Cytotoxic 7-Methoxylated Caged Xanthones from the Twigs of Garcinia oligantha

Main observation and conclusion Nineteen unprecedented 7-methoxylated caged xanthones(1—19)were isolated from the twigs of Garcinia oligantha under the guidance of NMR spectroscopy.Their structures and absolute configurations were demonstrated by extensive spectroscopic data,single-crystal X-ray diffraction,electronic circular dichroism(ECD)calculations,and the modified Mosher's method.Compound 1 is a rare scalemic 7-methoxylated neo-caged xanthone,which was resolved using HPLC with CD detection on a chiral-phase AD column,and compounds 2—3 are rare 7-methoxylated caged xanthones with the hydrogenatedΔ^(8(8a))double bond.Fourteen compounds exhibited promising inhibitory activities against four human cancer cell lines with IC50 values ranging from 1.9 to 14.3μmol/L.A cell apoptosis analysis using flow cytometry showed that compound 11 could induce apoptosis in a dose dependent manner.Moreover,PARP,caspase-9,and Bcl-2 western blotting suggested that compound 11-induced apoptosis may be involved in caspase-dependent pathway.

Simultaneous Determination of Seven Components in Gamboge and Its Processed Products Using a Single Reference Standard

Objective To establish a quality control method for simultaneous determination of multiple components in gamboge. Methods A single reference standard for the determination of multiple components （SSDMC） with HPLC was proposed. Seven major components of gamboge including gambogenic acid （S）, β-morellic acid （C1）, 2R-30-hydroxygambogic acid （C2）, isogambogenic acid （C3）, gambogellic acid （C4）, 2R-gambogic acid （C5）, and 2S-gambogic acid （C6） were simultaneously analyzed using gambogenic acid as reference standard. The credibility and feasibility of SSDMC method were validated with respect to linearity, limits of detection and quantification, precision, stability, repeatability, accuracy, ruggedness, and robustness. The relative conversion factors （RCFs） of S and C1-6 were calculated. Twelve batches of gamboge including crude and processed products were successfully analyzed by applying the SSDMC and traditional external standard （ES） methods. Results The SSDMC method was credible and feasible. The RCFs of S and C1-6 were 1.000, 0.913, 0.864, 1.064, 0.777, 0.921, and 0.919, respectively. No significant difference was observed in the contents of the seven components between SSDMC and ES methods. The heat-processing technique caused a reduction in the seven components. Conclusion SSDMC is a simple, reliable, and effective method for the analysis of the complex multiple components in gamboge, and it is also a practical and economical approach.