• Natural Product Sciences
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• v.19 no.1
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• pp.8-14
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• 2013

The inhibitory effect and the structure-activity relationships of luteolin and its related derivatives isolated from Taraxacum mongolicum against MAO activities were investigated. The activity-guided isolation of extract from Taraxacum mongolicum led to the isolation of three flavonoids, luteolin, diosmetin, and luteolin-7-glucoside, a polyphenol, chlorogenic acid, a tyrosine and a uridine. The inhibitory activities of luteolin and its related derivatives against MAOs activities are dependent on their molecular structures. The presence of the phenolic hydroxy group at para-position is the active site for MAO-A inhibition as well as of MAO-B. The methoxy group has no potential on MAO-A inhibition. An additional phenolic hydroxy group at the ortho-position alleviates about 4-fold MAO-A inhibitory activity of phenolic hydroxy group at para-position. A carboxylic group seems to be critical for DBH inhibition and has no effects on MAO.

• 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.

• 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.

• Journal of Applied Biological Chemistry
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• v.51 no.2
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• pp.57-60
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• 2008

Eight compounds, including 2 flavones, luteolin (1) and apigenin (2), 2 flavonols, kaempferol (3) and quercetin (4), and 4 flavonoid glucosides, luteolin-7-O-${\beta}$-D-glucoside (5), apigetrin (6), astragalin (7), and isoquercitrin (8), isolated from the whole herb of Sonchus oleraceus L. were analyzed on the basis of chemical and spectroscopic evidence. This was the first time to report compounds 3, 4, 6, 7 and 8 from the Sonchus oleraceus L. The antioxidant activities of the isolated flavonoids and their glucoside derivatives were evaluated by DPPH free radical-scavenging assay, showing that compounds 1, 3, 4 and 8 exhibited stronger antioxidant activities compared with ${\alpha}$, tocopherol and curcumin. Flavonoids containing more hydroxyl groups exhibited better antioxidant activities. The antioxidant activity of flavonols was superior to their corresponding flavones, and that of aglycone are more potent than their glucoside derivatives.

• Natural Product Sciences
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• v.17 no.4
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• pp.367-371
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• 2011

Effects of the extract and fractions from Parasenecio pseudotaimingasa on rat lens aldose reductase (AR) inhibition have been investigated. Among them, the n-BuOH fraction was exhibited good inhibitory potencies ($IC_{50}$ value 1.42 ${\mu}g/ml$). Phytochemical constituents were isolated from the n-BuOH fraction by open column chromatography. Their structures were elucidated as luteolin-7-O-rutinoside (1) and luteolin-7-Oglucoside (2) on the basis of spectroscopic analysis. Compounds 1 and 2 exhibited strong AR inhibitory activity, with $IC_{50}$ values of 2.37 and 1.05 ${\mu}M$, respectively. This is the first report on the isolation of compounds 1 and 2 from P. pseudotaimingasa. These results suggest that P. pseudotaimingasa could be a useful material in the development of a novel AR inhibitory agent against diabetic complications.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.71-77
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• 2007

The antioxidant properties of twelve phenolic compounds, including matairesinol 4'-O-$\beta$-D-glucoside, 8'-hydroxyarctigenin 4'-O-$\beta$-D-glucoside, matairesinol, 8'-hydroxyarctigenin, N-feruloylserotonin 5-O-$\beta$-D-glucoside, N-(p-coumaroyl)-serotonin-5-O-$\beta$-D-glucoside, N-feruloylserotonin, N-(p-coumaroyl)serotonin, luteolin 7-O-$\beta$-D-glucoside, luteolin, acacetin 7-O-$\beta$-glucuronide, and acacetin, isolated from defatted safflower (Carthamus tinctorius L.) seeds were evaluated with regard to the DPPH, superoxide and hydroxyl radicals. Additionally, levels of phenolic compounds were determined by HPLC in two cultivars of safflower seeds. Among them, four serotonin derivatives showed potent DPPH ($IC_{50}=10.83-21.75\;{\mu}M$) and hydroxyl ($IC_{50}=75.93-374.63\;{\mu}M$) radical scavenging activities, and their activities were significantly stronger than that of ${\alpha}-tocopherol$. Four flavonoids ($IC_{50}=170.65-275.83\;{\mu}M$) and four lignans ($IC_{50}=114.22-406.10\;{\mu}M$) exhibited significant superoxide and hydroxyl radical scavenging activities, respectively, whereas these compounds contained less activity toward the DPPH and hydroxyl radicals than serotonin derivatives. The levels of serotonin derivatives, lignans and flavonoids in safflower seeds of two cultivars ranged from 49.30 to 260.40, 3.72 to 158.90, and 11.72 to 214.97 mg% (dry base), respectively. Of the two cultivars, 'Cheongsu' had somewthat higher concentrations of phenolic compounds than 'Uisan'. These results suggest that phenolic compounds in safflower seeds may playa role as protective phytochemical antioxidants against reactive oxygen-mediated pathological diseases.

