Reduction of beta-asarone in acori rhizoma by decoction

Beta-asarone, the major constituent of the essential oil from the traditional Chinese herbal drug "Acori rhizoma" is regarded as carcinogenic in rodents and potentially genotoxic. Thus, the limit for the ingestion of this constituent from herbal medicinal products has been set at 0.115 mg beta-asarone/person/day. The present study demonstrates that a decoction procedure, traditionally used for Chinese herbal preparations and intended as the standard procedure in Ph. Eur., was able to significantly reduce the amount of beta-asarone. HPLC analysis indicated that the content of beta-asarone in dried herbal drug ranged from 15.22 to 25.34 mg/g. During a 1-hour decoction, the amount of beta-asarone decreased more than 85 % and the aqueous extract contained the equivalent of only 0.46-2.19 mg beta-asarone per gram of herbal drug. If this aqueous extract was heated for a further 2 hours, the final content of beta-asarone was reduced to the equivalent of no more than 0.005 mg per gram of herbal drug. This low level of beta-asarone should be acceptable for therapeutic use. It was noted that decoction of Acori rhizoma in the presence of other herbal substances impaired, to some extent, the reduction in beta-asarone.