• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.41-48
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• 2002

The barks of oak trees (Quercus acutissima and Quercus variabilis) were collected, extracted with acetone-$H_2O$ (7:3, v/v), fractionated with hexane, $CH^2C1^2$ EtOAc and -$H_2O$, then freeze dried to give dark brown powder. The EtOAc soluble mixtures of the trees were chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. The structures of isolated compounds were characterized by $^1H$, $^13C$ and 2D-NMR spectroscopy and molecular weights were determined by FAB-MS spectra. The isolated compounds from Quercus acutissima were (+)-catechin, (+)-gallocatechin, gallic acid and taxifolin-3-O-$\beta$-D-glucopyranoside and the compounds from Quercus variahilis (+)-catechin, caffeic acid and taxifolin-3-O-$\beta$-D-glucopyranoside.

• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.276-280
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• 2007

In this work, caffeine and some catechin compounds + C, EC, EGC, and EGCG were extracted from green tea by using molecular imprinted polymers (MIP) as sorbent materials in a solid-phase extraction (SPE) process known as MISPE (molecular imprinted solid-phase extraction). For synthesis of MIP, caffeine was employed as the template, MAA as the monomer, EGDMA as the crosslinker, and AIBN as the initiator. A solution of caffeine (0.2 mg/mL in methanol) was utilized in the solid extraction cartridges following loading, washing, and elution procedures with acetonitrile, methanol, and methanol-acetic acid (90/10, %v/v) as the solvents, respectively. This solid-phase extraction protocol was applied for the extraction of caffeine and some catechin compounds from green tea. A comparison was made between the results obtained with the MIP cartridges and a traditional C18 reversed-phase cartridge. It was thereupon found that the recovery of caffeine by the MIPbased sorbent used in this work was almost two and four times greater than that by a commercially available C18 material. A quantitative analysis was conducted by high performance liquid chromatography (HPLC) using a C18 column (5 μm, 250 × 4.6 mm) with methanol/water (40/60, %v/v) as the mobile phase at a flow rate of 0.5 mL/min.

• Journal of the Korean Chemical Society
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• v.65 no.2
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• pp.106-112
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• 2021

12 kinds of (-)-catechin derivatives were designed and synthesized. The catechin derivatives were evaluated their antioxidant activities using DPPH method. Most of them showed good antioxidant activity, particularly compounds 1d, 1e and 1j exhibited more activity than butylated hydroxytoluene (BHT). Molecular docking studies for compounds 1d, 1e and 1j with STAT1 showed not only sufficent characteristics binding cavity but also agreement with the observed biological activity. Acording to docking results, the compounds showed greater than hydrogen bonding, hydrophobic interactions, electrostatic interactions, and Van der Waals interactions as compared to the reference compound. They formed hydrogen bonds with important residues such as Lys566, His568, Leu570, and Phe644. The compounds showed a novel hydrogen bonding interaction with Arg649, which was not reported previously. Our results might suggest the compounds could serve as a novel anti-oxidant agent.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.165-170
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• 2007

In this work, caffeine and some catechin compounds such as +C, EGC and EGCG were extracted from green tea using quercetin molecular imprinted polymers in solid-phase extraction. For synthesis of MIP, quercetin as the templates, MAA as the monomer, EGDMA as the crosslinker and AIBN as the initiator were used. For extraction of caffeine and catechin compounds from green tea, the solid-phase extractions of a load followed by wash and elution procedures were done with water, methanol and methanol:acetic acid=90:10 (vol.%) as the solvents, respectively. HPLC analysis (C18 column, 5 μm, 250×4.6 mm) with the mobile phase of methanol:water=40:60 (vol.%) at a flow rate of 0.5 ml/min was adopted for the quantitative determination. By solid-phase extraction, the resolutions of caffeine and some catechin compounds from green tea were increased. The quercetin-MIP had higher selectivity to +C compounds.

• Journal of Life Science
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• v.18 no.2
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• pp.273-278
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• 2008

Various biological resources from plants, animals, mushrooms, microorganisms, and foods were tested for the inhibitory activity against squalene synthase (SQS). Among 32 samples, more than one fourths (9 samples) exhibited significant SQS inhibitory activity. Interestingly, SQS inhibitory activity was detected in the samples such as green tea, fermented soybean paste, and plum juice. The SQS inhibitory activity of green tea was not only high but also stable. Its SQS inhibitors were supposed to be catechin derivatives, which have been known to be main bioactive components in green tea. The galloyl catechins showed higher SQS inhibitory activity compared to the nongalloyl catechins. Especially, (-)-epigallocatechin gallate appeared to be strongest inhibitor against squalene synthase ($IC_{50}=90{\mu}M$).

