hyperoside and isoquercitrin

Quercetin, one of the most abundant flavonoids in plant-based foods, commonly occurs in nature in various glycosylated forms. There is still a less explored aspect regarding the cause of diversity of its glycosides, depending on the sugar moiety attached. This work focuses on four wide-spread quercetin glycosides-hyperoside, isoquercitrin, quercitrin and rutin-by testing the property-tuning capacity of different sugar moieties and thus explains and predicts some of their functions in plant-based foods. The electron paramagnetic spectra of the semiquinone anion radicals of these glycosides were interpreted in terms of hyperfine coupling constants and linewidths, highlighting a clear link between spin density trends, the identity of the bound sugar, and their reactivity corroborated with their modelled structures. Redox potential and lipophilicity were connected to a specific flavonoid-enzyme interaction and correlated with their prooxidant reactivity assessed by oxidation of ferrous hemoglobin. Hyperoside and isoquercitin-galactose and glucose glycosides-exhibit the highest prooxidant reactivity owing to their lowest redox potential and lipophilicity whereas rutin and quercitrin-rutinose and rhamnose glycosides-behave vice versa. The ability of the tested glycosides to undergo HAT or SET-type reactions has also been tested using five different analytical assays, including inhibition of cytochrome c-triggered liposome peroxidation. In most cases, rutin proved to be the most unreactive of the four tested glycosides considering either steric or redox reasons whereas the reactivity hierarchy of the other three glycosides were rather assay dependent.

Topics: Antioxidants; Electron Spin Resonance Spectroscopy; Electrons; Free Radical Scavengers; Glycosides; Hydrogen; Lipids; Oxidants; Oxidation-Reduction; Quercetin; Rutin

As the interest in heirloom cultivars of apple trees, their fruit, and processed products is growing worldwide, studies of the qualitative and quantitative composition of biological compounds are important for the evaluation of the quality and nutritional properties of the apples. Studies on the variations in the chemical composition of phenolic compounds characterized by a versatile biological effect are important when researching the genetic heritage of the heirloom cultivars in order to increase the cultivation of such cultivars in orchards. A variation in the qualitative and quantitative composition of phenolic compounds was found in apple samples of cultivars included in the Lithuanian collection of genetic resources. By the high-performance liquid chromatography (HPLC) method flavan-3-ols (procyanidin B1, procyanidin B2, procyanidin C2, (+)-catechin and (-)-epicatechin), flavonols (rutin, hyperoside, quercitrin, isoquercitrin, reynoutrin and avicularin), chlorogenic acids and phloridzin were identified and quantified in fruit samples of heirloom apple cultivars grown in Lithuania. The highest sum of the identified phenolic compounds (3.82 ± 0.53 mg/g) was found in apple fruit samples of the 'Koštelė' cultivar.

Topics: Biflavonoids; Catechin; Chlorogenic Acid; Chromatography, High Pressure Liquid; Dietary Supplements; Flavonoids; Fruit; Glycosides; Lithuania; Malus; Phenols; Phlorhizin; Proanthocyanidins; Quercetin; Rutin

As a continuation of investigating

Topics: Antioxidants; Flavonoids; Galactosides; Impatiens; Kaempferols; Monosaccharides; Phenols; Plant Components, Aerial; Plant Extracts; Poland; Quercetin

Walnut (Juglans regia L.) is an abundant source of polyphenols. Although phenolic species in the walnut kernel have been studied comprehensively, their compositional profile in the internal fruit septum, a traditional nutraceutical material in China, has been rarely explored. In the current study, the methanolic extract of the walnut septum was analysed by Ultra-performance liquid chromatography coupled with Orbitrap mass spectrometry. Totally seventy-five phenolics belonging to flavonoids, tannins and phenolic acids were identified based on mass spectra, references and literatures. Among them, quercetin-3-O-galactoside, quercetin-rhamnose-pentoside, quercetin-3-O-glucoside, quercetin-rhamnose-hexoside, kaempferol-rhamnoside, and two isomers of quercetin-rhamnoside were reported for the first time in walnut. The total polyphenol content was found to be 122.78 ± 2.55 mg GAE/g dry weight in septum. This study is the first to comprehensively investigate and identify phenolic compounds in the fruit septum of walnut and indicates that the septum to be a rich resource of polyphenols.

Topics: China; Chromatography, Liquid; Dietary Supplements; Flavonoids; Fruit; Glucosides; Juglans; Mass Spectrometry; Nuts; Phenols; Polyphenols; Quercetin

Dried achene or anthocarpous accessory fruits of Rosa multiflora Thunb., Rosae fructus ("Eijitsu" in Japanese), have been used in clinical practice to improve constipation within traditional Japanese medicine. Recently, it has been claimed that the efficacy of this crude drug is decreasing, and multiflorin A, the purgative component, was not detected within the tested samples. In order to clarify the causes of this issue, we investigated Rosa section Synstylae (Rosaceae), including R. multiflora, growing in Japan and South Korea with a focus on the secondary metabolite, multiflorin A. We recognize that there are two chemotypes based on the presence (Type I) or absence (Type II) of multiflorin A. Type I contains quercitrin, multinoside A, multiflorin B, and multinoside A acetate as major index compounds. Type II contains hyperin, isoquercitrin, quercetin 3-O-glucuronide, and 3'-methoxy-isoquercitrin as the major index compounds. The chemotype of Rosa section Synstylae (Rosaceae) plants collected in Japan (excluding Tsushima Island) were all classified as Type I with exception of two species, R. luciae and R. sambucina. On the other hand, both Type I and Type II were detected within Rosae fructus obtained from R. multiflora collected in South Korea and Tsushima Island, Japan. The results indicate that Rosae fructus from R. multiflora (Type I) from Japan, excluding Tsushima Island, should be employed clinically, which we describe as purgative.

