• Journal of Cancer Prevention
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• v.21 no.3
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• pp.135-143
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• 2016

Background: Fraxetin (7,8-dihydroxy-6-methoxy coumarin), a coumarin derivative, has been reported to possess antioxidative, anti-inflammatory and neuroprotective effects. A number of recent observations suggest that the induction of heme oxygenase-1 (HO-1) inhibits inflammation and tumorigenesis. In the present study, we determined the effect of fraxetin on HO-1 expression in HaCaT human keratinocytes and investigated its underlying molecular mechanisms. Methods: Reverse transcriptase-PCR and Western blot analysis were performed to detect HO-1 mRNA and protein expression, respectively. Cell viability was measured by the MTS test. The induction of intracellular reactive oxygen species (ROS) by fraxetin was evaluated by 2′,7′-dichlorofluorescin diacetate staining. Results: Fraxetin upregulated mRNA and protein expression of HO-1. Incubation with fraxetin induced the localization of nuclear factor-erythroid-2-related factor-2 (Nrf2) in the nucleus and increased the antioxidant response element-reporter gene activity. Fraxetin also induced the phosphorylation of Akt and AMP-activated protein kinase $(AMPK){\alpha}$ and diminished the expression of phosphatase and tensin homolog, a negative regulator of Akt. Pharmacological inhibition of Akt and $AMPK{\alpha}$ abrogated fraxetin-induced expression of HO-1 and nuclear localization of Nrf2. Furthermore, fraxetin generated ROS in a concentration-dependent manner. Conclusions: Fraxetin induces HO-1 expression through activation of Akt/Nrf2 or $AMPK{\alpha}/Nrf2$ pathway in HaCaT cells.

• Korean Journal of Pharmacognosy
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• v.14 no.1
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• pp.1-3
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• 1983

Fraxin, fraxetin-8-glucoside, mp $204-205^{\circ}$ was isolated from the fresh bark of Fraxinus sieboldiana var. angustata Nakai, which is one of the indigenous plants of the Oleaceous family in Korea.

• Korean Journal of Pharmacognosy
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• v.24 no.3
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• pp.197-202
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• 1993

Three components, fraxetin-8-glucoside, esculetin-6-glucoside and mannitol, were isolated from the stem bark of Fraxinus chiisanensis var. stenophylla, F. japonica var. intermedia and F. densata. The MeOH extract of the cortex of F. densata had the antiinflammatory activity on the carrageenin-induced paw edema in rat. The MeOH extracts of the cortex of all three Fraxinus spp. have the potent analgesic activity on the HOAc-induced writhing syndrome in mouse and the hepatoprotective activity on the $CCl_4-induced$ fatty liver in rat: protection of ballooning formation and inhibition of sGPT and sGOT increased by $CCl_4$.

• Korean Journal of Pharmacognosy
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• v.12 no.3
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• pp.143-145
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• 1981

The methanol extract of the rootbark of Fraxinus sieboldiana Blume(Oleaceae) gave two coumarin glycosides, fraxin (fraxetin-8-glucoside), $C_{16}H_{18}O_{10},\;mp\;204^{\circ}\;and\;esculin\;(esculetin-6-glucoside),\;C_{15}H_{16}O_{9},\;mp\;204{\sim}205^{\circ}$. Beside, the methanol extract of the root bark was found to contain mannitol. ${\beta}-sitosterol$ is confirmed by massspectrometry.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.3
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• pp.277-283
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• 2023

Fraxinus rhynchophylla Hance (F. rhynchophylla) is a traditional medicinal plant that has been widely used in East Asia and has been used for chronic bronchitis, bacterial dysentery and improved eyesight. F. rhynchophylla contains various type of coumarins such as esculin, esculetin, fraxin and fraxetin. Esculetin possesses versatile activities including antioxidant, anti-inflammatory, antimicrobial, anticancer properties and improvement of atopic dermatitis. However, there is no research on the process of increasing active components in F. rhynchophylla. The objectives of the present study were to apply biotransformation technology to F. rhynchophylla for increasing the content of esculetin, and enhancing anti-inflammatory and antioxidant activities. F. rhynchophylla extract (FRE) treated with viscozyme L (FRE-VL) showed 3.1 times higher content of esculetin than FRE, and exhibited effects such as increased anti-inflammatory activity and DPPH radical scavenging activity. Based on the these results, it is concluded that biotransformed FRE-VL could be potentially applicable as a new active ingredient in the cosmetic field.

