Evaluation of angelicae radix (Touki) by the inhibitory effect on platelet aggregation.

Quality evaluation of Angelicae Radix (Touki) was discussed referring to its inhibitory effect on platelet aggregation. No better correlation was observed in quality determined morphologically from the above-ground part of Touki and that determined by anti-platelet aggregation (APA) effects. Phthalides and adenosine, known to be the major components of Touki, were found not sufficient to evaluate the Touki quality as regards APA active components have been studied and it was concluded that the APA effect of Touki results from the combined action of plural components. The importance of determining quality based on the action of total extract to meet the purpose for which the substance is to be used was suggested.