• Journal of Applied Biological Chemistry
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• v.52 no.1
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• pp.15-20
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• 2009

Poplar contains various flavonoids including naringenin, kaempferol, myricetin, apigenin, luteolin, rhamnetin, and quercetin. These flavonoids are synthesized from naringenin with various enzymes. However, none of genes from poplar involved in flavonoid biosynthesis have been biochemically characterized. We cloned PFNS I-1 from Populus deltoids by RT-PCR method. The open reading frame of PFNS I-1 consisted of 1,017-bp and it showed high similarity with other FNS genes. The purified recombinant PFNS I-1, expressed in Escherichia coli, catalyzed the reaction from flavanone (naringenin) to flavone (apigenin). The reaction of PFNS I-1 was enhanced by cofactors such as oxoglutarate, $Fe^{2+}$, ascorbate and catalase. Thus, it is concluded that PFNS N-1 encodes a flavone synthase I.

• Biomolecules & Therapeutics
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• v.7 no.4
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• pp.362-370
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• 1999

Propolis, a natural resinous compound collected from honey bees, contains many biochemical constituents(wax, flavonoids, phenolic compounds, etc.) and has been used in traditional medicines as early as 300 B.C. It was been demonstrated that ethanol, acetylsalicylic acid, ischemia reperfusion, non-steroidal antiin-flammatory drugs and stress induce gastric lesions by promoting the generation of reactive oxygen metabolites. Therefore, some drugs that are capable of scavenging or inhibiting the generation of reactive oxygen radicals might be expected to prevent the gastric mucosal injury. The aim of this study was 1) to examine the antiulcer effect of propolis, 2) to investigate the mechanism of action by determining gastric acid secretion, lipid per-oxidation, mucus content and proton pump ($H^+$/$K^+$-ATPase) activity on gastric mucus in varios experimental models, and finally, 3) to isolate and identify the pure compounds that exert antiulcer activity. Step 2-1 and 2-3 sub-sub fraction shoed a significant reduction of severity of gastirc damage at the dose of 25 mg/kg in various experimental models. We isolated 4 sub-sub-sub fractions by flash column chromatography of Step 2-1 sub-sub fraction and one sub-sub-sub fraction by recrystalization of Step 2-3 sub-sub fraction. The protective effects of propolis sub-sub-sub fraction manifested sifnificant effects in HCl-ethanol induced gastric erosion model and aspirin induced gastric ulcer model. These results showed that the gastric mucosal protective effect of propolis might result from the increase of mucus secretion, free radical scavenging effect as well as the reduction of acid secretion in accordance with the reduction of $H^+$/$K^+$-ATPase activitv. Three compounds were isolated and identified from sub-sub fraction of propolis which showed antiulcer effects. Subsequently, these compounds were identified as a flavonoid, namely, 2-acetoxy-5,7,-dihydroxy-flavanone, galangin and chrysin.

• Archives of Pharmacal Research
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• v.28 no.5
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• pp.534-540
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• 2005

Activity-guided fractionation of the CH$_2Cl_2$-soluble fraction of the roots of Sophora flavescens furnished five 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scaveng ers: trans-hexadecyl ferulic acid (1) cis-octadecyl ferulic acid (2), trans-hexadecyl sinapic acid (3), (-)-4-hydroxy-3-methoxy-(6aR,11aR)-8, 9-methylenedioxypterocarpan (4) and desmethylanhydroicaritin (8), along with nine known inactive compounds: (-)-maackiain (5), xanthohumol (6), formononetin (7), (2S)-2'-methoxykurarinone (9), (2S)-3${\beta}$,7,4'-trihydroxy-5-methoxy-8-(${\gamma},{\gamma}$- imethylallyl )-flavanone (10), (2S)-7,4'-dihydroxy-5-methoxy-8- (${\gamma},{\gamma}$-dimethylallyl ) -flavanone (11), umbelliferone (12), kuraridin (13), and trifolirhizin (14). Compounds 1-4 and 8 exhibited DPPH free radical scavenging effects at IC$_{50}$ values of 33.01 ${\pm}$ 0.20, 57.06 ${\pm}$ 0.16, 39.84 ${\pm}$ 0.36, 35.83 ${\pm}$ 0.47, and 18.11 ${\pm}$ 0.04${\mu}$M, respectively. L-Ascorbic acid, when used as a positive control, exhibited an IC$_{50}$ value of 7.39 ${\pm}$ 0.01 ${\mu}$M. Compounds 1-4 and 8 also appeared to exert significant scavenging effects on authentic ONOO-, with IC$_{50}$ values of 5.76 ${\pm}$ 1.19, 15.06 ${\pm}$ 1.64, 8.17 ${\pm}$ 4.97, 1.95 ${\pm}$ 0.29 and 4.06 ${\pm}$ 2.41 ${\mu}$M, respectively. Penicillamine (IC$_{50}$= 2.36 ${\pm}$ 0.79${\mu}$M) was used as a positive control. In addition, compounds 2,4,6,8, and 10 were isolated from this plant for the first time.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.672-679
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• 1998