Topics: Chromones; Flavonols; Fruit; Glycosides; Japan; Medicine, Traditional; Phytochemicals; Quercetin; Republic of Korea; Rosa

Abelmoschus manihot (L.) Medic., a folk herbal medicine in China, is a flowering plant belonging\ to Abelmoschus L. genus and Malvaceae family, which has been reported with an antidepressant activity. The\ study was designed to isolate flavonoids from Abelmoschus manihot corolla and explore the action mechanism\ of antidepressant activities. The flavonoids were isolated and purified by D101 macroporous resin column,\ polyamide column and Sephadex LH-20 sequentially and identified as myricetin-3-O-β-D-glucoside (1),\ gossypetin-8-O-β-D-glucuronide (2, G-8-G), gossypetin-3'-O-β-D-glucoside (3), quercetin-3'-glucoside (4, Q-3-G),\ isoquercitrin (5, IQT), hyperoside (6, HY), myricetin (7), quercetin (8, QT). Compounds 2, 4, 5, 6 and 8\ (15, 30 and 60 mg·kg−1) were orally administered to mice and the reaction was observed in tail suspension\ test (TST) and forced swimming test (FST). Western blot analysis was used in determination of the protein\ expressions of brain-derived neurotrophic factor (BDNF), tyrosine receptor kinase B (TrkB) and phosphorylation\ eukaryotic elongation factor 2 (p-eEF2). The results revealed that only Q-3-G and G-8-G (15, 30, 60 mg ·kg−1)\ significantly reduced the immobility time in FST and TST. Furthermore, Q-3-G and G-8-G remarkably increased\ the expression of BDNF and TrkB, and decreased the expression of p-eEF2. These results suggest that\ Q-3-G and G-8-G had an obvious antidepressant activity via up-regulation of BDNF expression. The\ new observation will provide a new direction in the development of antidepressant in the treatment of major depressive\ disorder (MDD).

Topics: Abelmoschus; Animals; Antidepressive Agents; Brain-Derived Neurotrophic Factor; China; Depressive Disorder, Major; Drugs, Chinese Herbal; Ethanol; Flavonoids; Hindlimb Suspension; Hippocampus; Mice; Plant Extracts; Quercetin; Swimming; Up-Regulation

The high-performance liquid chromatography fingerprint method is a simple and reliable technique to evaluate the quality of leaves of Magnolia officinalis Rehd.et Wils. var. biloba Rehd.et Wils. We used the following bioactive phenolic constituents as reference compounds: rutin, afzelin, hyperoside, isoquercitrin, quercetin-3-O-α-l-rhamnoside, honokiol and magnolol. The conditions of an Agilent 1200 HPLC were: YMC-Pack-ODS-AQ column (250 × 4.6 mm id S-5 μm, 12 nm), mobile phase acetonitrile and 0.2% phosphoric acid in a gradient elute mode, flow rate 1.0 mL/min, detection wavelength 280 nm and column temperature 30°C. The analytical method was validated in terms of linearity, stability, repeatability, precision and recovery tests. While performing fingerprint analysis, we identified 11 peaks as characteristic peaks and assessed the similarities of 17 samples collected from different geological regions of China. The peak areas were used to evaluate the variation in the chemical composition of the tested samples. For this purpose, we performed hierarchical cluster analysis of the peak areas. Our results indicate that simultaneous determination of multiple ingredients could be done through chromatographic fingerprint analysis. Therefore, this high-performance liquid chromatography fingerprint method was readily utilized to evaluate the quality of leaves of M. officinalis var.biloba, which are used in several traditional herbal preparations.

Topics: Biphenyl Compounds; China; Chromatography; Chromatography, High Pressure Liquid; Glucosides; Lignans; Magnolia; Mannosides; Phenols; Plant Extracts; Plant Leaves; Proanthocyanidins; Quercetin; Reference Values; Reproducibility of Results; Rutin; Temperature

A simple, inexpensive and efficient method based on the mixed cloud point extraction (MCPE) combined with high performance liquid chromatography was developed for the simultaneous separation and determination of six flavonoids (rutin, hyperoside, quercetin-3-O-sophoroside, isoquercitrin, astragalin and quercetin) in Apocynum venetum leaf samples. The non-ionic surfactant Genapol X-080 and cetyl-trimethyl ammonium bromide (CTAB) was chosen as the mixed extracting solvent. Parameters that affect the MCPE processes, such as the content of Genapol X-080 and CTAB, pH, salt content, extraction temperature and time were investigated and optimized. Under the optimized conditions, the calibration curve for six flavonoids were all linear with the correlation coefficients greater than 0.9994. The intra-day and inter-day precision (RSD) were below 8.1% and the limits of detection (LOD) for the six flavonoids were 1.2-5.0 ng mL(-1) (S/N=3). The proposed method was successfully used to separate and determine the six flavonoids in A. venetum leaf samples.

Topics: Apocynum; Cetrimonium; Cetrimonium Compounds; Chromatography, High Pressure Liquid; Flavonoids; Hydrogen-Ion Concentration; Kaempferols; Plant Extracts; Plant Leaves; Polyethylene Glycols; Quercetin; Rutin; Surface-Active Agents

It is evident from various epidemiological studies that consumption of fruits and vegetables is essential to maintain health and in the disease prevention. Present study was designed to examine phenolic contents and antioxidant properties of three varieties of Crataegus pinnatifida (Chinese hawthorn). Shanlihong variety exhibited elevated levels of total phenolics and flavonoid contents, including free and bond phenolics. Procyanidin B2 was most abundant phenolic compound in all samples, followed by epicatechin, chlorogenic acid, hyperoside, and isoquercitrin. The free ORAC values, and free hydro-PSC values were 398.3-555.8 μmol TE/g DW, and 299.1-370.9 μmol VCE/g DW, respectively. Moreover, the free cellular antioxidant activity (CAA) values were 678-1200 μmol of QE/100 g DW in the no PBS wash protocol, and 345.9-532.9 μmol of QE/100 g DW in the PBS wash protocol. C. pinnatifida fruit could be valuable to promote consumer health.

Topics: Antioxidants; Biflavonoids; Catechin; Chlorogenic Acid; Crataegus; Drug Evaluation, Preclinical; Flavonoids; Fruit; Glycosides; Hep G2 Cells; Humans; Oxidation-Reduction; Phenols; Plant Extracts; Proanthocyanidins; Quercetin

Quercetin is a plant-derived flavonoid and its cytotoxic properties have been widely reported. However, in nature, quercetin predominantly occurs as various glycosides. Thus far the cytotoxic activity of these glycosides has not been investigated to the same extent as quercetin, especially in animal models. In this study, the cytotoxic properties of quercetin (1), hyperoside (quercetin 3-O-galactoside, 2), isoquercitrin (quercetin 3-O-glucoside, 3), quercitrin (quercetin 3-O-rhamnoside, 4), and spiraeoside (quercetin 4'-O-glucoside, 5) were directly compared in vitro using assays of cancer cell viability. To further characterize the influence of glycosylation in vivo, a novel zebrafish-based assay was developed that allows the rapid and experimentally convenient visualization of glycoside cleavage in the digestive tract. This assay was correlated with a novel human tumor xenograft assay in the same animal model. The results showed that 3 is as effective as 1 at inhibiting cancer cell proliferation in vivo. Moreover, it was observed that 3 can be effectively deglycosylated in the digestive tract. Collectively, these results indicate that 3 is a very promising drug candidate for cancer therapy, because glycosylation confers advantageous pharmacological changes compared with the aglycone, 1. Importantly, the development of a novel and convenient fluorescence-based assay for monitoring deglycosylation in living vertebrates provides a valuable platform for determining the metabolic fate of naturally occurring glycosides.

