Preparative isolation and purification of anthocyanins from purple sweet potato by high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) was applied to the preparative isolation and purification of peonidin 3-O-(6-O-(E)-caffeoyl-2-O-β-D -glucopyranosyl-β-D -glucopyranoside)-5-O-β-D -glucoside ( 1 ), cyanidin 3-O-(6-O-p-coumaroyl)-β-D -glucopyranoside ( 2 ), peonidin 3-O-(2-O-(6-O-(E)-caffeoyl-β-D -glucopyranosyl)-6-O-(E)-caffeoyl-β-D -glucopyranoside)-5-O-β-D -glucopyranoside ( 3 ), peonidin 3-O-(2-O-(6-O-(E)-feruloyl-β-D -glucopyranosyl)-6-O-(E)-caffeoyl-β-D -glucopyranoside)-5-O-β-D -glucopyranoside ( 4 ) from purple sweet potato. Separation of crude extracts (200 mg) from the roots of purple sweet potato using methyl tert-butyl ether/n-butanol/acetonitrile/water/trifluoroacetic acid (1:4:1:5:0.01, v/v) as the two-phase solvent system yielded 1 (15 mg), 2 (7 mg), 3 (10 mg), and 4 (12 mg). The purities of 1 – 4 were 95.5%, 95.0%, 97.8%, and 96.3%, respectively, as determined by HPLC. Compound 2 was isolated from purple sweet potato for the first time. The chemical structures of these components were identified by ¹H NMR, ¹³C NMR and ESI-MSⁿ.     

Constituents of Clinopodium Umbrosum

The isolation and identification of fifteen crystalline components from the whole herb of Clinopodium umbrosum (Bieb.) C. Koch (Labiatae) are described. Their structures were determined on the basis of spectral evidence and chemical transformation. These compounds include five steroids (α-spinasterone, β-sitosterol, stigmasterol, α-spinasterol, and α-spinasteryl-3-O-β-glucopyranoside), four triterpenoids (3β-hydroxyurs-11-en-28,13-olide, betulinic acid, oleanolic acid, ursolic acid), four flavonoids (luteolin, luteolin-7-O-β-glucopyranoside, apigenin-7-O-β-glucuronide, and apigenin-7-O-β-methylglucuronate), and two lignolic acids [3-(3,4-dihydroxyphenyl)- lactic acid and rosmarinic acid].     

Quality Assessment of Veratrum nigrum L. by LC-ELSD Fingerprints and LC Quantitative Analysis

A rapid and sensitive LC-MS method has been developed for the determination of luteolin-7-O-β-d-glucoside in rat plasma after solvent extraction. Separation was on an Elite Hypersil ODS2 column (250 mm × 4.6 mm i.d., 5 μm) with a mobile phase of acetonitrile-0.3% acetic acid (26:74, v/v). The samples were analyzed by using positive electrospray ionization MS in selected ion monitoring mode. The selected ions for luteolin-7-O-β-d-glucoside and the internal standard, isoquercitrin, were m/z 448.95 and m/z 464.95. Good linearity was observed over the range of 20–2,000 ng mL⁻¹ with a lower limit of quantification of 20 ng mL⁻¹. No interference peaks or matrix effects were observed. The validated method was applied to the pharmacokinetic study of luteolin-7-O-β-d-glucoside in rat plasma after intravenous administration of Kudiezi Injection.

     

Ultra-high-performance liquid chromatography-Quadrupole-Exactive-Orbitrap-tandem mass spectrometry-based putative identification for Eucommiae Folium (Duzhongye) and its quality-marker candidate for pharmacopeia

