Airway Smooth Muscles Relaxant and Mast Cells Stabilizing Activity of Some Medicinal Plants Used in Managing Asthma in North-Western Nigeria

Cassia occidentalis whole plant (C.O.W.P), Jatropha curcas leaves (J.C.L.), Ximenia americana Santalales leaves (X.A.L.), and Eucalyptus citriodora leaves (E.C.L.) have been revealed to be widely used by locals of north-western Nigeria for the management of asthma. This study was aimed at providing a pharmacological rationale for the ethnomedical use of these plants in the management of asthma. The four extracts were screened for their effects on the spontaneous contraction of isolated rabbit ileum strip; also on pre-contracted isolated guinea Pig ileum strip; on pre-contracted isolated Guinea Pig trachea chain; and on ovalbumin-induced peritoneal mast cell degranulation in Wistar rats. Ethanol extracts of C.O.W.P., E.C.L., J.C.L., and X.A.L. at 100 mg/mL remarkably relaxed spontaneous contractions of isolated rabbit ileum. Greatest relaxation was obtained with X.A.L. Ethanol extracts of C.O.W.P., E.C.L., J.C.L., and X.A.L. statistically significantly (p 0.05) inhibited histamine-induced contractions of isolated guinea pig ileum. In addition, the four extracts statistically significantly inhibited (p 0.05) histamine-induced contraction of isolated guinea pig trachea. The ethanol leaves extracts of C. occidentalis and Jatropha curcas exhibited mast cell stabilizing effect in ovalbumin-induced rat peritoneal mast cell degranulation. However, Eucalyptus citriodora and Ximenia Americana did not protect against ovalbumin-induced rat peritoneal mast cell degranulation. C.O.W.P., E.C.L., J.C.L., and X.A.L all possess broncho-relaxant activity, while only C.O.W.P. and J.C.L. exhibited mast cell stabilizing activity in laboratory animals thus supporting the traditional use of the plant in inflammatory and allergic conditions including asthma.