Myricetin and its glycosides are important flavonols commonly found in plants, and they are natural organic compounds with diverse pharmacological activities. Numerous studies have demonstrated that myricetin and its glycosides are strong antioxidants that have great potential in preventing, alleviating and assisting the treatment of chronic non-infectious diseases such as cancer, diabetes, and cardiovascular diseases. In addition, myricetin and its glycosides also have antiviral, antibacterial, anti-inflammatory, analgesic, liver protection and other pharmacological activities. Myricetin contains more hydroxyl groups in the parent ring structure than other flavonoids, so myricetin and its glycosides have stronger pharmacological activities than other flavonols or flavonoids such as quercetin and kaempferol. Therefore, myricetin and its glycosides have great development and application prospects. In this paper, the classification and distribution of myricetin and its glycosides, their pharmacological activity and mechanism, as well as comparison with other flavonoids were reviewed. In addition, limitations of the current research and application of myricetin and its glycosides were analyzed, and the further studies on pharmacological activities as well as their dose-activity relationship, structure-activity relationship, chemical modification, biosynthesis and application prospects of myricetin and its glycosides were discussed and proposed.
Flavonoids ; Flavonols ; Glycosides ; Quercetin

OBJECTIVETo establish the quality control standard of Xindi soft capsule.

METHODQuercetin, kaempferol and isorhamnetin were isolated by TLC with chloroform-ethyl formate-formic acid (5:4:1). The chromatographic separation was performed on a Diamonsil C18 column (4.6 mm x 250 mm, 5 microm). Acetonitrile-water-phosphoric (30:70:0.1) as mobile phase. The flow rate was 1 mL x min(-1) and column temperature was set at 40 degrees C. The UV detection wavelength was set at 254 nm.

RESULTQuercetin, Kaempferol and Isorhamnetin could be identified by TLC. Quercetin showed a good linear relationship at a range of 0.412-1.648 microg, r = 0.999 9, the average recovery was 96.8%, and RSD was 0.9% (n = 6). Kaempferol showed a good linear relationship at a range of 0.021-0.083 microg, r = 0.999 8, the average recovery was 96.9%, and RSD was 2.0% (n = 6). Isorhamnetin showed a good linear relationship at a range of 0.183-0.732 microg, r = 0.999 9, the average recovery was 97.1%, and RSD was 1.6% (n = 6).

CONCLUSIONThe method is accurate with the good reproducibility and can be used for the quality control of Xindi soft capsule.

Capsules ; Chromatography, Thin Layer ; Drugs, Chinese Herbal ; administration & dosage ; chemistry ; isolation & purification ; standards ; Flavonols ; analysis ; Hippophae ; chemistry ; Kaempferols ; analysis ; Plants, Medicinal ; chemistry ; Quality Control ; Quercetin ; analysis ; Reproducibility of Results

OBJECTIVETo establish a RP-HPLC method for simultaneous determination of total quercetin, kaempferol and isorhamnetin in rat plasma after oral administration of Folium Mori extract (FME).

METHODSAfter a single dose of FME (110 mg/kg) was taken, rat plasma samples were collected. The samples were hydrolyzed with hydrochloric acid (c=3.0 mol/L), the mixed solution was extracted with ether acetone mixture. The total quercetin, kaempferol and isorhamnetin in plasma samples were determined by HPLC, pharmacokinetic parameters were calculated by DAS 3.0 software.

RESULTSThe method was linear over the concentration ranges of 0.0545-8.70, 0.0954-14.7 and 0.0545-8.55 μg/ml for quercetin, kaempferol and isorhamnetin, respectively (r=0.9979, 0.9993, 0.9981). The absolute recoveries were 85.3%-86.1%, 79.4%-86.7% and 62.8%-89.7%, respectively and the assay recoveries were all from 94.7% to 107%. The relative standard deviation (RSD) of intra-and inter-day were less than 9.5% and 9.8%, respectively. The main pharmacokinetic parameters were as follows: T(1/2z) was 92.7, 67.9 and 54.2 h; Tmax was 0.400, 0.400 and 3.87 h; AUC(0-∞) was 68.0, 67.5 and 32.8 mg/h/L; MRT(0-∞) was 128, 85.2 and 72.0 h for quercetin, kaempferol and isorhamnetin, respectively.

