• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.558-565
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• 2015

Katsura tree (Cercidiphyllum japonicum Sieb. Et Zucc) leaves were collected, air-dried and extracted with 70% aqueous acetone, then concentrated and sequentially fractionated using n-hexane, methylene chloride ($CH_2Cl_2$), ethylacetate (EtOAc), and $H_2O$. The EtOAc fraction was chromatographed on a Sephadex LH-20 column with various aqueous MeOH eluting solvents and finally treated with acetone-$H_2O$ (7:3, v/v) to isolate a gallotannin. According to the NMR analysis, including HSQC and HMBC, and with the comparison of authentic literature data, the isolate was elucidated as 6-m-digalloyl-1,2,3,4-tetra-O-galloyl ${\beta}$-D-(+)-glucose, one of hydrolyzable tannins and one of gallotannins. The compound was only gallotannin which was firstly isolated from the extracts of Katsura tree leaves, and has not been reported before in domestic tree sources.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.498-502
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• 2009

Cornus fructus has been used as a tonic, astringent, and haemostatic agent in Korea, China, and Japan. In this study, the fruit of Cornus officinalis was treated with different osmotic pressures, pH values, heat, and ethanol percentages in order to establish optimum extraction conditions for gallic acid, an example of a hydrolyzable tannin. The extract was analyzed by HPLC and LC-MS/MS to identify the gallic acid. As a result, the highest extraction rate of gallic acid (1.57 mg/g) occurred when the Cornus fructus was extracted with 100% ethanol for 1 hr at $80^{\circ}C$. Also, when it was treated with 70% ethanol for 24 and 48 hr, contents of gallic acid were 1.35 and 1.50 mg/g, respectively.

• Journal of Life Science
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• v.27 no.3
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• pp.325-333
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• 2017

High level of plasma cholesterol is strongly associated with the development of atherosclerosis and coronary heart disease. Clinical trials designed to reduce plasma cholesterol level by diet or pharmacological intervention have resulted in marked reduction of disease incidence. The enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase which reduces cholesterol biosynthesis in the liver is the key enzyme of the mevalonate pathway that produces cholesterol. In this study, 71 naturally occurring phenolic compounds were tested for inhibitory activities against HMG-CoA reductase. Eleven compounds out of 71 showed inhibitory activities: three hydrolyzable tannin (geraniin, acetonyl geraniin and pentagalloyl ${\beta}-D-glucose$), four benzoic acid derivatives (benzoic acid, trans-cinnamic acid, 2,4-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid), and four naphthoquinone derivatives (1,2-naphthoquinone, 1,4-naphthoquinone, plumbagin and shikonin). At the concentration of $10{\mu}g/ml$, 1,4-naphthoquinone inhibited HMG-CoA reductase by 99.4%, and then plumbagin 91.4%, pentagalloyl ${\beta}-D-glucose$ 46.6%, 2,4-dihydroxybenzoic acid 40.9%, shikonin 37.7%, 1,2-naphthoquinone 36.6%, trans-cinnamic acid 32.0%, acetonyl geraniin 30.2%, benzoic acid 28.5%, geraniin 28.3% and 2,5-dihydroxybenzoic acid 22.3%, respectively. $IC_{50}$ values of 1,4-naphthoquinone and plumbagin was $2.1{\mu}g/ml$ and $5.8{\mu}g/ml$, respectively.