(2S)-taxifolin is an important flavonoid that has anti-inflammatory and anti-oxidation effects. It is widely used in pharmaceutical and nutraceutical industries. Flavone 3-hydroxylase (F3H) can catalyze the synthesis of (2S)-taxifolin and other 3-hydroxylated flavonoids from (2S)-eriodictyol. Due to the low catalytic efficiency of F3H, the titer of many 3-hydroxyflavones, such as taxifolin, synthesized by microbial method is relatively low. In this study, a SmF3H was identified from the transcriptome of Silybum marianum (L.) Gaertn. The results of fermentation showed that SmF3H can catalyze the flavone 3-hydroxylation reaction, and its catalytic efficiency was significantly higher than that of commonly used SlF3H from Solanum lycopersicum. Six promoters with different transcription strength were selected to optimize the synthesis pathway from the flavonoid precursor (2S)-naringenin to (2S)-taxifolin. The results showed that the highest titer of (2S)-taxifolin (695.90 mg/L in shake flask) could be obtained when the P(GAL7) promoter was used to control the expression of SmF3H. The titer of (2S)-taxifolin was further improved to 3.54 g/L in a 5-L fermenter, which is the highest titer according to current available literatures.
Antioxidants ; Flavonoids ; Milk Thistle ; Quercetin/analogs & derivatives*

OBJECTIVETo develop an HPLC method for fingerprint study of both Senecio scandens and S. scandens.

METHODFingerprints of the two Senecio herbs were compared. And the concentrations of main peaks in them were semi-quantified as chlorogenic acid or hyperoside. Chromatography was performed on a Shiseido Capcell Pak MG II C18 (4.6 mm x 250 mm, 5 microm) column using a gradient elution of acetonitrile-water containing 0.2% acetic acid. And detection wavelength was 360 nm.

RESULTSignificant difference was found in the fingerprint of the two herbs. Eleven peaks were picked out for the evaluation of S. scandens and S. scandens, respectively. They were identified to be either organic acid compounds or flavones by HPLC-UV and LC-ESI-MS analysis. And semi-quantification of them showed the concentrations of organic acid compounds and flavones in S. scandens were 2.29- and 15.56- folds of those in S. scandens, respectively.

CONCLUSIONThe developed HPLC method is suitable for the fingerprint study for both of S. scandens and S. scandens. It is robust and producible enough to be used for the quality evaluation on S. scandens.

Chlorogenic Acid ; analysis ; Chromatography, High Pressure Liquid ; methods ; Quercetin ; analogs & derivatives ; analysis ; Senecio ; chemistry

OBJECTIVETo study the water soluble constituents from Amomum villosum.

METHODThe constituents were separated and purified with chromatographic methods, identified by NMR, MS, UV and IR.

RESULTTwo quercetin glycosides: quercitrin (quercetin-3-O-alpha-L-rhamnoside I) and isoquercitrin (quercetin-3-O-beta-D-glucoside II) were isolated and identified.

CONCLUSIONI and II were isolated for the first time from A. villosum.

Amomum ; chemistry ; Fruit ; chemistry ; Plants, Medicinal ; chemistry ; Quercetin ; analogs & derivatives ; chemistry ; isolation & purification

OBJECTIVETo investigate the chemical constituents from the aerial parts of Hyperricum monogynum.

METHODCompounds were isolated by various column chromatography and identified by spectral analysis.

RESULTTen compounds were isolated and identified as quercetin, quercitrin, hyperoside, rutin, (-)-epicatechin, 3,5-dihydroxy-1-methoxy-xanthone, 3,4-O-isopropylidenyl shikimic acid, shikimic acid, daucosterol, and oleanoic acid.

CONCLUSIONAll compounds were isolated from this plant for the first time.

Hypericum ; chemistry ; Plant Components, Aerial ; chemistry ; Plants, Medicinal ; chemistry ; Quercetin ; analogs & derivatives ; chemistry ; isolation & purification

OBJECTIVETo study the chemical constituents of the seeds of Cuscuta chinensis.

METHODThe separation was carried out by polyamide and silica gel chromatography, and the compounds were identified by means of physico-chemical and spectroscopic methods.

RESULTSEight compounds were isolated from the plant and identified as quercetin 3-O-beta-D-galactoside-7-O-beta-D-glucoside (I), quercetin 3-O-beta-D-apiofuranosyl-(1-->2)-beta-D-galactoside (II), hyperoside (III), isorhamnetin (IV), kaempferol (V), quercetin (VI), d-sesamin (VII) and 9(R)-hydroxy-d-sesamin (VIII).

CONCLUSIONCompounds IV and VII were isolated from Cuscuta for the first time, and I, II and VIII were characteristic constituents for this vegetable drug.

Cuscuta ; chemistry ; Flavonols ; Plants, Medicinal ; chemistry ; Quercetin ; analogs & derivatives ; chemistry ; isolation & purification ; Seeds ; chemistry

To investigate the chemical constituents from Commelina communis, fifteen compounds were separated and purified by silica gel, Sephadex LH-20, and ODS column chromatography, and semi-preparative HPLC. By analyses of NMR and MS data as well as their physical and chemical properties, the structures of these compounds were identified as chrysoeriol-7-O-beta-D-glucoside( 1), methyl gallate(2), p-coumaric acid(3), protocatechuic acid(4), caffeic acid(5), p-hydroxybenzoic acid(6), 2-phenethyl-beta-D-gly-cosidase(7) , rhaponticin(8) , (7S, 8R) -dihydrodehydrodiconiferyl alcohol-9-O-beta-D-glucoside (9), isovitexin (10) , isofurcatain (11), isorhamnetin-3-O-beta-D-glucoside(12) , quercetin-3-O-alpha-L-rhamnoside (13) , isoquercitrin (14) , and 1, 2-dihydro-6, 8-dime-thoxy-7-1-(3, 5-dimethoxy-4-hydroxyphenyl) -N1, N2-bis-[2-( 4-hydroxyphenyl) ethyl] -2, 3-naphthalene dicarboxamide (15). Compounds 2, 5-9, 11, 13 were obtained from the genus Commelina for the first time.
Caffeic Acids ; analysis ; Chromatography, High Pressure Liquid ; Commelina ; chemistry ; Glucosides ; analysis ; Hydroxybenzoates ; analysis ; Quercetin ; analogs & derivatives ; analysis

OBJECTIVETo find out the correlation between the content of taxifolin in Polygonum orientale and the storage time.

