• Natural Product Sciences
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• v.9 no.2
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• pp.56-59
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• 2003

Chemical studies on the constituents of the leaves of Murraya paniculata (Lynn) Jack have furnished three highly-oxygenated flavonoids; gardenin E (1), gardenin A (2), and gardenin C (3). Structures of the compounds were elucidated based on NMR, MS, UV, IR data and also by comparison with the previous works. The antimicrobial activities of these compounds and the crude extracts were also evaluated.

• Natural Product Sciences
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• v.22 no.1
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• pp.1-12
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• 2016

Compositional differences in flavonoids are varied in the big family of Compositae. By summarizing our previous analytical studies and other scientific evidences, new strategy will be possible to further analyze flavonoids and utilize them for human health. The HPLC analytical method has been established in terms of linearity, sensitivity, accuracy, and precision. Herbs of the family of Compositae have considerable amounts of peroxynitrite ($ONOO^-$)-scavenging effects and their phenolic substances. These effects may contribute to the prevention of disease associated with excess production of $ONOO^-$, depending on the high content of flavonoid substances.

• Korean Journal of Pharmacognosy
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• v.23 no.4
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• pp.201-210
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• 1992

Scutellariae plants contain a large number of flavonoids and in addition, many of them are with unusual A- and/or B-ring substitutions. The total number of flavonoids reported up to the middle of 1991 are 137 including 89 of flavones, flavonols and their glycosides including 3 C-glycosides$(1{\sim}89)$, 39 of flavanones, dihydroflavonols and their glycosides $(90{\sim}128)$, 8 of chalcones $(129{\sim}136)$ and one biflavonoid, 8, 8'-bibaicalein(137). More than half of the flavonoids are with either unusual 5-metboxy(2'-methoxy in case of chalcones) in A-ring and/or 2'-oxygenation(2-oxygenation in case of chalcones) in B-ring substitutions. Four flavones, four flavanones and two chalcones are with methylation at 5-OH(2'-OH in case of chalcones) and six of them also have 2'-oxygenations(2- in case of chalcones). Sixtyeight out of total 137 flavonoids have oxygenated substitution at 2'-(2- in case of chalcones) position of B-ring and in addition, 27 of them have another oxygen function at 6'-(6- in case of chalcones) and 18 of them have additional oxygen substitutions either at 3'-, 5'-,3',6'-or 3', 4', 5'-(3, 4, 5- in case of chalcones) positions. The distribution and isolation of flavonoid components of Scutellariae plants are tabulated with references.

• Korean Journal of Pharmacognosy
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• v.47 no.4
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• pp.295-300
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• 2016

Flavonoids are widely reported to be beneficial to human health. Among flavonoids, in general, flavonoid aglycons have better biological activities than flavonoid glycosides, in that aglycons can easily penetrate through cell membrane because of their low polarity. Therefore, kaempferol, quercetin and various their glycosides were evaluated for their abilities to inhibit NO and $PGE_2$ productions in LPS-induced RAW 264.7 cells. Of these flavonoids and flavonoid glycosides, kaempferol-7-O-${\beta}$-D-glucoside(kp-7-glu) which possesses a glycoside at C-7 position of the A ring in kaempferol, potently inhibited NO, $PGE_2$ and $TNF-{\alpha}$, $IL-1{\beta}$, IL-6 productions in LPS-induced RAW 264.7 macrophages.

• Journal of the Korean Magnetic Resonance Society
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• v.22 no.3
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• pp.54-63
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• 2018

Nymphaea tetragona, also known as waterlilies, is aquatic plant in the family of Nymphaeceae. Three flavonoids(3, 4, and 5) and one mixed flavonoids were separated from this plant. The mixed flavonoid consisted of two flavonoids; a well-known quercetin(1) and a new natural flavonoid(2). The latter also has two chiral centers and their configurations were established by ROESY experiment. Two glycoflavonoids were determined as isoquercetin and quercetin-3-O-${\beta}$-xyropyranosyl-($1{\rightarrow}2$)-${\beta}$-galactopyroside. The $^1H$ NMR spectra for 4 and 5 dissoloved in $DMSO-d_6$ solvent showed resonance proximity and and severely overlap in the glycoside region, hindering the determination of the configurations of the stereogenic centers of the sugar moieties. This problem was solved through the spin simulation. Here, the exact NMR parameters for the sugar moieties of 4 and 5 were listed.