CONCLUSIONThe method established in this study is accurate, reliable and reproducible, and can be applied for determination of total quercetin, kaempferol and isorhamnetin in rat plasma after oral administration of FME; the pharmacokinetic studies showed that the distribution of drugs is rapid and elimination is very slow.

Administration, Oral ; Animals ; Chromatography, High Pressure Liquid ; methods ; Flavonols ; blood ; pharmacokinetics ; Kaempferols ; blood ; pharmacokinetics ; Male ; Plant Extracts ; pharmacokinetics ; Quercetin ; blood ; pharmacokinetics ; Rats ; Rats, Sprague-Dawley

OBJECTIVEStudy on the of content variety of flavonoids in the course of processing Cortex Moutan,and discuss the preparation mechanism of Cortex Moutan Carbonisatum (CMC).

METHODHPLC method was developed for the determination of flavonoids in various extent of CMC, the sample was extracted by ultrasound 30 min twice along with ethanol 50 mL. Chromatographic conditions were as follows: wavelength 360 nm, gradient eluant of methanol--0.5% per hundred trifluoroacetic acid.

RESULTThe content of the three flavonoids cuts down along with the processing time and the rising temperature.

CONCLUSIONThe impact of various extent of processing on flavonoids content of the CMC is very great. The overall trend is that high temperature and long time lead to the lower of the content of flavonoids. This provides a basis data for the further study on the hemostatic mechanism and quality control of CMC.

Chromatography, High Pressure Liquid ; Drugs, Chinese Herbal ; chemistry ; Flavonoids ; chemistry ; isolation & purification ; Flavonols ; chemistry ; isolation & purification ; Kaempferols ; chemistry ; isolation & purification ; Paeonia ; chemistry ; Quercetin ; chemistry ; isolation & purification ; Temperature

A new flavonol derivative, meliglabrin (1) along with three known flavonols, ternatin (2), meliternatin (3), and 5,4′-dihydroxy-3,7,3′-trimethoxyflavon (4) were isolated from the leaves of Melicope glabra (Blume) T.G. Hartley. Their structures were determined using extensive spectroscopic methods, including UV, IR, HRESIMS, 1D and 2D NMR. Compounds 1 – 4 were evaluated for their cytotoxicity against murine leukemia P-388 cells, compound 4 showed moderate activity.
Flavonols ; Leukemia ; Rutaceae

To study the chemical constituents of the traditional Chinese herb Baeckea Frutescens L., a new flavonol glycoside, named 6, 8-dimethylkaempferol-3-O-alpha-L-rhamnoside (1), together with seven known compounds: quercetin (2), quercetin-3-O-alpha-L-rhamnoside (3), myricetin (4), myricetin-3-O-alpha-L-rhamnoside (5), gallic acid (6), ursolic acid (7) and 1,3-dihydroxy-2-(2'-methoxylpropionyl)-5-methoxy-6-methylbenzene (8) were isolated by using silica gel column chromatography, polyamide column chromatography and recrytallization. Their structures were identified on the basis of physicochemical properties and spectroscopic analysis. Among them, compounds 2-7 were isolated from this plant for the first time and compound 8 was first isolated from plant.
Flavonoids ; chemistry ; isolation & purification ; Flavonols ; chemistry ; isolation & purification ; Glycosides ; chemistry ; isolation & purification ; Kaempferols ; chemistry ; isolation & purification ; Molecular Structure ; Myrtaceae ; chemistry ; Plants, Medicinal ; chemistry ; Quercetin ; chemistry ; isolation & purification ; Toluene ; analogs & derivatives ; chemistry ; isolation & purification ; Triterpenes ; chemistry ; isolation & purification

AIMTo develop a method for assaying Ginkgo flavones in rat hepatical microsome.

