• Journal of Applied Biological Chemistry
• /
• v.62 no.4
• /
• pp.361-366
• /
• 2019

Isorhamnetin 3-O-glucoside, a member of the flavonol group, has been reported to be effective for inflammatory and ulcer, as well as to alleviate diabetic complications such as neuropathy, nephropathy and retinopathy. Isorhamnetin 3-O-glucoside has been extracted from several plants. Biotransformation is a valuable tool, which is used to produce value-added chemicals with inexpensive compounds. To synthesis isorhamnetin 3-O-glucoside from quercetin, two genes (PGT E82L and ROMT-9) were introduced into Escherichia coli, respectively. In order to synthesis isorhamnetin 3-O-glucoside from quercetin, a co-culture fermentation system was developed by optimizing the medium and temperature for biotransformation, the cell mix ratio, Isopropyl-β-ᴅ-thiogalactoside induction time, and quercetin feed concentration. Finally, isorhamnetin 3-O-glucoside was biosynthesized up to 181.2 mg/L under the optimized biotransformation condition, which was higher 4.7 times than previously reported (39.6 mg/L).

• Korean Journal of Pharmacognosy
• /
• v.34 no.1 s.132
• /
• pp.18-24
• /
• 2003

The repeated column chromatographic separation of the MeOH extract of Laportea bulbifera Weddell resulted in the isolation of five flavonoids. Structures of the isolated compounds have been identified as $isorhamnetin-7-O-{\alpha}-L-rhamnoside$ (1), $isorhamnetin-3-O-{\alpha}-L-rhamnoside$ (2), $isorhamnetin-3,7-O-{\alpha}-L-dirhamnoside$ (3), $isorhamnetin-3-O-{\alpha}-L-rhamnopyranosyl-(1{\rightarrow}2)-{\beta}-galactopyranoside$ (4), $isorhamnetin-3-O-{\alpha}-rhamosyl-(1{\rightarrow}2)-rhamnoside$ (5) by spectroscopic means.

• Journal of Korean Medicine for Obesity Research
• /
• v.15 no.2
• /
• pp.93-103
• /
• 2015

Objectives: It was investigated the cytoprotective efficacies of isorhamnetin, a flavonoid originally derived from Hippophae rhamnoides L., against oxidative stress-induced apoptosis in C2C12 myoblasts. Methods: The effects of isorhamnetin on cell growth, apoptosis and reactive oxygen species (ROS) generation were evaluated by trypan blue dye exclusion assay, 4',6-diamidino-2-phenylindole staining and flow cytometry. The levels of apoptosis-regulatory and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway-related proteins, and caspase activities (caspase-3 and -9) were determined by Western blot analysis and colorimetric assay, respectively. Results: Our results revealed that treatment with isorhamnetin prior to hydrogen peroxide ($H_2O_2$) exposure significantly increased the C2C12 cell viability and, indicating that the exposure of C2C12 cells to isorhamnetin conferred a protective effect against oxidative stress. Isorhamnetin also effectively attenuated $H_2O_2$-induced apoptosis and ROS generation, which was associated with the restoration of the upregulation of Bax and downregulation of Bcl-2 induced by $H_2O_2$. In addition, $H_2O_2$ enhanced the activation of caspase-9 and -3, and degradation of poly (ADP-ribose)-polymerase, a typical substrate protein of activated caspase-3; however, these events were almost totally reversed by pretreatment with isorhamnetin. Moreover, isorhamnetin increased the levels of heme oxygenase-1, a potent antioxidant enzyme, associated with the induction of Nrf2. Conclusions: Our data indicated that isorhamnetin may potentially serve as an agent for the treatment and prevention of muscle disorders caused by oxidative stress.

• Korean Journal of Food Science and Technology
• /
• v.37 no.1
• /
• pp.90-94
• /
• 2005

Absorption, metabolism, and tissue concentrations of quercetin were examined and compared in mice and rats after oral administration of quercetin at 50 or 100 mg/kg. Quercetin was absorbed quickly in mice and reached maximum plasma concentration in I hr post-administration, and declined sharply after 4 hr. Plasma concentration of isorhamnetin, a major metabolite, also increased sharply, indicating rapid metabolic conversion, but elevated level was maintained longer than that of quercetin. Quercetin and isorhamnetin were found predominantly in glucuronide/sulfate-conjugate forms in both mice and rats. Tissue concentrations of quercetin and isorhamnetin in mice and rats were in the order of liver>kidney>spleen>plasma both 1 and 6 hr postadministration. These results show that quercetin is absorbed in mice after oral feeding and quickly metabolized into isorhamnetin as demonstrated in humans and other animal species. The results also can be used to explain various pharmacological activities reported in mouse models.

• Journal of Applied Biological Chemistry
• /
• v.50 no.4
• /
• pp.254-258
• /
• 2007

Five flavonoids, isorhamnetin 3-O-${\beta}$-D-galactosyl-4'-O-${\beta}$-D-glucoside (1), isorhamnetin 3,4'-di-O-${\beta}$-D-glucoside (2), isorhamnetin 3-O-${\beta}$-D-(6-O-${\alpha}$-L-rhamnosyl)glucosyl-4'-O-${\beta}$-D-glucoside (3), isorhamnetin 3-O-${\beta}$-D-(6-O-${\alpha}$-L-rhamnosyl)glucoside (4), and isorhamnetin 3-O-${\beta}$-D-(6-O-${\alpha}$-L-rhamnosyl) galactoside (5) were isolated from the stems of Opuntia humifusa (Raf.) Raf. and their structures were identified based on LC-MS and NMR data.