Eucommiae Folium (Duzhongye) is a traditional Chinese medicine with a long history of use in China. However, its quality-marker in Chinese Pharmacopoeia is poorly defined nowadays. The study, therefore, conducted an ultra-high-performance liquid chromatography coupled with hybrid quadrupole-orbitrap tandem mass spectrometry analysis to obtain accurate data. The obtained data were then compared with the authentic standards library using Xcalibur 4.1 software package and TraceFinder General Quan. Through the comparison, the study has putatively identified 26 bioactive compounds, which include 17 flavonoid derivatives (catechin, quercetin 3-gentiobioside, quercetin 3-O-β-D-glucose-7-O-β-D-gentiobioside, taxifolin, myricetin 3-O-galactoside, myricitrin, hyperoside, rutin, isoquercitrin, quercetin 3-O-β-xylopyranoside, quercitrin, isorhamnetin 3-O-β-D-glucoside, quercetin, kaempferol, S-eriodictyol, S-naringenin, and phloridzin), four caffeoylquinic acids (neochlorogenic acid, chlorogenic acid, isochlorogenic acid A, and isochlorogenic acid C), two alkaloids (vincamine and jervine), one lignan (pinoresinol), one xanthone (cowaxanthone B), and one steroid (cholesteryl acetate). Of these, flavonoid isoquercitrin is recommended as the new and additional pharmacopeia quality-marker candidate, which can not only overcome the unreliability of old quality-marker but also recognize the possible counterfeit.     

A Rapid Method for Qualitative and Quantitative Analysis of Major Constituents in Dengzhanxixin Injection by LC-DAD-ESI–MSn

For the first time a rapid method for qualitative and quantitative analysis of constituents in Dengzhanxixin injection was established by liquid chromatography with electrospray ionization–tandem mass spectrometry. Eighteen compounds including flavonoids and phenolic acids were characterized or tentatively identified. Ten of these compounds, including 5-O-caffeoylquinic acid, caffeic acid, 1,3-O-dicaffeoylquinic acid, 6′-O-caffeoylerigeroside, scutellarin, 3,4-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid, erigoster B, apigenin-7-O-glucuronide and 4,5-O-dicaffeoylquinic acid, were further quantified as marker substances by LC-DAD using a C₁₈ column at 0.4 mL min^?1 within 37 min. The quantitative method was validated for ten interesting compounds, including linearity, accuracy, precisions, LOQ and LOD, which was proved to be sensitive, reproducible and accurate. The study might provide a comprehensive method for the quality assessment of dengzhanxixin injection.     

Chemical characteristics of different parts of Coreopsis tinctoria in China using microwave‐assisted extraction and high‐performance liquid chromatography followed by chemometric analysis

Coreopsis tinctoria, also called “snow chrysanthemum” in China, is a flower tea material that has been reported to possess excellent pharmacological properties such as antioxidant and antidiabetic activities. The chemical characteristics of different parts (flowers, buds, seeds, stems, and leaves) of C. tinctoria were investigated based on microwave‐assisted extraction and the simultaneous determination of 13 major active compounds by high‐performance liquid chromatography, including taxifolin‐7‐O‐glucoside, chlorogenic acid, (R/S)‐flavanomarein, isocoreopsin, quercetagetin‐7‐O‐glucoside, isookanin, 5,7,3′,5′‐tetrahydroxyflavanone‐7‐O‐glucoside, marein, 3,5‐dicaffeoylquinic acid, coreopsin, okanin, 5,7,3′,5′‐tetrahydroxyflavanone, and N¹,N⁵,N¹⁰,N¹⁴‐tetra‐p‐coumaroylspermine. Chemometric analysis based on the contents of investigated compounds from 13 samples showed that C. tinctoria and the related flower tea materials, Chrysanthemum morifolium cv “Hangju” and “Gongju,” were in different clusters, and different parts (flowers, buds, seeds, stems, and leaves) of C. tinctoria were obviously different. This study is helpful for the quality control and pharmacological evaluation of different parts from C. tinctoria and its related products.     

