Antithrombotic effects of some flavonoids alone and combined with acetylsalicylic acid.

In the rat, a selection of two experimental models of "prethrombotic states", one of venostatic thrombosis and one of arterial thrombosis was used to compare the antithrombotic of three flavonoid preparations: O,-(beta-hydroxyethyl)-rutosides (HR), an association of trihydroxyethylrutoside and coumarin (troxerutin) and 7-mono-hydroxyethylrutoside (7-Mono-HR), as well as acetylsalicylic acid (ASA). The flavonoids were very effective "protectors" on the prethrombotic models, but only ASA was active on the model of arterial thrombosis. No compound showed a clear protection on the venostatic model if direct activation by kaolin was used. However, if an indirect activation by vessel wall stimulation was used, 7-Mono-HR possessed a marked protective effect. The most favourable results were obtained with an association of 7-Mono-HR and ASA, which could be considered for investigation in clinical thrombosis prophylaxis.