isoquercitrin and myricetin

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

Phytochemicals such as flavonoids, vitamins, and polyphenols have been shown to have beneficial effects in metabolic disease. To determine if select flavonoids regulate hepatic apolipoprotein A-I (apo A-I) and high-density lipoprotein (HDL) synthesis, we examined the effects of quercetin, isoquercetin, and myrescetin on apo A-I gene expression in HepG2 (hepatocytes) and Caco-2 (intestinal) cells.. Apo A-I gene expression was measured by Western blotting, quantitative reverse-transcription polymerase chain reaction, and transient transfection. Estrogen receptor α (ESR1) and estrogen receptor β expression were measured by Western blotting, and ESR1 expression was inhibited using ESR1-specific short inhibitory RNA (siRNA).. Quercetin and isoquercetin, but not myrecetin, induced apo A-I protein and mRNA synthesis, and induced apo A-I promoter activity. Induction by quercetin required an estrogen-responsive region of the apo A-I promoter. Addition of estrogen receptor blocker ICI-182780 to quercetin-treated cells inhibited the effects of quercetin on apo A-I gene expression. Down-regulation of ESR1 with ESR1 siRNA had no effect on basal apo A-I gene expression; however it prevented quercetin-mediated induction of apo A-I gene expression.. We conclude that quercetin induces apo A-I gene expression at least in part through induction of ESR1 and may be useful in treating hypoalphalipoproteinemia.

Topics: Apolipoprotein A-I; Caco-2 Cells; Down-Regulation; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Flavonoids; Fulvestrant; Gene Expression Regulation; Hep G2 Cells; Hepatocytes; Humans; Hypoalphalipoproteinemias; Isoflavones; Lipoproteins, HDL; Liver; Promoter Regions, Genetic; Quercetin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

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

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

Buckwheat is well-known as a crop rich in flavonoids, however, attention has usually only been paid to the main flavonoid rutin as an important natural antioxidant or as a possible allelopathic compound. Therefore, some of the other constituents found within individual plant parts of buckwheat (isoquercitrin, quercetin, catechin, and myricetin), as well as changes of their level during the growing season, were determined by HPLC analysis. The effects of these compounds on plant growth were proved on seven plant species. In buckwheat, isoquercitrin represented the largest component of the selected compounds. The strongest inhibitive effects on the growth of those selected plants were produced by catechin. Quercetin and isoquercitrin had weak inhibitive effects. Myricetin did not show any influence on plant growth. Hence we suppose that myricetin, isoquercetin and quercetin do not have important function in allelopathy of buckwheat. Buckwheat as row material for functional foods could be a significant source of another antioxidant, isoquercitrin.

Topics: Catechin; Chromatography, High Pressure Liquid; Fagopyrum; Flavonoids; Flowers; Magnoliopsida; Plant Growth Regulators; Plant Leaves; Plant Roots; Plant Stems; Quercetin; Seasons