuminum cyminum L. by using a two-phase solvent system composed of n-hexane–methanol–water (5:4:1, v/v/v). The targeted compounds were isolated, collected, purified by HSCCC in the head–tail mode, and then analyzed by gas chromatography (GC). A total of 12.72 ± 0.22 mg of cuminaldehyde and 10.61 ± 0.27 mg of p-menta-1,4-dien-7-al were obtained from 50 mg of the essential oil of C. cyminum L. in less than 6 h, with purities of 95.42% and 97.21%, respectively. In addition to GC-EI/MS, the identity of the cuminaldehyde was further confirmed with the retention time using the method of standard addition, while, the structural identification of p-menta-1,4-dien-7-al was performed with GC-EI/MS, ¹H NMR and ¹H–¹H COSY.     

High-speed counter-current chromatographic isolation of ricinine,an insecticide from Ricinus communis

The alkaloid ricinine, an insecticide for leaf-cutting ant (Atta sexdens rubropilosa), was obtained from Ricinus communis. A two-phase solvent system composed of CH₂Cl₂/EtOH/H₂O (93:35:72, v/v/v) was used for high-speed counter-current chromatographic (HSCCC) isolation of ricinine in high yield and with over 96% purity, as determined by liquid and gas chromatography–mass spectrometry (LC–MS and GC–MS). Identification of ricinine was performed by comparison of ¹H NMR, ¹³C NMR and LC–MS/MS data.     

高速逆流色谱法分离制备母丁香和公丁香中的5种非挥发性化合物

应用高速逆流色谱法从母丁香和公丁香中快速分离了3种已知非挥发性化合物,并利用相同方法从公丁香中分离出2种色原酮类化合物。两相溶剂系统A为正己烷-乙酸乙酯-甲醇-水(5:8:6:13, v/v/v/v),系统B为正己烷-乙酸乙酯-甲醇-水(5:8:9:10, v/v/v/v),以系统A的上相为固定相,系统A和B的下相为流动相,利用梯度洗脱方式,在主机转速为880 r/min、流速1.2 mL/min条件下,成功地从70 mg母丁香粗提物中分离得到12.3 mg鞣花酸、9.6 mg鼠李素、17.2 mg槲皮素,从50 mg公丁香粗提物中分离得到5,7-二甲氧基-2-甲基色原酮10.2 mg、5,7-二甲氧基-2,6-二甲基色原酮8.6 mg,纯度均在96%以上。各化合物的结构均由质谱和核磁共振氢谱、碳谱鉴定。利用该方法可以对丁香不同药用部位中的非挥发性化合物进行有效的分离和纯化。     

Separation of proanthocyanidins isolated from tea leaves using high-speed counter-current chromatography

The proanthocyanidin extract from tea (Camellia sinensis) leaves was purified for the further study of the biological role of proanthocyanidins in blister blight leaf disease of tea, which is caused by the fungus Exobasidium vexans. An aqueous acetone extract of proanthocyanidins prepared from healthy tea leaves was partially purified using Sephadex LH-20 chromatography. The crude proanthocyanidin extract obtained was fractionated with high-speed counter-current chromatography (HSCCC) using the solvent system n-hexane–EtOAc–MeOH–water (1:5:1:5). The purity of the each isolated fraction after a single HSCCC run was evaluated by high-performance liquid chromatography (HPLC). Seven fractions of high purity were isolated. The identity of the compound present in each fraction isolated was established using electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy. Five proanthocyanidins and two flavanol digallates, (−)-epigallocatechin digallate (EGCDG) and (−)-epicatechin digallate (ECDG) were isolated. Comparison of spectral data of the proanthocyanidins isolated with those previously reported indicated that all five were known B-type proanthocyanidins with 2,3-cis stereochemistry in both the upper (u-unit) and the terminal (t-unit) units, and 4R configuration of the C-ring in the u-unit. The proanthocyanidins were established to be dimers composed of (−)-epigallocatechin gallate (EGCG), (−)-epicatechin gallate (ECG) and (−)-epiafzelechin gallate (EAG) units with the following structures: EGCG-(4β → 6)-EGCG, ECG-(4β → 6)-EGCG, EGCG-(4β → 6)-ECG, EAG-(4β → 6)-EGCG, ECG-(4β → 6)-ECG by analysis of spectral data. Therefore HSCCC offers a powerful method for the separation of a group of closely related naturally occurring compounds.     

