• Natural Product Sciences
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• v.13 no.2
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• pp.110-113
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• 2007

Five flavonoid derivatives, pinostrobin (1), pinocembrin (2), alpinetin (3), cardamonin (4) and boesenbergin A (5) were isolated from the rhizomes of Boesenbergia pandurata. All compounds were elucidated based on its spectroscopic data and by the comparison with the previous works. 2D NMR technique was used for the structure elucidation of boesenbergin A to complement the data reported previously. The extracts and pure compounds were screened for cytotoxic activity against HL-60 cancer cell lines (human promyelocytic leukemia). Cytotoxic screening showed most of the extracts and pure compounds isolated from the rhizomes of Boesenbergia pandurata were active against HL-60 cancer cell line. The chloroform extract and boesenbergin A showed the most potent cytotoxic activity.

• Food Science and Preservation
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• v.15 no.5
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• pp.699-705
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• 2008

This study compared amino acids and effective components of Viola mandshurica produced in Korea with those of Chinese plants, as part of a study on nutritional andfunctional materials, to aid in the development of a valuable food. The contents of reducing sugar, free sugar, polyphenols, and soluble protein in the flowers of V. mandshurica were higher than in other fractions, being 10,485.11 mg%, 118.85 mg%, 1,259.26 mg%, and 23.67 mg%, respectively. Total flavonoid content of Chinese leaves was the highest at 2,370.75 mg%, followed by 1,844.43 mg% in Korean leaves. Free amino acids were highest in Korean leaves (5,345.21 mg%), followed by roots (4,692.24 mg%), flowers (3,807.87 mg%), and leaves of China plants (3,613.81 mg%). Arginine accounted for 55% of free amino acids in the roots, and all plant fractions contained more valine, aspartic acid, glutamic acid, alanine, and arginine, than other amino acids. The total content of amino acid derivatives was the highest (9,058.80 mg%) in Korean leaves. Especially, $\alpha$-aminoadipic acid constituted over 50% of total amino acid derivatives in all plant parts of V. mandshurica. When mineral contents were analyzed, leaves grown in China showed the highest content of 5,917.57 mg%, and the contents of K, Ca, and Mg were much greater than those of other minerals, together comprising over 95% of total mineral content in leaves and flowers from Korea.

• Journal of Life Science
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• v.33 no.2
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• pp.169-175
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• 2023

As a protective defensive mechanism against ultraviolet (UV) light exposure in skin tissue, melanocytes produce the pigment melanin. Tyrosinase plays a key role in melanin production in melanocytes. However, the overproduction of melanin can lead to lesions, such as freckles and dark spots. Thus, it is clinically important to find a modulating molecule to control melanogenesis by regulating tyrosinase expression and/or activity. It is known that catechin, a plant flavonoid, can reduce melano- genesis through the downregulation of tyrosinase expression. Here, we tested whether catechin derivatives isolated from the stem bark of Ulmus parvifolia have an effect on melanin production by regulating tyrosinase in mouse melanoma cells and in vitro mushroom tyrosinase. The catechin derivatives used in this study included C5A, C7A, C7G, and C7X. Treatments using these catechin derivatives reduced melanin production in mouse melanoma B16F10 cells in which melanogenesis was stimulated by α-MSH. Notably, the anti-melanogenic effects of catechin derivatives were similar to those of kojic acid, a well-known anti-melanogenic molecule. Both C5A and C7A directly inhibited the activity of tyrosinase isolated from mushrooms in vitro. Furthermore, our in silico computational simulation showed that these two compounds were expected to bind to the active site of tyrosinase, which is similar to kojic acid. In addition, all four catechin derivatives reduced tyrosinase protein expression. In summary, our results showed that catechin derivatives can reduce melanogenesis by regulating tyrosinase activity or expression. Thus, this study suggests that catechin derivatives isolated from U. parvifolia can be novel modulators of melanin production.

