An onion variety has natural antithrombotic effect as assessed by thrombosis/thrombolysis models in rodents

Introduction: Prevention of arterial thrombotic diseases has a high priority in developed countries. As inappropriate diet has been shown to be an important risk factor for thrombotic events, regular antithrombotic diet may offer a convenient and effective way of prevention. The aim of the present study was to test onion extracts for antithrombotic effect and to identify the effective varieties in Allium cepa. Materials and methods: A shear-induced platelet function test (haemostatometry) was used to screen for antithrombotic potential. Onion extracts showing significant antithrombotic activity in vitro were further assessed in vivo by using a laser-induced thrombosis test in mice. Results and conclusions: An onion variety, Toyohira, showed significant antithrombotic activity both in vitro and in vivo. Toyohira showed thrombolytic activity in addition to the antiplatelet effect. Superkitamomiji, 2935A, and K83211 showed only thrombolytic activity. Quercetin, the richest fLavonoid in onion, was measured, but no correlation was found between quercetin content and antithrombotic activity. It is concluded that onion A. cepa can be classified into varieties with or without antithrombotic and thrombolytic effects. This should be taken into account in future population studies on the antithrombotic effects of vegetables. (C) 2004 Elsevier Ltd. All rights reserved.