Menispermi Rhizoma is the dried rhizome of Menispermum dauricum DC. (Menispermaceae), which commonly used to treat sore throat, enteritis, and dysentery in traditional Chinese medicine. To clarify the chemical basis of the total alkaloids of M. Rhizoma, HPLC was used to analyze total alkaloids, and then representative chemical constituents were separated by tracking. Nineteen compounds, including two new alkaloids (1R-methymenidaurine A-α-N-oxide (1) and 1R-7'-hydroxymethyl-menidaurine A (2)), thirteen known alkaloids, and four known flavonoids were isolated and identified using spectroscopic methods. Meanwhile, seven characteristic peaks were identified from the total alkaloids using HPLC analysis. Furthermore, compounds 1-18 were screened in vitro for their inhibitory effect against nitric oxide production in BV-2 microglia cells stimulated by lipopolysaccharide. Among them, six compounds showed weak inhibition, and the IC50 values of compounds 1 and 2 were 56.87 ± 1.61 and 53.67 ± 1.52 mM, respectively.
Keywords: Menispermi Rhizoma; anti-inflammatory activity; basic chemical substances; total alkaloids; traceability separation.