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/

1. We examined the effect of hydroalcoholic extract (HE), obtained fro m the barks of Drymis winteri J.R. et Forster (Winteraceae), against c ontraction caused by several mediators involved in asthma and allergy, and also that caused by ovalbumin and compound 48/80 in guinea-pig tr achea. 2. HE (0.5-2 mg/ml) added to the bath 20 min earlier antagonize d the contractions elicited by bradykinin, prostaglandin E-2 and capsa icin in a concentration-dependent and noncompetitive manner. 3. HE ant agonized, in a graded bit apparently competitive fashion, contractions induced by substance P, [beta-ala(8)]neurokinin A-(4-10), a selective NK2 agonist, and the stable analog of thromboxane A(2) (U 46619). How ever, HE had only a slight effect against contractions induced by hist amine and had no effect against responses induced by acetylcholine and the selective NK1 agonist, substance P-methylester. 4. In guinea-pig trachea (GPT) from animals that had been previously sensitized activel y to ovalbumin, HE antagonized ovalbumin-mediated contraction in a tim e and concentration-dependent manner. In addition, HE caused graded di splacement to the right of contraction evoked by compound 48/80 in GPT from nonsensitized animals. 5. It is concluded that HE contains activ e principle(s) which interact via distinct mechanisms with several med iators known to participate in asthma and allergy. Furthermore, HE con centration dependently attenuated ovalbumin and compound 48/80-mediate d contractions in GPT from sensitized and nonsensitized animals, respe ctively. (C) 1997 Elsevier Science Inc.