• Archives of Pharmacal Research
• /
• v.29 no.4
• /
• pp.287-292
• /
• 2006

In this study, we isolated two new isorhamnetin glycosides, designated as nelumboroside A (3) and nelumboroside B (4), as well as the previously-characterized isorhamnetin glucoside (1) and isorhamnetin rutinoside (2), from the n-BuOH fraction of Nelumbo nucifera stamens. The structures of the two new compounds were then determined, using chemical and spectroscopic techniques. All isolated isorhamnetin glycosides 1-4 showed marked antioxidant activities in the DPPH, and $ONOO^-$ assays.

• Biomolecules & Therapeutics
• /
• v.20 no.4
• /
• pp.406-412
• /
• 2012

This study was performed to examine the hepatoprotective effect of isorhamnetin-3-O-galactoside, a flavonoid glycoside isolated from Artemisia capillaris Thunberg (Compositae), against carbon tetrachloride ($CCl_4$)-induced hepatic injury. Mice were treated intraperitoneally with vehicle or isorhamnetin-3-O-galactoside (50, 100, and 200 mg/kg) 30 min before and 2 h after $CCl_4$ (20 ${\mu}l/kg$) injection. Serum aminotransferase activities and hepatic level of malondialdehyde were significantly higher after $CCl_4$ treatment, and these increases were attenuated by isorhamnetin-3-O-galactoside. $CCl_4$ markedly increased serum tumor necrosis factor-${\alpha}$ level, which was reduced by isorhamnetin-3-O-galactoside. The levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and heme oxygenase-1 (HO-1) protein and their mRNA expression levels were significantly increased after $CCl_4$ injection. The levels of HO-1 protein and mRNA expression levels were augmented by isorhamnetin-3-O-galactoside, while isorhamnetin-3-O-galactoside attenuated the increases in iNOS and COX-2 protein and mRNA expression levels. $CCl_4$ increased the level of phosphorylated c-Jun N-terminal kinase, extracellular signal-regulated kinase and p38, and isorhamnetin-3-O-galactoside reduced these increases. The nuclear translocation of nuclear factor kappa B (NF-${\kappa}B$), activating protein-1, and nuclear factor erythroid 2-related factor 2 (Nrf2) were significantly increased after $CCl_4$ administration. Isorhamnetin-3-O-galactoside attenuated the increases of NF-${\kappa}B$ and c-Jun nuclear translocation, while it augmented the nuclear level of Nrf2. These results suggest that isorhamnetin-3-O-galactoside ameliorates $CCl_4$-induced hepatic damage by enhancing the anti-oxidative defense system and reducing the inflammatory signaling pathways.

• Biomolecules & Therapeutics
• /
• v.23 no.4
• /
• pp.357-366
• /
• 2015

Isorhamnetin (3-methylquercetin) is a flavonoid derived from the fruits of certain medicinal plants. This study investigated the photoprotective properties of isorhamnetin against cell damage and apoptosis resulting from excessive ultraviolet (UV) B exposure in human HaCaT keratinocytes. Isorhamnetin eliminated UVB-induced intracellular reactive oxygen species (ROS) and attenuated the oxidative modification of DNA, lipids, and proteins in response to UVB radiation. Moreover, isorhamnetin repressed UVB-facilitated programmed cell death in the keratinocytes, as evidenced by a reduction in apoptotic body formation, and nuclear fragmentation. Additionally, isorhamnetin suppressed the ability of UVB light to trigger mitochondrial dysfunction. Taken together, these results indicate that isorhamnetin has the potential to protect human keratinocytes against UVB-induced cell damage and death.

• Natural Product Sciences
• /
• v.14 no.2
• /
• pp.81-85
• /
• 2008

Isorhamnetin isolated from Oenanthe javanica significantly inhibited proliferation and collagen production in HSC-T6 cells in concentration- and time-dependent manners. Pretreatment of HSC-T6 cells with isorhamnetin significantly inhibited serum-induced ERK phosphorylation, in a similar manner as PD98059, a known MEK inhibitor. These results suggested that isorhamnetin reduced collagen production in HSC-T6 cells, in part, via inhibition of ERK signaling pathway.

• Natural Product Sciences
• /
• v.18 no.3
• /
• pp.190-194
• /
• 2012

The effects of methanol extract of the leaves of Brassica juncea and its major component, isorhamnetin 3-O-${\beta}$-D-glucopyranoside on hepatic alcohol metabolizing enzymes were investigated. The methanol extract and isorhamnetin 3-O-${\beta}$-D-glucopyranoside supplementations increased the activities of microsomal ethanol oxidizing system and aldehyde dehydrogenase in a dose-dependent manner, and had mild effects on the activities of alcohol dehydrogenase and catalase. Isorhamnetin 3-O-${\beta}$-D-glucopyranoside alleviated the adverse effect of ethanol ingestion by enhancing the activities of alcohol oxidizing emzymes, microsomal ethanol oxidizing system and aldehyde dehydrogenase.