• Journal of the Korean Wood Science and Technology
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• v.43 no.2
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• pp.214-223
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• 2015

The bark of Acer komarovii was collected, ground, and extracted with 70% aqueous acetone to obtain concentrates. The concentrates were suspended in $H_2O$, and then successively partitioned with n-hexane, dichloromethane and ethylacetate to be freeze dried. A portion of ethylacetate fraction was chromatographed on a Sephadex LH-20 and a RP C-18 column with various aqueous MeOH-$H_2O$ (1:0, 1:1, 1:2, 1:5, 1:7, 1:9, 1:10, 3:1, and 4:1, v/v) eluents. Four compounds were isolated; (-)-epicatechin (9.6 g), procyanidin A2 (epicatechin-($4{\beta}{\rightarrow}8$, $2{\beta}{\rightarrow}O{\rightarrow}7$)-epicatechin) (1.3 g), procyanidin B2 (epicatechin-($4{\beta}{\rightarrow}8$)-epicatechin) (40.0 mg), and cinnamtannin B1 (epicatechin-($4{\beta}{\rightarrow}8$, $2{\beta}{\rightarrow}O{\rightarrow}7$)-epicatechin-($4{\beta}{\rightarrow}8$)-epicatechin) (690 mg). The analysis of the bark procyanidins showed that the basic unit constituting condensed tannins was only (-)-epicatechin. This study, for the first time, report the procyanidins of Acer komarovii bark.

• Natural Product Sciences
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• v.21 no.1
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• pp.66-70
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• 2015

Content analysis of flavonoids (epicatechin, epicatechin gallate, and rutin) present in the leaves of Boehmeria nivea (originating from Geumsan-myeon, Biin-myeon, Hansan-myeon, and Baeksu-eup) and their commercial products (ramie tteok, ramie songpyeon, ramie bory-tteok, and ramie tea) was conducted by HPLC. The content of epicatechin, epicatechin gallate, and rutin was highest in the leaves of B. nivea from Geumsan-myeon (0.138 mg/g), Baeksu-eup (1.654 mg/g) and Geumsan-myeon (12.205 mg/g), respectively. With respect to commercial products, the content of epicatechin and epicatechin gallate was highest in ramie tea, with concentrations of 1.879 and 1.090 mg/g, respectively. Given these flavonoid concentrations, B. nivea leaf extracts have the potential to be used as additives in natural medicinal products, health supplements, and beverages.

• Applied Biological Chemistry
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• v.41 no.1
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• pp.110-117
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• 1998

Seven kinds of polyphenol compounds having ACE activities were isolated and purified by Sephadex LH-20, MCI-gel CHP-20, ${\um}-Bondapak\;C_{18}$ and Fuji-gel ODS $G_3$ sucessively from cacao bean(Ghana). The chemical structures of each compound were determined and identified using analyzers such as $^1H-NMR$, $^{13}C-NMR$, IR, MS, polarimeter and Elemental Analysis. Inhibition effects of isolated polyphenols on angiotensin converting enzyme (concerned with hypertension) were also observed. The results obtained were as follows,; The compounds isolated and identified were confirmed and determined as compound 1 [(+)-catechin], compound 2 [(-)-epicatechin], compound 3 [procyanidin B-1 : (-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(+)catechin], compound 4 [procyanidin B-2 : (-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(-)-epicatechin], compound 5 [procyanidin B-7 : (-)-epicatechin-$(4{\beta}{\rightarrow}6)$-(+)-catechin], campound 6 (procyanidin B-2,3,3'-O -digallate), compound 7 [cinnamtannin A-2 : (-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(-)-epicatechin-$(4{\beta}{\rightarrow}8)$-(-)-epicatechin]. In the inhibition effect on ACE, procyanidin B-2,3,3'-O-digallate (compound 6) showed a higher value of 94.6% for ACE in $100\;{\um}M$ than other compounds such as (+)-catechin (compound 1), (-)-epicatechin (compound 2), procyanidin B-1 (compound 3), procyanidin B-2 (compound 4), procyanidin B-7 (compound 5) and cinnamtannin A-2 (compound 7) showing 67.9%, 61.9%, 88.6%, 82.5%, 72.2% and 82.3% for ACE, respectively. Inhibition of $4{\beta}{\rightarrow}8$ in coupling bond on the ACE enzyme was more effective than that of $4{\beta}{\rightarrow}6$. Procyanidin containing gallate inhibited more effectively than those containing not any. It was also observed that a lot of hydroxy group in the compounds increased the inhibitory effect.

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1322-1326
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• 2013

New antifungal agents are required to compensate for the increase in resistance to standard antifungal agents of Candida albicans, which is an important opportunistic fungal pathogen that causes minor infections in many individuals but very serious infections in those who are immune-compromised. In this study, combinations of theaflavin and epicatechin are investigated as potential antifungal agents and also to establish whether antifungal synergy exists between these two readily accessible and cost-effective polyphenols isolated from black and green tea. The results of disc diffusion assays showed stronger antibacterial activity of theaflavin:epicatechin combinations against C. albicans NCTC 3255 and NCTC 3179, than that of theaflavin alone. Minimum inhibitory concentrations (MICs) of 1,024 ${\mu}g/ml$ with theaflavin and 128-256 ${\mu}g/ml$ with theaflavin:epicatechin combinations were found. The fractional inhibitory concentration indexes were calculated, and the synergy between theaflavin and epicatechin against both isolates of C. albicans was confirmed. Theaflavin:epicatechin combinations show real potential for future use as a treatment for infections caused by C. albicans.

