Determination of doping higenamine in Chinese herbal medicines and their concentrated preparations by LC-MS/MS

The World Anti-Doping Agency (WADA) has included higenamine in the β2 agonist (S3) category of the Prohibited List since 2017 due to its pharmacological effects on adrenergic receptors. Although higenamine contained in Chinese herbal medicines has been identified by previous studies, comprehensive investigation on the higenamine content of Chinese herbs and their concentrated preparations is still required. This study aimed to determine the levels of higenamine in Chinese medicinal materials and their concentrated preparations used in Chinese medicine prescriptions in Taiwan. The levels of higenamine in Chinese medicinal materials, including Cortex Phellodendri, Flos Caryophylli, Fructus Euodiae, Fructus Kochiae, Plumula Nelumbinis, Radix Aconiti Preparata, Radix Aconiti Lateralis Preparata, and Radix Asari, and their concentrated preparations were determined by a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Our results showed that the amounts of higenamine were detected and quantified in studied Chinese medicinal materials and their concentrated preparations, except for Flos Caryophylli, Radix Aconiti Preparata, and Radix Aconiti Lateralis Preparata. Plumula Nelumbinis and Cortex Phellodendri have higher levels of higenamine when compared to other Chinese herbs tested in the present study. The highest level of higenamine was 2100 μg/g found in the Plumula Nelumbinis medicinal material. In contrast with Plumula Nelumbinis and Cortex Phellodendri, higenamine levels below 10 μg/g were found in other most of the studied Chinese medicinal materials and their concentrated preparations. This study confirmed that various Chinese herbs and their concentrated preparations contained higenamine, and it provided more coherent and comprehensive information for reducing the potential risk of higenamine misuse in sports.