Topics: Animals; Flavonoids; Glucosides; Glycosides; Glycosylation; HCT116 Cells; Humans; Molecular Structure; Quercetin; Structure-Activity Relationship; Vertebrates; Zebrafish

The aim of our study was to explore variation peculiarities of qualitative and quantitative composition of phenolic compounds in leaf samples of rowan (Sorbus aucuparia L.) plants growing in natural habitats of Lithuania during their growth season using the HPLC method. In rowan leaf samples, collected during different phenological stages, qualitative and quantitative estimation of neochlorogenic acid, chlorogenic acid, caffeic acid, hyperoside, isoquercitrin, rutin, astragalin, ( - )-epicatechin, procyanidin B1 and procyanidin B2 was performed. Analysis of the qualitative and quantitative composition of phenolic compounds in ethanol extracts of leaf samples of S. aucuparia growing in natural habitats of Lithuania revealed a close relationship between the content of phenolic compounds in S. aucuparia raw plant material and different growth stages.

Topics: Antioxidants; Biflavonoids; Catechin; Chlorogenic Acid; Chromatography, High Pressure Liquid; Lithuania; Phenols; Plant Leaves; Proanthocyanidins; Quercetin; Seasons; Sorbus

Laetia suaveolens, known as "casinga-cheirosa", crude extract EB719 has previously shown cytotoxic activity against prostate cancer and squamous cell carcinoma. For the first time, seven molecules were isolated from its apolar-α-tocopherol (1) and sitosterol (2)-and polar-3-O-caffeoylquinic acid (3), 4-O-caffeoylquinic acid (4), 5-O-feruloylquinic acid (5), hyperoside (6), and isoquercitrin (7)-fractions. Acute toxicity was determined in a two-stage experiment: (1) a reduced number of Balb-c male mice received 5000 mg/kg of EB719 to allow evaluation of general activity and other 27 parameters, plus death, up to the establishment of non-lethal dose (NLD), as well as lethal dose 50% (LD50); (2) NLD was administered and diazepam introduced as reference drug. EB719 showed LD50=178.0 mg/kg, and NLD 156.3 mg/kg. In stage one EB719 did not influence general activity, but provoked impairment in grasp reflexes, tail squeeze and breathing; piloerection and cyanosis were increased. In stage two, alterations occurred in auricular reflex, piloerection and breathing after diazepam administration, but not in response to EB719. Intestinal hemorrhage caused by local bleeding was observed after necropsy, and may be the main cause of animals' death other than a systemic effect of the extract. Although the isolated compounds are biologically and pharmacologically active in both men and animal systems, it is premature to relate their occurrence in EB719 to the observed intestine hemorrhage in mice.

Topics: alpha-Tocopherol; Animals; Body Weight; Diazepam; Gastrointestinal Hemorrhage; Humans; Lethal Dose 50; Male; Mice; Mice, Inbred BALB C; Organ Size; Piloerection; Plant Extracts; Quercetin; Quinic Acid; Respiration; Salicaceae; Sitosterols

Phenolic compounds in buds and leaves of three varieties of black currant in Finland were identified by HPLC-DAD-ESI-MS/MS. Forty-three phenolic compounds of flavonol glycosides, proanthocyanidins and phenolic acids were found in variety "Mikael" whereas only thirty-five in "Mortti" and "Jaloste n:o 15". Glycosides of quercetin and kaempferol were the major phenolics. Rutin, hyperoside, isoquercitrin, kaempferol-3-O-rutinoise, kaempferol-3-O-glucoside, quercetin-3-O-(6″-malonyl)-glucoside and a kaempferol-malonylhexoside were the most abundant flavonol glycosides. The contents of flavonol glycosides ranged from 1 to 7 mg/g fresh weight in leaves showing typically an increasing trend from July to August, reaching the highest values in early October in "Mikael" and the end of August in "Mortti" and "Jaloste n:o 15". This is the first systematic report of the composition and content of phenolic compounds in buds and leaves of black currant.

Topics: Chromatography, High Pressure Liquid; Finland; Flavonols; Flowers; Glycosides; Kaempferols; Phenols; Plant Leaves; Proanthocyanidins; Quercetin; Ribes; Rutin; Seasons; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

To enrich the active compounds from plasma samples, a novel and simple method has been developed using a porous membrane envelope based on the ultrafiltration technique combining with high-performance liquid chromatography. The ultrafiltration device is a sealed porous membrane envelope prepared with a polypropylene sheet to effectively separate the active small molecules and large biomolecules, and a sample carrier is held inside the envelope to load plasma samples. The enrichment of hyperoside and isoquercitrin from rat plasma was used as an example. Significant factors of this method, such as membrane types, the desorption solvent, and the desorption time were optimized for the ultrafiltration method. Under the optimal conditions, correlation coefficients of 0.999 and 0.998 were obtained for hyperoside and isoquercitrin, respectively, with a linear range between 0.5 and 100μg/mL. The absolute extraction recoveries from 83.2% to 86.8% were achieved. The detection limits of the method for hyperoside and isoquercitrin were 0.22 and 0.20μg/mL, respectively. Compared with protein precipitation, solid-phase extraction and commercial ultrafiltration membrane methods, our proposed method demonstrates lower detection limits and lower cost for extraction. Also, it consumes less plasma samples and is found to be applicable to biological samples.

Topics: Animals; Apocynum; Chromatography, High Pressure Liquid; Equipment Design; Limit of Detection; Membranes, Artificial; Plant Extracts; Polypropylenes; Porosity; Quercetin; Rats; Solid Phase Extraction; Ultrafiltration

The aim of this study was to determine the composition and content of phenolic compounds in the ethanol extracts of apple leaves and to evaluate the antioxidant activity of these extracts. The total phenolic content was determined spectrophotometrically, as well as the total flavonoid content in the ethanol extracts of apple leaves and the antioxidant activity of these extracts, by the ABTS, DPPH, and FRAP assays. The highest amount of phenolic compounds and flavonoids as well as the highest antioxidant activity was determined in the ethanol extracts obtained from the apple leaves of the cv. Aldas. The analysis by the HPLC method revealed that phloridzin was a predominant component in the ethanol extracts of the apple leaves of all cultivars investigated. The following quercetin glycosides were identified and quantified in the ethanol extracts of apple leaves: hyperoside, isoquercitrin, avicularin, rutin, and quercitrin. Quercitrin was the major compound among quercetin glycosides.

