TY - JOUR
T1 - Polyalthic acid isolated from Croton reflexifolius has relaxing effect in Guinea pig tracheal smooth muscle
AU - Sánchez-Mendoza, María Elena
AU - Reyes-Trejo, Benito
AU - De La Rosa, Leticia
AU - Rodríguez-Silverio, Juan
AU - Castillo-Henkel, Carlos
AU - Arrieta, Jesús
N1 - Funding Information:
We are grateful to Ernestina Cedillo Portugal (Herbario Jorge Espinosa, Departamento de Preparatoria Agrícola, Universidad Autónoma Chapingo) for the identification of the plant material and MVZ Alberto Pizaña of Insti-tuto Nacional de Enfermedades Respiratorias (México) for the experimental animals. We also thank Mr. Concepción Castellanos for collecting the plant material. This work was suported by a grant from the Escuela Superior de Medic-ina del Instituto Politécnico Nacional (México) (proyecto 20070451).
PY - 2008/10
Y1 - 2008/10
N2 - The relaxing activity of Croton reflexifolius H.B.K (Euphorbiaceae) leaves was assessed in isolated guinea pig tracheal rings. The dichloromethane extract of C. reflexifolius was the most active relaxant (EC50 = 118.98 ± 5.927 μg/mL), and within this extract polyalthic acid was identified as the main active relaxing agent. Polyalthic acid showed a relaxing effect on tracheal rings precontracted with carbachol (EC50 = 183.71 ± 3.28 μM), histamine (6.24 ± 0.28 μM), and KCl (195.79 ± 10.36 μM). The pretreatment with polyalthic acid did not affect the concentration response curve to histamine, and it reduced the Emax of carbachol without affecting its EC50, thus suggesting that polyalthic acid produces a mild antimuscarinic activity. In addition, neither glibenclamide, l-NAME nor propranolol modified the effect of polyalthic acid, although the latter enabled isoproterenol activity. In conclusion, this study represents the first in which the relaxing effect of C. reflexifolius on tracheal rings of guinea pig was clearly demonstrated. Polyalthic acid, which was the main active agent in this relaxing action, produced a mild antimuscarinic activity in a noncompetitive manner. Its relaxing effect was independent of the contractile agent employed and was not related with β-adrenergic receptors, K channels, or nitric oxide. Further experiments are needed to clarify the mechanism of action of polyalthic acid.
AB - The relaxing activity of Croton reflexifolius H.B.K (Euphorbiaceae) leaves was assessed in isolated guinea pig tracheal rings. The dichloromethane extract of C. reflexifolius was the most active relaxant (EC50 = 118.98 ± 5.927 μg/mL), and within this extract polyalthic acid was identified as the main active relaxing agent. Polyalthic acid showed a relaxing effect on tracheal rings precontracted with carbachol (EC50 = 183.71 ± 3.28 μM), histamine (6.24 ± 0.28 μM), and KCl (195.79 ± 10.36 μM). The pretreatment with polyalthic acid did not affect the concentration response curve to histamine, and it reduced the Emax of carbachol without affecting its EC50, thus suggesting that polyalthic acid produces a mild antimuscarinic activity. In addition, neither glibenclamide, l-NAME nor propranolol modified the effect of polyalthic acid, although the latter enabled isoproterenol activity. In conclusion, this study represents the first in which the relaxing effect of C. reflexifolius on tracheal rings of guinea pig was clearly demonstrated. Polyalthic acid, which was the main active agent in this relaxing action, produced a mild antimuscarinic activity in a noncompetitive manner. Its relaxing effect was independent of the contractile agent employed and was not related with β-adrenergic receptors, K channels, or nitric oxide. Further experiments are needed to clarify the mechanism of action of polyalthic acid.
KW - Bronchodilator
KW - Croton reflexifolius
KW - Euphorbiacea
KW - Guinea pig trachea
KW - Mexican traditional medicine
KW - Polyalthic acid
UR - http://www.scopus.com/inward/record.url?scp=57649229727&partnerID=8YFLogxK
U2 - 10.1080/13880200802315881
DO - 10.1080/13880200802315881
M3 - Artículo
SN - 1388-0209
VL - 46
SP - 800
EP - 807
JO - Pharmaceutical Biology
JF - Pharmaceutical Biology
IS - 10-11
ER -