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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., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Six new prenylated xanthones (1: -6: ) and seventeen known xanthones were isolated from extracts of Garcinia bracteata leaves. Their structures were determined by extensive NMR and MS spectroscopic data analysis. The inhibitory activities of the isolates were assayed on HeLa, A549, PC-3, HT-29, and WPMY-1 cell lines. Compounds 1: and 15: -17: showed moderate inhibitory effects on tumor cell growth, with IC 50 s ranging from 3.7 to 14.7 µM., Competing Interests: The authors declare no conflict of interest., (Georg Thieme Verlag KG Stuttgart · New York.)

Four pairs of previously undescribed caged xanthones (1-4) and twelve known caged xanthones (5-16) were isolated from the leaf extract of Garcinia bracteata. Their structures were unambiguously elucidated on the basis of spectroscopic methods. The planar structure and relative configuration of 1 was confirmed by X-ray crystallographic analysis. The enantiomers of compounds 1, 2, 4 were further resolved by semi-preparative chiral HPLC, and the absolute configurations of enantiomers of compounds 1 and 4 were determined by measurement and calculation of electronic circular dichroism (ECD) spectra and specific rotations. The inhibitory activities of the isolated compounds against human HeLa, A549, PC-3, HT-29, and WPMY-1 cell lines were assayed, and garcibractatin A (4) showed the most potent inhibitory activities in vitro with IC 50 values from 1.11 to 2.93 μM. A preliminary structure-activity relationship has been discussed, and some helpful conclusions have been drawn., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Four new dihydroxanthone derivatives (1-4), four new tetrahydroxanthone derivatives (5-8), two new xanthone derivatives (9 and 10), and two known caged tetrahydroxanthones were isolated from extracts of the leaves of Garcinia oligantha by bioassay-guided fractionation. These structures of the new compounds were elucidated by NMR and MS spectroscopic data analysis, and the absolute configurations of compounds 1 and 5-7 were determined by electronic circular dichroism and/or single-crystal X-ray diffraction analysis. Compounds 6-9 were shown to be unusual xanthone derivatives with an isopropyl group, which was confirmed by the X-ray crystallographic structure of compound 8. The inhibitory activities of these isolates against four human tumor cell lines (A549, HepG2, HT-29, and PC-3) were assayed, and compounds 1, 2, 5, 11, and 12 showed inhibitory effects on tumor cell growth, with IC50 values ranging from 2.1 to 8.6 μM.

Five new prenylated benzoylphloroglucinol derivatives, garciesculentones A-E (1-5), a new xanthone, garciesculenxanthone A (6), and 15 known compounds were isolated from the petroleum ether extract and the EtOAc-soluble fraction of a 80% (v/v) EtOH extract of Garcinia esculenta. The structures of the new compounds were elucidated by 1D- and 2D-NMR spectroscopic analysis and mass spectrometry. Experimental and calculated ECD and a convenient modified Mosher's method were used to determine the absolute configurations. The cytotoxicity of these compounds were evaluated by MTT assay against three human cancer cell lines (HepG2, MCF-7, and MDA-MB-231) and against normal hepatic cells (HL-7702). In addition, these isolates were evaluated for their inhibitory effects on interferon-γ plus lipopolysaccharide-induced nitric oxide production in RAW264.7 cells.

Garcinia plants are one of the rich sources of natural xanthones and benzophenones which have attracted a great deal of attention from the scientists in the fields of chemistry and pharmacology. Recently, many structurally unique constituents with various bioactivities, especially anti-tumor activity, have been isolated from Garcinia plants. This concise review focused on the anti-cancer activity natural products isolated from Chinese Garcinia plants, and the research finding by authors and collaborators over the past several years were cited.