• Journal of the Korean Wood Science and Technology
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• v.47 no.4
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• pp.498-508
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• 2019

This study was carried out to investigate the potential of Korean red pine (Pinus densiflora) inner bark extracts as an antidiabetic agent. The ethyl acetate soluble fraction of the bark extracts was chromatographed on a Sephadex LH-20 column to yield five compounds, which structures were elucidated by NMR spectroscopy. The isolated compounds were (+)-catehin, (-)-epicatechin, taxifolin, taxifolin-3'-O-${\beta}$-D-(+)-glucose and $\tilde{n}$-courmaric acid. The antidiabetic activity of the different fractions, including the crude extracts and isolated compounds, was evaluated by ${\beta}$-cells insulin secretion and glucose uptake in skeletal muscle cells. The insulin secretion was 128% for taxifolin at $25{\mu}g/mL$. However, the other samples had no effect on this test. For the glucose uptake activity assay, $1{\mu}M$ insulin and 2 mM metformin were used as controls. Both the crude extract and taxifolin showed relatively low activity values, but the other samples yielded glucose uptake values over 260%. ${\rho}$-courmaric acid showed the highest uptake (270%). The results confirmed that Korean red pine extracts may be used as a hypoglycemic agent.

• Korean Journal of Pharmacognosy
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• v.47 no.3
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• pp.246-250
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• 2016

Pinus densiflora contained diverse phenol compounds like flavonoid, phenylpropanoid and tannin. PineXol$^{(R)}$ is nutraceutical preparation which was treated from bark of Pinus densiflora. Validation and contents determination of taxifolin, (+)-catechin and procyanidion B1 for the preparation of Pinus densiflora (PineXol$^{(R)}$) were confirmed using High-Performance Liquid Chromatography (HPLC). As a result, content of taxifolin, (+)-catechin and procyanidin B1 were, respectively 4.90%, 2.35% and 8.19%. These analysis method and results could be used as important basic data for the preparation of Pinus densiflora.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.78-84
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• 2000

Two flavanones and one flavone were isolated from the diethylether soluble fraction of ethanol extract of Larix leptolepis heartwood. These compounds were identified 3,3',4',5,7-pentahydroxyflavanone(taxifolin), 3,4',5,7-tetrahydroxyflavanone(aromadendrin) and 3,3',4',5,7-pentahydroxyflavone(quercetin) by instrumental analyses using UV, IR, MS and NMR spectrometries. Antioxidative activies of these compounds were investigated by 1,1-diphenyl-2-picrylhydrazyl(DPPH) free radical scavenging activity. Quercetin and taxifolin indicated high free radical scavenging activities compared to ${\alpha}$-tocopherol and BHT(butylated hydroxytoluene).

• Journal of Forest and Environmental Science
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• v.38 no.3
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• pp.159-173
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• 2022

Genus of Rhododendron has been used in traditional medicine since ancient times and is known to be effective in immune function, inflammation, and cold symptoms. And the reason for this activity is the flavanonol type among flavonoids in the genus of Rhododendron. Among the flavanonol types, Taxifolin-3-O-arabinopyranoside was isolated from the root of native R. mucronulatum in Korea, and the structure was finally identified through HPLC, LC-MS/MS, ¹H-NMR, and ¹³C-NMR. Taxifolin-3-O-arabinopyranoside is a compound mainly found in R. mucronulatum, a representative species of the genus of Rhododendron, and exhibits antioxidant, anti-inflammatory, and anti-atopic activities. In this study, Taxifolin-3-O-arabinopyranoside was chemotaxonomic significant in 5 species of the genus Rhododendron native to Korea (R. mucronulatum, R. mucronulatum var. ciliatum, R. schlippenbachii, R. yedoense var. Poukhanense, R. japonicum for. Flavum). Compared with the existing literature, Taxifolin-3-O-arabinopyranoside was identified for the first time in 4 species of Rhododendron except for the R. mucronulatum.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.83-87
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• 2000

The five phenolic compounds of peony root were isolated by Sephadex LH-20 column chromatography. Their chemical structures were identified by spectroscopic methods (UV, FT-IR, FAB-MS and $^1H$ .&^13C$-NMR). The complete structures of these compounds were elucidated to be (+)-taxifolin-3-0-$\beta$-D-glucopyranoside, benzoic acid, gallic acid, (-)-epicatechin and (+)-catechin. The concentrations of five phenolic compounds in the peony root of three Korean cultivars (Youngchonjakyak, Euisungjakyak and Jomjakyak) were determined by reverse-phase HPLC. The constituents concentration in Youngchonjakyak were generally higher than in Euisungjakyak and Jomjakyak. The concentrations of (+)-taxifolin-3-O-$\beta$-D-glucopyranoside, benzoic acid, gallic acid, (-)-epicatechin and (+)-catechin in three different cultivars were ranged 0.23-0.52%, 0.20-0.30%, 0.26-0.28%, 0.09-0.12% and 0.34-0.63%, respectively.

