Bioanalytical investigation of asarone in connection with Acorus calamus oil intoxications

Abstract

Preparations of the plant Acorus calamus (calamus or sweet flag) (A. calamus) are available via internet trade and marketed as being hallucinogenic. In 2003-2006, the Swedish Poisons Information Centre received inquiries about 30 clinical cases of intentional intoxication with A. calamus products. The present investigation aimed to identify alpha- and beta-asarone, considered active components of A. calamus, and metabolites thereof in urine samples collected in seven of these cases. To further aid the identification of asarone biotransformation products, a calamus oil preparation was incubated with the fungus Cunninghamella elegans, which is used as a microbial model of mammalian drug metabolism. Using gas chromatography-mass spectrometry (GC-MS) analysis in selected ion monitoring mode, alpha-asarone was detected in five urine samples at concentrations ranging between approximately 11 and 1150 microg/L and beta-asarone in four of those at approximately 22-220 microg/L. A previously identified asarone metabolite, trans-2,4,5-trimethoxycinnamic acid (trans-TMC), was detected in the fungus broth by liquid chromatography-tandem mass spectrometry whereas cis-TMC was tentatively identified in the human urine samples. Using GC-MS, a hydroxylated asarone metabolite was identified both in fungus broth and urine samples. However, this study demonstrated no evidence for the presence of 2,4,5-trimethoxyamphetamine, claimed as a hallucinogenic component of A. calamus. The main clinical symptom reported by the patients was prolonged vomiting that sometimes lasted more than 15 h.