Polar Constituents from Sageretia Thea Leaf Characterized by HPLC‐SPE‐NMR Assisted Approaches

Nine glycosides ( 1–9 ) were characterized from the n‐butanol‐soluble fraction of the ethanolic extract of the leaves of Sageretia thea by the general approach. Among these, Compounds 6 and 7 were identified as a mixture. Application of HPLC‐SPE‐NMR in two selected fractions led to the separation of this mixture and the characterization of three additional minors ( 10–12 ). Among these, 7‐O‐methylmyricetin 3‐O‐α‐l ‐arabinofuranoside ( 8 ) is a new natural product and eight compounds, i.e. glucofragulin A ( 1 ), quercetin‐3‐O‐α‐l ‐arabinopyranoside ( 5 ), 3‐O‐β‐d ‐galactopyranoside ( 6 ), 3‐O‐β‐d ‐glucopyranoside ( 7 ), and 3‐O‐α‐l ‐arabinofuranoside ( 11 ), myricetin‐3‐O‐α‐l ‐arabinofuranoside ( 9 ) and 3‐O‐β‐d‐glucopyranoside ( 10 ), and quercetrin ( 12 ), are found for the first time from the title plant.     

Four new ursane‐type saponins from Morina nepalensis var. alba

Four new ursane‐type saponins, monepalosides C–F, together with a known saponin, mazusaponin II, were isolated from Morina nepalensis var. alba Hand.‐Mazz. Their structures were determined to be 3‐O‐α‐L ‐arabinopyranosyl‐(1 → 3)‐&[alpha;‐L ‐rhamnopyranosyl‐(1 → 2)]‐α‐L ‐arabinopyranosylpomolic acid 28‐O‐β‐D ‐glucopyranosyl‐(1 → 6)‐β‐D ‐glucopyranoside (monepaloside C, 1 ), 3‐O‐α‐L ‐arabinopyranosyl‐(1 → 3)‐&[alpha;‐L ‐rhamnopyranosyl‐(1 → 2)]‐β‐D ‐xylopyranosylpomolic acid 28‐O‐β‐D ‐glucopyranosyl‐(1 → 6)‐β‐D ‐glucopyranoside (monepaloside D, 2 ), 3‐O‐α‐L ‐arabinopyranosyl‐(1 → 3)‐&[beta;‐D ‐glucopyranosy‐(1 → 2)]‐α‐L ‐arabinopyranosylpomolic acid 28‐O‐β‐D ‐glucopyranosyl‐(1 → 6)‐β‐D ‐glucopyranoside (monepaloside E, 3 ) and 3‐O‐β‐D ‐xylopyranosylpomolic acid 28‐O‐β‐D ‐glucopyranoside (monepaloside F, 4 ) on the basis of chemical and spectroscopic evidence. 2D NMR techniques, including ¹H–¹H COSY, HMQC, 2D HMQC‐TOCSY, HMBC and ROESY, and selective excitation experiments, including SELTOCSY and SELNOESY, were utilized in the structure elucidation and complete assignments of ¹H and ¹³C NMR spectra. Copyright © 2002 John Wiley & Sons, Ltd.     

Two new acylated flavonoid glycosides from Morina nepalensis var. alba Hand.‐Mazz.

From the whole plant of Morina nepalensis var. alba Hand.‐Mazz., two new acylated flavonoid glycosides ( 1 and 2 ), together with four known flavonoid glycosides ( 3–6 ), were isolated. Their structures were determined to be quercetin 3‐O‐[2″′‐O‐(E)‐caffeoyl]‐α‐L ‐arabinopyranosyl‐(1→6)‐β‐D ‐galactopyranoside (monepalin A, 1 ), quercetin 3‐O‐[2″′‐O‐(E)‐caffeoyl]‐α‐L ‐arabinopyranosyl‐(1→6)‐β‐D ‐glucopyranoside (monepalin B, 2 ), quercetin 3‐O‐α‐L ‐arabinopyranosyl‐(1→6)‐β‐D ‐galactopyranoside (rumarin, 3 ), quercetin 3‐O‐β‐D ‐galactopyranoside ( 4 ), quercetin 3‐O‐β‐D ‐glucopyranoside ( 5 ) and apigenin 4^′‐O‐β‐D ‐glucopyranoside ( 6 ). Their structures were determined on the basis of chemical and spectroscopic evidence. Complete assignments of the ¹H and ¹³C NMR spectra of all compounds were achieved from the 2D NMR spectra, including H–H COSY, HMQC, HMBC and 2D HMQC‐TOCSY spectra. Copyright © 2002 John Wiley & Sons, Ltd.     

