PROBLEM TO BE SOLVED: To provide a new platelet aggregation inhibitor relieving or preventing various symptoms caused by the platelet aggregation, and a bloodstream-improving agent and an antithrombotic agent by using the above inhibitor as an active ingredient.SOLUTION: This platelet aggregation inhibitor is provided by containing at least 1 compound selected from a group of compounds having oxygen-containing ring structures expressed by formulas (1) to (6) as an active ingredient, and the bloodstream-improving agent and antithrombotic agent containing the above compound as the active ingredient are also provided. As the platelet aggregation inhibitor, especially (R)-2-deceno-&delta-lactone is preferable.COPYRIGHT: (C)2009,JPO&INPIT【課題】血小板凝集による様々な症状を軽減し、もしくは予防することができる新規な血小板凝集抑制剤、および該抑制剤を有効成分とする血流改善剤、抗血栓剤の提供。【解決手段】下記式(1)乃至(6)で示される含酸素環状構造を有する化合物群から選ばれた少なくとも1つの化合物を有効成分として含有する血小板凝集抑制剤、および該化合物を有効成分とする血流改善剤、抗血栓剤。該血小板凝集抑制剤としては、特に、(R)-2-デセノ-δ-ラクトンが好ましい。【選択図】 なし