Topics: Antioxidants; Benzothiazoles; Biphenyl Compounds; Flavonoids; Malus; Oxidation-Reduction; Phenols; Picrates; Plant Extracts; Plant Leaves; Quercetin; Rutin; Sulfonic Acids

To study HPLC characteristic fingerprint of Sedum lineare from different harvest periods, and to compare with its related species Sedum sarmentosum.. The HPLC fingerprints of Sedum lineare from different collecting periods were established and compared with Sedum sarmentosum by the same detection method.. Hyperin, isoquercitrin and astragaloside were identified from the HPLC fingerprint of Sedum lineare. The fingerprint of Sedum lineare growing in the same area but different environment were basically identical; while there were remarkable differences of Sedum lineare growing in the same place but from different harvest periods, with the area of most common peaks changing from little to great, and slightly different peak number. The HPLC fingerprint of the two Sedum species had four common peaks, but could be distinguished from each other. The optimal harvest period of these two species should be full-bloom stage.. The established method can provide reference for identification and quality analysis of Sedum lineare.

Topics: Chromatography, High Pressure Liquid; Drugs, Chinese Herbal; Plants, Medicinal; Quality Control; Quercetin; Reproducibility of Results; Seasons; Sedum

Two antioxidant active compounds were isolated from the methanol extract of Camellia sasanqua using various in vitro assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH), β-carotene bleaching and reducing power assays. The ethyl acetate (EtOAc) fraction of the methanol extract had the highest DPPH radical-scavenging activity with an Inhibition Concentration (IC50) value of 18.3 ± 1.63 μg mL(-1). Sephadex LH-20 column chromatography was used to separate the EtOAc fraction into eight fractions (F1-F8). Antioxidant activity was significantly higher in fraction 5 with an IC50 value 14.61 ± 0.02 μg mL(-1). Fraction 5 was further separated by HPLC preparative with Capcellpak C18 MG followed by the Cosmosil 5C18-AR-II column, using a guided DPPH radical-scavenging assay. The compounds isolated were identified as: Hyperoside (1) and isoquercitrin (2) after recrystallization from ethanol, based on Mass Spectrum (MS) and Nuclear Magnetic Resonance (NMR) analyses. Their DPPH radical-scavenging activities based on the 50% scavenging concentration decreased in the following order: Isoquercitrin (21.6 mM) > hyperoside (27.5 mM). The antioxidant activities of hyperoside and isoquercitrin were 67.52 ± 0.64 and 64.33 ± 0.51%, respectively, in the β-carotene bleaching assay. These compounds were found to have good reducing powers (OD value: 2.5-3.8) at concentrations of 50-140 μg mL(-1), using the potassium ferricyanide reduction method. Although, these compounds are well-known, hyperoside (1) was isolated from this herb for the first time.

Topics: Antioxidants; Camellia; Chromatography, High Pressure Liquid; Magnetic Resonance Spectroscopy; Quercetin; Spectrometry, Mass, Fast Atom Bombardment

To Set up a method for determining the contents of the five flavonoids simultaneously in the HuangKui capsule and analyze their specific chromatograms.. HPLC method was used. The analytical column was Thermo scientific Hypersil GOLD (250 mm x 4.6 mm, 5 microm). The mobile phase was composed of acetonitrile (A) and 0.2% orthophosphoric acid (B) with gradient elution. The flow rate was 0.8 mL/min and detection wavelength was 360 nm. The column temperature was maintained at 30 degrees C.. Contents of the five flavonoids (Rutin, Hyperoside, Isoquercitrin, Myricetin, Quercitrin) had good resolution with the correlation coefficients exceed 0.9999 and the average percent recovery lied in 98.46% to 100.33%. The chromatograms of the HuangKui capsule shared 15 common peaks in which 5 of them were recognized by the reference standard. Chromatograms of 10 lots of HuangKui capsule were analyzed with the similarities over 0.95.. The proposed method of contents determination and chromatogram analysis has strong characteristic and specificity. This method is fast, easy and reliable, and can be applied for quality control of the preparation.

Topics: Abelmoschus; Capsules; Chromatography, High Pressure Liquid; Drugs, Chinese Herbal; Flavonoids; Quality Control; Quercetin; Reproducibility of Results; Rutin

The anti-peroxyl radical quality of two aqueous rooibos infusions and solutions of their most abundant glycosylated polyphenols was evaluated using pyrogallol red and fluorescein-based oxygen radical absorbance ratios. It was observed that the artificial infusions, prepared using only the most abundant polyphenols present in rooibos and at concentrations similar to those found in the natural infusions, showed greater antioxidant quality than the latter infusions, reaching values close to those reported for tea infusions. Additionally, the antimicrobial activity of the natural and artificial infusions was assessed against three species of bacteria: Gram (+) Staphylococus epidermidis and Staphylococcus aureus and Gram (-) Escherichia coli. When compared to the natural infusions the artificial beverages did not demonstrate any bacterostatic/cidal activity, suggesting that the antibacterial activity of rooibos is related to compounds other than the glycosylated polyphenols employed in our study.

Topics: Anti-Bacterial Agents; Apigenin; Aspalathus; Beverages; Chalcones; Escherichia coli; Flavonoids; Free Radical Scavengers; Glucosides; Microbial Sensitivity Tests; Peroxides; Plant Extracts; Polyphenols; Quercetin; Rutin; Staphylococcus aureus; Staphylococcus epidermidis

To investigate the chemical constituents of Psidium guajava L, the EtOH/H(2)O extract of the fresh leaves was subjected to various chromatography. One diphenylmethane, one benzophenone, and eight flavonoids were isolated and elucidated as 2,6-dihydroxy-3-formaldehyde-5-methyl-4-O-(6″-O-galloyl-β-D-glucopyranosyl)-diphenylmethane (1), 2,6-dihydroxy-3,5-dimethyl-4-O-(6″-O-galloyl-β-D-glucopyranosyl)-benzophenone (2), kaempferol (3), quercetin (4), quercitrin (5), isoquercitrin (6), guaijaverin (7), avicularin (8), hyperoside (9), reynoutrin (10) by spectroscopic methods, including 1D and 2D NMR and HR-ESI-MS spectrometry as well as by comparison with published data. Compounds 5 and 10 are obtained from P. guajava for the first time, and compound 1 is a new diphenylmethane compound.