Separation and purification of four flavonol diglucosides from the flower of Meconopsis integrifolia by high‐speed counter‐current chromatography

Flavonoids are the main components of Meconopsis integrifolia (Maxim.) Franch, which is a traditional Tibetan medicine. However, traditional chromatography separation requires a large quantity of raw M. integrifolia and is very time consuming. Herein, we applied high‐speed counter‐current chromatography in the separation and purification of flavonoids from the ethanol extracts of M. integrifolia flower. Ethyl acetate/n‐butanol/water (2:3:5, v/v/v) was selected as the optimum solvent system to purify the four components, namely quercetin‐3‐O‐β‐d‐ glucopyrannosy‐(1→6)‐β‐d‐ glucopyranoside (compound 1 , 60 mg), quercetin 3‐O‐[2’’’‐O‐acetyl‐β‐d‐ glucopyranosyl‐(1→6)‐β‐d‐ glucopyranoside (compound 2 , 40 mg), quercetin 3‐O‐[3’’’‐O‐acetyl‐β‐d‐ glucopyranosyl‐(1→6)‐β‐d‐ glucopyranoside (compound 3 , 11 mg), and quercetin 3‐O‐[6’’’‐O‐acetyl‐β‐d‐ glucopyranosyl‐(1→6)‐β‐d‐ glucopyranoside (compound 4 , 16 mg). Among the four compounds, 3 and 4 were new acetylated flavonol diglucosides. After the high‐speed counter‐current chromatography separation, the purities of the four flavonol diglucosides were 98, 95, 90, and 92%, respectively. The structures of these compounds were identified by mass spectrometry and NMR spectroscopy.     

Structure elucidation of a sodium salified anthraquinone from the seeds of Cassia obtusifolia by NMR technique assisted with acid–alkali titration

A new sodium salt of anthraquinone named sodium emodin‐1‐O‐β‐gentiobioside, together with nine known compounds, viz. rubrofusarin‐6‐O‐β‐D ‐gentiobioside, chrysophanol‐1‐O‐β‐D ‐glucopyranosyl‐(1–3)‐β‐D ‐glucopyranosyl‐(1–6)‐β‐D ‐glucopyranoside, obtusifolin‐2‐O‐β‐D ‐glucopyranoside, aurantio‐obtusin‐6‐O‐β‐D ‐glucopyranoside, physcion‐8‐O‐β‐D ‐glucopyranoside, 1‐hydroxyl‐2‐acetyl‐3,8‐dimethoxy‐6‐O‐β‐D ‐apiofuranosyl‐(1–2)‐β‐D ‐glucosylnaphthalene, toralactone‐9‐O‐β‐D ‐gentiobioside, aurantio‐obtusin, rubrofusarin‐6‐O‐β‐D ‐apiofuranosyl‐(1–6)‐O‐β‐D ‐glucopyranoside, was isolated from the seeds of Cassia obtusifolia and its structure was elucidated by ¹H and ¹³C NMR technique assisted with acid–alkali titration. The change of chemical shifts of sodium emodin‐1‐O‐β‐gentiobioside before and after acid–alkali titration was also characterized. Copyright © 2011 John Wiley & Sons, Ltd.     