• Natural Product Sciences
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• v.22 no.2
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• pp.87-92
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• 2016

Endothelial dysfunction in atherosclerosis is associated with increasing oxidative stress that could be reversed by antioxidant. Therefore epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC) and catechin (C) of tea flavonoids were investigated for their roles in regenerating endothelial cell. Peripheral blood mononuclear cells (PB-MNCs) were isolated, plated and cultured in medium with/without treatment of EGCG, ECG, EGC and C. Results showed that among all EGCG, ECG, EGC and C concentrations tested, $12.5{\mu}mol/L$ was not cytotoxic for peripheral blood-derived endothelial progenitor cells (PB-EPCs). Treatment of EGCG, ECG, EGC or C increased the percentages of CD34, CD133, VEGFR-2 expressions and suppressed hydrogen peroxide-induced percentages of reactive oxygen species (ROS) level in PB-EPCs. Taken together, our current results showed that EGCG, ECG, EGC or C of tea flavonoids could induce differentiation of PB-MNCs into PB-EPCs as well as protect PB-EPCs from oxidative damage by suppresing the intracellular ROS levels.

• Natural Product Sciences
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• v.22 no.2
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• pp.77-81
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• 2016

A reversed-phase high-performance liquid chromatographic method is described for the simultaneous determination of three antibacterial flavonoids, artocarpanone, artocarpin, and cycloartocarpin in ethyl acetate extracts from Artocarpus heterophyllus heartwoods. Separation was achieved using a TSK-gel ODS-80Tm column ($5{\mu}m$, $4.6{\times}150mm$) at $25^{\circ}C$ with a gradient elution system of methanol and water as follows: 0-8 min, 60:40; 8-27 min, 80:20; 27-35 min, 60:40, v/v, at a flow rate of 1 mL/min, and a quantitative UV detection at 285 nm. The method was validated by measuring the key parameters, including specificity, linearity, sensitivity, accuracy, repeatability and reproducibility. A high degree of specificity and sensitivity was achieved. The calibration curves for all three flavonoids showed good linearity with a coefficient of determinations ($R^2$) of ${\geq}0.9995$. The recoveries of the method were from 98-104%, with good reproducibility and repeatability (RSD values of less than 2%) were also achieved. Ethyl acetate was the best solvent for extraction of these three flavonoids using the heat reflux conditions for 1 h. This optimized sample preparation and HPLC method can be practically used for a routine standardization process of the extracts from the A. heterophyllus heartwoods.

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.650-659
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• 2014

Large quantities of Korean wild grape (Vitis coignetiae, KWG) pomace, a by-product of grape juice and wine manufacture, are generated annually, and disposal cost of KWG pomace is now increasing. Therefore, this study was conducted to determine total polyphenol, flavonoid, and anthocyanin content in whole KWG, KWG skin and KWG pomace and to identify and quantify flavonoids found in whole KWG and KWG pomace using LC/MS/MS. Spectral analysis showed high total polyphenol and flavonoid in KWG skin extracted with 75% ethanol (p < 0.05). KWG pomace had higher amount of total polyphenol, flavonoid and anthocyanin than whole grape (p < 0.05). Sixteen flavonoids were identified, but only 10 flavonoids were quantifiable from whole KWG and KWG pomace. Both epicatechin and rutin were the major flavonoids, and 521 or 147 ng/g of epicatechin (p < 0.05) and 305 or 110 ng/g of rutin (p > 0.05) were found in whole KWG and KWG pomace, respectively. The results show that KWG pomace is a very rich source of flavonoids, thus KWG pomace can be used as a functional food additive. Plans to include KWG pomace in food production are necessary.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.633-644
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• 2006

In last couple of decades the use of natural compounds like flavonoids as chemopreventive agents has gained much attention. Our current study focuses on identifying chemopreventive flavonoids and their mechanism of action on human prostate cancer cells. Human prostate cancer cells (PC3), stably transfected with activator protein 1 (AP-1) luciferase reporter gene were treated with four main classes of flavonoids namely flavonols, flavones, flavonones, and isoflavones. The maximum AP-1 luciferase induction of about 3 fold over control was observed with $20\;{\mu}M$ concentrations of quercetin, chrysin and genistein and $50\;{\mu}M$ concentration of kaempferol. At higher concentrations, most of the flavonoids demonstrated inhibition of AP-1 activity. The MTS assay for cell viability at 24 h showed that even at a very high concentration $(500\;{\mu}M)$, cell death was minimal for most of the flavonoids. To determine the role of MAPK pathway in the induction of AP-1 by flavonoids, Western blot of phospho MAPK proteins was performed. Four out of the eight flavonoids namely kaempferol, apigenin, genistein and naringenin were used for the Western Blot analysis. Induction of phospho-JNK and phospho-ERK activity was observed after two hour incubation of PC3-AP1 cells with flavonoids. However no induction of phospho-p38 activity was observed. Furthermore, pretreating the cells with specific inhibitors of JNK reduced the AP-1 luciferase activity that was induced by genistein while pretreatment with MEK inhibitor reduced the AP-1 luciferase activity induced by kaempferol. The pharmacological inhibitors did not affect the AP-1 luciferase activity induced by apigenin and naringenin. These results suggest the possible involvement of JNK pathway in genistein induced AP-1 activity while the ERK pathway seems to play an important role in kaempferol induced AP-1 activity.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.164.2-165
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• 2001