Topics: Benzhydryl Compounds; Benzophenones; Flavonoids; Gallic Acid; Glucosides; Glycosides; Magnetic Resonance Spectroscopy; Molecular Structure; Plant Leaves; Psidium; Quercetin; Spectrometry, Mass, Electrospray Ionization

A novel method, micro-solid-phase extraction based on membrane-protected molecularly imprinted polymer, was developed to extract hyperoside and isoquercitrin in rat plasma. Synthesized hyperoside MIPs were packed in a porous polyether sulfone membrane envelope to perform extraction. The parameters sorbent materials, membrane types, extraction time and desorption conditions were optimized for micro-solid-phase extraction. Under the optimal conditions, correlation coefficients, 0.998 and 0.999, were obtained for hyperoside and isoquercitrin, respectively, with the linear range between 1 and 120 μg/mL. The absolute extraction recoveries from 84.5 to 89.3% were found. The method detection limits of hyperoside and isoquercitrin were 0.24 and 0.22 μg/mL, respectively. Compared with traditional methods, solid-phase extraction, liquid-liquid extraction and protein precipitation, the developed method was simple, highly efficient for extraction, environmentally friendly, and particularly suitable for complex biological samples.

Topics: Animals; Chromatography, High Pressure Liquid; Quercetin; Rats; Solid Phase Extraction

Ionic liquids-based microwave-assisted extraction (ILs-MAE) of medicinal or useful compounds from plants was investigated as an alternative to conventional organic solvent extractions. The extraction and the preconcentration of aqueous two-phase (ATP) systems have been integrated. Various operating parameters were systematically considered by single-factor and L(9) (3(4)) orthogonal array experiments. 1-Butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]) has been selected to extract Apocynum venetum. The extract was then converted to the top phase by [bmim][BF(4)]/NaH(2)PO(4) system which was suitable for the preconcentration. Reversed phase high performance liquid chromatography (RP-HPLC) with ultraviolet detection was employed for the analysis of hyperin and isoquercitrin in Apocynum venetum. The optimal experiment approach could provide higher detection limit of hyperin and isoquercitrin which were 3.82 μg L(-1) and 3.00 μg L(-1) in Apocynum venetum. The recoveries of hyperin and isoquercitrin were 97.29% (RSD = 1.02%) and 99.40% (RSD = 1.13%), respectively, from aqueous samples of Apocynum venetum by the proposed method. Moreover, the extraction mechanism of ILs-MAE and the microstructures and chemical structures of the herb before and after extraction were also investigated. The method exhibited potential applicability with other complicated samples.

Topics: Apocynum; Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; Imidazoles; Ionic Liquids; Medicine, Chinese Traditional; Microwaves; Quercetin; Spectrophotometry, Ultraviolet; Water

The traditional use of lotus leaves as an anti-inflammatory remedy is associated with the occurrence of phenolic compounds. In this study the first CE method for the analysis of all major phenolic constituents in Nelumbo nucifera leaves is presented. It permits the separation of nine relevant markers in less than 10 min. The optimized procedure was fully validated and then used to analyze diverse samples collected in Vietnam. They revealed significant qualitative and quantitative differences depending on growing area and season. Yet, in all of them, quercetin-3-O-β-D-glucuronide, hyperoside, and isoquercitrin were the most dominant flavonoids.

Topics: Electrophoresis, Capillary; Nelumbo; Phenols; Plant Leaves; Quercetin; Regression Analysis; Reproducibility of Results; Sensitivity and Specificity; Vietnam

To establish HPLC fingerprint of Bidens biternata from different habitats and determine the contents of hyperoside, isoquercetin, astragalin and bipinnatapolyacetylpside.. Analysis was carried on Hypersil ODS C18 column (4.6 mm x 250 mm, 5.0 microm) with acetonitrile and 3% acetic acid as the mobile phase in a gradient elution. The contents of 4 components were determined simultaneously.. The fingerprint of 10 populations were established and the data were analyzed by the similarity evaluation software. There were almost no differences between the similarities of 10 population, but the contents of 4 main compoerls were different among them.. This method is stable and reliable which could be applied in quality assessment.

Topics: Bidens; Chromatography, High Pressure Liquid; Drugs, Chinese Herbal; Ecosystem; Flavones; Kaempferols; Plant Components, Aerial; Plants, Medicinal; Quality Control; Quercetin; Reproducibility of Results; Solvents

To explore the mechanism of the absorption of flavonoids from Abelmoschus manihot flowers, in situ intestinal recirculation was performed to study the effect of the absorption at different concentrations and different intestinal regions. To evaluate the conditions of the absorption of six flavonoids from Abelmoschus manihot flowers, the concentrations of Abelmoschus manihot in the perfusion solution were determined by HPLC at predesigned time. And we have investigated the inhibitory effect of six flavonoids from Abelmoschus manihot flowers on P-glycoprotein (P-gp) drug efflux pump. The results demonstrated that the absorption rates of flavonoids from Abelmoschus manihot flowers are not significantly different (P > 0.05) at various drug concentrations, the absorption of flavonoids from Abelmoschus manihot flowers is a first-order process with the passive diffusion mechanism. The absorption rates of each of flavonoids are significantly different. The absorption rate of flavonoid glycoside was lower than that of aglycone; the flavonoids from Abelmoschus manihot flowers could be absorbed in all of the intestinal segments. The best parts of intestine to absorb hyperoside and myricetin are jejunum and duodenum, separately. Verapamil could enhance the absorption of isoquercitrin, hyperoside, myricetin and quercetin-3'-O-glucoside by inhibiting P-glycoprotein (P-gp) drug efflux pump.

Topics: Abelmoschus; Animals; ATP Binding Cassette Transporter, Subfamily B; Flavonoids; Flowers; Glucosides; Intestinal Absorption; Male; Perfusion; Plant Extracts; Plants, Medicinal; Quercetin; Rats; Rats, Sprague-Dawley; Verapamil

Depression is the most common psychiatric comorbidity in patients with epilepsy. Searching for antiepileptic (anticonvulsant) and antidepressant-like medicines from natural products is very important for the treatment of this disease. The flower of Abelmoschus manihot (Linn.) Medicus has been reported to have neuroprotective effect against cerebral ischemia injury. In order to further explore the activity of Abelmoschus manihot on the central nervous system, the anticonvulsant and antidepressant-like effects of Abelmoschus manihot ethanol extract (AMEE) as well as its potential active components in vivo was investigated in the present study. It was found that AMEE could protect mice against PTZ-induced clonic convulsions and mortality. AMEE could also decrease immobility time in the FST in mice. Furthermore, the potential active components of AMEE in rat brain were identified by ultra performance liquid chromatography-mass spectrometer (UPLC-MS). Five parent components including isoquercitrin, hyperoside, hibifolin, quercetin-3'-O-glucoside, quercetin and three metabolites were detected in rat brain after administration of AMEE. In conclusion, eight flavonoids were identified in rat brain after administration of AMEE; meanwhile, these flavonoids might represent the potential bioactive components of AMEE and contribute to its anticonvulsant and antidepressant-like activity in vivo.

