Sinomenine N-oxide

Simultaneous determination of sinomenine and its metabolites desmethyl-sinomenine and sinomenine N-oxide in rat plasma by liquid chromatography tandem mass spectrometry.[Pubmed:38234029]

J Sep Sci. 2024 Jan;47(1):e2300790.

Sinomenine is an active ingredient extracted from herb medicine, which has been prescribed to treat rheumatoid arthritis in clinics. The present work was to develop a simple method to simultaneously determine sinomenine and its metabolites desmethyl sinomenine and Sinomenine N-oxide in rat plasma by liquid chromatography tandem mass spectrometry. Precursor-to-product transitions for detection were m/z 330.2 > 239.1 for sinomenine, m/z 316.2 > 239.1 for desmethyl-sinomenine, m/z 346.2 > 314.1 for Sinomenine N-oxide and m/z 286.2 > 153.2 for morphine (internal standard), respectively. During the validation and sample quantification, an excellent linear calibration range was observed for all the analytes with correlation coefficients more than 0.999 (r > 0.99). The extraction recovery was more than 85%. No significant matrix effect and carryover were observed. The precision was less than 6.45%, whereas accuracy ranged from -4.10% to 7.23%. The validated method has been successfully applied to the pharmacokinetic study of sinomenine, desmethyl sinomenine, and Sinomenine N-oxide in rat plasma after oral administration of sinomenine at a single dose of 5 mg/kg. The results suggested that sinomenine was rapidly metabolized into its metabolite desmethyl sinomenine and Sinomenine N-oxide.

Identification and characterization of the metabolites of sinomenine using liquid chromatography combined with benchtop Orbitrap mass spectrometry and nuclear magnetic resonance spectroscopy.[Pubmed:38211350]

Rapid Commun Mass Spectrom. 2024 Feb 15;38(3):e9669.

RATIONALE: Sinomenine, a major bioactive compound isolated from Sinomenium acutum, has been used for the treatment of rheumatoid arthritis and other cardio-cerebrovacular diseases. However, the metabolism of this drug has not been fully investigated. The current work was carried out to investigate the in vitro metabolism of sinomenine in liver microsomes. METHODS: The metabolites were generated by incubating sinomenine (3 muM) with the liver microsomes in the presence of NADPH at 37 degrees C. The structure of the metabolites was characterized using liquid chromatography coupled to high-resolution mass spectrometry (HRMS). Two major metabolites synthesized and their structures were further confirmed using nuclear magnetic resonance spectroscopy. RESULTS: Under the current conditions, 12 metabolites were found and structurally identified using high resolution MS and MS(2) spectra. Among these metabolites, M1, M2, M3, M4, M5, M6, M7, M9, M11, and M12 were first reported. The metabolites M8 and M10 were synthesized and unambiguously identified as N-desmethyl-sinomenine and Sinomenine N-oxide, respectively. The phenotyping study revealed that the formation of M8 was catalyzed by CYP2C8, 2C19, 2D6, and 3A4, whereas the formation of M3, M6, and M10 were exclusively catalyzed by CYP3A4. The metabolic pathways of sinomenine include N-demethylation, O-demethylation, dehydrogenation, oxygenation, and N-oxygenation. CONCLUSIONS: N-Demethylation and N-oxygenation were the primary metabolic pathways of sinomenine. This study provides new insight into the in vitro metabolism of sinomenine, which would help prospects of sinomenine disposition and safety assessments.

New N-oxide alkaloids from the stems of Sinomenium acutum.[Pubmed:36572115]

Fitoterapia. 2023 Mar;165:105404.

Six new alkaloids (1-6) and six known alkaloids (7-12) were obtained from the stems of Sinomenium acutum. Among them, compounds 1-3 and 6 were four N-oxide alkaloids. The structures and absolute configurations of these new alkaloids were elucidated through comprehensive data of 1D and 2D NMR, HRESIMS and ECD spectra. All isolated compounds were evaluated in vitro for their inhibitory activities against nitric oxide (NO) production and inhibitory effects on AChE. Among them, the Sinomenine N-oxide (9) was the most potent NO production inhibitor, with an IC(50) value of 23.04 muM.

Two new morphinane alkaloids from Sinomenium acutum.[Pubmed:21623515]

J Asian Nat Prod Res. 2011 Jun;13(6):523-8.

Two new morphinane alkaloids, 1-hydroxy-10-oxo-sinomenine (1) and 4,5-epoxy-14-hydroxy Sinomenine N-oxide (2), have been isolated from the stems of Sinomenium acutum. Their structures were established by various spectral analyses, especially 2D NMR experiments. The structure of 2 was confirmed by single crystal X-ray diffraction. The absolute configurations of 1 and 2 were deduced by comparison of CD spectra with the known alkaloid sinomenine (3). Compound 1 was tested for DPPH inhibition and gave IC(50) of 27.9 muM. Compound 2 was tested for neuroprotective effect and showed significant activity against beta-amyloid(25-35)-induced oxidative injury (*P < 0.05) at 10 muM in PC-12 cells.

Morphinane alkaloids with cell protective effects from Sinomenium acutum.[Pubmed:16038566]

J Nat Prod. 2005 Jul;68(7):1128-30.

One new morphinane alkaloid, Sinomenine N-oxide (1), and one new natural occurring morphinane alkaloid, N-demethylsinomenine (2), together with six known alkaloids, 7,8-didehydro-4-hydroxy-3,7-dimethoxymorphinan-6-ol (3), sinomenine (4), sinoacutine (5), N-norsinoacutine, acutumine, and acutumidine, were isolated from the stems of Sinomenium acutum. Their structures were elucidated on the basis of spectroscopic analysis and chemical methods. Compounds 2, 3, and 5 have protective effects against hydrogen peroxide-induced cell injury.