The ethanol extract and its chloroform fraction of Sophora flavescens Ait. exhibited growth inhibition on some food poisoning bacteria. The minimum inhibitory concentration of the above extracts were $50{\sim}500\;ppm$ and below 50 ppm Listeria monocytogenes (ATCC 19111, 19112, 19113, 19114, 15313). By silica gel column chromatography twice, antimicrobial active compound S-10-6 was isolated from chloroform fraction of Sophora flavescens Ait. The fraction S-10-6 showed strong growth inhibition at 10 ppm on 5 strains of L. monocytogenes, Bacillus subtilis ATCC 14593 and Staphylococcus aureus KFCC 11764 but Esherichia coli ATCC 25922 was not inhibited at 100 ppm and also confirmed bactericidal effect at 30 and 50 ppm on 5 strains of L. monocytogenes. The antimicrobial compound S-10-6 was identified as kushenol F, a kind of flavanone compound, by EI/MS, $^1H-NMR\;and\;^{13}C-NMR$.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.680-687
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• 1998

The ethyl acetate fraction from ethanol extract of Glycyrrhiza uralensis FISCH showed growth inhibition on 5 strains of Listeria monocytogenes (ATCC 19111, 19112, 19113, 19114 and 15313) at $50{\sim}100\;ppm$. By silica gel column chromatography twice, antimicrobial active compound G-4-4 was isolated from ethyl acetate fraction of Glycyrrhiza uralensis FISCH. The G-4-4 fraction showed growth inhibition at $10{\sim}50\;ppm$ and confirmed bactericidal effect at 50 and 100 ppm on 5 strains of Listeria monocytogenes. Staphylococcus aureus KFCC 11764 was inhibited at $30{\sim}50\;ppm$ of G-4-4 but Escherichia coli ATCC 25922 was not inhibited at 100 ppm. The antimicrobial active substance G-4-4 was identified as liquiritigenin, a kind of flavanone compound, by IR, MS, $^1H-NMR\;and\;^{13}C-NMR$.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.465-469
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• 2014

The extraction of flavanones such as naringin, narirutin, naringenin, hesperidin, and hesperetin from grapefruit peels was performed using subcritical water extraction (SWE), hot water extraction, and conventional methods such as methanol and ethanol extraction. We analyzed the total flavanone content using high-performance liquid chromatography (HPLC) for each extracting method. Among the three methods, SWE was the optimal method with optimal operating conditions of $170^{\circ}C$ temperature and 10 min operating time. The maximum total flavanone extracted was $86.539{\pm}3.52mg/g$ grapefruit peels. Moreover, we treated the extracts with 60% ${\beta}$-cyclodextrin and then analyzed the surface structure of the encapsulated compounds by field emission-scanning electron microscopy (FE-SEM). The results indicated that the encapsulation in ${\beta}$-cyclodextrin improved solubilization, and the inclusion complex could serve as food supplements.

• YAKHAK HOEJI
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• v.36 no.6
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• pp.548-555
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• 1992

The biological activities of fruits of Poncirus trifoliata have been studied. 70% Ethanol extract of Ponciri Fructus was fractionated with ether, ethyl acetate and n-butanol by turns. The ether fraction showed antibacterial activity on Staphylococcus aureus and inhibited the contractability of the isolated mice ileum. The ethyl acetate and n-butanol fractions showed the anti-edematous effect on the carrageenin-induced edema of rat hindpaw. From the n-butanol fraction, one of the flavonoid glycoside was isolated and identified as poncirin. Ponciri Fructus contained about 6% poncirin which was 5,7-dihydroxy-4´-methoxy flavanone rhamnoglucoside and poncirin showed antiinflammatory activities. Poncirin was considered as the major effective component of Ponciri Fructus.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1295-1299
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• 2010

Recently, recombinant Streptomyces venezuelae has been established as a heterologous host for microbial production of flavanones and stilbenes, a class of plant-specific polyketides. In the present work, we expanded the applicability of the S. venezuelae system to the production of more diverse plant polyketides including flavones and flavonols. A plasmid with the synthetic codon-optimized flavone synthase I gene from Petroselium crispum was introduced to S. venezuelae DHS2001 bearing a deletion of the native pikromycin polyketide synthase gene, and the resulting strain generated flavones from exogenously fed flavanones. In addition, a recombinant S. venezuelae mutant expressing a codon-optimized flavanone $3{\beta}$-hydroxylase gene from Citrus siensis and a flavonol synthase gene from Citrus unshius also successfully produced flavonols.

• Archives of Pharmacal Research
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• v.20 no.4
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• pp.368-371
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• 1997

In an effort to increase of the antitumor activity of 2(S)-$2^{I}$,$5^{I}$-trihydroxy-7, 8-dimethoxyflavanone isolated from Scutellaria indica, we synthesized its analogues, II, III and IV. They showed potent cytotoxicity in vitro against cancer cell lines, L1210, K562 and A549. On the basis of $ED_50$ values against the cancer cell lines, III exhibited about 2-7 times stronger activity than I against various cell lines. We tested the antitumor activity of the analogues against Sarcoma 180 cells in vivo and evaluated the structure-activity relationship. The antitumor activity appeared to be related to the hydrogen bond between carbonyl group at C-4 and hydroxyl group at C-5, in contrast to cytotoxic action.

• YAKHAK HOEJI
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• v.52 no.4
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• pp.274-278
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• 2008

Two known lavandulylated flavanones, leachianone A (1) and sophoroaflavanone G (2), were isolated from the roots of S. flavascens Ait. The structures of these compounds were determined on the basis of IR, 1D and 2D NMR in addition to direct comparison with authentic compounds. However, leachianone A (1) and sophoroflavanone G (2) did not have growth inhibition activity against any microorganisms (MIC, >200 ${\mu}g/ml$).