Alkaloids from Houttuynia cordata and Their Antiplatelet Aggregation Activities

AimTo study the chemical constituents from Houttuynia cordata and to test their antiplatelet aggregation activities.MethodsThe chemical constituents were isolated and purified by silica gel column chromatography and their structures were elucidated on the basis of spectral analysis. The antiplatelet aggregation activities were evaluated by Born's method, using rat PRP induced by ADP and thrombin.ResultsNine alkaloids were isolated and their structures were identified as norcepharadione B (1), 4, 5-dioxodehydroasimilobine (2), cepharadione B (3), aristololactam B II (4), aristololactam A II (5), sauristolactam (6), piperolactam A (7), splendidine (8), and aristololactam F II (9). Antiplatelet aggregation test indicated significant inhibitory activities of compounds 1, 2, 4–7, 9 induced by ADP and 1, 2, 4, 7 induced by thrombin.ConclusionCompounds 2, 6, 7, 9 were isolated from the genus Houttuynia for the first time. Compounds 1, 2, 4, 7 showed significant inhibitory effects on both ADP-induced and thrombin-induced platelet aggregation.