Topics: Abelmoschus; Animals; Anticonvulsants; Antidepressive Agents; Brain; Chromatography, Liquid; Drug Evaluation; Ethanol; Exercise Test; Flavonoids; Flowers; Male; Mice; Mice, Inbred ICR; Pentylenetetrazole; Plant Extracts; Quercetin; Rats; Rats, Sprague-Dawley; Seizures; Time Factors

Leaf extracts from Tripodanthus acutifolius (Ruiz and Pavón) Van Tieghem have long been used in Argentinean traditional medicine as anti-inflammatory, however, there is no scientific evidence which supports this use in the literature.. The present study was conducted to evaluate the ability of five phenolic compounds purified from infusion prepared from Tripodanthus acutifolius leaves to inhibit key enzymes in inflammatory processes. As anti-inflammatory compounds frequently possess free radical scavenging activities, purified substances were comparatively evaluated to asses their free radical scavenging properties. Genotoxic effects were also evaluated.. Compounds were evaluated on their ability to inhibit hyaluronidase and cyclooxygenase-2 (COX-2) activities to assess their anti-inflammatory capacities. Free radical scavenging activity was assessed by: 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH), superoxide anion assay and the inhibition on lipid peroxidation. Genotoxicity was evaluated by Bacillus subtilis rec assay.. Fractionation of Tripodanthus acutifolius infusion yielded a novel phenylbutanoid derivative (tripodantoside) and four known flavonoid glycosides (rutin, nicotiflorin, hyperoside and isoquercitrin). Flavonoids produced higher inhibition on hyluronidase activity (IC(50) approximately 1.7 mM) than tripodantoside (IC(50)=27.90 mM). A similar COX-2 inhibition activity was exerted by tripodantoside and monoglycosilated flavonoids (IC(50) approximately 50 microM). Compounds were strong radical scavengers, with effective concentration 50 (EC(50)) values for DPPH in the range of 2.7-6.3 microg/mL, and for superoxide anion in the range of 3.9-8.7 microg/mL. All compounds scavenged peroxyl radicals in the lipid peroxidation assay. The substances showed no genotoxic effects.. The anti-inflammatory effects, free radical scavenging activities and lack of genotoxicity of purified compounds may support the folk use of infusion from Tripodanthus acutifolius leaves as anti-inflammatory.

Topics: Animals; Anti-Inflammatory Agents; Bacillus subtilis; Biphenyl Compounds; Cattle; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; DNA Damage; Dose-Response Relationship, Drug; Flavonoids; Free Radical Scavengers; Humans; Hyaluronoglucosaminidase; Lipid Peroxidation; Loranthaceae; Phenols; Picrates; Plant Leaves; Quercetin; Recombinant Proteins; Rutin

The extract of the root of Acanthopanax chiisanensis Nakai is used for the treatment of inflammation. To analyse the action mechanism of this extract, the effect of hyperin (quercetin-3-O-beta-d-galactose) isolated from the ethyl acetate fraction of the root of A. chiisanensis on nitrite production and induction of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS, 1 microg/mL)-stimulated rat peritoneal macrophages were examined. The effect of the structurally related compounds, isoquercitrin (quercetin-3-O-beta-d-glucose) and quercetin (an aglycone of the two compounds) isolated from the extract of the leaves of Vaccinium koreanum Nakai was also examined to compare the effect. It was shown that hyperin inhibited the LPS-induced iNOS expression and nitrite production. Of the three compounds, quercetin showed the most potent inhibitory activity. The phosphorylation of p44/42 mitogen activated protein kinase (MAPK), p38 MAPK and c-Jun N-terminal kinase (JNK) were also inhibited by these compounds. These findings suggested that hyperin in the extract of the root of A. chiisanensis inhibits nitric oxide (NO) production through inhibition of the expression of iNOS by attenuation of p44/p42 MAPK, p38 MAPK and JNK, and thus participates in the antiinflammatory activity of the extract.

Topics: Animals; Eleutherococcus; JNK Mitogen-Activated Protein Kinases; Lipopolysaccharides; Macrophages, Peritoneal; Male; Mitogen-Activated Protein Kinase Kinases; Nitric Oxide; Nitric Oxide Synthase Type II; Nitrites; Plant Extracts; Plant Roots; Quercetin; Rats; Rats, Sprague-Dawley

A new flavonol glycoside 7-O-methyl-kaempferol 4'-beta-D-galactopyranoside (rhamnocitrin 4'-beta-D-galactopyranoside) (1) was isolated from the aerial parts of Astragalus hamosus. The known flavonols hyperoside (2), isoquercitrin (3) and astragalin (4) were also identified. Structures of the compounds were elucidated by chemical and spectral methods.

Topics: Astragalus Plant; Chromatography, High Pressure Liquid; Flavonoids; Glucosides; Kaempferols; Magnetic Resonance Spectroscopy; Molecular Structure; Quercetin

The leaves and fruits of strawberry tree - Arbutus unedo L., collected from two separate geographic locations in Croatia were investigated to determine their flavonoid composition and content. Quercitrin, isoquercitrin, hyperoside and rutin were identified in all leaf samples by means of thin-layer chromatography; the fruits contained only isoquercitrin. Chlorogenic acid was present in some leaf samples. The content of flavonoids depended on the plant organ investigated, date of collection and the locality. Spectrophotometric determination of the flavonoids indicated that the leaves are richer in flavonoids (0.52-2.00%) than fruits (0.10-0.29%).

Topics: Croatia; Ericaceae; Flavonoids; Fruit; Plant Leaves; Quercetin

Our previous studies identified hyperoside (HP), isoquercitrin (IQ) and epicatechin (EC) to be the major active flavonoid components of the hawthorn phenolic extract from hawthorn fruits demonstrating inhibitory effect on in vitro Cu(+2)-mediated low density lipoproteins oxidation. Among these three hawthorn flavonoids, EC was the only one detectable in plasma after the oral administration of hawthorn phenolic extract to rats. The present study aims to investigate the intestinal absorption mechanisms of these three hawthorn flavonoids by in vitro Caco-2 monolayer model, rat in situ intestinal perfusion model and in vivo pharmacokinetics studies in rats. In addition, in order to investigate the effect of the co-occurring components in hawthorn phenolic extract on the intestinal absorption of these three major hawthorn flavonoids, intestinal absorption transport profiles of HP, IQ and EC in forms of individual pure compound, mixture of pure compounds and hawthorn phenolic extract were studied and compared. The observations from in vitro Caco-2 monolayer model and in situ intestinal perfusion model indicated that all three studied hawthorn flavonoids have quite limited permeabilities. EC and IQ demonstrated more extensive metabolism in the rat in situ intestinal perfusion model and in vivo study than in Caco-2 monolayer model. Moreover, results from the Caco-2 monolayer model, rat in situ intestinal perfusion model as well as the in vivo pharmacokinetics studies in rats consistently showed that the co-occurring components in hawthorn phenolic extract might not have significant effect on the intestinal absorption of the three major hawthorn flavonoids studied.