• Journal of the Korean Wood Science and Technology
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• v.32 no.6
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• pp.43-49
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• 2004

Three flavonoids, quercetin, taxifolin, and kaempferol were isolated from the woods of Liriodendron tulipifera. Their structures were determined by spectral analysis. Based on 1, l-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity method, the antioxidative activities of three isolated compounds and their acetates were measured in order to search for natural antioxidants. The IC₅₀ of quercetin (1), taxifolin (2), and kaempferol (3) were 3.6, 3.9, and 4.1 ㎍/㎖, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.459-464
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• 2002

This experiment was conducted to know the changes of bioactive component content in four-year-old peony (Paeonia lactiflora Pall.) root with various drying methods such as room temperature drying, $50^{\circ}C$ heat-air drying, room temperature drying after $80^{\circ}C$ boiling water treatment and freeze drying, and to establish the optimum drying method for high quality production of Paeoniae Radix. For this purpose, the contents of paeoniflorin, albiflorin and five phenolic compounds (gallic acid, benzoic acid, (+)-catechin, (-)-epicatechin and (+)-taxifolin 3-O-$\beta$-D-glucopyranoside) in peony root with different drying methods were analyzed by RP-HPLC. The contents of paeoniflorin, albiflorin and (+)-taxifolin 3-O-$\beta$-D-glucopyranoside at room temperature drying were higher than in the other drying methods and that of gallic acid at 8$0^{\circ}C$ boiling water treatment was the highest among that of all drying methods. In the case of freeze drying, the contents of (+)-catechin, benzoic acid and (-)-epicatechin were the highest among those of all drying methods. As increase of drying and treatment temperature, the contents of paeoniflorin, albiflorin, (+)-taxifolin 3-O-$\beta$-D-glucopyrano-side, (+)-catechin and benzoic acid were decreased.

• Journal of the Korean Wood Science and Technology
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• v.38 no.4
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• pp.359-374
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• 2010

This study was carried out to investigate the chemotaxonomical correlation and chemical constituents of domestic Quercus spp. barks. The barks of Q. mongolica, Q. aliena, Q. serrata, Q. acutissima, Q. dentata, and Q. variabilis were collected in the experimental forest of Kangwon National University. The combined extracts were successively fractionated with n-hexane, methylene chloride and ethyl acetate using a separation funnel. A portion of the ethyl acetate and H2O soluble materials of each species were chromatographed on a Sephadex LH-20 column using various aqueous MeOH and EtOH-hexane as washing solvents. Spectrometric analysis such as NMR and MS, including TLC, were performed to characterize the structures of the isolated compounds. Ellagic acid (0.03 g), (+)-catechin (4.59 g), taxifolin (3.35 g), and glucodistylin (20.52 g) were isolated from Q. mongolica bark. Gallic acid (0.18 g), (+)-catechin (8.52 g), (+)-gallocatechin (0.09 g), taxifolin (0.54 g), and glucodistylin (3.28 g) were characterized from Q. acutissima bark. Gallic acid (0.38 g), ellagic acid (0.11 g), (+)-catechin (2.01 g), (+)-gallocatechin (0.12 g), and glucodistylin (0.39 g) were identified from Q. dentata bark. Ellagic acid (1.51 g), (+)-catechin (21.91 g), and glucodistylin (3.91 g) were purified from Q. aliena bark. Ellagic acid (0.84 g), (+)-catechin (0.82 g), taxifolin (4.02 g), and glucodistylin (21.50) were isolated from Q. serrata bark. Gallic acid (0.24 g), caffeic acid (0.05 g), (+)-catechin (0.32 g), and glucodistylin (0.65 g) were purified from Q. variabilis bark. (+)-Catechin and glucodistylin were isolated from all the barks. Glucodistylin can be a taxonomic index on Quercus spp.

• Applied Biological Chemistry
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• v.37 no.2
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• pp.105-109
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• 1994

Five cytotoxic and antioxidative flavonoids were isolated from the stem bark of Cudrania tricuspidata by consecutive purification using HP-20, silicagel and prep-HPLC. They were identified as taxifolin, orobol, eriodictyol, dihydrokaempferol and steppogenin by means of spectral studies. The antioxidative activities $(IC_{50})$ assayed by TBA method of these compound $1{\sim}5$ to were 6, 3, 3, >50, and $10\;{\mu}g/ml$, respectively. The effect on the growth inhibition $(IC_{50})$ of these compounds against P388 cell line were found to be 0.18, 3.3, 15 and $6.2\;{\mu}g/ml$, respectively in the order of compound 2 to 5.

• Biomolecules & Therapeutics
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• v.18 no.2
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• pp.191-196
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• 2010

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl- 2-picrylhydrazyl (DPPH), a total extract of the twigs of Stewartia koreana (Theaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of six phenolic compounds, ampelopsin (1), catechin (2), proanthocyanidin-A2 (3), fraxin (4), (2R, 3R)-taxifolin-3-${\beta}$-D-glucopyranoside (5), and (2S, 3S)-taxifolin-3-${\beta}$-D-glucopyranoside (6), as active principles. Their structures were elucidated by spectroscopic studies. Compounds 1-6 were isolated for the first time from this plant. Among them, three compounds 1-3 showed the significant antioxidative effects on DPPH, and riboflavin originated superoxide quenching activity. In riboflavin-nitrobluetetrazolium (NBT)-light system, compound 1 showed better superoxide quenching activity than vitamin C.