Disease relevance of Flavonoid

• Action of 3-methylquercetin on poliovirus RNA replication [1].
• 3-Methylquercetin (3MQ) is a natural compound isolated from Euphorbia grantii that selectively inhibits poliovirus replication, but has no effect on encephalomyocarditis virus [2].
• After oral dosing of isorhamnetin, the mean values (n = 10) of C(max) were 57.8, 64.8 and 75.2 ng . mL(-1) which were achieved at a T(max) of 8.0, 6.4 and 7.2 h for oral doses of 0.25, 0.5 and 1.0 mg . kg(-1) body weight, respectively [3].
• Furthermore, lipid peroxidation in blood, liver, and kidney associated with diabetes mellitus declined after the administration of isorhamnetin [4].
• To our knowledge, this is the first report against human hepatocellular carcinoma cells (BEL-7402) of isorhamnetin [5].

High impact information on Flavonoid

• In the present study, we have administered several flavonoids to human HaCaT keratinocytes and determined that 3,4'-dihydroxy flavone (3,4'-DHF) exerts a slight stimulatory effect on cell growth, although other flavonoids, including kaempferol, quercetin, and isorhamnetin, exhibited growth inhibitory properties [6].
• After one intraperitoneal administration of 50 mg/kg quercetin to hamsters, a urinary ether extract contained 2% quercetin and 97% 3'-O-methylquercetin [7].
• When the urine was treated first with beta-glucuronidase and sulfatase, 13% quercetin and 87% 3'-O-methylquercetin were recovered [7].
• The fact that 3-methylquercetin rarely accumulates in plants in significant amounts, and given its important role as an antiviral and antiinflammatory agent that accumulates in response to stress conditions, prompted us to purify and characterize the enzyme involved in its methylation [8].
• Serratula tinctoria (Asteraceae) accumulates mainly 3,3'-dimethylquercetin and small amounts of 3-methylquercetin as an intermediate [8].

Chemical compound and disease context of Flavonoid

• Moreover, inhibitors of poliovirus replication, such as cycloheximide or 3-methylquercetin, block the disappearance of these polypeptides [9].
• In this paper, we show that when cells are infected with poliovirus in the presence of guanidine or 3-methylquercetin, both inhibitors of poliovirus replication, complete cleavage of p220 occurs by 3.5 h postinfection [10].
• Isorhamnetin, a flavonol aglycone, isolated from the traditional Chinese medicine Hippophae rhamnoides L., was investigated in its cytotoxicity and its influence on human hepatocellular carcinoma cells (BEL-7402) [5].

Biological context of Flavonoid

• Taken together, these results show for the first time, to our knowledge, that quercetin and isorhamnetin prevent AngII-induced endothelial dysfunction by inhibiting the overexpression of p47(phox) and the subsequent increased O(2)(-) production, resulting in increased nitric oxide bioavailability [11].
• The structures of the flavonoid glycosides were analysed after alkaline hydrolysis, and were identified as 3-sophoroside/sophorotrioside-7-glucoside/sophoroside of kaempferol, quercetin and isorhamnetin (this last found in trace amount) [12].
• Pretreatment with isorhamnetin resulted in remarkable increase of cell viability (P<0.05) and modulation of secretion disorders mediated by ox-LDL in a concentration-dependent manner [13].
• These effects were obtained via inhibition of lectin-like ox-LDL receptor-1 upregulation, interference of ox-LDL-mediated intracellular signaling pathway (p38MAPK activation, NF-kappaB nuclear translocation, eNOS expression) and the antioxidant activity of isorhamnetin [13].
• The corresponding mean values for isorhamnetin area under the curver (AUC) from 0 to 60 h were 838.2, 1262.8, 1623.4 ng . h . mL(-1) [3].

Anatomical context of Flavonoid

• The vasodilator responses of quercetin and isorhamnetin were not significantly modified after removal of the endothelium in the thoracic aorta or in the mesenteric bed [14].
• In addition, both tamarixetin (T) and isorhamnetin (I), in the mucosal tissue from sacs exposed to the whole wine, were significantly elevated approximately two fold (P < 0.05; P < 0.01, respectively) [15].
• Isorhamnetin prevent endothelial cell injuries from oxidized LDL via activation of p38MAPK [13].
• Again, isorhamnetin was a potent inhibitor of lysis of red blood cells despite the presence of a 3'-OCH3 function [16].
• Cardiovascular effects of isorhamnetin and quercetin in isolated rat and porcine vascular smooth muscle and isolated rat atria [17].

Associations of Flavonoid with other chemical compounds

• Analysis of quercetin and some of its metabolites (isorhamnetin, tamarixetin, kaempferol) in plasma samples were performed by HPLC [18].
• At 6 h, AngII induced a marked increase in O(2)(-) production as measured by dihydroethidium fluorescence, which was prevented by quercetin and isorhamnetin [11].
• We analyzed the effects of quercetin and its methylated metabolite isorhamnetin on the aortic endothelial dysfunction induced by incubation with angiotensin II (AngII) in vitro for 6 h [11].
• An O-methyltransferase (OMT) which catalyzes the methylation of 3-methylquercetin to 3,7-dimethylquercetin, the second step of methyl transfers toward the biosynthesis of polymethylated flavonol glucosides, has been isolated from Chrysosplenium americanum shoot tips [19].
• Their structures were elucidated as isorhamnetin 3- O-glucoside, rutinoside, neohesperidoside, 2 (G)-rhamnosylrutinoside, quercetin glucoside, neohesperidoside, and 2 (G)-rhamnosylrutinoside by paper and thin layer chromatography, UV, (13)C-NMR, and mass spectroscopy [20].

Gene context of Flavonoid

• The antioxidant capacities of quercetin, 3'-O-methylquercetin, and of some of their conjugated derivatives were compared by the measurement of the conjugated dienes resulting from the Cu2+-induced oxidation of human LDL [21].
• Isorhamnetin pretreatment inhibited the ox-LDL-induced downregulation of eNOS, upregulation of lectin-like ox-LDL receptor-1, phosphorylation of the p38MAPK and translocation of NF-kappaB [13].
• The concentrations of Ginkgo flavonol in Bcap37/MDR1 cells were lower than those in parent cells (P<0.05 for quercetin, P<0.01 for isorhamnetin, Mann-Whitney U test) [22].
• Quercetin and kaempferol inhibited the ATPase activity, and isorhamnetin stimulated the ATPase activity (P<0.05 for isorhamnetin, Mann Whitney U test) [22].

Analytical, diagnostic and therapeutic context of Flavonoid

• High-performance liquid chromatography (HPLC) profiles of plasma samples from OVX + R rats revealed that mean plasma concentration of active metabolites (quercetin and isorhamnetin) from rutin was 9.46+/-1 microM, whereas it was undetectable in SH and OVX rats [23].
• The antihemostatic specificity of isorhamnetin toward antihemorrhagic compounds isolated previously from hemostatic herbs used in traditional Chinese medicine was examined [24].
• In vitro bioassays proved that, among endogenous flavonoids, quercetin and isorhamnetin possess a good inhibitory aphid reproduction rate [25].
• The results of flow cytometry assay indicated that the percentage of hypodiploid BEL-7402 cells were 13.77+/-1.05% after 48 h treatment with 50 microg ml(-1) isorhamnetin [5].
• The cytotoxic effects of isorhamnetin showed dose- and time-dependency against BEL-7402 cells, with IC(50) equal to 74.4+/-1.13 microg ml(-1) after treatment with isorhamnetin for 72 h [5].

References