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Bisnordihydrotoxiferine and vellosimine from Strychnos divaricans root: Spasmolytic properties of bisnordihydrotoxiferine
Author(s) -
Da Silva B. A.,
De Araújo Filho A. P.,
Mukherjee R.,
Chiappeta A. De A.
Publication year - 1993
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.2650070607
Subject(s) - verapamil , acetylcholine , procaine , calcium , tetrodotoxin , chemistry , histamine , ileum , pharmacology , intracellular , calcium in biology , oxytocin , voltage dependent calcium channel , endocrinology , antagonist , medicine , biology , receptor , biochemistry
Bisnordihydrotoxiferine and vellosimine, two tertiary indole alkaloids have been isolated from the root of Strychnos divaricans . Bisnordihydrotoxiferine antagonized in a nonspecific manner, oxytocin and acetylcholine induced contractions in the rat uterus and acetylcholine and histamine responses in the guinea‐pig ileum. Bisnordihydrotoxiferine, like verapamil, produced effects on voltage dependent Ca 2+ channels. For example in guinea‐pig ileum, bisnordihydrotoxiferine ( p D' 2 3.92±0.09) and verapamil ( p D' 2 6.00±0.11) inhibited KCl induced contractions. Furthermore, bisnordihydrotoxiferine ( p D' 2 4.37±0.02) and verapamil ( p D' 2 6.83±0.10) also antagonized CaCl 2 induced contractions of K + ‐depolarized rat uterus. When compared with sodium nitroprusside, an antagonist of receptor operated Ca 2+ channels, bisnordihydrotoxiferine had no effect. However, in the aorta, the alkaloid (IC 50 , 6.10 × 10 −6 M) antagonized the intracellular calcium dependent transient contractions of noradrenaline and it was about four times more potent than procaine (IC 50 , 2.30 × 10 −5 M), a known inhibitor of the release of Ca 2+ from intracellular stores. Bisnordihydrotoxiferine may produce nonspecific spasmolytic actions mainly by inhibiting intracellular calcium mobilization and to a lesser extent by inhibiting voltage dependent calcium channels in smooth muscles.