We examined the effects of six xanthones from the pericarps of mangosteen, Garcinia mangostana, on the cell growth inhibition of human leukemia cell line HL60. All xanthones displayed growth inhibitory effects. Among them, alpha-mangostin showed complete inhibition at 10 microM through the induction of apoptosis.

A cell growth inhibitory effect of drupanin and baccharin, ingredients of propolis, was found in human cancer cell lines. These compounds induced apoptosis in the cells characterized by morphological and nucleosomal DNA fragmentation analysis. Their effects were less potent compared with that of artepillin C, which is a known anticancer compound from propolis. Importantly, HL60 cells were more sensitive to drupanin than were Con A-stimulated peripheral blood lymphocytes, whereas the potency of artepillin C was the opposite of that of drupanin.Key words propolis; drupanin; cell growth inhibition; apoptosis; human tumor cell Propolis is a sticky mixed substance that is collected from plant materials by honeybees.1) It has been considered that propolis is a protective wall against the enemies of bees. Propolis has been uesd as a folk medicine in Europe and Japan, and it is believed that propolis exerts a therapeutic or preventive effect in inflammation, heart disease, and even diabetes mellitus and cancer. Chemical analysis using GCmass spectrometry demonstrated that approximately 150 polyphenolic compounds including flavonoids and cinnamic acid derivatives are present in propolis.2) There have been several reports indicating various biological activities of propolis and its constituents, such as anticancer, 3,4) antioxidant, 5) antiinflammatory 6) and antibiotic 7) activities. Evaluation of the biological activities of ingredients in propolis and elucidation of the mechanisms of their functions provide substantial clues for the development of new drug candidates. In the course of phytochemical studies on biologically active compounds from propolis, we examined the anticancer activity of the ethanol extract fraction from propolis and found that two cinnamic acid derivatives showed growth inhibitory activity against human tumor cell lines. It has been reported that artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) from propolis exhibits antitumor activity by induction of apoptosis in human tumor cell lines in vitro. 8,9) In the present study, we demonstrated cell growth inhibition by drupanin and (E)-3-prenyl-4-(2,3-dihydrocinnamoyloxy) cinnamic acid, named baccharin by us, in human tumor cell lines and compared them with artepillin C.Brazilian propolis was extracted with 90% ethanol (EtOH) at room temperature to yield the extract. The EtOH extract was chromatographed over silica gel and the column (70 mm i.d.ϫ330 mm) was eluted stepwise with 2-70% CHCl 3 -methanol (MeOH). The 11 CHCl 3 -MeOH-eluted fractions were evaporated and then solubilized with 100% EtOH. The fractions were examined for cell growth inhibition and the fractions showing growth inhibitory effect against human tumor cell lines were further analyzed with HPLC (column: Shiseido AG120; gradient system-A solvent: 20% CH 3 CN/2% AcOH and B solvent: 100% CH 3 CN/2% AcOH; 20-100%; 0-60 min; flow rate: 1 ml/min; detection: UV 280 nm). After purification of the active compounds, their structures were determined by nuclear magnetic resonance ( 1 H-NMR) ana...

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We examined the in vitro effects of the benzophenone derivatives garcinol, isogarcinol, and xanthochymol on cell growth in four human leukemia cell lines. All of the compounds exhibited significant growth suppression due to apoptosis mediated by the activation of caspase-3. A loss of mitochondrial membrane potential was found in garcinol-and isogarcinol-induced apoptosis, but not in xanthochymol-induced apoptosis. The growth inhibitory effects of isogarcinol and xanthochymol were more potent than that of garcinol, which is a well-known cytotoxic benzophenone derivative.