Inhibitory effect of xanthomicrol and 3 alpha-angeloyloxy-2 alpha-hydroxy-13,14Z-dehydrocativic acid from Brickellia paniculata on the contractility of guinea-pig ileum.
Chemical fractionation of Brickellia paniculata methanolic extract by monitoring its inhibitory effect on K(+)-induced contraction in guinea-pig ileum in vitro led to the isolation of 5,4'-dihydroxy-6,7,8-trimethoxyflavone (xanthomicrol) and the labdane-diterpene 3 alpha-angeloyloxy-2 alpha-hydroxy-13,14 Z-dehydrocativic acid (AAHDD). Both compounds inhibited the tonic contraction the effect being highly potent when a mixture in a proportion of 3 : 1 (xanthomicrol/AAHDD) was assayed. The phasic component of the contractile response with K(+) was also reduced by the compounds. Xanthomicrol depressed the spasms induced with ACh, Hist, and BaCl(2) and its effect on Ca (2+) concentration-response curve showed a type of non-surmountable calcium blocking action; unlike the flavonoid, AAHDD produced a parallel rightward shift of the concentration-response curve to calcium, suggesting a competitive antagonism with an estimated pA(2) of 4.66. Obtained results support, in part, the popular use of B. paniculata as a spasmolytic remedy.
Meckes
Mariana
M
Calzada
Fernando
F
Paz
Daniel
D
Rodríguez
Jaime
J
Ponce-Monter
Héctor
H
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D019659:Asteraceae; D017609:Barium Compounds / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D004224:Diterpenes / Q000494:pharmacology; D047309:Flavones; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D009281:Naphthalenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010421:Pentanoic Acids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology
C462037:3-angeloyloxy-2-hydroxy-13,14-dehydrocativic acid; D017609:Barium Compounds; D002712:Chlorides; D004224:Diterpenes; D047309:Flavones; D005419:Flavonoids; D009281:Naphthalenes; D010421:Pentanoic Acids; D010936:Plant Extracts; C433017:labdane; C024986:barium chloride; C462036:xanthomicrol; D011189:Potassium Chloride; D006632:Histamine; D000109:Acetylcholine; D002118:Calcium