Flavonol Glycosides with α‐Glucosidase Inhibitory Activities and New Flavone C‐Diosides from the Leaves of Machilus konishii

Seventeen flavonoids, five of which are flavone C‐diosides, 1 – 5 , were isolated from the BuOH‐ and AcOEt‐soluble fractions of the leaf extract of Machilus konishii. Among 1 – 5 , apigenin 6‐C‐β‐D ‐xylopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 2 ), apigenin 8‐C‐α‐L ‐arabinopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 4 ), and apigenin 8‐C‐β‐D ‐xylopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 5 ) are new. Both 4 and 5 are present as rotamer pairs. The structures of the new compounds were elucidated on the basis of NMR‐spectroscopic analyses and MS data. In addition, the ¹H‐ and ¹³C‐NMR data of apigenin 6‐C‐α‐L ‐arabinopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 3 ) were assigned for the first time. The isolated compounds were assayed against α‐glucosidase (type IV from Bacillus stearothermophilus). Kaempferol 3‐O‐(2‐β‐D ‐apiofuranosyl)‐α‐L ‐rhamnopyranoside ( 12 ) was found to possess the best inhibitory activity with an IC₅₀ value of 29.3 μM .     

NMR analysis of mono‐ and difructosyllactosucrose synthesized by 1F‐fructosyltransferase purified from roots of asparagus (Asparagus officinalis L.)

Two novel oligosaccharides, mono‐ and difructosyllactosucrose {[O‐β‐D ‐fructofuranosyl‐(2 → 1)]_n‐β‐D ‐fructofuranosyl‐O‐[β‐D ‐galactopyranosyl‐(1 → 4)]‐α‐D ‐glucopyranoside, n = 1 and 2} were synthesized using 1^F‐fructosyltransferase purified form roots of asparagus (Asparagus officinalis L.). Their ¹H and ¹³C NMR spectra were assigned using several NMR techniques. The spectral analysis was started from two anomeric methines of aldose units, galactose and glucose, since they showed separate characteristic signals in their ¹H and ¹³C NMR spectra. After assignments of all the ¹H and ¹³C signals of two units of aldose, they were discriminated as galactose and glucose using proton–proton coupling constants. The HMBC spectrum revealed the galactose residue attached to C‐4 of glucose, fructose residue attached to the C‐1 of glucose, and further fructosyl fructose linkage extended from the glucosyl fructose residues. Copyright © 2002 John Wiley & Sons, Ltd.     

Application of high‐performance countercurrent chromatography for the isolation of steroidal saponins from Liriope plathyphylla

High‐performance countercurrent chromatography (HPCCC) with electrospray light‐scattering detection was applied for the first time to isolate a spirostanol and a novel furostanol saponin from Liriope platyphylla. Due to the large differences in K_D values between the two compounds, a two‐step HPCCC method was applied in this study. The primary HPCCC employed methylene chloride/methanol/isopropanol/water (9:6:1:4 v/v, 4 mL/min, normal‐phase mode) conditions to yield a spirostanol saponin ( 1 ). After the primary HPCCC run, the solute retained in the stationary phase (SP extract) in HPCCC column was recovered and subjected to the second HPCCC on the n‐hexane/n‐butanol/water system (1:9:10 v/v, 5 mL/min, reversed‐phase mode) to yield a novel furostanol saponin ( 2 ). The isolated spirostanol saponin was determined to be 25(S)‐ruscogenin 1‐O‐β‐d ‐glucopyranosyl (1→2)‐[β‐d ‐xylopyranosyl (1→3)]‐β‐d ‐fucopyranoside (spicatoside A), and the novel furostanol saponin was elucidated to be 26‐O‐β‐d ‐glucopyranosyl‐25(S)‐furost‐5(6)‐ene‐1β‐3β‐22α‐26‐tetraol‐1‐O‐β‐d ‐glucopyranosyl (1→2)‐[β‐d ‐xylopyranosyl‐(1→3)]‐β‐d ‐fucopyranoside (spicatoside D).     

Two New Phenylpropanoid Glycosides from the Leaves and Flowers of Erica arborea

Two new phenylpropanoid glucosides, 1,2‐erythro‐1‐(3,4,5‐trimethoxyphenyl)‐2‐(β‐D ‐glucopyranosyloxy)propan‐1,3‐diol ( 1 ) and 7,8‐threo‐2′,8‐epoxysyringylglycerol‐7‐O‐α‐D ‐glucopyranoside (ericarboside; 2 ) have been isolated together with four known compounds 2′,7‐epoxysyringylglycerol‐8‐O‐β‐D ‐glucopyranoside (ficuscarpanoside B; 3 ), benzylrutinoside (hydrangeifolin; 4 ), phenethylrutinoside ( 5 ), and caffeic acid from the BuOH soluble part of the MeOH extract of the leaves and flowers of E. arborea L. Final purification of the compounds was achieved on a reversed‐phase HPLC. Their structures have been elucidated by extensive 1D‐ and 2D‐NMR, and mass spectroscopic techniques.     

