[Flavonoids: antithrombotic agents or nutrients?].

Flavonoids are a vast group of natural substances, but their pharmacological properties have not all been explored. The term flavonoid is used at large to designate a series of more than 4,000 molecules, which in fact can have very heterogenous molecular structures. We have shown that some flavonoids are good inhibitors of cyclic nucleotide phosphodiesterase (PDE). The most active PDE inhibitors among the flavonoids were also good inhibitors of the aggregation of human platelets in vitro. This suggests that flavonoids could serve as a template for the development of new anti-platelet drugs. However, a direct extrapolation of our experimental results to possible therapeutical use of flavonoid-containing medicinal plant extracts is not possible. The metabolic fate of these plant flavonoids is poorly understood, and their absence of toxicity has not always been clearly demonstrated. Flavonoids are also present in a regular diet in significant amounts. The role of these dietary flavonoids in the prevention of thrombotic diseases or atherosclerosis should also be investigated.