- CLAISEN REARRANGEMENTS-XV STRUCTURE REVISION OF THE COUMARIN, CELERIN, BY SYNTHESIS
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The four possible structures, 9,12,17 and 26 for celerin have been synthesised and the structure of the natural product revised to 8-hydroxy-7-methoxy-5-(1,1-dimethylallyl)coumarin 26.Efficient alternative synthetic routes to sibiricol 5, coumurrayin 6 and pinnarin 13 have been established.
- Murray, R. D. H.,Jorge, Z. D.
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- Natural and semisynthetic oxyprenylated aromatic compounds as stimulators or inhibitors of melanogenesis
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It has been very recently shown how naturally occurring oxyprenylated coumarins are effective modulators of melanogenesis. In this short communication we wish to generalize the potentialities as skin tanning or whitening agents of a wider panel of natural and semisynthetic aromatic compounds, including coumarins, cinnamic and benzoic acids, cinnamaldehydes, benzaldehyde, and anthraquinone derivatives. A total number of 43 compounds have been tested assaying their capacity to inhibit or stimulate melanin biosynthesis in cultured murine Melan A cells. The wider number of chemicals herein under investigation allowed to depict a detailed structure-activity relationship, as the following: (a) benzoic acid derivatives are slightly pigmenting agent, for which the effect is more pronounced in compounds with longer O-side chains; (b) independently from the type of substitution, cinnamic acids are able to increase melanin biosynthesis, while benzaldehydes are able to decrease it; (c) coumarins with a 3,3-dimethylallyl or shorter skeletons as substituents in position 7 are tanning agents, while coumarins with farnesyloxy groups are whitening ones; (d) double oxyprenylation in position 6 and 7 and 3,3-dimethylallyl or geranyl skeletons have slight depigmenting capacities, while farnesyl skeletons tend to marginally increase the tanning effect; (e) the presence of electron withdrawing groups (acetyl, COOH, and -Cl) and geranyl or farnesyl oxyprenylated chains respectively in positions 3 and 7 of the coumarin nucleus lead to a whitening effect, and finally (f) oxyprenylated anthraquinones have only a weak depigmenting capacity.
- Genovese, Salvatore,Epifano, Francesco,Medina, Philippe de,Caron, Nicolas,Rives, Arnaud,Poirot, Marc,Poirot, Sandrine Silvent,Fiorito, Serena
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p. 181 - 190
(2019/03/23)
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- Synthesis and evaluation of antibacterial and anti-inflammatory properties of naturally occurring coumarins
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Coumarins are a group of heterocyclic compounds naturally present in a large variety of plant families. Nevertheless, oxyprenylated coumarins have been only recently seen as valuable and promising biologically active phytochemicals. In this study, we synthesized three naturally occurring O-prenylcoumarins (1), (2), and (3), and evaluated their antibacterial and anti-inflammatory properties in view of their therapeutic potential against periodontal disease. The three O-prenylcoumarins were synthesized using well-known schemes leading to the chromen-2-one nucleus. The periodontal pathogen Porphyromonas gingivalis was found to be highly susceptible to all three O-prenylcoumarins with minimal inhibitory concentration values in the range of 12.5-25 mg/ml; the non-prenylated forms of the coumarins did not show any activity. The antibacterial activity of (1), (2), and (3) appeared to result from its ability to permeate the cell membrane. Using the U937-3xkB-LUC human monocytic cell line, compounds (2) and (3) dose-dependently inhibited lipopolysaccharide-induced NF-kB activation, while (1) did not. The non-prenylated forms of the coumarins were either inactive or much less potent. In conclusion, O-prenylcoumarins (2) and (3) by exhibiting a dual mode of action including antibacterial and anti-inflammatory activities may represent promising targeted therapeutic agents for localized treatment of periodontal diseases.
- Azelmat, Jabrane,Fiorito, Serena,Taddeo, Vito Alessandro,Genovese, Salvatore,Epifano, Francesco,Grenier, Daniel
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p. 399 - 405
(2015/09/07)
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