METHODSQuercetin, isorhamnetin and keampferol were added to microsome incubate and incubated for a given time then extracted with ether-acetone. After evaporated, the residue was reconstituted with 100 microL of phosphate buffer solution (pH 2.0)-tetrahydrofuran-methanol-isopropanol (60:15:10:20). An aliquot of 20 microL was injected into the HPLC system. According to the result of estimate by means of HPLC, the results of metabolism of Ginkgo flavones in different conditions was compared.

RESULTSThe assay was linear over the rang of 0.2-8 mg.L-1 for Ginkgo flavones. The limit of quantification was 0.1 mg.L-1 (n = 3). The recoveries of three components of Ginkgo flavones were 99.9%-113.8% for quercetin (RSD < 0.8%), 100.8%-117.3% for isorhamnetin (RSD < 1.9%) and 100.7%-116.5% for keampferol (RSD < 1.03%, n = 5).

CONCLUSIONThe method is simple, fast and accurate. It can be used for investigation of the metabolism of Ginkgo flavones.

Animals ; Chromatography, High Pressure Liquid ; Flavonols ; isolation & purification ; metabolism ; Ginkgo biloba ; chemistry ; In Vitro Techniques ; Kaempferols ; isolation & purification ; metabolism ; Microsomes, Liver ; metabolism ; Plant Leaves ; chemistry ; Plants, Medicinal ; chemistry ; Quercetin ; isolation & purification ; metabolism ; Rats

OBJECTIVETo investigate the chemical constituents in the ethyl acerate extract of Lysimachia fortunei.

METHODThe compounds were isolated by silica gel chromatography, and their structures were elucidated by NMR data and references.

RESULTNine natural constituents were isolated, and their structures were identified as 9, 19-cyclolanost-24-en-3-one (1), 24-ethyl-5alpha-cholesta-7, 22(E)-dien-3-one (2), 1-pentatriacontanol (3), beta-stigmasterol (4), 24-ethyl-5alpha-cholesta-7, 22(E)-dien-3beta-ol (5), palmitic acid (6), isorhamnetin (7), kaempferol (8) and quercetin (9) respectively.

CONCLUSIONAll compounds mentioned above were isolated from this plant for the first time, and compound 1, 2 and 5 were obtained from the genus for the first time.

Cholestadienes ; chemistry ; isolation & purification ; Flavonols ; chemistry ; isolation & purification ; Kaempferols ; chemistry ; isolation & purification ; Palmitic Acid ; chemistry ; isolation & purification ; Plants, Medicinal ; chemistry ; Primulaceae ; chemistry ; Quercetin ; analogs & derivatives ; Triterpenes ; 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

Chemical constituents were isolated and purified from the water extract of Artemisia annua by column chromatography of HP-20 macroporous resin, silica gel, ODS, Sephadex LH-20, HW-40, and semi-preparative RP-HPLC. Their structures were elucidated by physicochemical properties and spectral analyses. As a result, Fifteen compounds were isolated and identified as vitexnegheteroin M(1), sibricose A5(2), securoside A(3), citrusin D(4), annphenone(5), E-melilotoside(6), esculetin(7), scopoletin-7-O-β-D-glucoside(8), eleutheroside B_1(9), chrysosplenol D(10), patuletin-3-O-β-D-glucopyranoside(11), quercetin-7-O-β-D-glucoside(12), rutin(13), apigenin 6,8-di-C-β-D-glucopyranoside(14), isoschaftoside(15), among them, compounds 1-4 were identified from Artemisia for the first time. Additionally, the isolates were evaluated for their inhibitory effects on the production of PGE_2 in LPS-simulated RAW264.7 macrophages. The results showed that compounds 1, 2, 8, and 10-15 could reduce PGE_2 levels, to a certain extent.
Apigenin ; Artemisia annua ; Quercetin ; Rutin