Differential antagonistic effect of hydroalcoholic extract from Hymenaea martiana hayne arzeik on kinin and other agonist‐induced contractions of the isolated rat uterus and Guinea‐pig ileum

Abstract

AbstractThis study was undertaken to evaluate the action of the hydroalcoholic extract (HE) from the bark of Hymenaea martiana on bradykinin (BK), lysyl‐bradykinin (L‐BK), acetylcholine (ACh), angiotensin II (AII), prostaglandin F2a (PGF2a), serotonin (5‐HT), oxytocin (Ot) and histamine (His)‐induced contractions of the isolated rat uterine muscle and guinea‐pig ileum. The HE (50–200 μg/mL) added to the bath for 20 min caused a concentration‐dependent rightward displacement of BK, L‐BK and ACh‐induced contractions in the rat uterus, allied to a discrete but significant reduction of maximal responses to the latter two agonists. By contrast, at the same range of concentrations the HE antagonized in a concentration‐dependent but noncompetitive manner the contractions induced by AII, but only at high concentrations (200 μg/mL) it significantly inhibited contractions evoked by both PGF2a and Ot, while contractile responses induced by 5‐HT were not affected. In the guinea‐pig ileum, the HE of H. martiana (50 and 100 μg/ml) caused a discrete rightward displacement of the BK and ACh concentration—response curves. Higher concentrations of the HE of H. martiana (200 μg/mL) caused a marked depression of BK and ACh‐induced maximal responses. These findings show that the active principle(s) presents in the HE from the bark of H. martiana exhibits an interesting pharmacological profile against several neurotransmitter‐induced contractions in nonvascular smooth muscles. Such actions may be relevant for supporting, at least in part, the use of this plant in folk medicine.