The Studies On Chemical Constituents From The Rhizome Of Menispermum Dauricum DC. And Pharmacological Activities

ObjectiveTo study the chemical constituents from the dried rhizome of Menispermum dauricum DC,especially the alkaloids.To evaluate its anti-inflammatory and anti-tumor activities in vitro.MethodsThe dried rhizome of Menispermum dauricum was extracted with 95%ethanol by reflux.The total alkaloids were extracted from total extracts with alkali-extraction,acid-precipitation and organic solvent extraction.The total alkaloids were isolated systematically and purified by silica gel column chromatography,ODS column chromatography,preparative and semi-preparative high performance liquid chromatography.The structures of compounds were identified by modern spectral techniques including NMR,MS and UV.The anti-inflammatory activities of compounds were evaluated by lipopolysaccharide-induced NO production model in RAW264.7 cells.MTT was used to evaluate the inhibitory effects on colon cancer cells.ResultsTwelve alkaloids were isolated from the chloroform part of 95%ethanol extract of rhizome of M.dauricum DC and identified as menisoxoisoaporphine A（1）,menisoxoisoaporphine B（2）,menisoxoisoaporphine C（3）,bianfugecine（4）,daurioxoisoporphine B（5）,oxoisoporphine B（6）,tyraminoporphine（7）,N-demethyl-N-formyldehydronuciferine（8）,6-acetyl-5,6-dihydro-1,2-dimethoxy-4H-dibenzo[de,g]-quinoline（9）,sinotumine G（10）,acutuminine（11）,（+）-cheilanthifoline（12）.The results of anti-inflammatory activity showed that compounds 1,5,6 and 9 had different degrees inhibitory effects on LPS-induced NO production.The results of anti-tumor activity showed that all compounds had almost no inhibitory effect on colon cancer cells,with IC₅₀ values greater than 50μM.ConclusionsThe 12 alkaloids isolated from M.dauricum were classified into four structural types.Compounds 1-7 are alkaloids with oxoisoaporphine structure,compounds 8-10 are alkaloids with aporphine structure,compound 11 is an alkaloid with morphanes structure,and compound 12 is an alkaloid with protoberberine structure.Among the twelve alkaloids,compounds 1-3 are new compounds,compound 9 is a new natural product,and compounds10 and 12 were isolated from this genus for the first time.The results of anti-inflammatory activity showed that compounds 1,5,6 and 9 had different degrees of anti-inflammatory effects.The results of anti-tumor activity showed that all compounds had almost no inhibitory effect on colon cancer cells.