Action of the extract of drymis winteri on contraction induced by inflammatory mediators, compound 48/80 and ovalbumin of the guinea-pig trachea in vitro

Abstract

1. 1. We examined the effect of hydroalcoholic extract (HE), obtained from the barks of Drymis winteri J.R. et Forster (Winteraceae), against contraction caused by several mediators involved in asthma and allergy, and also that caused by ovalbumin and compound 48/80 in guinea-pig trachea. 2. 2. HE (0.5–2 mg/ml) added to the bath 20 min earlier antagonized the contractions elicited by bradykinin, prostaglandin E 2 and capsaicin in a concentration-dependent and noncompetitive manner. 3. 3. HE antagonized, in a graded but apparently competitive fashion, contractions induced by substance P, [β-ala 8]neurokinin A-(4–10), a selective NK 2 agonist, and the stable analog of thromboxane A 2 (U 46619). However, HE had only a slight effect against contractions induced by histamine and had no effect against responses induced by acetylcholine and the selective NK 2 agonist, substance P-methylester. 4. 4. In guinea-pig trachea (GPT) from animals that had been previously sensitized actively to ovalbumin, HE antagonized ovalbumin-mediated contraction in a time- and concentration-dependent manner. In addition, HE caused graded displacement to the right of contraction evoked by compound 48/ 80 in GPT from nonsensitized animals. 5. 5. It is concluded that HE contains active principle(s) which interact via distinct mechanisms with several mediators known to participate in asthma and allergy. Furthermore, HE concentration dependently attenuated ovalbumin and compound 48/80-mediated contractions in GPT from sensitized and nonsensitized animals, respectively.