Tracheal relaxation of five medicinal plants used in Mexico for the treatment of several diseases

摘要

Objective:To assess the relaxant effect of several organic extracts obtained fromAgastache mexicana(A. mexicana),Cochlospermum vitifolium(C. vitifolium),Cordia morelosana(C. morelosana),Lepechinia caulescens(L. caulescens)andTalauma mexicana(T. mexicana) used inMexican traditional medicine for the treatment of several diseases.Methods:Extracts were obtained by maceration at room temperature using hexane, dichloromethane and methanol for each plant material.The organic extracts were evaluatedex vivo to determine their relaxant activity on the contractions induced by carbachol(cholinergic receptor agonist,1 μmol/L) in isolated rat tracheal rings.Results:A total of15 extracts were evaluated(three for each species).All test samples showed significant relaxant effect, in a concentration-dependent manner, on the contractions induced by1 μmol/L carbachol, with exception of extracts fromC. morelosana.Active extracts were less potent than theophylline [phosphodiesterase inhibitor,EC50:(28.79±0.82) μg/mL] that was used as positive control.Concentration-response curves revealed that the extracts with more significant effects were dichloromethanic extracts ofT. mexicana [Emax:(103.03±3.32)% andEC50:(159.39±3.72) μg/mL) andC. vitifolium [Emax:(106.58±2.42)% andEC50:(219.54±7.61) μg/mL].Finally, hexanic and dichloromethanic extracts fromA. mexicana were fully effective but less potent than T. mexicana andC. vitifolium.Conclusions:Less polar extracts obtained fromA. mexicana,T. mexicana and C. vitifolium exhibited greater relaxant effect on tracheal rat rings, which allows us to suggest them as sources for the isolation of bioactive molecules with potential therapeutic value in the treatment of asthma.