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Further studies on the antidiarrhoeal activity of bisnordihydrotoxiferine, a tertiary indole alkaloid in rodents
Author(s) -
Thomas G.,
de F. F. Melo Diniz M.,
Mukherjee R.
Publication year - 1992
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.2650060207
Subject(s) - antidiarrhoeal , ileum , yohimbine , histamine , alkaloid , pharmacology , acetylcholine , antispasmodic , indole alkaloid , chemistry , biology , stereochemistry , biochemistry , receptor , castor oil , antagonist
The dimeric tertiary indole alkaloid bisnordihydrotoxiferine isolated from the root bark of Strychnos trinervis (Vell.) Mart. inhibited, on i.p. administration, Escherichia coli ‐induced diarrhoea and cholera toxin‐stimulated intestinal fluid accumulation in mice. The respective ED 50 values were 10.6 and 20.0 mg/kg. The activity of bisnordihydrotoxiferine was unaffected by nalorphine or yohimbine, suggesting that the opioid and α 2 ‐adrenoceptors respectively, are not important for its antidiarrhoeal action. In smooth muscle studies, bisnordihydrotoxiferine antagonized in a noncompetitive and reversible manner, the contractions produced by histamine, acetylcholine and substance P in guinea‐pig ileum and by 5‐hydroxytryptamine and arachidonic acid in rat fundic strip. The respective p D ' 2 values (mean ± SEM) were 5.21 ± 0.29, 5.20 ± 0.29, 5.35 ± 0.12, in the ileum and 4.95 ± 0.13 and 3.66 ± 0.12 in the fundic strip. The values of slopes of the regression lines differed significantly from unity in all cases. Bisnor was inactive against PGE 2 ‐induced contractions in the ileum. The mechanism of action of the alkaloid may be related to nonspecific antagonism of gastrointestinal smooth muscle stimulant activity of several endogenous substances.