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Nine new and unique xanthone derivatives, including one novel hybrid monoterpene-tetrahydroxanthone (1), three dihydro-xanthone derivatives (2 - 4), and five skeleton-rearranged xanthone derivatives (5 – 9), were obtained from a 95% EtOH extract of Garcinia oligantha leaves by a LC-MS-guided fractionation procedure. The structures of the new compounds were elucidated by analysis of their 1D and 2D NMR and MS data. The relative configurations of 2 and 8 were determined via X-ray crystallographic data analysis, while the absolute configurations of 1 – 2 , 5 – 9 were assigned based on a comparison of calculated and experimental ECD and/or OR data. In SRB, PI-exclusion and Hoechst staining assays, 6 showed strong cytotoxic activities which could dose-dependently induce Taxol-insensitive quiescent LNCaP cell death. Additionally, a preliminary mechanism investigation using immunoblotting and Caspase-3 activity assay, indicated that 6 induced quiescent LNCaP cell death potentially through caspase-dependent mitochondrial apoptosis pathway. Image 1 • Nine new and unique xanthone derivatives (1 – 9) were isolated from Garcinia oligantha by LC-MS-guided fractionation. • Equilibrium Geometry Calculation has been used to quickly find out the low-energy input geometries in the ECD calculations. • The ACs of 2, 6 – 8 were determined by X-ray crystallographic analysis and/or the combination of two chiroptical methods. • 6 could induce Taxol-insensitive quiescent LNCaP cell death through caspase-dependent mitochondrial apoptosis pathway. [ABSTRACT FROM AUTHOR]

A global transcriptional regulator, MgrA, was previously identified as a key determinant of virulence in Staphylococcus aureus. An 80% EtOH extract of Uncaria gambier was found to attenuate the virulence of S. aureus via its effects on MgrA. Using bioassay-guided fractionation, a polyphenolic polymer, uncariitannin, was found to be the main bioactive constituent of the extract, and its structure was characterized using spectral and chemical analysis. The molecular weight and polydispersity of uncariitannin were determined by gel permeation chromatography-refractive index-light scattering analysis. An electrophoretic mobility shift assay showed that uncariitannin could effectively inhibit the interaction of MgrA with DNA in a dose-dependent manner. Treatment with uncariitannin could decrease the mRNA and protein levels of Hla in both the S. aureus Newman and USA300 LAC strains. Further analysis of Hla expression levels in the Newman Δ mgrA and Newman Δ mgrA /pYJ335- mgrA strains indicated that uncariitannin altered Hla expression primarily in an MgrA-dependent manner. A mouse model of infection indicated that uncariitannin could attenuate MRSA virulence. In conclusion, uncariitannin may be a potential candidate for further development as an antivirulence agent for the treatment of S. aureus infection. [ABSTRACT FROM AUTHOR]

Abstract: A novel asymmetric ent-kauranoid dimer, lushanrubescensin J ( 1 ), was isolated from Isodon rubescens var. lushanensis. Its structure was elucidated by the spectroscopic evidences. The stereochemistry was confirmed by the single crystal X-ray diffraction of its tetraacetate. Compound ( 1 ) exhibited potent inhibitory activity against K562 cells with IC50 =0.93μg/mL. [Copyright &y& Elsevier]

The Pd-catalyzed reactions of in situ generated arynes with o-iodoanilines in the presence of carbon monoxide are described. [ABSTRACT FROM AUTHOR]

Hypersubones A (II) and B (II) are tested on their cytotoxicity against 4 human cancer cell lines: the HepG2 human hepatocarcinoma cell line, the Eca109 esophageal carcinoma cell line, the HeLa cervical cancer cell line and the A549 non-small cell lung cancer cell line. [ABSTRACT FROM AUTHOR]

Evaluation of the antiviral activity of gymnothespirolignans A (I) and (II) reveals promising activities. [ABSTRACT FROM AUTHOR]

Oliganthins A (I), B (II), C (III) and D (IV) as well as the known gaudichaudione H are isolated from the stems of the title species. [ABSTRACT FROM AUTHOR]