(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 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

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

AIMTo study the chemical constituents of Knoxia corymbosa Willd.

METHODSChromatography was used to isolate and purify the chemical constituents, their structures were identified by spectral analysis.

RESULTSFour flavonol glycosides were identified as quercetin-7-O-alpha-L-arabinosyl-3-O-beta-D-6"-acetylglucopyranoside (1), kaempferol-7-O-alpha-L-arabinosyl-3-O-beta-D-glucopyranoside (2), quercetin-3-O-beta-D-glucopyranoside (3), quercetin-3-O-beta-D-6"-acetylglucopyranoside (4).

CONCLUSIONCompound 1 is a new flavonol glycoside. The other flavonol glycosides were isolated from Knoxia corymbosa Willd for the first time.

Glucosides ; chemistry ; isolation & purification ; Molecular Conformation ; Molecular Structure ; Plants, Medicinal ; chemistry ; Quercetin ; analogs & derivatives ; chemistry ; isolation & purification ; Rubiaceae ; chemistry

OBJECTIVETo establish a method for the determination of quercetin-3-O-beta-D-glucopyranosyl-7-O-beta-D-gentiobioside in Semen Descurainiae.

METHODHPLC was used with self-made quercetin-3-O-beta-D-glucopyranosyl-7-O-beta-D-gentiobioside as reference substances.

RESULTThe average collection was 99.78%, RSD 2.4%.

CONCLUSIONThe method is appropriate for quality control of Semen Descurainiae.

Brassicaceae ; chemistry ; Chromatography, High Pressure Liquid ; Glucosides ; analysis ; Plants, Medicinal ; chemistry ; Quality Control ; Quercetin ; analogs & derivatives ; analysis ; Seeds ; chemistry

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

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 technical conditions of the extraction and purification of the active composition from Polygonum orientale and Crataegus pinnatifida Bge. in Hongye Xingtong soft capsules with the macroporous resin.

METHODThe orientm, isorientm and hyperoside were used as index to screen the five kinds of resins. And the technical conditions of the enrichment and purification of D101 resin selected out of above were all-round studied.

RESULTThe D101 was fit for adsorbing orientm, isorientm and hyperoside. Under the optimal conditions, the transfer rate of orientm, isorientm and hyperoside was above 91%, and the total solid was cut down by more than 60%.

CONCLUSIONThe D101 is greatly effective for the enrichment and purification of the active composition of P. orientale and C. pinnatifida Bge.

Crataegus ; chemistry ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Polygonum ; chemistry ; Quercetin ; analogs & derivatives ; chemistry ; isolation & purification ; Resins, Synthetic ; chemistry