Topics: Animals; Biological Transport; Caco-2 Cells; Catechin; Chromatography, High Pressure Liquid; Crataegus; Flavonoids; Humans; Intestinal Absorption; Intestinal Mucosa; Intestines; Male; Models, Biological; Molecular Structure; Phlorhizin; Quercetin; Rats; Rats, Sprague-Dawley; Reproducibility of Results

Leaf spots and root rots are major fungal diseases in Camptotheca acuminata that limit cultivation of the plant for camptothecin (CPT), a promising anticancer and antiviral alkaloid. Bioassays showed that pure CPT and flavonoids (trifolin and hyperoside) isolated from Camptotheca effectively control fungal pathogens in vitro, including Alternaria alternata, Epicoccum nigrum, Pestalotia guepinii, Drechslera sp., and Fusarium avenaceum, although antifungal activity of these compounds in the plant is limited. CPT inhibited mycelial growth by approximately 50% (EC50) at 10-30 microg/mL and fully inhibited growth at 75-125 microg/mL. The flavonoids were less effective than CPT at 50 microg/mL, particularly within 20 days after treatment, but more effective at 100 or 150 microg/mL. CPT, trifolin, and hyperoside may serve as leads for the development of fungicides.

Topics: Alternaria; Ascomycota; Camptotheca; Camptothecin; Fungicides, Industrial; Fusarium; Plant Leaves; Plants; Quercetin

The present study was to investigate oral absorption of the two similar flavonoid glycosides, isoquercitrin (IQ, quercetin-3-O-glucoside) and hyperoside (HP, quercetin-3-O-galactoside) in rats. Two groups of male SD rats received an oral dose of either IQ (4.5 mg/kg) or HP (6.0 mg/kg). Blood samples were collected via jugular vein at time intervals after drug administration and the plasma concentrations of the studied compounds were analyzed by HPLC. The stability of IQ and HP in the GI tract was also measured by incubation with various GI contents from rats. The results showed that unchanged IQ was barely detectable whereas the glucuronidated quercetin (the aglycone of IQ) was found to be the major form in plasma after oral administration of IQ. In contrast, HP could not be detected in plasma neither as unchanged form nor its aglycone or conjugated aglycone form. Additional in vitro stability studies demonstrated that HP is more stable than IQ in the GI tract. This suggests that IQ could be hydrolyzed easier than HP to its aglycone in GI tract before being absorbed. In conclusion, IQ, as a flavonoid glucoside, could be rapidly absorbed and transformed into glucuronidated quercetin and such absorption might be related to the hydrolysis of the type of sugar moieties attached to its aglycone molecule.

Topics: Animals; Flavonoids; Glycosides; Hydrolysis; Intestinal Absorption; Male; Molecular Structure; Quercetin; Rats; Rats, Sprague-Dawley

Quercetin is an important dietary flavonoid with putative beneficial effects in the prevention of cancer and CVD. The in vivo bioactivity of quercetin depends on its bioavailability, which varies widely between foods. We used an in situ rat intestinal perfusion model to study whether differential small intestinal hydrolysis of the sugar moiety of five naturally occurring quercetin glycosides determines the small intestinal uptake and subsequent biliary excretion of quercetin. After 30 min perfusion, a decrease of intact quercetin glycoside in perfusate was observed for quercetin-3-O-ss-glucoside (20.9 (sem 1.4) micromol/l) and quercetin-4'-O-ss-glucoside (23.5 (sem 1.6) micromol/l), but not of quercetin-3-O-ss-galactoside, quercetin-3-O-ss-rhamnoside and quercetin-3-O-alpha-arabinopyranoside. Appearance of free quercetin in perfusate and conjugated quercetin metabolites (quercetin, isorhamnetin, and tamarixetin) in portal and peripheral plasma and bile were also significantly greater after treatment with quercetin-3-O-ss-glucoside or quercetin-4'-O-ss-glucoside compared with any of the other glycosides. Thus, the type of sugar moiety is a major determinant of the small intestinal absorption of quercetin glycosides, but the position (3 or 4') of the glucose moiety does not further influence absorption. The poor bioavailability of important dietary quercetin glycosides has implications for their in vivo bioactivities.

Topics: Animals; Bile; Biological Availability; Diet; Glycosides; Intestinal Absorption; Intestine, Small; Male; Perfusion; Portal Vein; Quercetin; Rats; Rats, Wistar

Recent experimental data point to an interaction of dietary flavonol monoglucosides with the intestinal Na-dependent glucose transporter 1 (SGLT1). To investigate this interaction in more detail, we performed experiments with SGLT1-containing brush-border-membrane vesicles (BBMV) from pig jejunum. The flavonol quercetin-3-O-glucoside (Q3G) concentration-dependently inhibited Na-dependent uptake of radioactively labelled d-glucose into BBMV. Uptake of l-leucine was not inhibited by Q3G, indicating a specific interaction of the glucoside with SGLT1. Whereas the maximal transport rate of concentration-dependent initial glucose uptake was not altered in the presence of Q3G, the constant for half-maximal glucose uptake was increased, suggesting a competitive type of inhibition of glucose uptake by Q3G. Trans-stimulation experiments suggested the transport of Q3G via SGLT1. In addition, Q3G decreased the Na-independent diffusive uptake of glucose into BBMV. Other flavonoids were also tested for their inhibitory effect on d-glucose uptake. Among the tested quercetin glycosides, only the 4'-O-glucoside (Q4G) also inhibited Na-dependent glucose uptake into BBMV, whereas the 3-O-galactoside, the 3-O-glucorhamnoside and the aglycone quercetin itself were ineffective. Glucosides of some other flavonoid classes such as naringenin-7-O-glucoside, genistein-7-O-glucoside and cyanidin-3,5-O-diglucoside were ineffective as well. Thus, dietary quercetin monoglucosides, for example, Q3G and Q4G, have an impact on intestinal nutrient transporters such as SGLT1 and related systems.

