Antihistamine activity of Bryophyllum calycinum

1. The juice obtained by pressing the leaves of Bryophyllum calycinum (Crassulaceae) exhibited histamine-blocking activity. 2. The juice contains flavonoid compounds, carbohydrates and mineral salts. A flavonoid fraction (fraction B) obtained by partitioning the juice between n-butanol and water con...

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Bibliographic Details
Published in:	Brazilian journal of medical and biological research Vol. 25; no. 9; p. 929
Main Authors:	Nassis, C Z, Haebisch, E M, Giesbrecht, A M
Format:	Journal Article
Language:	English
Published:	Brazil 1992
Subjects:	Animals Brazil Bronchoconstriction - drug effects Capillary Permeability - drug effects Dose-Response Relationship, Drug Female Gastric Mucosa - drug effects Guinea Pigs Histamine - pharmacology Histamine H1 Antagonists - analysis Histamine H1 Antagonists - isolation & purification Histamine H1 Antagonists - pharmacology Ileum - drug effects Male Muscle Contraction - drug effects Muscle, Smooth - drug effects Plant Extracts - analysis Plant Extracts - isolation & purification Plant Extracts - pharmacology Plants, Medicinal Rats Rats, Wistar Brazil
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Summary:	1. The juice obtained by pressing the leaves of Bryophyllum calycinum (Crassulaceae) exhibited histamine-blocking activity. 2. The juice contains flavonoid compounds, carbohydrates and mineral salts. A flavonoid fraction (fraction B) obtained by partitioning the juice between n-butanol and water contained the substance responsible for the antihistamine activity. 3. When assayed on the isolated guinea pig ileum, 50 mg/ml juice and 0.15 mg/ml fraction B produced parallel and concentration-dependent rightward displacement of the concentration-response curve to histamine (EC50 (FL): 1.30 (0.26-5.28) x 10(-7) M, 15.80 (5.90-23.30) x 10(-7) M, 12.50 (7.62-14.90) x 10(-7) M, in the absence and presence of 50 mg/ml juice and 12 mg/ml fraction B, respectively) apparently in a competitive manner. The antagonism was specific for histamine, i.e., did not modify the response to acetylcholine, KCl and BaCl2 and was reversible upon washing. Vascular permeability responses of rats to intracutaneous 1.0, 5.0 or 10.0 micrograms histamine were decreased by about 20-25% in animals pretreated with 4 ml/kg of juice or with 12 mg/kg fraction B. The juice (4 ml/kg) protected guinea pigs from death by asphyxia induced by 5 mg histamine and the protection lasted at least 1 h. 4. However, since the juice was ineffective in protecting the gastric mucosa from histamine-induced ulceration, we conclude that the antihistamine effect of the juice and fraction B was produced by blockade of H1 and not H2 receptors.
ISSN:	0100-879X