title: Diterpenes isolated from Croton zambesicus inhibit KCl-induced contraction.
abstract: A mixture of two new diterpenes was isolated from a dichloromethane extract of Croton zambesicus: ent-18-hydroxytrachyloban-3beta-ol (1) and ent-18-hydroxyisopimara-7,15-diene-3beta-ol (2). The two compounds crystallised together and were separated after derivatisation of the pimarane derivative with osmium tetroxide. The structure of 1 was elucidated by 1D- and 2D-NMR analysis and by X-ray diffraction of a crystal containing both compounds while 2 was only identified by crystallographic data. As this plant is widely used in African folk medicine against hypertension, we have analysed the vasorelaxant activity of the isolated molecules. The mixture of the two compounds inhibited the KCl-induced contraction of male Wistar rat aorta (IC (50) = 1 microg/mL), while the purified trachylobane (compound 1) and the hydroxylated pimarane showed a lower activity than the mixture.
authors.affiliation: Laboratoire de Pharmacognosie, Unité d'Analyse Chimique et Physico-Chimique des Médicaments, Université Catholique de Louvain, Bruxelles, Belgium. chiara.baccelli@cham.ucl.ac.be
authors.forename: Chiara
authors.initials: C
authors.lastname: Baccelli
authors.forename: Sébastien
authors.initials: S
authors.lastname: Block
authors.forename: Benoit
authors.initials: B
authors.lastname: Van Holle
authors.forename: André
authors.initials: A
authors.lastname: Schanck
authors.forename: David
authors.initials: D
authors.lastname: Chapon
authors.forename: Bernard
authors.initials: B
authors.lastname: Tinant
authors.forename: Luc Van
authors.initials: LV
authors.lastname: Meervelt
authors.forename: Nicole
authors.initials: N
authors.lastname: Morel
authors.forename: Joelle
authors.initials: J
authors.lastname: Quetin-Leclercq
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D002121:Calcium Channel Blockers / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D029802:Croton / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D008297:Male; D015394:Molecular Structure; D011189:Potassium Chloride / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D014661:Vasoconstriction / Q000187:drug effects; D014665:Vasodilator Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D004224:Diterpenes; D014665:Vasodilator Agents; C507329:ent-18-hydroxyisopimara-7,15-diene-3beta-ol; C507330:ent-18-hydroxytrachyloban-3beta-ol; D011189:Potassium Chloride