Screening of nine vasoactive medicinal plants for their possible calcium antagonistic activity. Strategy of selection and isolation for the active principles of <i>Olea europaea</i> and <i>Peucedanum ostruthium</i>

Abstract

Abstract Fourteen different extracts of nine vasoactive medicinal plants used in European and African phytotherapy and traditional medicine were pharmacologically tested for their possible calcium antagonistic mode of action. The criteria for the selection of plants were: use in traditional medicine in the treatment of cardiovascular diseases, ‘nonspecific’ spasmolytic activity (mode of action not known), natural compounds with structural similarities to already known ‘calcium‐antagonists’ or calcium‐antagonists that have been found in species of the same tribe. All plant extracts were investigated against contractions of aortic strips induced by K + ‐depolarization. Extracts derived from Ammi visnaga, Guajacum officinale, Olea europaea, Peucedanum ostruthium and Ruta graveolens showed a clear activity, while Cryptolepis sanguinolenta, Leonurus cardiaca, Passiflora incarnata and Solidago gigantea showed no effect in this test. A comparison between K + ‐ and norepinephrine‐induced contractions evaluated the selectivity of the inhibition, which is demonstrated by the isolation and identification strategy for the Ca ++ ‐antagonistic principles of Olea europaea leaves and Peucedanum ostruthium rhizomes.