Haixue Kuang

Chemical constituents from the flower of Datura metel L.

Phytochemical investigation of the 50% ethanol eluate fraction of macroporous resin for the flower of Datura metel L. led to the isolation of a new compound named yangjinhualine A (1) and five known megastigmane sesquiterpenes through repeated silica gel and ODS column chromatography and semipreparative HPLC. The structures of these compounds were determined by spectroscopic methods, including 2D-NMR, ESI-MS, and HR-ESI-MS spectrometry as well as by comparison with published data. Five known megastigmane sesquiterpenes were also isolated from D. metel L. for the first time.

Lignan constituents from Chloranthus japonicus Sieb.

A new coumarinolignan glucoside named yinxiancaoside C, along with five known benzofuran lignans, have been isolated from the whole plant of Chloranthus japonicus Sieb. The structures of compounds 1–6 were elucidated by chemical and spectroscopic methods including 1D-NMR, 2D-NMR, ESI-MS and HR-ESI-MS. Five known benzofuran lignans were firstly discovered in the Chloranthaceae. In addition, the cytotoxic activity of the isolated compounds against human hepatoma (Hepg-2), ovarian carcinoma (OV420), and breast cancer (MCF-7) cells was investigated by MTT method.

Quantitative analysis and chromatographic fingerprinting for the quality evaluation of Forsythia suspensa extract by HPLC coupled with photodiode array detector

A simple and reproducible HPLC-photodiode array detector method has been described for evaluating and controlling quality of Forsythia suspensa extract (FSE). First, by analysis of chromatographic fingerprints, the similarities of chromatograms of FSE samples from the same pharmaceutical company exceeded 0.999, 0.997 and 0.960, respectively, although they were much lower from different pharmaceutical companies. Second, by further comparing many batches of extract chromatograph charts with the corresponding reference herb materials, the common peaks 3, 5, 7 and 10 were defined as marker peaks, which were identified as (+)-pinoresinol-beta-D-glucoside, forsythiaside, phillyrin and phillygenin, respectively. Third, four marker peaks were simultaneously determined based on fingerprint chromatogram for further controlling the quality of FSE quantitatively. Namely, the newly developed method was successfully applied to analyze 38 batches of FSE samples supplied by three pharmaceutical factories, which showed acceptable linearity, intra-day precision (RSD<2.76%), inter-day precision (RSD<3.43%) and the average recovery rates in the range of (95.38+/-2.96)% to (101.60+/-3.08)%. At last, hierarchical clustering analysis and Bayes discriminant analysis statistical methods were used to classify and differentiate the 38 FSE samples to provide the basis for guiding reasonable use of FSE and controlling its quality better.

Baimantuoluosides D-G, four new withanolide glucosides from the flower of Datura metel L.

In our search for bioactive anti-psoriasis compounds from the flower of Datura metel L, we isolated four new withanolide glucosides, baimantuoluosides D, E, F and G (1–4). The structures of the new compounds are (5α,6α,7β,22R)-5,6,7,27-tetrahydroxy-1-oxowitha-2,24-dien-27-O-β-D-glucopyranoside (1), (5α,6β,7α,22R)-5,6,7,27-tetrahydroxy-1-oxowitha-2,24-dien-27-O-β-D-glucopyranoside (2), (5α,6β,7α,12β,22R)-5,6,7,12,27-pentahydroxy-1-oxowitha-2,24-dien-27-O-β-D-glucopyranoside (3), and (5α,6β,22R)-5,6,27-trihydroxy-1-oxowitha-2,24-dien-27-O-β-D-glucopyranoside (4) on the basis of chemical and physicochemical evidence.

Development and application of a rapid and efficient CZE method coupled with correction factors for determination of monosaccharide composition of acidic hetero-polysaccharides from Ephedra sinica

INTRODUCTIONnEphedrine alkaloids cannot account for all the effects of Ephedra sinica and the polysaccharides are also demonstrated to be one of the main bioactive constituents of E. sinica. However, no work has been reported on the analysis of monosaccharide composition of purified polysaccharides isolated from the stem of E. sinica.nnnOBJECTIVEnTo develop a rapid and efficient capillary zone electrophoresis (CZE) method based on pre-column derivatisation with 1-phenyl-3-methyl-5-pyrazolone for the simultaneous determination of neutral and acidic sugars of purified polysaccharides from E. sinica.nnnMETHODOLOGYnThree polysaccharides (ESP-A3, ESP-A4 and ESP-B4) were isolated and purified by ion exchange and gel-filtration chromatography from the stem of E. sinica. The effects of background electrolyte pH and concentration, applied voltage and temperature on the separation were investigated. Meanwhile, factors affecting the hydrolysis of ESP-B4 with sulphuric acid were investigated by changing the hydrolysis time, acid concentration and hydrolytic temperature to achieve complete hydrolysis. The standard curves coupled with correction factors were used to calculate molar ratios.nnnRESULTSnThe optimal CZE method coupled with correction factors was successfully applied to the determination of molar ratios of three purified polysaccharides and their corresponding partial acid hydrolysis products. ESP-A3, ESP-A4 and ESP-B4 were all typical acidic hetero-polysaccharides and consisted of xylose, arabinose, glucose, rhamnose, mannose, galactose, glucuronic acid and galacturonic acid, and their corresponding molar ratios were 6.8:7.5:1.0:14.0:13.7:22.3:10.2:3.8 for ESP-A3, 1.2:4.1:1.0:5.1:1.6:17.3:3.1:2.2 for ESP-A4, and 1.0:4.5:1.0:2.0:1.0:5.5:1.5:50.0 for ESP-B4.nnnCONCLUSIONnThe results provided scientific evidence for the further study of the structure and bioactivity of complex acidic E. sinica polysaccharides.

