RESUMEN
This study investigates the effects of essential oil of Pterodon polygalaeflorus (EOPP) and ß-caryophyllene (ß-CAR). EOPP and ß-CAR relaxed the basal tone of ileum smooth muscle in a concentration-dependent manner (IC(50) s = 394.35 ± 62.12 and 68.65 ± 9.51 µg/mL respectively), an effect that was unaltered by hexamethonium, L-nitroarginine methyl ester or indomethacin. Both EOPP and ß-CAR evoked a concentration-dependent relaxation of ileum pre-contracted with KCl with an IC(50) value of 107.78 ± 10.47 and 17.35 ± 0.75 µg/mL, respectively. EOPP and ß-CAR inhibited the contractions induced by acetylcholine (ACh) and by KCl. In ileal preparations, the CaCl(2) -induced contractions were reduced by EOPP (300 µg/mL) and ß-CAR (100 µg/mL). Furthermore, CaCl(2) -induced contractions were also reduced by EOPP (300 µg/mL) and ß-CAR (100 µg/mL) in ileal preparations pretreated with ACh under Ca(2+) -free condition and in the presence of verapamil. EOPP (100 and 300 µg/mL) and ß-CAR (30 and 100 µg/mL) reduced the ACh-induced contractions of isolated rat ileum under Ca(2+) -free conditions. In the presence of high KCl and Ca(2+) -free conditions, EOPP (300 µg/mL) and ß-CAR (100 µg/mL) reduced the contractions induced by barium. A similar effect was also observed with verapamil. It is concluded that (i) ß-CAR is an important constituent involved in the myorelaxant and antispasmodic effects induced by EOPP; (ii) the inhibitory effect on intestinal contractility is myogenic and seems mainly mediated through an intracellular mechanism. However, the ability of EOPP and ß-CAR to decrease Ca(2+) influx through cytoplasmic membrane could not be discounted.