• Journal of the Korean Society of Food Culture
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• v.9 no.2
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• pp.131-136
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• 1994

The ethylacetate extract of Lactuca dentata Makino showed 6 flavonoidal components as detected by ferric chloride solution. The flavonoidal constituent of Lactuca dentata Makino was isolated and purified by the series of column chromatography. The chemical structure of one of the flavonoidal component named as compound E was identified by UV, IR and NMR spectrometry. The melting point range of compound E was $249.5^{\circ}C-251^{\circ}C$. The UV and IR spectra of purified compound E, and its genin were measured with the various shifting agents. The results of UV analysis showed the free state of hydroxy group at 3rd and 4th carbon and binding of sugar at the 7th carbon of compound. The sugar bound to the compound E was identified as glucose by TLC. The IR spectrum showed the presense of hydroxy group, conjugated carbonyl group and aromatic group. The analysis of NMR spectrum was done to the purified compound and its derivatives. The chemical shifts against hydrogen atom, hydroxy group, and the moiety of luteolin were observed in the NMR spectrum along with their position and number as well as type of sugar bound. The isolated and purified compound was identified as $luteolin-7-0-{\beta}-D-glucoside$.

• Biomolecules & Therapeutics
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• v.22 no.5
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• pp.390-399
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• 2014

Chalcones (1,3-diaryl-2-propen-1-ones), a flavonoid subfamily, are widely known for their anti-inflammatory properties. Propenone moiety in chalcones is known to play an important role in generating biological responses by chalcones. In the present study, we synthesized chalcone derivatives structurally modified in propenone moiety and examined inhibitory effect on nitric oxide (NO) production and its potential mechanisms. Among the chalcone derivatives used for this study, TI-I-174 (3-(2-Hydroxyphenyl)-1-(thiophen-3-yl)prop-2-en-1-one) most potently inhibited lipopolysaccharide (LPS)-stimulated nitrite production in RAW 264.7 macrophages. TI-I-174 treatment also markedly inhibited inducible nitric oxide synthase (iNOS) expression. However, TI-I-174 did not significantly affect production of IL-6, cyclooxygenase-2 (COX-2) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), implying that TI-I-174 inhibits production of inflammatory mediators in a selective manner. Treatment of macrophages with TI-I-174 significantly inhibited transcriptional activity of activator protein-1 (AP-1) as determined by luciferase reporter gene assay, whereas nuclear factor-${\kappa}B$ (NF-${\kappa}B$) activity was not affected by TI-I-1744. In addition, TI-I-174 significantly inhibited activation of c-Jun-N-Terminal kinase (JNK) without affecting ERK1/2 and p38MAPK, indicating that down-regulation of iNOS gene expression by TI-I-174 is mainly attributed by blockade of JNK/AP-1 activation. We also demonstrated that TI-I-174 treatment led to an increase in heme oxygenase-1 (HO-1) expression both at mRNA and protein level. Transfection of siRNA targeting HO-1 reversed TI-I-174-mediated inhibition of nitrite production. Taken together, these results indicate that TI-I-174 suppresses NO production in LPS-stimulated RAW 264.7 macrophages via induction of HO-1 and blockade of AP-1 activation.

• Toxicological Research
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• v.33 no.2
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• pp.79-96
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• 2017

A variety of xenobiotic chemicals, such as polycyclic aromatic hydrocarbons (PAHs), aryl- and heterocyclic amines and tobacco related nitrosamines, are ubiquitous environmental carcinogens and are required to be activated to chemically reactive metabolites by xenobiotic-metabolizing enzymes, including cytochrome P450 (P450 or CYP), in order to initiate cell transformation. Of various human P450 enzymes determined to date, CYP1A1, 1A2, 1B1, 2A13, 2A6, 2E1, and 3A4 are reported to play critical roles in the bioactivation of these carcinogenic chemicals. In vivo studies have shown that disruption of Cyp1b1 and Cyp2a5 genes in mice resulted in suppression of tumor formation caused by 7,12-dimethylbenz[a]anthracene and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, respectively. In addition, specific inhibitors for CYP1 and 2A enzymes are able to suppress tumor formation caused by several carcinogens in experimental animals in vivo, when these inhibitors are applied before or just after the administration of carcinogens. In this review, we describe recent progress, including our own studies done during past decade, on the nature of inhibitors of human CYP1 and CYP2A enzymes that have been shown to activate carcinogenic PAHs and tobacco-related nitrosamines, respectively, in humans. The inhibitors considered here include a variety of carcinogenic and/or non-carcinogenic PAHs and acethylenic PAHs, many flavonoid derivatives, derivatives of naphthalene, phenanthrene, biphenyl, and pyrene and chemopreventive organoselenium compounds, such as benzyl selenocyanate and benzyl selenocyanate; o-XSC, 1,2-, 1,3-, and 1,4-phenylenebis(methylene)selenocyanate.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.267-270
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• 2009

