We have studied the effects of a St. John's wort extract used in therapy on contractions
of various isolated organ preparations induced by diverse spasmogens. Although it
nonspecifically antagonized guinea pig ileum contractions induced by 7 different spasmogens,
it had no effect on depolarization-induced contractions of rat aorta or those induced
by acetylcholine, histamine or serotonin in the guinea-pig trachea. Spontaneous rhythmic
contractions of rat portal veins were also not affected by the extract. Serotonin-induced
contractions of rat aorta were most effectively inhibited by the agent. The observed
effects of the extract were more prominent after it was washed out of the organ bath.
Surprisingly, however, the extract also exerted negative inotropic and chronotropic
effects on the rat atrium preparation. Our observations revealed several pharmacological
properties of the Hypericum extract, and thus could be helpful in identifying and
characterizing its active components and their modes of action.
References
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Altura B M, Altura B T.
Differential effects of substrate depletion on drug induced contractions of rabbit
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Chatterjee S S, Koch E, Nöldner M, Biber A, Erdelmeier C.
Hyperforin and hypericum extract: Interaction with some neurotransmitter systems.
Phytomedicine.
1996;
3
(Suppl. 1)
106
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Chatterjee S S, Nöldner M, Koch E, Erdelmeier C.
Antidepressant activity of Hypericum perforatum and Hyperforin The neglected possibility.
Pharmacopsychiatry.
1998 ;
31
(Suppl.)
7-15
Danielle Straumann
CERMOL SA
Centre de Recherche Moléculaire
62 rue de Lyon
CH-1203 Geneva
Switzerland
