Quercetin-3-O-glucuronide

1 Carum sp. 2 Castanea sp. 3 Casuarina sp. 4 Cichorium sp. 5 Coriandrum sp. 6 Cornus sp. 7 Epilobium sp. 8 Euphorbia sp. 9 Filipendula sp. 10 Foeniculum sp. 11 Hepatica sp. 12 Heterotheca sp. 13 Melaleuca sp. 14 Phaseolus sp. 15 Pimpinella sp. 16 Potentilla sp. 17 Vitis sp.

Miquelianin (Quercetin 3-O-glucuronide) is a metabolite of quercetin and a type of natural flavonoid.

In Vitro:Miquelianin shows an antioxidant effect in human plasma. At 50 μM, miquelianin suppresses the consumption of the three antioxidants lycopene, β-carotene and α-tocopherol significantly[1]. In vitro studies indicate that miquelianin is able to reach the central nervous system from the small intestine[2]. Miquelianin significantly reduces the generation of β-amyloid (Aβ) peptides by primary neuron cultures generated from the Tg2576 AD mouse model. It is also capable of interfering with the initial protein-protein interaction of Aβ1–40 and Aβ1–42 that is necessary for the formation of neurotoxic oligomeric Aβ species[3]. Treatment with 0.1 μM miquelianin suppresses ROS generation, cAMP and RAS activation, phosphorylation of ERK1/2 and the expression of HMOX1, MMP2, and MMP9 genes. Miquelianin suppresses invasion of MDA-MB-231 breast cancer cells and MMP-9 induction, and inhibits the binding of [3H]-NA to b2-AR. Miquelianin may function to suppress invasion of breast cancer cells by controlling b2-adrenergic signaling, and may be a dietary chemopreventive factor for stress-related breast cancer[4].

In Vivo:Miquelianin treatment, compared to vehicle-control treatment, significantly improves AD-type deficits in hippocampal formation basal synaptic transmission and long-term potentiation[3]. A flavonoid fraction obtained from a crude extract of Hypericum perforatum (St. John's wort) is remarkably active in the forced swimming test. Miquelianin is one of the compound separated from the fraction[5].

References:
[1]. Terao J, e al. Protection by quercetin and quercetin 3-O-beta-D-glucuronide of peroxynitrite-induced antioxidant consumption in human plasma low-density lipoprotein. Free Radic Res. 2001 Dec;35(6):925-31. [2]. Juergenliemk G, et al. In vitro studies indicate that miquelianin (quercetin 3-O-beta-D-glucuronopyranoside) is able to reach the CNS from the small intestine. Planta Med. 2003 Nov;69(11):1013-7. [3]. Butterweck V, et al. Flavonoids from Hypericum perforatum show antidepressant activity in the forced swimming test. Planta Med. 2000 Feb;66(1):3-6. [4]. Yamazaki S, et al. Quercetin-3-O-glucuronide inhibits noradrenaline-promoted invasion of MDA-MB-231 human breast cancer cells by blocking β₂-adrenergic signaling. Arch Biochem Biophys. 2014 Sep 1;557:18-27. [5]. Ho L, et al. Identification of brain-targeted bioactive dietary quercetin-3-O-glucuronide as a novel intervention for Alzheimer's disease. FASEB J. 2013 Feb;27(2):769-81.

Quercetin represses apolipoprotein B expression by inhibiting the transcriptional activity of C/EBPbeta.[Pubmed:25875015]

PLoS One. 2015 Apr 15;10(4):e0121784.

Quercetin is one of the most abundant polyphenolic flavonoids found in fruits and vegetables and has anti-oxidative and anti-obesity effects. Because the small intestine is a major absorptive organ of dietary nutrients, it is likely that highly concentrated food constituents, including polyphenols, are present in the small intestinal epithelial cells, suggesting that food factors may have a profound effect in this tissue. To identify novel targets of quercetin in the intestinal enterocytes, mRNA profiling using human intestinal epithelial Caco-2 cells was performed. We found that mRNA levels of some apolipoproteins, particularly apolipoprotein B (apoB), are downregulated in the presence of quercetin. On the exposure of Caco-2 cells to quercetin, both mRNA and protein levels of apoB were decreased. Promoter analysis of the human apoB revealed that quercetin response element is localized at the 5'-proximal promoter region, which contains a conserved CCAAT enhancer-binding protein (C/EBP)-response element. We found that quercetin reduces the promoter activity of apoB, driven by the enforced expression of C/EBPbeta. Quercetin had no effect on either mRNA or protein levels of C/EBPbeta. In contrast, we found that quercetin inhibits the transcriptional activity of C/EBPbeta but not its recruitment to the apoB promoter. On the exposure of Caco-2 cells to quercetin 3-O-glucuronide, which is in a cell-impermeable form, no notable change in apoB mRNA was observed, suggesting an intracellular action of quercetin. In vitro interaction experiments using quercetin-conjugated beads revealed that quercetin binds to C/EBPbeta. Our results describe a novel regulatory mechanism of transcription of apolipoprotein genes by quercetin in the intestinal enterocytes.

Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles.[Pubmed:25974109]

PLoS One. 2015 May 14;10(5):e0126481.

Controlling bioaerosols has become more important with increasing participation in indoor activities. Treatments using natural-product nanomaterials are a promising technique because of their relatively low toxicity compared to inorganic nanomaterials such as silver nanoparticles or carbon nanotubes. In this study, antimicrobial filters were fabricated from natural Euscaphis japonica nanoparticles, which were produced by nebulizing E. japonica extract. The coated filters were assessed in terms of pressure drop, antimicrobial activity, filtration efficiency, major chemical components, and cytotoxicity. Pressure drop and antimicrobial activity increased as a function of nanoparticle deposition time (590, 855, and 1150 microg/cm2(filter) at 3-, 6-, and 9-min depositions, respectively). In filter tests, the antimicrobial efficacy was greater against Staphylococcus epidermidis than Micrococcus luteus; ~61, ~73, and ~82% of M. luteus cells were inactivated on filters that had been coated for 3, 6, and 9 min, respectively, while the corresponding values were ~78, ~88, and ~94% with S. epidermidis. Although statistically significant differences in filtration performance were not observed between samples as a function of deposition time, the average filtration efficacy was slightly higher for S. epidermidis aerosols (~97%) than for M. luteus aerosols (~95%). High-performance liquid chromatography (HPLC) and electrospray ionization-tandem mass spectrometry (ESI/MS) analyses confirmed that the major chemical compounds in the E. japonica extract were 1(ss)-O-galloyl pedunculagin, Quercetin-3-O-glucuronide, and kaempferol-3-O-glucoside. In vitro cytotoxicity and disk diffusion tests showed that E. japonica nanoparticles were less toxic and exhibited stronger antimicrobial activity toward some bacterial strains than a reference soluble nickel compound, which is classified as a human carcinogen. This study provides valuable information for the development of a bioaerosol control system that is environmental friendly and suitable for use in indoor environments.

Miquelianin (Quercetin 3-O-glucuronide) is a metabolite of quercetin and a type of natural flavonoid.

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