Topics: Animals; Biological Transport; Diet; Glucose; Glucosides; Intestinal Mucosa; Jejunum; Leucine; Membrane Glycoproteins; Microvilli; Monosaccharide Transport Proteins; Quercetin; Sodium-Glucose Transporter 1; Swine

In contrast to chemically defined drugs, most herbal medicinal products (HMPs) are poorly characterized in terms of their pharmaceutical properties. In many cases it is assumed that the plant extract as a whole is the active moiety, since it is often difficult to identify the individual components responsible for the pharmacological activity and even more difficult to assess synergies among the various components. However, where the active components have been identified, it should be possible to compare products with respect not only to content uniformity but also to their biopharmaceutical properties. The aim of this study was to investigate and compare the dissolution characteristics of several St John's wort products under biorelevant conditions. Components of St John's wort known, or suspected, to play a role in its antidepressant activity include phloroglucines, naphthodianthrones and the flavonoids. Since these groups have a broad spectrum of polarity and solubility, dissolution was studied for representative compounds from each group. Although the labelling indicates that several of the products studied should be pharmaceutically equivalent, dissolution under biorelevant conditions revealed that they have quite different release profiles and cannot be considered switchable. It was concluded that biorelevant dissolution testing can be a powerful tool for comparing HMPs as well as synthetically produced drug products.

Topics: Antidepressive Agents; Bridged Bicyclo Compounds; Capsules; Chemistry, Pharmaceutical; Chromatography, High Pressure Liquid; Ethanol; Hypericum; Kinetics; Methanol; Phloroglucinol; Plant Extracts; Quercetin; Reproducibility of Results; Rutin; Solubility; Solvents; Terpenes; Time Factors

An ethanolic extract of Drosera madagascariensis inhibited human neutrophil elastase with an IC50 of 9.4 microg/ml. The naphthoquinones present in the extract were not responsible for this effect, but flavonoids like quercetin (IC50 0.8 microg/ml), hyperoside (IC50 0.15 microg/ml) and isoquercitrin (IC50 0.7 microg/ml) contributed to inhibition of the enzyme. In guinea-pig ileum the extract (0.5-1 mg/ml) induced a spasmolytic effect via affecting cholinergic M3 receptors and histamine H1 receptors, respectively. At contractile prostanoid receptors of guinea-pig trachea the Drosera extract was not effective.

Topics: Animals; Anti-Inflammatory Agents; Drosera; Enzyme Inhibitors; Guinea Pigs; Humans; Ileum; Leukocyte Elastase; Muscle Contraction; Muscle, Smooth; Parasympatholytics; Plant Extracts; Quercetin; Receptors, Cholinergic; Receptors, Histamine H1; Receptors, Prostaglandin; Trachea

A simple HPLC method with photodiode-array (PDA) ultraviolet detection was developed for the simultaneous determination of four active polyphenol components of hawthorn (Crataegus), chlorogenic acid, epicatechin, hyperoside and isoquercitrin, in rat plasma. Following extraction from the plasma samples with ethyl acetate-methanol (2:1, v/v), these four compounds were successfully separated using a C18 column with a gradient elution of 5 and 25% acetonitrile in 25 mM phosphate buffer (pH 2.4). The flow-rate was set at 1 ml/min and the eluent was detected at 325 nm for chlorogenic acid, 278 nm for epicatechin, and 360 nm for both hyperoside and isoquercitrin. Narignin (0.82 microg) was used as the internal standard and was detected at 278 nm. The method is linear over the studied range of 0.16-40, 0.63-160, 0.13-32 and 0.13-30 microg/ml for chlorogenic acid, epicatechin, hyperoside and isoquercitrin, respectively. The correlation coefficient for each analyte was greater than 0.995. The intra-day and inter-day precision of the analysis was better than 4 and 7%, respectively. The extraction recoveries at low to high concentration were greater than 85% for both epicatechin and chlorogenic acid, and greater than 94% for both hyperoside and isoquercitrin. The detection limits were 0.04, 0.20, 0.03 and 0.03 microg/ml for chlorogenic acid, epicatechin, hyperoside and isoquercitrin. The developed method was used to analyze the plasma concentrations of the four analytes after the intravenous administration of hawthorn polyphenol extract to rats.

Topics: Animals; Catechin; Chlorogenic Acid; Chromatography, High Pressure Liquid; Crataegus; Quercetin; Rats; Reference Standards; Reproducibility of Results; Sensitivity and Specificity; Spectrophotometry, Ultraviolet

To study the chemical constituents of Taraxacum mongolicum.. Compounds were separated by column chromatography on silica gel and polyamide, and their structures were determined by spectral analysis and chemical evidence.. Two flavonoid compounds were separated and elucidated as isoquercitrin and hyperin.. These two compounds were isolated from the plant for the first time.

Topics: Flavonoids; Plants, Medicinal; Quercetin; Taraxacum

The traditional herbal remedy from Psidium guajava leaves has been medically proposed in Mexico as effective treatment of acute diarrhea. A methanolic leaf extract was subjected to a bioassay-guided isolation of spasmolytic constituents. Six fractions were separated on a polyvinylpolypyrrolidine (PVPP) column using a water methanol-gradient. The fraction containing flavonols inhibited peristalsis of guinea pig ileum in vitro. A trace of quercetin aglycone together with five glycosides was isolated from this active fraction and identified as quercetin 3-O-alpha-L-arabinoside (guajavarin); quercetin 3-O-beta-D-glucoside (isoquercetin); quercetin 3-O-beta-D-galactoside (hyperin); quercetin 3-O-beta-L-rhamnoside (quercitrin) and quercetin 3-O-gentobioside. Biological activity of each pure compound was studied in the same bioassay. Obtained results suggest that the spasmolytic activity of the Psidium guajava leaf remedy is mainly due to the aglycone quercetin, present in the leaf and in the extract mainly in the form of five flavonols, and whose effect is produced when these products are hydrolyzed by gastrointestinal fluid.

Topics: Animals; Antidiarrheals; Drug Evaluation, Preclinical; Gastric Acid; Glycosides; Guinea Pigs; Hydrolysis; Ileum; Male; Methanol; Mexico; Muscle Relaxation; Muscle, Smooth; Parasympatholytics; Plant Extracts; Plants, Medicinal; Quercetin

Topics: Antitussive Agents; Asthma; Bronchitis; Expectorants; Flavonoids; Galactosides; Humans; Kaempferols; Plant Extracts; Plants, Medicinal; Quercetin; Rutin