• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.3 s.58
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• pp.153-160
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• 2006

We synthesized 2',4'-dimethoxyflavone and investigated the effects on melanogenesis. To determine the effects as a whitening agent, various in uitro tests were performed such as free radical scavenging activity, melanin assay, tyrosinase activity and expression of tyrosinase, TRP-1 and TRP-2 (western blot and RT-PCR) in Bl6 melanoma cells. 2',4'-Dimethoxyflavone showed neither free radical scavenging activities against 1,1- diphenyl -2-picrylhydrazvl (DPPH) radical and inhibition of mushroom tyrosinase activity, 2',4'-dimethoxyflavone significantly inhibited melanin production in B16 melanoma cells. 2',4'-Dimethoxyflavone treatment (48h) suppressed the biosynthesis of melanin up to 27% at $5{\mu}g/mL$ and reduced tyrosinase activity up to 20% at $5{\mu}g/mL$ in B16 melanoma cells. 2',4'-Dimethoxyflavone was also able to significantly inhibit tyrosinase and TRP-1 expression in protein and mRNA level. These results suggest that 2',4'-dimethoxyflavone inhibits melanin biosynthesis at the level of enzyme activity and protein mRNA expression B16 melanoma cells. Therefore, 2',4'-dimethoxyflavone may be useful as a new whitening agent in cosmetics.

• YAKHAK HOEJI
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• v.41 no.2
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• pp.149-152
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• 1997

Three compounds were isolated from the n-BuOH fraction of buds of Eugenia caryophyllata and their structures were identified as 3,3',4-tri-O-methylellagic acid, 3-O--${\beta}$ -D-glucopyranosyl-3,5,4'-trihydroxy-7,3'-dimethoxyflavone and gallic acid by chemical and spectral evidence.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.245-245
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• 1994

From the active fraction, cytotoxic constituents 1-5 were isolated and identified to be 2(S)-5,7-dihydroxy-8,2'-dimethoxyflavanone (1), wogonin (5,7-dihydroxy-8-methoxyflavone, 2), 5,7-dihydruxy-8,2'-dimethoxyflavone (3), 2(5) -5,7,2'-trihydroxy-8-methoxyflavanone (4), 2(S) - 5,2',5'-trihydroxy-7,8-dimethoxyflavanone (5), respectively, with those of specimens$\^$1-2)/

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.345-350
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• 2003

5,7-Dihydroxyflavones and their Ο-methylated flavone analogs were prepared and evaluated their anti-inflammatory activity to decipher the structure-activity relationships. Most of the analogs were achieved from 2,4,6-trihydroxyacetophenone in 4 steps. 5,7-Dihydroxy-4 -methoxyflavone (4c) and 7-hydroxy-4 ,5-dimethoxyflavone(6c) were prepared following a different synthetic pathway. Among the synthetic flavones tested, 5-hydroxy-7-methoxyflavone analogs (3a-3e) showed moderate inhibitory activities of $PGE_2$ production from LPS-induced RAW 264.7 cells.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1261-1264
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• 2007

Bioassay-directed fractionations of the seed extracts of Trichosanthes kirilowii, have resulted in the isolation of two new compounds, 2-(4-hydroxy-3-methoxyphenyl)-3-(2-hydroxy-5-methoxyphenyl)-3-oxo-1-propanol (2) and isoetin 5'-methyl ether (5,7,2',4'-tetrahydroxy-5'-methoxyflavone) (3), together with two known compounds, 7-hydroxychromone (1) and 5,7,4'-trihydroxy-3',5'-dimethoxyflavone (tricin, 4). Their structures were characterized by spectroscopic analysis such as 2D-NMR, HRTOFMS, and UV. Compound 3 showed cytotoxicity against human lung cancer cell line A549, human skin melanoma SK-Mel-2, and mouse melanoma B16F1, with IC50 of 0.92, 8.0, and 7.23 μg/mL, respectively.

• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.171-175
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• 2006

Alnus japonica Steud (Betulaceae) has long been used as a Korean traditional medicine for gastric disorders, hepatitis, and fatty liver. As a part of our study on the identification of secondary metabolites of naturally occurring bioactive compounds, we isolated 1,7-bis(4-hydroxyphenyl)-3,5-heptanediol(1), 5-hydroxy-1,7bis(4-hydroxyphenyl)-3-heptanone(2), 5,3'-dihydroxy-7,4'-dimethoxyflavone(3) and 3,5,7,3',4'-pentahydroxyflavone(4) from the dichloromethane and ethylacetate-soluble fractions of Alnus japonica Steud. These compounds showed significant antioxidant activity in a concentration-dependent manner. The $IC_{50}$ values of compounds 1, 2, 3 and 4 were 30.1, 37.4, 20.2 and 13.7 ${\mu}g/mL$, respectively, through the scavenging capacity of 1,1-diphenyl-2-picrylhydrazyl radical assay.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3219-3223
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• 2014

