- Natural oxyprenylated coumarins are modulators of melanogenesis
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Naturally occurring coumarins 7-isopentenyloxycoumarin, auraptene, and umbelliprenin are able to modulate the biosynthesis of melanin in murine Melan-a cells probably through the interaction with selected biological targets like estrogen receptor β and aryl hydrocarbon receptor. Such a modulation strictly depends on the individual structure of the coumarin: the presence of a 3,3-dimethylallyloxy side chain is a structural determinant for tanning activation whereas a farnesyl one leads to the opposite effect. The parent compound with a free OH group, umbelliferone, did not provide any interaction. Other coumarins assayed, having shorter chains and/or being substituted in other positions, and prenyloxypsoralens, were not active or not further investigated in this context being cytotoxic at low doses.
- Fiorito, Serena,Epifano, Francesco,Preziuso, Francesca,Cacciatore, Ivana,di Stefano, Antonio,Taddeo, Vito Alessandro,de Medina, Philippe,Genovese, Salvatore
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p. 274 - 282
(2018/05/14)
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- Structure-activity relationships for naturally occurring coumarins as β-secretase inhibitor
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The present study was demonstrated to evaluate the effects of naturally occurring coumarins (NOCs) including simple coumarins, furanocoumarins, and pyranocoumarins on the inhibition of β-secretase (BACE1) activity. Of 41 NOCs examined, some furanocoumarins inhibited BACE1 activity, but simple coumarins and pyranocoumarins did not affect. The most potent inhibitor was 5-geranyloxy-8-methoxypsoralen (31), which has an IC50 value of 9.9 μM. Other furanocoumarin derivatives, for example, 8-geranyloxy-5- methoxypsoralen (35), 8-geranyloxypsoralen (24), and bergamottin (18) inhibited BACE1 activity, with the IC50 values 25.0 μM. Analyses of the inhibition mechanism by Dixon plots and Cornish-Bowden plots showed that compounds 18, 31 and 35 were mixed-type inhibitor. The kinetics of inhibition of BACE1 by coumarins 24 was non-competitive inhibitors.
- Marumoto, Shinsuke,Miyazawa, Mitsuo
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p. 784 - 788
(2012/03/22)
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- Synthesis of 8-geranyloxypsoralen analogues and their evaluation as inhibitors of CYP3A4
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Furanocoumarins have been shown to inhibit CYP3A4 in vitro with varying degrees of potency [Pharmacogenetics 1997, 7, 391-396; Chem. Res. Toxicol. 1998, 11, 252-259; Drug Metab. Dispos. 1997, 25, 1228-1233; Br. J. Pharmacol. 2000, 130, 1369-1377]. In this study, we report the effects of a series of novel furanocoumarins based on the naturally occurring derivative 8-geranylepoxypsoralen which has been shown to be a more potent inhibitor of CYP3A4 than its 5-position-substituted counterpart bergamottin [Drug Metab. Dispos. 2000, 28, 766-771; Jpn. J. Pharmacol. 2000, 82, 122-129]. Compounds were designed, synthesised and tested for their ability to inhibit CYP3A4 activity in human liver microsomes using testosterone as the marker substrate. Both the saturated and unsaturated phenolic furanocoumarin derivatives were found to be inactive. However, the 8-alkyloxy-furanocoumarin analogues were shown to inhibit CYP3A4 activity in a dose dependent manner, with IC50 values ranging from 0.78 ± 0.11 to 3.93 ± 0.53 μM. The reduced furan derivative dihydro-8-geranyloxypsoralen showed a 4-fold decrease in inhibitory potency, suggesting that the furan moiety plays a role in the interaction between these compounds and CYP3A4.
- Row,Brown,Stachulski,Lennard
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p. 3865 - 3871
(2007/10/03)
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