Identification and quantification of anthocyanins,flavonoids, and phenolic acids in flowers of Rhododendron arboreum and evaluation of their antioxidant potential

The current study aimed to investigate the anthocyanins, non-anthocyanins (flavonoids and phenolic acids), and free radicals scavenging potential in the flowers of Rhododendron arboreum using ultra high performance liquid chromatography with ion mobility quadrupole time of flight tandem mass spectrometry. A total of 25 constituents including nine anthocyanins, six phenolic acids, and ten flavonoids were identified in the flower extract. The major anthocyanins identified were cyanidin-3-O-β-galactoside ( 1 ), cyanidin-3-O-α-arabinoside ( 4 ), and cyanidin-3-O-rhamnoside ( 8 ), while quercetin glycosides were the main identified flavonoids in R. arboreum flowers. Additionally, ultra high performance liquid chromatography methods were developed and validated for the quantification of nine compounds (anthocyanins, flavonoid glycosides, and phenolic acids); five of them were quantified using internal standards. The extracts were analyzed for total phenolics (123.6 mg GAE/g), anthocyanin content (1.76% w/w), and evaluated for antioxidant properties against 2,2-diphenyl-1-picrylhydrazyl radical (IC₅₀: 102.06 and 96.92 μg/mL) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical cation (112.25 and 45.59 μM TE/g) assays. The profiling of R. arboreum for anthocyanins is reported for the first time. The findings suggest that the flowers are a promising source of bioactive constituents and could be used as functional food, antioxidants, and nutraceuticals.     

LC-MS Determination and Pharmacokinetic Study of Luteolin-7-O-β-d-glucoside in Rat Plasma after Administration of the Traditional Chinese Medicinal Preparation Kudiezi Injection

A rapid and sensitive LC-MS method has been developed for the determination of luteolin-7-O-β-d-glucoside in rat plasma after solvent extraction. Separation was on an Elite Hypersil ODS2 column (250 mm × 4.6 mm i.d., 5 μm) with a mobile phase of acetonitrile-0.3% acetic acid (26:74, v/v). The samples were analyzed by using positive electrospray ionization MS in selected ion monitoring mode. The selected ions for luteolin-7-O-β-d-glucoside and the internal standard, isoquercitrin, were m/z 448.95 and m/z 464.95. Good linearity was observed over the range of 20–2,000 ng mL^?1 with a lower limit of quantification of 20 ng mL^?1. No interference peaks or matrix effects were observed. The validated method was applied to the pharmacokinetic study of luteolin-7-O-β-d-glucoside in rat plasma after intravenous administration of Kudiezi Injection.     

A new flavone glucoside from Stachys aegyptiaca

In addition to 5,7,3′-trihydroxy-6,4′-dimethoxyflavone, 5,7,3′-trihydroxy-6,8,4′-trimethoxyflavone, isoscutellarein, luteolin, and luteolin-7-O-glucoside, the methanol extract of the aerial parts of Stachys aegyptiaca yielded a new flavone identified as luteolin 3′,4′-dimethylether-7-O-β-D-glucoside on the basis of chemical and spectroscopic methods. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 444–445, September–October, 2007.     

Chemical composition and antioxidant activity of aerial parts of Ferula longipes Coss. ex Bonnier and Maury

This is the first study on the phytochemistry and antioxidant activity of Ferula longipes Coss. ex Bonnier and Maury (Apiaceae). A new flavonoid quercetin-3-O-α-L-rhamnopyranoside-7-O-ß-D-[2-O-caffeoyl]-glucopyranoside (1), along with 10 known compounds kaempferol-3-O-α-L-rhamnopyranoside (2), quercetin-3-O-α-L-rhamnopyranoside (3), kaempferol-3-O-ß-D-glucopyranoside-7-O-α-L-rhamnopyranoside (4), isorhamnetin-3-O-α-L-rhamnopyranoside-7-O-ß-D-glucopyranoside (5), quercetin-3-O-α-L-rhamnopyranoside-7-O-ß-D-glucopyranoside (6), isorhamnetin-3,7-di-O-β-D-glucopyranoside (7), apigenin (8), apigenin-7-O-ß-D-glucopyranoside (9), 3,5-dicaffeoylquinic acid (10), deltoin (11) were isolated from the aerial parts of Ferula longipes Coss. Structures elucidation was performed by comprehensive 1D and 2D NMR analyses, mass spectrometry and by comparison with literature data. The compounds 1, 3, 4, 6, 7 and 10 were evaluated for their antioxidant activity, compound 1 exhibited the best antiradical activity potential and showed IC₅₀ and A_0.5 values 5.70, 7.25, 5.00, and 2.63 μg/mL towards DPPH free radical-scavenging, ABTS, CUPRAC, and reducing power assays, respectively compared with BHA, BHT and ascorbic acid which were used as positive controls.     