Phenolic Compounds from Elsholtzia Bodinieri Van't

Seven phenolic compounds, including one new compound trans‐3,4,3′,5′‐tetrahydroxy‐4′‐methylstilbene 4‐O‐β‐D‐xylopyranosyl‐(1→6)‐β‐D‐glucopyranoside ( 1 ), together with six known compounds (+)‐hinokiol ( 2 ), 6‐hydroxy‐5,7‐dimethoxycoumarin ( 3 ), caffeic acid ( 4 ), vanillic acid ( 5 ), 4‐hydroxy‐2,6‐dimethoxyphenol‐1‐O‐β‐D‐glucopyranoside ( 6 ) and 4‐allyl‐2,6‐dimethoxyphenol‐1‐O‐β‐D‐glucopyranoside ( 7 ), were isolated from the root bark of Elsholtzia bodinieri Van't. Their structures were determined on the basis of spectroscopic and chemical evidence.     

Megastigmane Glycosides from Docynia indica and Their Anti‐inflammatory Activities

Using various chromatographic methods, three new megastigmane glycosides, docynicasides A – C ( 1  –  3 ) and ten known, (6S,9R)‐vomifoliol 9‐O‐β‐d ‐xylopyranosyl‐(1′′→6′)‐O‐β‐d ‐glucopyranoside ( 4 ), hyperin ( 5 ), quercitrin ( 6 ), quercetin 3‐α‐l ‐arabinofuranoside ( 7 ), naringenin 7‐O‐β‐d ‐glucopyranoside ( 8 ), phloridzin ( 9 ), phloretin 2′‐O‐β‐d ‐xylopyranosyl‐(1→6)‐β‐d ‐glucopyranoside ( 10 ), pinosylvin 3‐O‐β‐d ‐glucopyranoside ( 11 ), tormentic acid ( 12 ), and chlorogenic acid methyl ester ( 13 ) were isolated from the fruits of Docynia indica. Their chemical structures were elucidated by physical and chemical methods. All the isolated compounds were evaluated for the inhibitory activity on NO production in LPS‐stimulated BV2 cells. As the results, compounds 3  –  5 showed significant inhibitory activity on LPS‐stimulated NO production in BV2 cells with the IC₅₀ values ranging from 21.0 to 29.3 μm .     

Constituents of the Whole Herb of Clinoponium laxiflorum

The isolation and identification of twenty‐two components (including one new compound) from the whole herb of Clinoponium laxiflorum (Hay) Matsum (Labiatae) are described. Their structures were determined on the basis of spectral and chemical transformation. One new compound is methyl rosmarinate. The other twenty‐one compounds include three steroids (α‐spinasterol, α‐spinasteryl‐3‐O‐β‐D‐glucopyranoside, and β‐sitosteryl‐3‐O‐β‐glucopyranoside), three triterpenes (oleanolic acid, ursolic acid, and betulinic acid), nine flavonoids (didymin, apigenin‐7‐O‐β‐glucopyranoside, luteolin‐7‐O‐β‐glucopyranoside, isosakuranetin, narigenin, apigenin, luteolin, narirutin, and hesperidin), three lignolic acids (rosmarinic acid, 3‐(3,4‐dihydroxyphenyl)lactic acid, and caffeic acid), and three phenols (4‐hydroxybenzaldehyde, 3,4‐dihydroxybenzaldehyde, and 3,4‐dihydroxybenzoic acid).     

1H and 13C NMR and X‐ray diffraction data for a diosgenyl N,O‐protected glucopyranoside

The assignments of ¹H and ¹³C NMR chemical shifts together with x‐ray diffraction data for synthesized diosgenyl 3,4,6‐tri‐O‐acetyl‐2‐deoxy‐2‐tetrachlorophthalimido‐β‐D ‐glucopyranoside are described. The structure of this glycoside was established by using homo‐ and heteronuclear two‐dimensional NMR techniques. X‐ray diffraction data for this compound are also reported. Copyright © 2002 John Wiley & Sons, Ltd.     