Ochnaflavone, a naturally occurring biflavonoid composed of two units of apigenin (5,7,4'-trihydroxyflavone) joined via a C-O-C linkage, was first synthesized and evaluated its inhibitory activity on $PGE_2$ production. Total synthesis was accomplished through modified Ullmann diaryl ether formation as a key step. Coupling reactions of 4'-halogenoflavones and 3'-hydroxy-5,7,4'-trimethoxyflavone were explored in diverse reaction conditions. The reaction of 4'-fluoro-5,7-dimethoxyflavone (2c) and 3'-hydroxy-5,7,4'-trimethoxyflavone (2d) in N,N-dimethylacetamide gave the coupled compound 3 in 58% yield. Synthetic ochnaflavone strongly inhibited PGE2 production ($IC_{50}=1.08{\mu}M$) from LPS-activated RAW 264.7 cells, which was due to reduced expression of COX-2. On the contrary, the inhibition mechanism of wogonin was somewhat different from that of ochnaflavone although wogonin, a natural occurring anti-inflammatory flavonoid, showed strong inhibitory activity of $PGE_2$ production ($IC_{50}=0.52{\mu}M$), and seems to be COX-2 enzyme inhibition. Our concise total synthesis of ochnaflavone enable us to provide sufficient quantities of material for advanced biological studies as well as to efficiently prepare derivatives for structure-activity relationship study.

• Korean Journal of Pharmacognosy
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• v.23 no.4
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• pp.234-239
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• 1992

Seven flavonoid components were isolated from fr. C of Scutellariae radix which showed antagonistic effects against bradykinin(BK). The results indicated that two oxygen functions (either -OH or $-OCH_3$) at 2'- and 6'-positions and/or an oxygen function at 6-position of flavone seemed to be favored for the BK inhibitory activities. Skullcapflavone-II(IV) which contains $6-OCH_3$, 2'-OH and $6-OCH_3$ in the structure was the most active among the flavones tested.

• Preventive Nutrition and Food Science
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• v.3 no.4
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• pp.315-319
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• 1998

Previously, the methanolic extract of Paeonia moutan seeds was found to potently inhibit soybean lipoxy-genase (SLO). Hence to isolate SLO inhibitor, the defattd methaniolic extract of the seeds was consecutively partitioned wiht ether, ethyl acetate,n-butanol ,adn water. The ether souble fraction showing strong inhibitory activity against SLO was further fractionated into a strongly acidic, a weakly acidic, and a neutral fractions. The strongly acidic components of the ether extract were successively subjected to chromatography on a silica gel, Sephadex LH-20, and preparative HPLC. Four phenolic compounds were isolated , and twio of them showing a strong SLO inhibition activity were identified as luteolin (IC50=2.32$\mu\textrm{g}$/ml) and 5,6,4'-trihydroxy-7,3'- dimethoxylflavone (IC50=0.31$\mu\textrm{g}$/ml) by UV, IR, 1H-& 13C-NMR, and MS spectroscopy. In addition, two flavonoids showed significantly antioxidative activity as strong as that of of $\alpha$-tocopherol (p<0.05) in the autoxidation system of linoleic acid. These results suggest that luteolin and 5,6,4'-trihydroxy-7,3'-dimethoxy-flavone may be used as a potential source of anti-inflammatory agents with antioxidative activity.

• Archives of Pharmacal Research
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• v.18 no.6
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• pp.440-448
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• 1995

Fitty two flavones were synthesized from polyoxygenated dibenzoylmethanes which were obtained by a modified Baker-Venkatarman rearrangement, of 2-benzoyl oxyacetophenones. The following flavones among them showed good cytotoxic activities against L1210 and HL60 cells ; 2'-benzoyloxy-5,7-dimethoxyflavone $(8.2{\mu}g/ml,{\;}5.0 {\mu}g/ml)$, 2'-benzyloxy-5,7,8-trimethoxyflavone $(5,9 {\mu}g/ml,{\;}11.0{\mu}g/ml,{\;}2.7{\mu}g/ml)$, 2'-hydroxy-5,7,8-trimethoxyflavone $(9.8{\mu}/ml,{\;}6.2{\mu}g/ml)$, 2'-benzyloxy-5-hydroxyflavone $(5.2 {\mu}g/ml,{\;}3.6{\mu}g/ml)$, and 5,2'-dihydroxyflavone $(5.1{\mu}g/ml,{\;}4.0{\mu}g/ml)$. Presence of 5-methoxy group potentiated the cytotoxic activity, while the existence of 7-methoxy group decreased the activity. 5-Hydroxy or methoxy activates 4-carbonyl group, while 7-methoxy group deactivates the acrbonyl group. From these observation it was concluded that the activation of carbonyl group at C-4 of a flavone is important for the enahncement of the cytotoxic activity. The presence of both 5-hydroxy and 2-benzyloxy-or 2-hydroxy group enhanced the antitumor activity; 2'-benzyloxy-5-hydroxy-7-methoxyflaone 9T/C=144%), 5.2'-dihydroxy-7-methoxyflavone (T/C=132%) and 5,2'-dihydroxy-6,78,6' trtramethoxyflvone (T/C = 172%) 2'hexanolytion of 5,2'-dihydroxy-flavones did not improve the natitumor activity; 2' hexanoyloxy-5-hydroxy-7-methoxyflavone showed T/C = 132%, about the same as that of 5,2'-dihydroxy-7-methoxyflvone (T/C=130%)