1. Nat Prod Commun. 2010 Mar;5(3):369-72.

Vasoconstrictor and inotropic effects induced by the root bark extracts of
Anthocleista schweinfurthii.

Ngombe NK, Kalenda DT, Quetin-Leclercq J, Morel N.

Laboratoire de pharmacognosie, Louvain Drug Research Institute, Université
catholique de Louvain, Av. E. Mounier 72, 1200 Bruxelles, Belgium.

The present study was undertaken to investigate the cardiovascular effect of
three extracts from the root bark of Anthocleista schweinfurthii Gilg.: an
aqueous extract (AE), a dichloromethane extract (DCMR) and a fraction enriched in
cardiac glycoside type compounds (CARDAN). In isolated perfused frog heart, bolus
injection of the extracts produced a positive inotropic effect. The responses to 
AE and DCMR, but not to CARDAN, were depressed by propranolol. In isolated rat
aorta, DCMR produced a transient increase in contractile tension while AE and
CARDAN induced a sustained constriction. AE vasoconstrictor effect was abolished 
by phentolamine, while contraction evoked by CARDAN was antagonized by verapamil.
In aortic rings contracted in low K+ media, the addition of K+ evoked a
relaxation, which was abolished by ouabain, depressed by DCMR but not affected by
either A(E) or CARDAN. These observations indicate that Anthocleista
schweinfurthii contains substances that promote vasoconstriction and increase
cardiac contraction. The effect of DCMR was only partially mediated by inhibition
of the Na+ pump while the mechanism of action of A(E) and CARDAN was distinct
from the inhibition of the Na+, K+ - ATPase pump, but could involve adrenergic
receptors, or either direct or indirect activation of L-type calcium channels.

PMID: 20420309 [PubMed - indexed for MEDLINE]