Publications by authors named "Omar Santana"

The presence and extent of genetic variation in saffron crocus are still debated, as testified by several contradictory articles providing contrasting results about the monomorphism or less of the species. Remarkably, phenotypic variations have been frequently observed in the field, such variations are usually unstable and can change from one growing season to another. Considering that gene expression can be influenced both by genetic and epigenetic changes, epigenetics could be a plausible cause of the alternative phenotypes.

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A chemical study of Bethencourtia hermosae, aerial parts and in vitro root cultures, transformed by Agrobacterium rhizogenes, afforded the hitherto unreported sesquiterpenes ceratopicanol angelate (1), 8β-hydroxy-african-4(5)-en-3-one tiglate (4), 8β-hydroxy-african-4(5)-en-3-one 3'-angeloxy-2'-methylbutanoate (5), 1α,8β-dihydroxy-african-4(5)-en-3-one 8β-angelate (7) and 6α,8β-dihydroxy-african-4(5)-en-3-one 8β-angelate (8). In addition, 8β-hydroxy-african-4(5)-en-3-one (6) was isolated for the first time from a natural source, along with the rare sesquiterpenoid senecrassidiol (10) and two jacaranone derivatives 14 and 16. Known pyrrolizidine alkaloids, together with previously unreported hermosine (23), have also been isolated from this plant.

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The chemical composition and biological activity of cultivated and wild medicinal and aromatic plants from Morocco (Artemisia herba-alba, Lippia citriodora, Mentha pulegium, M. spicata, Myrtus communis, Rosmarinus officinalis, and Thymus satureioides) are described. The essential oils (EOs) of these species have been analyzed by GC-MS.

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Eleven eremophilanolides, 1-3 and 6-13, and two eremophilanes, 24 and 25, were isolated from Senecio candidans and S. magellanicus from the Magallanes Region (Chile). Compounds 2, 3, 9, and 10 have not been previously reported as natural products.

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Background: Four cardiac peptide hormones, namely vessel dilator, long-acting natriuretic peptide (LANP), kaliuretic peptide, and atrial natriuretic peptide (ANP) have anticancer effects.

Materials And Methods: The effects of these four cardiac hormones on human c-Jun-N-terminal kinase 2 (JNK2) were examined in human small cell lung cancer and human prostate cancer cells.

Results: Vessel dilator, LANP, kaliuretic peptide and ANP maximally reduced expression of JNK2 by 89%, 56%, 45%, and 28%, respectively (each at p<0.

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In the context of the study on plant defensive compounds we have isolated the main alkaloid from Hippeastrum puniceum (Amaryllidaceae), 3-O-acetyl-narcissidine (1), and its biological activities tested against two divergent insect species and several plant species. 1 was isolated from the bioactive alkaloidal fraction of H. puniceum.

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We have tested the insect antifeedant and toxic activity of 43 norditerpenoid alkaloids on Spodoptera littoralis and Leptinotarsa decemlineata including eserine (physostigmine), anabasine, and atropine. Antifeedant effects of the test compounds were structure- and species-dependent. The most active antifeedants to L.

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In this work the antifeedant effects of the halogenated monoterpenes 1-13 were tested against several divergent insect species. These compounds have been isolated from Plocamium cartilagineum (6 was isolated as an acetyl derivative), except for 4, which was isolated from Pantoneura plocamioides. We have also included the semisynthetic derivatives 1a, 2a, and 7.

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The new sesquiterpenes, 5alpha-senecioyloxysilphinen-3-one (5), 5alpha-tigloyloxysilphinen-3-one (7), and 3beta-hydroxy-5alpha-angeloyloxysilphinene (8), and the known compounds (6S)-2,10-bisaboladien-1-one (1), 6,7-epoxy-3(15)-caryophyllene (2), 6,7-epoxy-2,9-humuladiene (3), 5alpha-angeloyloxysilphinen-3-one (4), and 5alpha-acetoxysilphinen-3-one (6) were isolated from bioactive fractions of Senecio palmensis. The structures of these compounds were established by spectroscopic analysis and chemical evidence. The semisynthetic analogues silphinen-3,5-dione (9), 5alpha-hydroxysilphinen-3-one (10), 5beta-hydroxysilphinen-3-one (11), 5beta-acetoxysilphinen-3-one (12), and 5beta-isobutyryloxysilphinen-3-one (13) were generated to carry out a structure-activity study on the antifeedant action of these molecules against several divergent insect species.

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