Red Wine and Ginkgo Biloba extracts induce vasorelaxant and antioxidant effects on the digital veins of healthy horses

We evaluated the vasorelaxant and antioxidant properties of Red Wine (RW) and Ginkgo biloba (GB), two plant extracts available in standardized preparation, on isolated equine digital veins (EDVs).

EDVs were removed from limbs of healthy horses in a slaughterhouse. Then, concentration-response curves (CCRCs) to RW and GB (10-10 g/L - 10-3 g/L) were determined using the organ bath technique. The role of the endothelium and the nitric oxide (NO) pathway was evaluated by performing CCRCs on either des-endothelialized veins or veins incubated with NO pathway inhibitors (L-NAME or ODQ). The antioxidant effect of both RW and GB was estimated by an acetylcholine test. A reference CCRC was first performed to validate the oxidative effect of homocysteine (a superoxide anion generator) and the antioxidant effect of tempol (100 μM). Then, tempol was replaced by RW (30 μg/L) or GB (100 μg/L).

RW produed a relaxation which was inhibited on both des-endothelialized rings and on rings incubated with L-NAME or ODQ. Homocysteine-induced impairment of acetylcholine relaxation was partially restored by RW and GB. These results showed that RW and GB exert veins vasorelaxation but also antioxidant effects. The vasorelaxant effect of RW mainly involved a role of the endothelium and NO pathway, while GB induced endothelium-independent vasorelaxation.

We showed that RW and GB extracts possess vasorelaxant and antioxidant properties on EDVs. Beneficial effects of RW and GB reported in equine clinical practice could be linked at least to their vasculo-protective action that requires further investigation in laminitic horses.