Higenamine Hydrochloride

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.

Allergic rhinitis (AR) is a prevalent nasal inflammatory disorder, and pyroptosis plays a crucial role in aggravating AR. Current medications for AR treatment still have deficiencies, and finding new agents is of great interest. Mahuang Fuzi Xixin decoction (MFXD), an ancient Chinese medicine, is now commonly used to treat AR, which has anti-inflammatory and immunomodulatory effects, but its underlying mechanism is unknown.

This study aims to evaluate the effects of MFXD on AR and explore its potential mechanisms in view of the regulatory effect on pyroptosis.

MFXD, Mahuang, Fuzi, and Xixin water extracts were analyzed using ultra high performance liquid chromatography-Orbitrap-high-resolution accurate mass spectrometry. In in vivo study, the effects of MFXD on AR treatment were evaluated in an ovalbumin-induced mouse model. Mice were administered saline (control and model groups), MFXD (1.375, 2.75 g/kg), and dexamethasone (2.5 mg/kg) for 13 days. AR symptoms were evaluated by blinded observers. Immunoglobulin E (IgE) and histamine levels were measured using enzyme-linked immunosorbent assays. Expression of pyroptosis-related proteins (NLRP3, ASC, Caspase-1 p10/p20, GSDMD-N and IL-1β) in AR mouse nasal mucosa were estimated by immunohistochemistry. In in vivtro study, the effects of MFXD on pyroptosis were assessed in human nasal epithelial cells (HNEpCs) stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP), and incubated with MFXD (12.5, 25, and 50 μg/mL). Pyroptosis-related protein expression was measured by western blotting.

Thirty-three compounds in MFXD were identified, including ephedrine, pseudoephedrine, higenamine, aconine, aconitine, benzoylmesaconitine, benzoylhypaconine and hypaconitine. In the in vivo study, oral taken of MFXD/dexamethasone significantly ameliorated AR symptoms, reduced swelling of the nasal mucosa, and decreased the levels of IgE and histamine in AR mice serum. MFXD/dexamethasone attenuated histopathological changes and reduced the expression of pyroptosis-related proteins in nasal mucosa, indicating the inhibitory effect on nasal epithelial pyroptosis. In the in vitro study, MFXD (50 μg/mL) significantly alleviated cytotoxicity, protected cells from swelling and rupture, and downregulated the expression of pyroptosis-related proteins in LPS/ATP-induced HNEpCs.

MFXD suppressed nasal epithelial pyroptosis by inhibiting the NLRP3/Caspase-1/GSDMD-N signaling pathway, which alleviates AR. Our results offer valuable insights into potential AR therapies and provide evidence for the clinical utilization of MFXD to treat AR.