Researches On Chemical Constituents Of Ilex Atifolia Thunb.,Trichilia Connaroides (Wight&Arn.) Bentv.,and Swietenia Mahagoni(L.)Jacq.

The polysaccharides of Ilex latifolia Thunb.,as well as the hydrophobic components of Trichilia connaroides(Wight&Arn.)Bentv.and Swietenia mahagoni(L.)Jacq.were investigated in this study,Four novel polysaccharides and 43hydrophobic compounds(including 22 new compounds)were isolated from these three plants,and their structures were characterized by several spectroscopy methods.Two alcohol precipitation products were acquired from the leaves of I.latifolia by water-extraction,alkaline-extraction and ethanol precipitation.Crude polysaccharides IL50 and ILB80 were obtained after deproteinization,dialysis,and lyophilization.Further separation and purification were performed through DEAE columns and Sephadex G-75 columns to obtain four refined polysaccharides ILP50-2,ILBP80-2A,ILBP80-2B,and ILBP80-2C.The homogeneity of the four polysaccharides was verified by UV analysis and HPSEC-MALS-RID analysis,and their molecular weights were determined to be 1.49×10~5 g/mol,1.45×10~4 g/mol,6.22×10~3 g/mol,and 4.07×10~3 g/mol,respectively.The monosaccharide compositions of the four polysaccharides were analyzed by PMP pre-column derivatization.Results showed that the four polysaccharides were heteropolysaccharides.ILP50-2 was composed of mannose,rhamnose,glucose,galactose,and arabinose;ILBP80-2A,ILBP80-2B and ILBP80-2C were all composed of mannose,rhamnose,glucose,galactose,xylose and arabinose.Furthermore,the types and linkages of sugar residues were confirmed by FT-IR analysis,methylation analysis,and NMR analysis,and the primary structures of the four polysaccharides were also deduced.The advanced structures of four polysaccharides were analyzed by Congo red experiment and scanning electron microscope(SEM)analysis.Congo red experiment indicated that these four polysaccharides contained no triple-helix structure;the SEM analysis results showed that the different apparent morphology of four polysaccharides under the high magnification electron microscope,which may be related to their molecular properties such as molecular weights,monosaccharide compositions,and primary structures.The methanol extract of T.connaroides was separated and purified by ethyl acetate extraction,silica gel column chromatography,MPLC,and HPLC.By multiple spectroscopy methods(NMR,HRESIMS,CD,IR,etc.),a total of 30 compounds were identified,including three new limonoids:connanoids A-C(1-3),four new triterpenoids:connapenes A-D(4-7),eight new steroids:connasterols A-H(8-15),a new natural product(23R)-3β-stigmast-5-ene-3,23-diol(16),and fourteen known compounds trichisin B(17),trichisin G(18),trijugin C(19),trijugin D(20),trijugin E(21),chisomicine A(22),trichiliton G(23),trichiliton I(24),3β,21-dihydroxy-24-methylenecycloartane(25),ergost-5,24(28)-diene-3β,23S-diol(26),(23R,24R)-ergost-5-ene-3β,23-diol(27),(E)-volkendousin(28),(Z)-volkendousin(29),and 3β-hydroxy-5α,6α-epoxy-7-megastigmen-9-one(30).Seven new compounds,mahagoloids A-G(31-37),together with six known compounds swietephragmin I(38),swietephragmin F(39),swietephragmin H(40),swietephragmin D(41),swietephragmin C(42),and swietenitin D(43),were isolated from the fruits of S.mahagoni.Their structures were elucidated by several spectroscopic data analysis.