Contribution à la phytochimie du genre Gentiana. XXV. Etude des composés flavoniques et xanthoniques dans les feuilles de Gentiana X marcailhouana RY. Nouveaux cinnamoyl-C-glucosides flavoniques

Phytochemistry of genus Gentiana XXV: Study of the flavonic and xanthonic compounds in leaves of Gentiana X marcailhouana RY . New cinnamoyl-C-glucosyl-flavones Nine flavonic compounds: isoorientin ( 1 ), isovitexin ( 2 ), isoorientin-4′-O-β-D -glucoside ( 3 ), isovitexin-4′-O-β-D -glucoside ( 4 ), luteolin-7-O-β-D -glucoside ( 5 ), trans-cafeoyl-2′′-isoorientin ( 6 ), trans-feruloyl-2′′-isoorientin ( 7 ), trans-p-coumaroyl-2′′-isoorientin ( 8 ), p-O-β-D -glucosyl-trans-cafeoyl-2′′-isoorientin ( 9 ) and three xanthones: gentioside ( 10 ), isogentisine ( 11 ), mangiferin ( 12 ), have been identified from leaves of Gentiana X marcailhouana RY . Compounds 8 and 9 were described for the first time. The cyclitol L -(+)-bornesitol ( 13 ) has been also isolated.     

Preparative Isolation and Purification of Flavonoids and Protocatechuic Acid from Sea Buckthorn Juice Concentrate (Hippophaë rhamnoides L. ssp. rhamnoides) by High-Speed Counter-Current Chromatography

High-speed counter-current chromatography (HSCCC)—a support free all liquid–liquid chromatography technique—has been successfully used for the preparative isolation of isorhamnetin 3-O-β-d-glucoside, isorhamnetin 3-O-β-rutinoside, quercetin 3-O-β-d-glucoside, syringetin 3-O-β-d-glucoside and protocatechuic acid from sea buckthorn juice concentrate (Hippophaë rhamnoides L. ssp. rhamnoides, Elaeagnaceae). The preparative HSCCC instrument was a multilayer coil planet centrifuge equipped with three preparative coils. Separation was performed with a two phase solvent system (n-hexane–n-butanol–water, 1:1:2 v/v/v) in ‘head-to-tail’ mode. Each injection of 4.1 g crude ethyl acetate extract yielded isorhamnetin 3-O-β-d-glucoside (95 mg), isorhamnetin 3-O-β-rutinoside (10 mg), quercetin 3-O-β-d-glucoside (5 mg), and protocatechuic acid (34 mg) with purities >98%. The flavonoid syringetin 3-O-β-d-glucoside (2 mg) was a novel compound for H. rhamnoides. Chemical structures of all compounds were determined by HPLC–ESI–MS–MS, 1D-NMR (¹H, ¹³C, DEPT 135) spectroscopy and for elucidation of glycosidic linkages 2D-NMR (HMBC) spectroscopy was used.     

Separation of betacyanins from flowers of Amaranthus cruentus L. in a polar solvent system by high‐speed counter‐current chromatography

Betacyanin extract of Amaranthus cruentus L. flowers was fractionated by semi‐preparative high‐speed counter‐current chromatography in a highly polar solvent system: propan‐1‐ol/acetonitrile/(NH₄)₂SO_{4satd. soln}/H₂O (1.0:0.5:1.2:1.0, v/v/v/v) in tail‐to‐head mode with 76% retention of the stationary phase. The crude extract as well as the fractions containing betacyanins were analyzed by liquid chromatography with tandem mass spectrometry as well as by high‐resolution ion‐trap time‐of‐flight mass spectrometry detection technique for the molecular formulae and multi‐step fragmentation pattern elucidation. Four betacyanins; namely, amaranthin, betanin, 6′‐O‐formyl‐amaranthin, and 6′‐O‐malonyl‐amaranthin as well as their diastereomeric forms differing in the configuration of the C‐15 carbon atom were identified in the fractions. Amaranthin was the dominant pigment in the extract and was additionally analyzed by nuclear magnetic resonance correlation techniques after the counter‐current chromatographic and high‐performance liquid chromatographic isolation. Betacyanins were highly enriched during a single high‐speed counter‐current chromatographic step; therefore, the tentative identification of new compounds for the whole Amaranthaceae family, 6′‐O‐formyl‐amaranthin and 6′‐O‐malonyl‐amaranthin was possible. Different elution profiles of the pigments observed in the counter‐current chromatographic system in comparison to high‐performance liquid chromatography system confirm a complementarity of both the techniques especially in the separation of diastereomeric pairs of betacyanins.     