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.3
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• pp.251-256
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• 2009

Investigation of antioxidative constituents from the ethanol extract of Quercus gilva branches led to the identification of four compounds; catechin (1), epi-catechin (2), tyrosol (3) and tiliroside (4). The antioxidative activity was examined using DPPH radical and superoxide anion radical scavenging method. The isolated compounds 1, 2, 3 and 4 exhibited 94.2 %, 93.4 %, 33.6 % and 11.2 % scavenging activities respectively against DPPH radicals at the concentration of $100{\mu}L$/mL. As well, the compounds $1{\sim}4$ showed respectively 60.2 %, 35.1 %, 20.6 %, 4.5 % inhibition activities against superoxide anion radicals at $200{\mu}L$/mL. Interestingly, the compounds $1{\sim}4$ were isolated for the first time from Quercus gilva Blume.

• The Journal of the Korea Contents Association
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• v.12 no.1
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• pp.338-345
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• 2012

This study was developed to test the effectiveness catechin beverage drinking as exercise supplementary food for obese women. The effects of catekin were determined by weight, total cholesterol, triglycerides, High density lipoprotein cholesterol, high density lipoprotein cholesterol. Twenty-seven obese women were participated in this study. Eight women were tea catechin drinking group, Nine women were exercise group, and ten women were tea catekin drinking-combined with exercise group. After catechin drinking or exercise conducted, blood lipid factor were analyzed. body weight and triglycerides low density lipoprotein cholesterol levels were significantly decreased in tea catekin drinking combined with exercise group (p<0.001) and exercise group (p<0.001). total cholesterol were significantly decreased in three groups (p<0.05). It is thought that together catechin drinking and exercise can maximize weight loss of obese woman and reducing of blood lipid factor.

• 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 Microbiology and Biotechnology
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• v.31 no.7
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• pp.1011-1021
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• 2021

The root bark of Ulmus davidiana var. japonica (Japanese elm) is used in Korea and other East Asian countries as a traditional herbal remedy to treat a variety of inflammatory diseases and ailments such as edema, gastric cancer and mastitis. For this study, we investigated the lipid metabolism and anti-obesity efficacy of ethyl alcohol extract of Ulmus davidiana var. japonica root bark (UDE). First, HPLC was performed to quantify the level of (+)-catechin, the active ingredient of UDE. In the following experiments, cultured 3T3-L1 pre-adipocytes and high-fat diet (HFD)-fed murine model were studied for anti-obesity efficacy by testing the lipid metabolism effects of UDE and (+)-catechin. In the test using 3T3-L1 pre-adipocytes, treatment with UDE inhibited adipocyte differentiation and significantly reduced the production of adipogenic genes and transcription factors PPARγ, C/EBPα and SREBP-1c. HFD-fed, obese mice were administered with UDE (200 mg/kg per day) and (+)-catechin (30 mg/kg per day) by oral gavage for 4 weeks. Weight gain, epididymal and abdominal adipose tissue mass were significantly reduced, and a change in adipocyte size was observed in the UDE and (+)-catechin treatment groups compared to the untreated control group (^***p < 0.001). Significantly lower total cholesterol and triglyceride levels were detected in UDE-treated HFD mice compared to the control, revealing the efficacy of UDE. In addition, it was found that lipid accumulation in hepatocytes was also significantly reduced after administration of UDE. These results suggest that UDE has significant anti-obesity and lipid metabolism effects through inhibition of adipocyte differentiation and adipogenesis.

• Korean Journal of Pharmacognosy
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• v.51 no.4
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• pp.291-296
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• 2020

Filipendula glaberrima (FG) is a plant endemic to South Korea. It is economically important as a food source and used as a medicine in treating ailments. Filipendula flowers are characterized by the presence of several polyphenolic constituents. The aim of this study is to determine the content of (+)-catechin in Filipendula glaberrima collected from different regions at different flowering stages. High-performance liquid chromatography with a gradient elution system (0.5% acetic acid in water : acetonitrile = 95 : 5 to 0 : 100 for 35 min) was used. A reverse-phase INNO column with UV detection at 278 nm was employed. The results revealed that F. glaberrima from Mt. Odae has the highest (+)-catechin content (10.600 mg/g). Furthermore, its content was the lowest in samples collected during the pre-flowering period and the highest at the early-flowering stage. This study provides a basis in establishing the optimal period and the best region for collecting F. glaberrima with maximized (+)-catechin yield.