Water‐Soluble Constituents from the Liverwort Marchantia polymorpha

Four new glycosides, the bibenzyl glycoside α,β‐dihydrostilbene‐2,4′,5‐triol 2,5‐di‐(β‐D ‐glucopyranoside) ( 1 ), the shikimic acid glycoside shikimic acid 4‐(β‐D ‐xylopyranoside) ( 2 ), and two phenylethanoid glycosides 2‐(3,4‐dihydroxyphenyl)ethyl O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐allopyranoside ( 3 ) and 2‐(3,4‐dihydroxyphenyl)ethyl O‐β‐D ‐xylopyranosyl‐(1→6)‐β‐D ‐allopyranoside ( 4 ), together with three known aromatic glycosides were isolated from the H₂O‐soluble fraction of the EtOH extract of the liverwort Marchantia polymorpha. Their structures were elucidated on the basis of chemical and spectroscopic evidences.     

Target‐guided isolation of polar antioxidants from Abelmoschus esculentus (L). Moench by high‐speed counter‐current chromatography method coupled with wavelength switching and extrusion elution mode

An off‐line two‐dimensional high‐speed counter‐current chromatography strategy combined with the wavelength switching technique and extrusion elution mode was successfully developed and applied to the isolation of polar antioxidants from Abelmoschus esculentus (L).Moench. Target‐guided by the result of 2,2‐diphenyl‐1‐picrylhydrazyl screening assay, four antioxidants were obtained with purities over 90% through orthogonal high‐speed counter‐current chromatography separation. UV spectroscopy, mass spectrometry and ¹H NMR spectroscopy were employed to identify their structures, which were assigned as l ‐tryptophan, quercetin‐3‐O‐sophoroside, 5,7,3′,4′‐tetrahydroxyflavonol‐3‐O‐[β‐d ‐rhamnopyranosil‐(1→2)]‐β‐d ‐glucopyranoside, and quercetin‐3‐O‐glucoside. Each monomer exhibited significant antioxidant activity. The results demonstrated that proposed method could be an effective approach to isolate bioactive compounds from complex natural products.     

Separation of five compounds from leaves of Andrographis paniculata (Burm. f.) Nees by off‐line two‐dimensional high‐speed counter‐current chromatography combined with gradient and recycling elution

An off‐line two‐dimensional high‐speed counter‐current chromatography method combined with gradient and recycling elution mode was established to isolate terpenoids and flavones from the leaves of Andrographis paniculata (Burm. f.) Nees. By using the solvent systems composed of n‐hexane/ethyl acetate/methanol/water with different volume ratios, five compounds including roseooside, 5,4′‐dihydroxyflavonoid‐7‐O‐β‐d ‐pyranglucuronatebutylester, 7,8‐dimethoxy‐2′‐hydroxy‐5‐O‐β‐d ‐glucopyranosyloxyflavon, 14‐deoxyandrographiside, and andrographolide were successfully isolated. Purities of these isolated compounds were all over 95% as determined by high‐performance liquid chromatography. Their structures were identified by UV, mass spectrometry, and ¹H NMR spectroscopy. It has been demonstrated that the combination of off‐line two‐dimensional high‐speed counter‐current chromatography with different elution modes is an efficient technique to isolate compounds from complex natural product extracts.     

Preparative isolation of flavonoid compounds from Oroxylum indicum by high‐speed counter‐current chromatography by using ionic liquids as the modifier of two‐phase solvent system

A preparative high‐speed counter‐current chromatography method for isolation and purification of flavonoid compounds from Oroxylum indicum was successfully established by using ionic liquids as the modifier of the two‐phase solvent system. Two flavonoid compounds including baicalein‐7‐O‐diglucoside and baicalein‐7‐O‐glucoside were purified from the crude extract of O. indicum by using ethyl acetate–water–[C₄mim][PF₆] (5:5:0.2, v/v) as two‐phase solvent system. 36.4 mg of baicalein‐7‐O‐diglucoside and 60.5 mg of baicalein‐7‐O‐glucoside were obtained from 120 mg of the crude extract. Their purities were 98.7 and 99.1%, respectively, as determined by HPLC area normalization method. The chemical structures of the isolated compounds were identified by ¹H‐NMR and ¹³C‐NMR.     