Optimization of the chromatographic determination of polyphenols in the aerial parts ofCichorium intybus L.

Summary The aim of this work was to contribute to the phytochemical characterization ofCichorium intybus L. var.silvestre, chicory. Semi-preparative HPLC analysis was applied to an extract of fresh wild chicory leaves to separate and collect the main polyphenolic compounds. HPLC-diode-array detection (DAD), HPLC-MS, and NMR were used for the complete chemical characterization of all the compounds isolated. The molecules characterized were monocaffeoyl tartaric acid, chicoric acid, monocaffeolyp-hydroxycinnamoyl tartaric acid, caffeoyl feruloyl tartaric acid, chlorogenic acid, quercetin-3-O-glucuronide, luteolin-7-O-glucuronide, and quercetin-3-O-glucoside. The chromatographic behaviour of the main components of the extract of the leaves has been compared on three different stationary phases-LiChrosorb RP18, Luna C₁₈, and Luna Phenyl-Hexyl.     

Combination of preparative HPLC and HSCCC methods to separate phosphodiesterase inhibitors from Eucommia ulmoides bark guided by ultrafiltration-based ligand screening

Phosphodiesterase (PDE) inhibitors are widely used because of their various pharmacological properties, and natural products are considered the most productive source of PDE inhibitors. In this work, a new ultrafiltration–high-performance liquid chromatography (HPLC)–diode-array detection–mass spectrometry based ligand screening was developed for the first screening of PDE inhibitors from Eucommia ulmoides bark, and then the target bioactive compounds were prepared by combination of stepwise preparative HPLC and high-speed countercurrent chromatography (HSCCC) methods. Experiments were conducted to optimize the parameters in ultrafiltration, stepwise preparative HPLC, and HSCCC to allow rapid and effective screening and isolation of active compounds from complex mixtures. Seven lignans with purity over 97 % were isolated and identified by their UV, electrospray ionization mass spectrometry, and NMR data as (+)-pinoresinol-4,4′-di-O-β-D-glucopyranoside (1), (+)-pinoresinol-4-O-β-D-glucopyranosyl(1?→?6)-β-D-glucopyranoside (2), (+)-medioresinol-4,4′-di-O-β-D-glucopyranoside (3), (+)-syringaresinol-4,4′-di-O- β-D-glucopyranoside (4), (?)-olivil-4′-O-β-D-glucopyranoside (5), (?)-olivil-4-O-β-D- glucopyranoside (6), and (+)-pinoresinol-4-O-β-D-glucopyranoside (7). Compound 2 was first isolated from the genus Eucommia. Lignan diglucopyranosides (compounds 1–4) shower a greater inhibitory effect than lignan monoglucopyranosides (compounds 5–7). The method developed could be widely applied for high-throughput screening and preparative isolation of PDE inhibitors from natural products.     

4-O-β-d-GLUCOPYRANOSYL-d-GLUCONIC ACID (CELLOBIONIC ACID) PRODUCED BY OZONATION OF CELLOBIOSE: ISOLATION BY HPLC AND ASSIGNMENT OF NMR CHEMICAL SHIFTS

Mild ozonation of cellobiose in acetic acid almost exclusively favors oxidation of the reducing end, thus yielding 4-O-β-d-glucopyranosyl-d-gluconic acid (“cellobionic acid”). This compound can be quantitatively separated from the substrate by preparative HPLC using acetonitrile/phosphate buffer on an aminopropyl silica column. The product was identified using one and two dimensional NMR techniques. ¹³C and ¹H NMR chemical shifts are reported.     