• 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 $luteolin-7-0-{\beta}-D-glucoside$.

• Korean Journal of Plant Taxonomy
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• v.41 no.1
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• pp.10-15
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• 2011

Fifteen populations comprising three taxa and a putative hybrid of Fallopia sect. Reynoutria in Korea were examined for their leaf flavonoid constituents. Nineteen flavonoid compounds were isolated and identified; they were glycosylated derivatives of the flavonols quercetin and kaempferol, and of the flavones apigenin and luteolin. Among them, quercetin 3-O-galactoside and quercetin 3-O-glucoside were major flavonoid constituents, and present in all taxa. The flavonoid data appear to be very useful for taxon delimitation, and all taxa examined are readily distinguished by their flavonoid profiles. In addition, the flavonoid data suggest that the Nonsan population may be of hybrid origin involving F. japonica var. japonica, F. forbesii, and F. sachalinensis. In F. japonica var. japonica, there is no apparent correlation between their levels of polyploidy and flavonoid chemistry, but geographical variation of the flavonoid profiles among some populations was detected.

• Food Science and Preservation
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• v.18 no.1
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• pp.53-58
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• 2011

Activity-guided isolation from an ethylacetate-soluble fraction of a 70% (v/v) ethanolic extract from the roots of Taraxacum ohwianum, using a pancreatic lipase inhibition assay, resulted in isolation and identification of five phenolic metabolites of previously known structure; these were 3,5-di-O-caffeoylquinic acid, chicoric acid, caffeic acid, protocatechuic aldehyde, and luteolin. All structures were confirmed by NMR and MS scpectroscopic data. Of these compounds 3,5-di-O-caffeoylquinic acid exhibited the most potent inhibitory activity, with $IC_{50}$ of $65.1{\pm}0.7\;{\mu}M$ against pancreatic lipase.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.617-623
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• 2006

In our ongoing search for bioactive compounds originating from the endemic species in Korea, we found that the hexane and EtOAc fractions of the MeOH extract from the root of Dystaenia takeshimana (Nakai) Kitagawa (Umbelliferae) showed cyclooxygenase-2 (COX-2) and 5- lipoxygenase (5-LOX) dual inhibitory activity by assessing their effects on the production of prostaglandin $D_2\;(PGD_2)$ and leukotriene $C_4\;(LTC_4)$ in mouse bone marrow-derived mast cells. By activity-guided fractionation, five coumarins, viz. psoralen (2), xanthotoxin (3), scopoletin (4), umbelliferone (5), and (+)-marmesin (6), together with ${\beta}-sitosterol$ (1), were isolated from the hexane fraction, and two phenethyl alcohol derivatives, viz. 2-methoxy-2-(4'-hydroxyphenyl)ethanol (7) and 2-hydroxy-2-(4'-hydroxyphenyl)ethanol (8), three flavonoids, viz. apigenin (9), luteolin (10), and cynaroside (11), as well as daucosterol (12) were isolated from the EtOAc fraction using silica gel column chromatography. In addition, D-mannitol (13) was isolated from the BuOH fraction by recrystallization. Two of the coumarins, scopoletin (4) and (+)- marmesin (6), the two phenethyl alcohol derivatives (7, 8) and the three flavonoids (9-11) were isolated for the first time from this plant. Among the compounds isolated from this plant, the five coumarins as well as the three flavonoids showed COX-2/5-LOX dual inhibitory activity. These results suggest that the anti-inflammatory activity of D. takeshimana might in part occur via the inhibition of the generation of eicosanoids.