Flavonoid Glycosides from the Leaves of Machilus philippinensis

Thirteen flavonoid glycosides ( 1‐7 , 11‐13 , 15 , 17 , and 18 ) were isolated from the EtOH extract of the leaves of Machilus philippinensis. Of these, kaempferol 3‐O‐(2‐O‐β‐D ‐apiofuranosyl)‐α‐L ‐rhamnopyranoside ( 1 ) and kaempferol 3‐O‐(2‐O‐β‐D ‐apiofuranosyl)‐a‐L ‐arabinofuranoside ( 2 ) are new natural products. By application of HPLC‐SPE‐NMR hyphenated technique, five additional flavonol glycosides were characterized ( 8‐10 , 14 , and 16 ). Their structures were elucidated based on spectroscopic analysis. Of these, quercetin 3‐O‐(6‐O‐α‐L ‐rhamnopyranosyl)‐β‐D ‐galactopyranoside ( 5 ) and kaempferol 3‐O‐α‐L ‐arabinopyranoside ( 15 ) showed moderate inhibitory activity against α‐glucosidase type IV from Bacillus stearothermophilus with the IC₅₀ values of 19.5 and 19.0 μM, respectively.     

Separation of α‐amylase inhibitors from Abelmoschus esculentus (L).Moench by on‐line two‐dimensional high‐speed counter‐current chromatography target‐guided by ultrafiltration‐HPLC

In this study, an on‐line two‐dimensional high‐speed counter‐current chromatography system based on a six‐port valve was developed. Target‐guided by ultrafiltration with high‐performance liquid chromatography, the one‐step isolation of three potential α‐amylase inhibitors from Abelmoschus esculentus (L).Moench was achieved by employing the developed orthogonal system and extrusion elution mode. The purities of three potential α‐amylase inhibitors were all over 95% as determined by high‐performance liquid chromatography. Furthermore, UV, mass spectrometry and ¹H NMR spectroscopy were applied to the structural identification of the isolated three target compounds, their structures were assigned as quercetin‐3‐O‐sophoroside (i), 5,7,3′,4′‐tetrahydroxy flavonol‐3‐O‐[β‐d ‐rhamnopyranosil‐(1→2)]‐β‐d ‐glucopyranoside (ii ) and isoquercitrin (iii), respectively. The Results demonstrated that the proposed method was highly efficient to screen and isolate enzyme inhibitors from complex natural products extracts, and on‐line two‐dimensional high‐speed counter‐current chromatography can effectively increase the peak resolution of target compounds.     

Analysis and retention behavior of isoflavone glycosides and aglycones in Radix Astragali by HPLC with hydroxypropyl‐β‐cyclodextrin as a mobile phase additive

In order to determine isoflavone glycosides (calycosin‐7‐O‐β‐d ‐glucoside and formononetin‐7‐O‐β‐d ‐glucoside) and aglycones (calycosin and formononetin), a simple HPLC method with isocratic elution employing hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) as a mobile phase additive was developed. Various factors affecting the retention of isoflavone glycosides and aglycones in the C₁₈ reversed‐phase column, such as the nature of cyclodextrins, HP‐β‐CD concentration, and methanol concentration, were systematically studied. The results show that HP‐β‐CD, as a very effective mobile phase additive, can markedly reduce the retention of isoflavone glycosides and aglycones, and the decrease magnitudes of isoflavone aglycones are more than those of their glycosides. The role of HP‐β‐CD in the developed HPLC method is attributed to the formation of the inclusion complexes between isoflavone glycosides (or aglycones) and HP‐β‐CD. So, the apparent formation constants of the isoflavone glycosides (or aglycones)/HP‐β‐CD inclusion complexes also were investigated. Isoflavone glycosides (and aglycones) form the 1:1 inclusion complexes with HP‐β‐CD, and the isoflavone aglycones/HP‐β‐CD complexes are more stable than the isoflavone glycosides/HP‐β‐CD complexes. Finally, the optimized method was successfully applied for the determination of isoflavone glycosides and aglycones in Radix Astragali samples.