Naringenin is a bioactive flavanone containing antioxidative, anti-inflammatory, and anticarcinogenic properties. The inhibitory effects on hyaluronidase of naringenin and its novel derivatives were evaluated. Among these flavonoids at $200{\mu}M$ concentration, 7-O-butyl naringenin had the highest inhibitory effect on hyaluronidase with 44.84%. In addition, For naringenin at concentrations of 0, 150, and $190{\mu}M$, the apparent Michaelis constants ($_{app}K_m$) were calculated to be $0.60{\pm}0.02$, $0.43{\pm}0.02$, and $0.41{\pm}0.01\;mg/mL$ of substrate, respectively; for 7-O-butyl naringenin at 0, 20, and $30{\mu}M$ concentrations, those were $0.44{\pm}0.03$ and $0.27{\pm}0.03\;mg/mL$, respectively. The $V_{max}$ values at 150 and $190{\mu}M$ naringenin were $0.59{\pm}0.02$ and $0.56{\pm}0.01\;mg/mL/min$, respectively; and those at 20 and $30{\mu}M$ 7-O-butyl naringenin were $0.50{\pm}0.02$ and $0.33{\pm}0.02\;mg/mL/min$, respectively. However, the slopes of each inhibitory reaction were not significantly different. Therefore, naringenin and 7-O-butyl naringenin were shown to be uncompetitive inhibitors. These results demonstrate the potential use of 7-O-butyl naringenin as an anti-inflammatory substance.

• Biomolecules & Therapeutics
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• v.31 no.3
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• pp.312-318
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• 2023

The natural flavonoid macakurzin C (1) exhibited adiponectin biosynthesis-inducing activity during adipogenesis in human bone marrow mesenchymal stem cells and its molecular mechanism was directly associated with a pan-peroxisome proliferator-activated receptor (PPAR) modulator affecting all three PPAR subtypes α, γ, and δ. In this study, increases in adiponectin biosynthesis-inducing activity by macakurzin C derivatives (2-7) were studied. The most potent adiponectin biosynthesis-inducing compound 6, macakurzin C 3,5-dimethylether, was elucidated as a dual PPARα/γ modulator. Compound 6 may exhibit the most potent activity because of the antagonistic relationship between PPARδ and PPARγ. Docking studies revealed that the O-methylation of macakurzin C to generate compound 6 significantly disrupted PPARδ binding. Compound 6 has therapeutic potential in hypoadiponectinemia-related metabolic diseases.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.266-271
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• 2023

The antioxidant capacity of the Psidium guajava leaf extracted with EtOH and their MeOH fractions using column chromatography were evaluated by 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging assays, total phenolic and flavonoid content, and Superoxide dismutase (SOD) assay. To determine its utility as a functional material, the crude extract was fractionated by flash column chromatography on ODS using a stepwise elution with combinations of MeOH/H₂O and then all the fractions were also investigated. In the results of antioxidant activities, the 40% and 60% MeOH fractions show the meaningful values, and then the two fractions were selected to examine the isolation and identification of the major constituents via HPLC and nuclear magnetic resonance. Further purification led to isolation of two quercetin derivatives; quercitrin (1) and isoquercetin (2). Through SOD assay, some methanol fractions via column chromatography and isolated compounds showed improved antioxidant activities compared to the extract.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1791-1794
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• 2013

Phytochemical investigation on dragon's blood of Dracaena cambodiana led to the discovery of two new flavonoid derivatives, cambodianin G (1) and cambodianin H (2). Their structures were elucidated on the basis of detailed spectroscopic analysis, including 1D and 2D NMR techniques and chemical methods. The two compounds were observed to exhibit antibacterial activities against Staphylococcus aureus, and compound 1 showed cytotoxicities against K562 and SGC-7901 cell lines.