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

Objective:To assess the relaxant effect of several organic extracts obtained from Agastache mexicana(A.mexicana),Cochlospermum vitifolium(C.vitifolium),Cordia morelosana(C.morelosana),Lepechinia caulescens(L.caulescens)and Talauma mexicana(71 mexicana)used in Mexican traditional medicine for the treatment of several diseases.Methods:Extracts were obtained by maceration at room temperature using hexane,dicliloromethane and methanol for each plant material.The organic extracts were evaluated ex vivo to determine their relaxant activity on the contractions induced by carbaehol(cholinergic receptor agonist,1μmol/L in isolated rat tracheal rings.Results:A total of 15 extracts were evaluated(three for each species).All test samples showed significant relaxant effect,in a concentration-dependent manner,on the contractions induced by 1μmol/L carbachol,with exception of extracts from C.morelosana.Active extracts were less potent than theophylline[phosphodiesterase inhibitor,EC_(50):(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 of T.mexhxma[E_(max):(103.03±3.32)%and EC_(50):(159.39±3.72)μg/mL)and C.vitifolium[Emax:(106.58±2.42)%and EC_(50):(219.54±7.61)μg/mL].Finally,hexanic and dichloromethanic extracts from A.mexicana were fully effective but less potent than T.mexicana,and C.vitifolium.Conclusions:Less polar extracts obtained from A.mexicana,71 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.