title: Vasorelaxant activity of diterpenes from Croton zambesicus and synthetic trachylobanes and their structure-activity relationships.
abstract: The diterpenes previously isolated from the leaves of Croton zambesicus were tested to evaluate their vasorelaxant activity on the Wistar rat aorta. Their vasorelaxant effect was compared to a series of synthetic trachylobanes and related polycyclic compounds on KCl- or noradrenaline-induced contractions in order to evaluate structure-activity relationships. We demonstrate the vasorelaxant properties of some pure trachylobane diterpenes at low concentration (IC50 < 10 microM) on KCl-induced contractions, but none have a significant effect in noradrenaline-induced contractions. Comparing structures and activity we observed that a C-14 carbonyl group associated with a C-15 hydroxy or ketone function or a C-3 carbonyl associated with a hydroxymethyl group plays an important role in the vasorelaxant activity of trachylobane diterpenes. We also observed that the absolute configuration or the cleavage of the C13-C16 cyclopropane bond does not have a marked effect on the activity. The cytotoxicity of all of these compounds has also been evaluated on HeLa cells in order to verify that the vasorelaxant activity was not correlated with general cytotoxicity.
authors.affiliation: Laboratoire de Pharmacognosie, Unité d'Analyse Chimique et Physico-Chimique des Médicaments et Pharmacognosie, Université Catholique de Louvain, UCL 72.30-CHAM, Avenue E. Mounier 72, 1200 Bruxelles, Belgium. Chiara.Baccelli@cham.ucl.ac.be
authors.forename: Chiara
authors.initials: C
authors.lastname: Baccelli
authors.forename: Ismael
authors.initials: I
authors.lastname: Navarro
authors.forename: Sébastien
authors.initials: S
authors.lastname: Block
authors.forename: Antonio
authors.initials: A
authors.lastname: Abad
authors.forename: Nicole
authors.initials: N
authors.lastname: Morel
authors.forename: Joëlle
authors.initials: J
authors.lastname: Quetin-Leclercq
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects; D001541:Benin; D029802:Croton / Q000737:chemistry*; D004224:Diterpenes / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D006367:HeLa Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D013329:Structure-Activity Relationship; D014665:Vasodilator Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D004224:Diterpenes; D014665:Vasodilator Agents