• KSBB Journal
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• v.8 no.1
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• pp.69-74
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• 1993

For an anti-plaque agent, two flavan-3-ols isolated from Theobroma cacao bean husk showed positive reactions with $H_2SO_4$-anisaldehyde solution, $FeCl_3$, and were identified as monomeric, dimeric flavan-3-ots in TLC. They were (-)-epicatechin and procyanidin B-2(epicatechin-(4$\beta$$\rightarrow$8)-epicatechin). The structures were established by spectroscopic and chemical methods. (-)-Epicatechin had moderate inhibitory activity on GTase at concentration of 1.0mM while procyanidin B-2 showed complete inhibition activity at the same concentration. The hydroxyl group of flavan-3-ol was supposed to be the essential element for inhibition on GTase.

• Korean Journal of Pharmacognosy
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• v.19 no.3
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• pp.170-173
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• 1988

(-)-Epicatechin, $mp\;234{\sim}6^{\circ}$, was isolated from the fresh roots of Rubus parvifolius together with a sterol mixture, which was found to be a mixture of ${\beta}-sitosterol\;(major)$, stigmasterol and campesterol.

• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.510-515
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• 2008

Microwave energy was applied to the extraction of functional catechins from grape seed. The solvent, absolute ethanol, reached the boiling point when exposed for less than 3 min microwave treatment at 100 W. The effects of independent variables in microwave-assisted extraction (MAE), including microwave power (0-160W, $X_1$), ethanol concentration (0-100%, $X_2$) and extraction time (1-5 min, $X_3$), were investigated on each response variable ($Y_n$), and the contents of catechin and its derivatives were determined via response surface methodology, thereby allowing us to predict their optimal extraction conditions. The predicted maximal values of (+)-catechin, procyanidin $B_2$, (-)-epicatechin, and (-)-epicatechin gallate were 137.99, 72.78, 222.38, and 9.59 mg%, respectively, under different MAE conditions. The predicted extraction conditions for maximum catechin responses were as follows: 104.10 W of microwave power, 45.35% of EtOH, and 4.89 min of extraction time for (+)-catechin (137.99 mg%), 133.16 W, 46.16% and 4.49 min for procyanidin $B_2$ (72.78 mg%), 136.00 W, 41.37% and 4.39 min for (-)-epicatechin (222.38 mg%), 143.20 W, 37.51% and 1.88 min for (-)-epicatechin gallate (9.59 mg%), respectively. The contents of (+)-catechin, procyanidin 1B2 and (-)-epicatechin in MAE were similarly influenced by three independent variables, whereas (-)-epicatechin gallate was influenced less profoundly by ethanol concentration and extraction time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1498-1502
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• 2005

This study evaluated the isolation and identification of biologically active compounds from the ethyl acetate fraction of grape seed extract (Campbell early). Ethyl acetate fraction was further purified with sephadex LP-20 column chromatography. Each biologically active compound for free radical scavenging effect and lipid peroxidation inhibition was isolated and identified with ${1}^H$ and${12}^C$-NMR. Major compounds were identified as (+)-catechin and (-)-epicatechin respectively. The amounts of (+)-catechin and (-)-epicatechin in grape seed were 45.7$\%$ and 35.1$\%$, respectively. The purified (+)-catechin and (-)-epicatechin showed more strong free radical scavenging effects ($RC_{50}$= 11.1 $\mu$g/mL and 10.4 $\mu$g/mL) than ethyl acetate fraction ($RC_{50}$= 15.4 $\mu$g/mL). However, ethyl acetate fraction showed much stronger lipid oxidative inhibition effect than the purified (+)-catechin and (-)-epicatechin.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.145-151
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• 2007

To investigate the chemical constituents of Acer tegmentosum, the bark were collected, air-dried and extracted with 70% aqueous acetone. Then it was successively partitioned with n-hexane, $CH_2Cl_2$, EtOAc and $H_2O$. Repeated Sephadex LH-20 column chromatography on the EtOAc soluble fraction gave five phenolic compounds. Their structures were elucidated as (+)-catechin (1), (-)-epi-catechin (2), Q-epicatechin-3-O-gallate (3), gallic acid (4) and 6'-0-galloylsalidroside (5) on the basis of spectroscopic evidences using $^1H-NMR$, $^{13}C-NMR$, 2D-NMR and MS spectroscopy, (-)-epicatechin-3-Ogallate (3), gallic acid (4), 6'-Ogalloylsalidroside (5) have not been reported in this plant yet.

• Korean Journal of Medicinal Crop Science
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• v.5 no.4
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• pp.302-306
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• 1997

One flavan 3-ol derivative was isolated from the stem of Acer mono Max, along with two known coumarins. On the basis of spectroscopic evidence, the structures of these compounds were established as (-) - epicatechin, scopoletin and isoscopoletin. Antioxidative activity of (-) - epicatechin was examined by the DPPH free radical scavenging method. Antioxidative activity of (-) - epicatechin $(RC_{50}\;:\;7.5\;{mu}g)$ was more greater than those of ${\alpha}-tocopherol\;(RC_{50}\;:\;12\;{mu}g)$ and $BHA\;(RC_{50}\;:\;14\;{mu}g)$.