Studies On The Bioactive Constituents Of Four Chinese Traditional And Herbal Medicines

Chinese traditional and herbal medicines have been used for hundreds of years to cure diseases and save people's life. In order to search for active components from Chinese traditional and berbal medicines, chemical studies have been carried out on four kinds of herbs including Dipsacus asper Wall., Senecio scandens Buch.-Ham, Homalomena occulta Schott, and Rhodobryum roseum Limp.Bioassay-guided fractionations of the n-BuOH soluble part of D. asper led to the isolation of phenolic acid derivatives as the cytotoxic components, as well as two new iridoid glucoside tetramers (dipsanosides A, B), five new iridoid glucoside dimers (dipsanosides C-G), and one new iridoid glucoside (dipsanoside F). In addition, nine known compounds loganin, cantleyoside, triplostoside A, lisianthioside, 6'-O-(3-D-apiofuranosyl sweroside, caffeic acid, 2, 6-dihydroxyl cinnamic acid, oleanic acid, and akebiasaponin D from the roots of Dipsacus asper. Their structures were determined by spectroscopic and chemical methods, including 1D and 2D NMR techniques.Bioassay-guided fractionations of the ethanol extracts of Senecio scandens led to the isolation of eight new jacaranone analogs 2~7,10, and 11, along with four known jacaranone analogs (1, 8, 9, 12). Among them, compounds 2-6 were obtained as tautomeric mixtures of α/β epimer. Their structures were elucidated on the basis of spectral and chemical evidences. The cytotoxic activities of these compounds were tested. Compounds 7, 8, 9, 11 showed potent cytotoxicities and compounds 2-6 exhibited moderate cytotoxicities against five tumor cell lines. Jacaranone ethyl ester (1), a benzoquinone derivative, was the major cytotoxic constituent in this plant with IC50 values at range of 0.5~1.0 μg/mL against various tumor cell lines. Structure-activity relationship (SAR) of these jacaranone analogs (1-8) isolated from S. scandens was also discussed. Moreover, during the process of bioassay-guided fractionation, 11 known compounds of other structural types were also isolated and characterized. The MeOH part of the ethanol extracts of S. scandens also showed...