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

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, Cuajacum 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.

Olea europaea leaf extract exerts L-type Ca2+ channel antagonistic effects

“…Besides this Rauwald et al have found 3,4-dihydroxyphenylethanol, i.e., hydroxytyrosol, the esterifying alcoholic component of the iridoid glycoside oleuropein, exerting vasodilative effects on isolated aortic rings, which have been interpreted as possible calcium antagonistic effects (Rauwald et al, 1991(Rauwald et al, , 1994, which would be in very good agreement to our present data. However, other components, yet unknown, in the extract may also contribute to the effect.…”

Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twins

“…Oleuropein was also shown to enhance nitric oxide production (Visioli et al, 1998b), whereas a direct calcium antagonistic activity was excluded. However, after bioassay directed fractionation, 3,4-dihydroxy-phenyl-ethanol, a degradation product of oleuropein, was shown to have such potential (Rauwald et al, 1994). Other ß-glucosidaseproduced metabolites of oleuropein and oleacin have been shown to inhibit the angiotensin converting enzyme (ACE) (Hansen et al, 1996).…”

Search for New Plant Constituents with Antiasthmatic and Antihypertonic Activity

“…Other research groups have subsequently conducted similar screening programs using rat thoracic aortas, guinea pig ileum, mouse myocardial cells, rat pituitary cells or cultured cells (43)(44)(45)(46)(47). Among the compounds listed in a review article written by Vuorela et al (48), furanocoumarines, coumarins and some mono-and sesquiterpenoids occupy a preferred place.…”