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Mass-spectrometric Analyses (mass-spectrometric + analysis)
Selected AbstractsA Highly Rearranged Pentaprenylxanthonoid from the Resin of Garcinia hanburyiHELVETICA CHIMICA ACTA, Issue 7 2010Si-Jia Tao Abstract Gamboketanol (1), a highly rearranged pentaprenylated xanthonoid, two new caged pentaprenylated xanthonoids, gambogefic acid A (2) and gambogellic acid A (3), together with two known compounds, were isolated from the acetone extract of the resin of Garcinia hanburyi. Their structures were established on the basis of extensive spectroscopic and mass-spectrometric analyses. The cytotoxicity of compounds 1,3 against HeLa tumor cell line was evaluated, with all of them being modestly active. [source] Two New Diterpenoid Lactams from Spiraea japonica var. ovalifoliaHELVETICA CHIMICA ACTA, Issue 6 2009Hai-Yang Liu Abstract Two new diterpenoid alkaloids, spiramilactams A (1) and B (2), were isolated from the basic fraction of a MeOH extract of whole plants of Spiraea japonica var. ovalifolia. Their structures were established on the basis of extensive spectroscopic and mass-spectrometric analyses. [source] Chemical Constituents of Polyalthia nemoralisHELVETICA CHIMICA ACTA, Issue 4 2007Xiu-Feng He Abstract Three new natural products, the taraxastane-type triterpenoid 1, the azafluorene-based constituent 2-hydroxyonychine (2), and the diterpenoid nemoralisin (3) were isolated from the EtOH extract of Polyalthia nemoralis, along with five known compounds. The structures of the new compounds were established by in-depth spectroscopic and mass-spectrometric analyses, as well as by chemical transformation. [source] A New Long-Chain Alkene and Antituberculosis Constituents from the Leaves of Pourthiaea lucidaCHEMISTRY & BIODIVERSITY, Issue 3 2010Jih-Jung Chen Abstract A new long-chain alkene, dotriacont-1-ene (1), was isolated from the leaves of Pourthiaea lucida, together with twelve known compounds. The structure of this new compound was determined by NMR and mass-spectrometric analyses. Among the isolated compounds, , -tocospiro A (2), , -tocopheryl quinone (4), and (E)-phytol (5) exhibited antituberculosis activities (MICs ,30,,g/ml) against Mycobacterium tuberculosis H37Rv in vitro. [source] A New Indole Alkaloid and Anti-Inflammatory Constituents from Strychnos cathayensisCHEMISTRY & BIODIVERSITY, Issue 7 2008Jih-Jung Chen Abstract A new indole alkaloid, 11,12-dimethoxyhenningsamine (1), was isolated from the roots of Strychnos cathayensis, together with 19 known compounds. The structure of this new compound was determined through spectroscopic and mass-spectrometric analyses. Among the isolated compounds, 11-methoxyhenningsamine (3) and aesculetin dimethyl ether (4) exhibited potent inhibition (IC50<5.5,,g/ml) on superoxide-anion generation and elastase release by human neutrophils in response to fMet-Leu-Phe/cytochalasin B. [source] Two New Antibacterial Sesquiterpenoids from Centipeda minimaCHEMISTRY & BIODIVERSITY, Issue 12 2007Heng-Xing Liang Abstract Two new guaiane-type sesquiterpene lactones, compounds 1 and 2, along with three known guaianolide- or pseudoguaianolides, were isolated from Centipeda minima (whole plant). Their structures were identified by spectroscopic and mass-spectrometric analyses. The configuration at C(5) of the guaiane framework of 1 was rationalized by quantum-mechanical calculations (Table,2). All compounds were found to be active against eight different microbial pathogens (Table,3), with MIC values in the range of 6.25,100,,g/ml. [source] Labdane Diterpenoid Glycosides from Aster veitchianusCHEMISTRY & BIODIVERSITY, Issue 3 2007Er-Wei Li Abstract Four new labdane-type rhamnopyranosides derived from 13-epimanool, compounds 1,4, with differently acetylated sugar moieties, were isolated from A. veitchianus. Their structures and absolute configurations were elucidated by chemical transformation, spectroscopic and mass-spectrometric analyses (IR, 1D- and 2D-NMR, HR-ESI-MS), as well as by single-crystal X-ray diffraction (compound 1). The isolates 2,4 were investigated for their cytotoxic properties against cultured human hepatoma (SMMC-7721), ovarian neoplasm (HO-8910), and leukemia (HL-60) cells, and for their antibacterial activities against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. [source] | ||||||||||