Influence of several Styrian wines on bovine coronary artery contractions induced by endogenous agents

In the current study, seven Styrian white wine varieties, as well as their corresponding grape skin extracts (GSE), were tested for possible antagonistic effects on several endogenous vasoconstrictors known to be involved in the pathogenesis of cardiovascular diseases via tissue contraction experiments. Results were compared to those of Zweigelt, the most cultivated Styrian red wine. Bovine coronary artery strips were attached to a force transducer connected to a bridge amplifier, and isometric force was recorded on a multipen recorder. Preincubation of the vessels with the dealcoholized wines (DAW; 330 microl/ml) inhibited the constrictions to histamine and serotonin (5-HT) NO-dependently in the range of 5-80% and 30-90%, respectively (Zweigelt 47% and 90%, respectively). The corresponding GSE (20 mg/ml) inhibited the coronary constrictions to histamine in the range of 40% to 80% (Zweigelt 80%). Additionally, all DAW antagonized the contractile responses to the thromboxane-mimetic U46619 and the isoprostane 8-iso-PGF2alpha, indicating a nonspecific inhibition. To characterize the vasoactive component(s), the Traminer GSE was separated representatively using ultrafiltration, solid phase extraction (SPE) on Isolute C18(EC), and Isolute SCX-2, as well as column chromatography (CC) on polyamide. The resulting fractions were subsequently bioassayed for vasorelaxing activity. Preliminary results refer to a very hydrophilic, nonpolyphenolic basic compound with a MW<1000 Da. Our findings demonstrate that certain Styrian wines have remarkable antagonistic effects on several endogenous agonists in vitro, and that also nonpolyphenolic components in grapes may contribute to cardiovascular protection. Further separation steps as well as phytochemical and pharmacological investigations are in progress.