• Natural Product Sciences
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• v.11 no.3
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• pp.150-154
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• 2005

The radical scavenging effect of the MeOH extract of Fraxini Cortex on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was examined. The $CH_2Cl_2$-and n-BuOH-soluble fractions of MeOH extract showed the promising DPPH radical scavenging effects, and further purified by silica gel, Sephadex LH-20 column chromatography, and reversed-phase C-18 MPLC to yield five coumarins, esculetin (1), fraxidin (2), fraxetin (3), fraxidin $8-O-{\beta}-D-glucopyranoside$ (fraxin methyl ether) (5), esculin (6), and a secoiridoid oleuropein (4), and a coumarin-secoiridoid escuside (7). Compounds 1, 3, and 4 showed potent DPPH radical scavenging effects, exhibiting $IC_{50}$ values of 14.68, 9.64, and $22.03\;{\mu}M$, respectively. Compounds 6 and 7 also showed moderate effects with $IC_{50}$ values of 147.79 and $72.73\;{\mu}M$, respectively. L-Ascorbic acid was used as a positive control and exhibited the $IC_{50}$ value of $50.31\;{\mu}M$.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.42-52
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• 2001

The barks of Fraxinus rhynchophylla, Fraxinus sieboldiana and Fraxinus mandshurica, ash trees grown in domestic, were collected, extracted with acetone-H$_2$O(7:3, v/v) and freeze dried to give some dark brown powder. A portion of the freeze dried powder was chromatographed on a Sephadex LH-20 and a TSK 40F column using a series of aqueous methanol, ethanol and ethanol-hexane mixture as eluents Some spectrometric analyses such as NMR and FAB-MS including TLC were performed to identify the structures of the isolated compounds. The bark extractives contained a large amount of coumarin derivatives in addition to a small amount of ester compounds.

• Korean Journal of Pharmacognosy
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• v.38 no.3 s.150
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• pp.287-290
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• 2007

Phytochemical investigation of the MeOH extract of the dried stem barks of Fraxinus rhynchophylla Hance (Oleaceae), as guided by cytoprotective activity against tert-butyl hydroperoxide (t-BHP)-induced cell injury in mouse hippocampal HT22 cells, furnished two coumarins, esculetin (1) and fraxetin (2). Compounds 1 and 2 had the significant cytoprotective effects on t-BHP-induced cellular oxidative injury in HT22 cells. Furthermore, compounds 1 and 2 showed potent DPPH radical scavenging effect, exhibiting $IC_{50}$ values of 14.68 and 9.64 ${\mu}M$, respectively.

• Natural Product Sciences
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• v.19 no.3
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• pp.236-241
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• 2013

A high-performance liquid chromatography-diode array detector (HPLC-DAD) method was established for quantitative evaluation of nine constituents of Fraxinus rhynchophylla such as four coumarins, esculin (1), fraxin (2), esculetin (3), fraxetin (4), three lignans, syringaresinol 4,4'-O-${\beta}$-diglucoside (5), pinoresinol 4-O-${\beta}$-glucoside (6), pinoresinol (9), one secoiridoid, oleuropein (7), and one coumarinolignan, cleomiscosin C (8). The preferred chromatographic condition was obtained on Phenomenex Gemini-NX (3 ${\mu}m$, C18 110A, $150{\times}4.60$ mm) and the mobile phase was composed of water and acetonitrile using a gradient elution. The wavelength was set at 220 nm. Extraction condition of these constituents in F. rhynchophylla was also optimized through extraction time, extraction solvent and extraction method using established method. From this study, extraction at $70^{\circ}C$ with the mixture of ethanol and water for more than 12 h was suggested to be good extraction condition for these constituents. Quantitation of nine constituents in different F. rhynchophylla samples was also successfully accomplished with the newly established method.

• Natural Product Sciences
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• v.26 no.2
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• pp.158-164
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• 2020

Helicobacter pylori is a well-known pathogen that is responsible for gastric disorders. Overcoming of the antibiotic-resistance is a main barrier to treat H. pylori infection. In our search for anti-H. pylori compounds from natural resources, bioactivity-guided isolation on the ethyl acetate fraction of Fraxinus mandshurica bark that had shown anti-H. pylori activity gave twelve compounds (1 - 12) of six coumarins, three phenylethanoids, two secoiridoids, and a lignan using silica gel column chromatography, Sephadex-LH 20, and recrystallization. The chemical structures were identified by spectroscopic data analysis, including 1D, 2D NMR, and mass spectrometry. Among them, compounds 2, 10, and 11 showed moderate growth inhibitory activity against three strains of H. pylori, compared with positive controls of quercetin and metronidazole. Compounds 5, 6, 8, and 12 exhibited the inhibitory activity against strains 26695 or 43504. This is the first report on the anti-H. pylori activity of this plant and the isolated compounds.