• Proceedings of the PSK Conference
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• 2003.04a
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• pp.241.2-241.2
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• 2003

We report the synthesis of key intermediates for the development novel flavonoid derivatives with potential antiinflammatory activity and propose a mechanism of the one-pot reaction. The various amines (1) for this work were commercially available. Secondary amines (2) were formed by nucleophilic attraction using ethyl benzoylacetate. The C-N bond formation proceeded at refluxing in toluene with catalytic amount of p-toluenesulfonic acid and a removal of water was important in this reaction. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.183.2-183.2
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• 2003

We report the synthesis of 3,4-dihydro-2-oxo-4-quinolines 5a-e for the development novel flavonoid derivatives with potential antiinflammatory activity and propose a mechanism of the one-pot reaction. The various amines (la-e) for this work were commercially available. We isolated that ester (2a-e) were formed by nucleophilic attraction using ethyl benzoylacetate. The C-N bond formation proceeded at refluxing in toluene with catalytic amount of p-toluenesulfonic acid and a removal of water and ethanol was important in this reaction. (omitted)

• Biomolecules & Therapeutics
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• v.15 no.1
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• pp.46-51
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• 2007

Bioassay-directed chromatographic fractionation of an ethyl acetate extract from leaves of sweet potato (Ipomoea batatas L.) afforded six quinic acid derivatives: 3,5-epi-dicaffeoylquinic acid (1), 3,5-dicaffeoylquinic acid (2), methyl 3,5-O-dicaffeoylquinate (3), methyl 3,4-dicaffeoylquinate (4), methyl 4,5-dicaffeoylquinic acid (5),4,5-dicaffeoylquinate (6), and two phenolic compounds: caffeic acid (7) and caffeic acid methyl ester (8) together with three flavonoids: quercetin 3-O-${\beta}$-D-glucopyranoside (9), quercetin 3-O-${\beta}$-D-glucopyranoside, isoquercitrin (10) and kaempferol 3-O-${\beta}$-D-glucopyranoside (11). The structures of these compounds were elucidated by the aid of spectroscopic methods. These compounds were assessed for antioxidant activities using three different cell-free bioassay systems. All isolates except 11 showed potent DPPH and superoxide anion radicals scavenging, and lipid peroxidation inhibitory activities. 3,5-epi-DCQA (1) and methyl quinates (3-5) along with flavonoide 9 were isolated for the first time from this plant.

• Korean Journal of Pharmacognosy
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• v.48 no.4
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• pp.285-288
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• 2017

A lignan and four flavonoid derivatives were isolated from the aerial parts of Panicum dichotomiflorum Michaux (Gramineae) through repeated column chromatography. Their chemical structures were identified as (-)-pinoresinol (1), tricin (2), luteolin (3), luteolin-4'-O-${\beta}$-D-glucopyranosde (4) and luteolin-7-O-${\beta}$-D-glucopyranosde (5), respectively, by spectroscopic analysis. These compounds were isolated for the first time from this plant.

• Archives of Pharmacal Research
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• v.16 no.1
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• pp.18-24
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• 1993

In this inverstigation, the various flavonoid aglycones were evaluated for their inhibitory activities against croton-oil or arachidonic acid induced mouse ear edema by oral or topical administration. The compounds tested were thirteen derivatives of flavan-3-ol(catechin and epicatechin), flavanone (flavanone and naringenin), flavone (flavone, chrysin and apigenin), flavonol(favonol, galangin, quercetin and morin) and isoflavone (biochanin A and 2-carbethoxy-5,7-dihydroxy-4'-methoxyisoflavone), along with hydrocortisone, indomethacin, 4-bormophenacyl bromide, nordihydroguaiaretic acid and phenidone as positive controls. A(isoflavone) were found to show broad inhibitoty activities (14-52%) against croton-oil or arachidonic acid induced ear edema by oral or topical application at the dose of 2 mg/mouse, although they showed less activity than hydrocortisone (26-88%) or indomethacin (36-80%). Flavonoid agtlycones tested showed higher activity when aplied topically than by the oral administration. It was also found that they inhibited arachidonic acid induced edema more profoundly than croton-oil induced edema by topical application. In arachidonic acid induced edema when applied topically, flavone derivatives such as flavone, chrysin and apigenin were revealed to be the good inhibitory agents in addition to flavonols and isoflavones. When quercetin and biochanin. A were selected for evaluating in carrageenan induced rat pleurisy and biochanin both flavonoids showed antiinflammatory activity at the dose of 70 mg/kg by the oral adminis-tration. All of these results revealed that flavonoid aglycones, especially 5,7-dihydroxy-flavonols having hydroxyl group(s) in B-ring and biochanin A (isoflavone) possessed in vivo antiinflammatory activity.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4352-4360
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• 2011