METHODHPLC was used to determine taxifolin. The chromatographic condition was as following: Diamonsil C18 column (4.6 mm x 200 mm, 5 microm), mobile phase acetonitrile -0.1% phosphoric acid (gradient elution), the detection wavelength 290 nm and flow rate 1.0 mL x min(-1), the column temperature 30 degrees C.

RESULTThe injection volume of taxifolin was in good linearity within 0.07 and 0.35 microg, the average recovery was 99.7% with RSD 0.2%. Taxifolin content was 0.84, 1.36, 1.75, 1.99 mg x g(-1) corresponding to storage time of 10, 7, 6, 5 years, respectively.

CONCLUSIONThe content of taxifolin decreased with the storage time. When the storage period is more than six years, the content is lower than that required by Chinese Pharmacopoeia (2010 version). This method has a good repeatability and accuracy, it provides a scientific reference for clinical use and quality evaluation of P. orientale.

Chromatography, High Pressure Liquid ; Drug Stability ; Drug Storage ; methods ; Drugs, Chinese Herbal ; analysis ; Polygonum ; chemistry ; Quercetin ; analogs & derivatives ; analysis

In this study, a rapid and sensitive analytical method was developed for the determination of 10 major compounds (procyanidin B1, catechin, procyanidin B2, rutin, isoquercitrin, kaempferol-3-O-rutinoside, astragalin, quercitrin, quercetin, and kaempferol) in Tetrastigma hemsleyanum by using ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC-MS/MS) in multiple-reaction monitoring (MRM) mode. UPLC-MS/MS assay with negative ion mode was performed on a Waters CORTECS C18 (2.1 mm x 100 mm, 1.6 μm) with the mobile phase consisting of acetonitrile (A) and 0.1% aqueous formic acid (B) in gradient elution at a flow rate of 0.25 mL · min(-1) and the column temperature was set at 45 °C. Under the optimized chromatographic conditions, good separation for 10 target compounds were obtained including chiral isomer procyanidins B1 and B2 were completely separated within 8.5 min. Satisfactory linearity was achieved with wide linear range and fine determination coefficient (r > 0.996 6), the overall recoveries were ranged from 95.44%-110.40% with the RSD ranging from 2.37%-8.69%. It is the first report about simultaneous analysis of 10 major flavonoids components in Tetrastigma hemsleyanum by using UPLC-MS/MS method, which affords highly sensitive, specific, speedy and efficient method for quality control of Tetrastigma hemsleyanum
Acetonitriles ; Chromatography, High Pressure Liquid ; Flavonoids ; chemistry ; Kaempferols ; Quercetin ; analogs & derivatives ; Rutin ; Tandem Mass Spectrometry ; Vitaceae ; chemistry

OBJECTIVETo establish an HPLC method for determination the contents of quercitrin in Polygonum capitatum and Relinqing granules.

METHODThe samples were analyzed on a Diamonsil C18 colunm (4.6 mm x 250 mm, 5 microm) eluted with the mobile phase consisted of methanol-1% HAc-THF. The flow rate was 1.0 mL x min-m. The detection wavelength was set at 258 nm and the column temperature was 25 degrees C.

RESULTThe calibration curve was linear in the range of 0. 081 64-0.4084 microg (r = 0.99997). The average recovery rate of quercitrin in P. capitatum was 102.3% (RSD 0.99%), and was 102.7% (RSD 2.2%) in Relinqing granules.

CONCLUSIONThe method is reliable and specific with good repeatability, and can be used for the quality control of P. capitatum and Relinqing granules. It can provide a science bases for the planting of polygonum capitatum.

Chromatography, High Pressure Liquid ; methods ; Drugs, Chinese Herbal ; analysis ; chemistry ; Polygonum ; chemistry ; Quercetin ; analogs & derivatives ; analysis ; chemistry ; Reproducibility of Results

OBJECTIVETo study the flavonoid constituents in fresh herb of Houttuynia cordata.

METHODVarious column packing materials including Diaion HP - 20, Sephadex LH - 20, ODS and silica gel were employed for the isolation and purification of compounds from H. cordata. The structures of the compounds were identified by physiochemical properties and spectral analysis.

RESULTFive compounds were isolated, and their structures were identified as quercetin-3-O-beta-D-galactoside-7-O-beta-D-glucoside (1), kaempferol-3-O-alpha-L-rhamnopyranosyl-(1 --> 6)-beta-D-glucopyranoside (2), quercitrin (3), hyperin (4), quercetin 3-O-alpha-L-rhamnopyranosyl-7-O-beta-D-glucopyranoside (5).

CONCLUSIONCompounds 1, 2 and 5 were separated from H. cordata for the first time.

Flavonoids ; chemistry ; isolation & purification ; Glycosides ; chemistry ; isolation & purification ; Houttuynia ; chemistry ; Plants, Medicinal ; chemistry ; Quercetin ; analogs & derivatives ; chemistry ; isolation & purification