Study On Chemical Constituents And Biological Activities Of Melodinus Khasianus

In this paper,the chemical constituents and biological activities of Melodinus khasianus were studied based on the preliminary experimental data.The first chapter reviewed chemical constituents and biological activities of alkaloids in genus Melodinus.Secondly,we carried out the isolation and structural identification of chemical compositions from M.khasianus,especially for alkaloids.Thirdly,the main chemical constituents in M.khasianus were detected by high resolution mass spectrometry and the fragmentation rule of alkaloids by mass spectrometry was discussed in detail.Fourthly,the immunosuppressuve,anti-inflammatory and cytotoxicity activities of the isolated alkaloids were evaluated.Finally,we concluded all the theories and practices in research process.In our search for natural products with bioactivities,investigation of the EtOAc-soluble fraction from the aerial parts of M.khasianus led to the isolation and identification of 10 new alkaloids along with 27 known compounds.The structure of new compounds was elucidated by means of spectroscopic analysis,including 1D and2D NMR,MS,UV and IR.The known compounds were identified by comparisons of spectral data in reported literatures.Immunosuppressive activity of alkaloids was evaluated by CCK-8 assay to text the inhibitory activity against mouse spleen cells.Compound 21 has the same immunosuppressive activity as DXM at 40?M concentration.Compound 27 showed some toxicity at 40?M concentration.NO scavenging effect was used as the basis for the detection of inflammatory fartors in anti-inflammatory experiments.Compounds 1,33 and 36 showed good NO scavenging effects in all tested alkaloids.The anti-inflammatory activity of all alkaloids in M.khasianus was preliminarily tested by detecting the expression levels of IL-6 and TNF-?secreted by RAW 264.7 inflammatory cells in different treatment groups.The inhibitory effect of Compound 1 at a concentration of 20?M on TNF-?was comparable to that of DXM.The inhibitory effects of compounds 33 and 36 on the expression of two inflammatory factors IL-6 and TNF-?were less pronounced.In the cytotoxic activity experiment,the toxicity of alkaloids to MOLT-4 and MCF-7cells was mainly detected.The results showed that most of the compounds with cytotoxic activity were aspidospermine-type indole alkaloids and a few were aspidospermine-quinolone type bisindole alkaloids.Compound 25 showed the strongest cytotoxicity to MOLT-4 and MCF-7 cells,with IC₅₀ values of 0.7 and 1.6,respectively.The chemical constituents and biological activities of M.khasianus were deeply understood and the natural product resources were enriched,which provided practical basis for the follow-up related research or drug development.