Isolation of secondary metabolites from Hortia oreadica (Rutaceae) leaves through high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) with a two-phase solvent system (hexane–ethanol–acetonitrile–water 10:8:1:1, v/v) was applied to examine the leaves of Hortia oreadica, which afforded the known limonoid guyanin (1), the alkaloids rutaecarpin (2) and dictamnine (6), the dihydrocinnamic acid derivatives methyl 5,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran-6-propanoate (3), 5,8-dimethoxy-2,2-dimethyl-2H-1-benzopyran-6-propanoic acid (4), together with the new E-3,4-dimethoxy-α(3-hydroxy-4-carbomethoxyphenyl)cinnamic acid (5). The recovery of compounds 1–6 was determined by comparison with LC-atmospheric pressure chemical ionization MS/MS data: 66.2%, 93.1%, 102.5%, 101.2%, 99.0% and 84.9%, respectively. Compound 3 showed IC₅₀ of 23.6 μM against Plasmodium falciparum and 15.6 μM against Trypanosoma brucei rhodesienses and was not toxic to KB cells (IC₅₀ > 100 μM).     

Preparative isolation and purification of antioxidative diarylheptanoid derivatives from Alnus japonica by high-speed counter-current chromatography

This study employed the online HPLC-2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS)(+) bioassay to rapidly determine the antioxidant compounds occurring in the crude extract of Alnus japonica. The negative peaks of the ABTS(+) radical scavenging detection system, which indicated the presence of antioxidant activity, were monitored by measuring the decrease in absorbance at 734 nm. The ABTS(+)-based antioxidant activity profile showed that three negative peaks exhibited antioxidant activity. High-speed counter-current chromatography (HSCCC) was used for preparative scale separation of the three active peaks from the extract. The purity of the isolated compounds was analyzed by HPLC and their structures were identified by (1)H- and (13)C-nuclear magnetic resonance spectrometry (NMR), heteronuclear multiple bond correlation (HMBC), and heteronuclear single quantum correlation (HSQC). Two solvent systems composed of n-hexane/ethylacetate/methanol/water (4:6:4:6, v/v) and of ethyl acetate/methanol/water (1:0.1:1, v/v) were performed in high-speed counter-current chromatography. Consequently, a total of 527 mg of hirsutanonol 5-O-β-D-glucopyranoside, 80.04 mg of 3-deoxohirsutenonol 5-O-β-D-glucopyranoside, and 91.0 mg of hirsutenone were obtained with purity of 94.7, 90.5, and 98.6%, respectively.     

Development of an efficient method for the preparative isolation and purification of chlorophyll a from a marine dinoflagellate Amphidinium carterae by high-speed counter-current chromatography coupled with reversed-phase high-performance liquid chromatography

In our research into chlorophylls of marine dinoflagellates, chlorophyll a was separated rapidly from the hexane extract of Amphidinium carterae in three steps. The first step was silica gel column chromatography, where elution was performed with 0–50% ethyl acetate in n-hexane. The second was high-speed counter-current chromatography using a two-phase solvent system consisting of n-hexane–ethyl acetate–methanol–water (5:5:5:1, v/v), and the third step was preparative reversed-phase high-performance liquid chromatography using a solvent system of acetone–water (89:11, v/v). HPLC analysis showed that the purity of chlorophyll a from the second step was over 83%, and after the third it was over 99%. Thirty milligrams of chlorophyll a was isolated from a crude sample of 250 mg of chlorophylls, and its structure was identified by analyzing its MS, ¹H NMR and ¹³C NMR spectra.     