Rapid separation of cyanidin‐3‐glucoside and cyanidin‐3‐rutinoside from crude mulberry extract using high‐performance countercurrent chromatography and establishment of a volumetric scale‐up process

This study describes the rapid separation of mulberry anthocyanins; namely, cyanidin‐3‐glucoside and cyanidin‐3‐rutinoside, using high‐performance countercurrent chromatography, and the establishment of a volumetric scale‐up process from semi‐preparative to preparative‐scale. To optimize the separation parameters, biphasic solvent systems composed of tert‐butyl methyl ether/n‐butanol/acetonitrile/0.01% trifluoroacetic acid, flow rate, sample amount and rotational speed were evaluated for the semi‐preparative‐scale high‐performance countercurrent chromatography. The optimized semi‐preparative‐scale high‐performance countercurrent chromatography parameters (tert‐butyl methyl ether/n‐butanol/acetonitrile/0.01% trifluoroacetic acid, 1:3:1:5, v/v; flow rate, 4.0 mL/min; sample amount, 200–1000 mg; rotational speed, 1600 rpm) were transferred directly to a preparative‐scale (tert‐butyl methyl ether/n‐butanol/acetonitrile/0.01% trifluoroacetic acid, 1:3:1:5, v/v; flow rate, 28 mL/min; sample amount, 5.0–10.0 g; rotational speed, 1400 rpm) to achieve separation results identical to cyanidin‐3‐glucoside and cyanidin‐3‐rutinoside. The separation of mulberry anthocyanins using semi‐preparative high‐performance countercurrent chromatography and its volumetric scale‐up to preparative‐scale was addressed for the first time in this report.     

Application of one-step inner-recycling counter-current chromatography for the preparative separation and purification of chemical constituents from the rhizome of Bergenia ciliate (haw.) Sternb

Bergenia ciliata (haw.) Sternb, the renowned pharmaceutical plant in Jammu and Kashmir of Pakistan, is widely applied in treating different illnesses including diabetes, diarrhea, and vomiting. This work employed an efficient one-step inner-recycling counter-current chromatography for preparative separating and purifying compounds with similar partition coefficients from the rhizome of Bergenia ciliate (haw.). Five compounds, including quercetin rhamnodiglucoside ( 1 ), quercetin-3-O-rutinoside ( 2 ), bergenine ( 3 ), kaempferol ( 4 ), and palmatic acid ( 5 ), were successfully separated using the optimized biphasic solvent system that contained ter-butylmetylether/n-butanol/acetonitrile/water (2:2:1:5, v/v) with the purities over 98%. Mass spectrometry and nuclear magnetic resonance were conducted for structural identification. As a result, our proposed strategy might be applied in separating compounds with similar partition coefficients, which was advantageous with regard to the less solvent and time consumption, and the increased number of theoretical plates.     

Triterpenoid saponins from the buds of Lonicera similis

Four new lupane triterpenoid saponins, along with one known lupane and eight hederagenin saponins, were isolated from the EtOH extract of the buds of Lonicera similis Hemsl. The structures of the new compounds were established as 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl 23-hydroxybetulinic acid 28-O-β-D-glucopyranosyl ester (lonisimilioside A, 1), 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl 23-hydroxybetulinic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (lonisimilioside B, 2), 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl betulinic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (lonisimilioside C, 3) and 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl betulinic acid 28-O-β-D-glucopyranosyl ester (lonisimilioside D, 4), respectively. The cytotoxic activities of the isolates against human cancer cell lines HepG2, MCF-7 and A-549 were evaluated. Only the monodesmosidic saponin with a free carboxyl group at C-28 (12) exhibited significant cytotoxicities against HepG2, MCF-7 and A-549 cell lines with the IC₅₀ values of 8.98 ± 0.19, 12.48 ± 0.45 and 11.62 ± 0.54 μM, respectively. Furthermore, Hoechst fluorescence 33342 staining was used to demonstrate that 12 could induce HepG2 and A-549 cells apoptosis significantly.