1: Planta Med. 2005 Nov;71(11):1036-9.

Diterpenes isolated from Croton zambesicus inhibit KCl-induced contraction.

Baccelli C, Block S, Van Holle B, Schanck A, Chapon D, Tinant B, Meervelt LV,
Morel N, Quetin-Leclercq J.

Laboratoire de Pharmacognosie, Unite d'Analyse Chimique et Physico-Chimique des
Medicaments, Universite Catholique de Louvain, Bruxelles, Belgium.
chiara.baccelli@cham.ucl.ac.be

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.

PMID: 16320205 [PubMed - indexed for MEDLINE]

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