Preparative isolation and purification of alkannin/shikonin derivatives from natural products by high-speed counter-current chromatography

Alkannin and shikonin (A/S) and their derivatives have been found in the roots of several Boraginaceous species and are also produced through plant tissue cultures. The chiral compounds A/S are potent pharmaceutical substances with a wide spectrum of biological and pharmacological activities like wound healing, antimicrobial, anti-inflammatory, anticancer and antioxidant activity. High-speed counter-current chromatography (HSCCC) was applied for the first time to the separation, preparative isolation and purification of A/S and their esters from extracts of Alkanna tinctoria roots, as well as commercial samples. The constituents of HSCCC fractions and their purity were determined by high-performance liquid chromatography-diode array detection-mass spectrometry (HPLC-DAD-MS), since DAD cannot detect oligomeric A/S derivatives that are present in most of the samples containing the respective monomeric derivatives. The purity of HSCCC fractions was compared with the one of fractions isolated by column chromatography (CC) using as stationary phases silica gel and Sephadex LH-20. As shown, the purity of monomeric alkannin/shikonin was greater by HSCCC than CC separation of commercial A/S samples.     

Preparative isolation and purification of two amides from Mallotus lianus Croiz by high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) was applied to the preparative isolation and purification of two amides from Mallotus lianus Croiz. In a single HSCCC separation, using the two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water (5:1:5:1 v/v), 247.5 mg of the enriched crude sample was separated to afford 10.3 mg of N-isobutyl-2E,4E,12Z-octadecatrienamide and 15.7 mg of (7Z,10Z,18Z)tricosa-7,10,18-trienamide, a novel compound, with the purities of 98.0 and 94.6%, respectively. The HSCCC fractions were analyzed by HPLC and chemical structures of the compounds were identified by 1D- and 2D-NMR, ESI-, and GC-MS.     

Preparative isolation and purification of three flavonoid glycosides from Taraxacum mongolicum by high-speed counter-current chromatography

A preparative high-speed counter-current chromatography (HSCCC) was successively applied to purify three flavonoid glycosides from the aerial part of Taraxacum mongolicum, a traditional Chinese medicine. Subsequent UV, MS, and NMR analyses have led to the characterization of three flavonoid glycosides including two new compounds isoetin-7-O-beta-D-glucopyranosyl-2'-O-alpha-L-arabinopyranoside and isoetin-7-O-beta-D-glucopyranosyl-2'-O-alpha-D-glucopyranoside, and a known compound, isoetin-7-O-beta-D-glucopyranosyl-2'-O-alpha-D-xyloypyranoside, which were first isolated from T. mongolicum. The two-phase solvent system composed of ethyl acetate/n-butanol/water (2:1:3, v/v/v) was performed in HSCCC. Consequently, a total of 25.7 mg isoetin-7-O-beta-D-glucopyranosyl-2'-O-alpha-L-arabinopyranoside, 19.1 mg isoetin-7-O-beta-D-glucopyranosyl-2'-O-alpha-D-glucopyranoside, and 10.6 mg isoetin-7-O-beta-D-glucopyranosyl-2'-O-alpha-D-xyloypyranoside were obtained with purity of 98.7, 98.3, and 99.1%, respectively, as determined by HPLC from 500 mg enriched extract after cleaning-up by polyamide resin.     

高速逆流色谱法快速分离制备枸杞中莨菪亭

建立了用高速逆流色谱(HSCCC)从枸杞中快速分离莨菪亭的方法。将枸杞的乙醇提取物经D-101大孔树脂初步纯化后直接进行高速逆流色谱分离,用薄层色谱-荧光法考察了莨菪亭在不同溶剂体系中的分配情况。结果表明,最佳的溶剂体系为氯仿-甲醇-水(10:7:3, v/v/v),取上相为固定相,下相为流动相,在主机转速为850 r/min、流速为1.5 mL/min、检测波长为365 nm的条件下,从200 mg样品中一次性分离制备可得到10.2 mg纯度达到98.3%的莨菪亭。制备所得的莨菪亭与对照品的高效液相色谱(HPLC)保留时间一致,且经核磁共振氢谱、碳谱鉴定结构;纯度经HPLC法测定。研究发现,氯仿-甲醇-水(10:7:3, v/v/v)体系可连续二次进样而样品的峰形未受明显的影响。实验结果表明用薄层色谱-荧光法可快速选定HSCCC溶剂体系,进而可快速、简便地制备高纯度的莨菪亭。