A strategy for characterization of triterpene saponins in Caulophyllum robustum hairy roots by liquid chromatography with electrospray ionization quadrupole time-of-flight mass spectrometry

Triterpene saponins are important bioactive constituents widely distributed in many plants. Saponins present in Caulophyllum (Berberidaceae) have not been fully characterized. In this study, we studied triterpene saponins from Caulophyllum robustum using liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry (LC-qTOF-MS). Rapid identification of Caulophyllum saponins was facilitated using low and high MS cone voltages to induce controlled fragmentation in positive mode. The full scan spectra at low cone voltage of 40V provided considerable structural information relating to aglycone skeletons, sugar types, and linked sequences for Caulophyllum saponins. Seven Caulophyllum aglycones were differentiated and identified by their diagnostic fragment ions combined with accurate mass measurements and characteristic fragmentation pathways. Peak intensity ratio of [aglycone+H-2H2O](+) to [aglycone+H-H2O](+) in full scan spectra acquired with low cone voltage is correlated with structural features of hederagenin and echinocystic acid and is useful for the discrimination of these positional isomers. However, at a high voltage of 200V, the saponin [M+H](+) ion and its fragmentation ions were not present; and the single saponin [M+Na](+) generated [Bα+Na](+) and [Y0α+Na](+) by in-source fragmentation, which provided structural information on the α- and β-sugar chains in the saponins. This approach enabled simultaneous acquisition of structural information on both aglycones and sugar chains from full scan spectra in one injection. Based on the developed strategy, 51 triterpene saponins of seven different classes were fully characterized or tentatively identified, of which 32 constituents were the first to be reported in genus Caulophyllum and 18 compounds were characterized as potentially new compounds.

Two new amide alkaloids from the flower of Datura metel L.

Two new amide alkaloids were isolated from the alkaloidal fraction of Datura metel L. Their structures were elucidated as (E)-methyl 4-(3-(4-hydroxyphenyl)-N-methylacrylamido) butanoate and 6,7-dimethyl-1-D-ribityl-quinoxaline-2,3(1H,4H)-dione-5-O-β-D-glucopyranoside on the basis of spectroscopic methods including HRESIMS, 1D and 2D NMR. Tropane alkaloids have for a long time been considered as characteristic ingredients of D. metel. However, the presence of amide alkaloids in D. metel was reported for the first time in this study.

A New Caffeoyl Phenylethanoid Glycoside from the Unripe Fruits of Forsythia suspensa

Abstract Aim To study the chemical constituents on the unripe fruits of Forsythia suspensa (Thunb.) Vahl in order to find new or biologically active components. Methods Compounds were isolated by repeated silica gel column and reversed-phase preparative high performance liquid chromatography. The structures were elucidated by spectroscopic methods, including 2D NMR and HRESIMS spectrometry as well as by comparison with published data. All the isolated compounds were examined for antibacterial activity against eight bacterial strains ( Staphylococcus aureus , Escherichia coli , Beta-hemolytic streptococci , Bacterium vulgare , Aeruginosus bacillus , Micrococcus pneumoniae , S. albus and B. dysenteriae ) in vitro by plate method. Results Five compounds were isolated from the unripe fruits of Forsythia suspensa , their structures were identified as phillygenin ( 1 ), (+)-isolariciresinol ( 2 ), phillyrin ( 3 ), forsythiaside ( 4 ) and lianqiaoxinside A ( 5 , 3, 4-dihydroxy- β -phenethyl- O -α- L -rhamnopyranosyl-(1→6)-3- O -caffeoyl-β- D -glucopyranoside). Conclusion Lianqiaoxinside A ( 5 ) is a new caffeoyl phenylethanoid glycoside, and the pharmacological screens eight bacterial strains in vitro disclosed that the principal antibacterial constituents from F. suspense were caffeyol phenylethanoid glycosides.

A new method for quantitative determination of two uronic acids by CZE with direct UV detection

A new method using capillary zone electrophoresis was developed for the rapid quantification of two common uronic acids, galacturonic acid and glucuronic acid, based on utilization of an alkaline background electrolyte with reversed electroosmotic flow (EOF) within 16u2009min. The method relies on in-capillary reaction and direct UV detection at the wavelength 270u2009nm. The optimum electrolyte solution was prepared of 130u2009mm sodium hydroxide, 36u2009mm disodium hydrogen phosphate dihydrate and 0.5u2009mm cetyltrimethylammonium bromide. EOF was reversed to detect uronic acids and to improve the separation of neutral sugars. The established method was validated and the results showed good linearity, high precision and satisfactory sensitivity. The newly developed method was successfully applied to analyze galacturonic acid and glucuronic acid content in Forsythia suspensa polysaccharides. The method is fast since only sample hydrolysis and dilution are required in the sample preparation.

Three new ursane-type triterpenes from the leaves of Rehmannia glutinosa

Three new ursane-type triterpenes, glutinosalactone A-C (1-3), were isolated from the 50% aqueous acetone extract of the leaves of Rehmannia glutinosa. Their structures were elucidated on the basis of spectral analysis (IR, NMR and MS spectroscopy). The cytotoxic effects of compounds 1-3 against three human cancer cell lines (MCF-7, MG63 and HepG2) were also evaluated. Compound 3 showed cytotoxic activities with IC50 values of 8.35-39.25 μM.