A four dimensional quantitative structure activity relationship analysis was applied to a series of 50 flavonoid inhibitors of $p56^{lck}$ protein tyrosine kinase by the molecular comparative electron topological method. It was found that the -log (IC50) values of the compounds were highly dependent on the topology, size and electrostatic character of the substituents at seven positions of the flavonoid scaffold in this study. Depending on the negative or positive charge of the groups correctly embedded in these substituents, three-dimensional bio-structure to increase or decrease -log (IC50) values in the training set of 39 compounds was predicted. The test set of 11 compounds was used to evaluate the predictivity of the model. To generate 4D-QSAR model, the defined function groups and pharmacophore used as topological descriptors in the calculation of activity were of sufficient statistical quality ($R^2$ = 0.72 and $Q^2$ = 0.69). Ligand docking approach by using Dock 6.0. These compounds include many flavonoid analogs, They were docked onto human families of p56lck PTKs retrieved from the Protein Data Bank, 1lkl.pdb.

• Journal of the Korean Chemical Society
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• v.64 no.2
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• pp.130-133
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• 2020

• Journal of the Korean Chemical Society
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• v.67 no.3
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• pp.181-190
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• 2023

Melanoma is a malignant skin tumor caused by damage to melanocytes that can spread to other organs. Hence, various studies have been conducted on preventing the spread of melanoma. Flavonoid-structured substances such as apigenin and galanzin are effective therapeutic agents for inhibiting the proliferation and metastasis of melanoma. In this study, luteolin, quercetin, and their respective derivatives were synthesized. These compounds inhibited cell proliferation of B16 melanoma cells. These results confirmed that the derivatives of quercetin and luteolin may be useful as therapeutic agents to prevent melanoma metastasis.

• Natural Product Sciences
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• v.6 no.4
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• pp.170-178
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• 2000

Flavonoids are natural polyphenolic compounds widely distributed in plant kingdom. Although many flavonoids were found to show anti-inflammatory activity in vitro and in vivo, the potency of anti-inflammatory activity was not enough for a clinical trial. Thus, a search for finding potential flavonoid molecules is continuing. In this review, in vivo anti-inflammatory activity of various flavonoid derivatives is summarized mainly based on the results obtained in authors' laboratories. Among them, several biflavonoids such as amentoflavone and ginkgetin were found to possess anti-inflammatory activity on animal models of acute/chronic inflammation comparable to nonsteroidal and steroidal anti-inflammatory drugs currently used. In respect of their action mechanisms, the effects on arachidonic acid metabolism and nitric oxide production were described. Some flavonoids directly inhibit cyclooxygenase and/or lipoxygenase. Biflavones such as ochnaflavone and ginkgetin are inhibitors of phospholipase $A_2$. In recent studies, certain flavonoids were also found to suppress cyclooxygenase-2 and inducible nitric oxide synthase expression induced by inflammatory stimuli. Therefore, it is suggested that anti-inflammatory activity of the certain flavonoids (mainly flavones, flavonols and biflavonoids) may be mediated by direct inhibition of arachidonic acid metabolizing enzymes as well as suppression of the enzyme expression involved in inflammatory responses.

• Biomolecules & Therapeutics
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• v.25 no.2
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• pp.91-104
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• 2017

Acute bronchitis and chronic obstructive pulmonary diseases (COPD) are essentially lung inflammatory disorders. Various plant extracts and their constituents showed therapeutic effects on several animal models of lung inflammation. These include coumarins, flavonoids, phenolics, iridoids, monoterpenes, diterpenes and triterpenoids. Some of them exerted inhibitory action mainly by inhibiting the mitogen-activated protein kinase pathway and nuclear transcription $factor-{\kappa}B$ activation. Especially, many flavonoid derivatives distinctly showed effectiveness on lung inflammation. In this review, the experimental data for plant extracts and their constituents showing therapeutic effectiveness on animal models of lung inflammation are summarized.