Bioactive principles from the roots of Lindera megaphylla

d-Dicentrine was isolated from the root of Lindera megaphylla. It inhibited the aggregation of washed rabbit platelets induced by ADP, collagen, arachidonic acid, and PAF. It also inhibited the high potassium- and norepinephrine-induced contraction of rat thoracic aorta. In rat ventricular cells treated with 3 microM d-dicentrine, the action potential duration (ADP50) was prolonged from 59.9 +/- 11.3 msec to 201 +/- 28.7 msec.