Cytotoxic prenylated xanthones from the young fruit of Garcinia mangostana

Three new prenylated xanthones, mangostenones C (1), D (2), and E (3), together with 16 known xanthones 4-19, were isolated from the young fruit (7-week maturity stage) of Garcinia mangostana. The structural elucidation of the new compounds was mainly established on the basis of 1D and 2D NMR and HR-MS spectroscopic analysis. Compound 1 showed cytotoxic properties against three human cancer cell lines, epidermoid carcinoma of the mouth (KB), breast cancer (BC-1), and small cell lung cancer (NCI-H187), with IC50 values of 2.8, 3.53, and 3.72 microg/ml, respectively. Among the isolates, alpha-mangostin (12), the major metabolite, exhibited the most potent effects against the BC-1 cells with an IC50 value of 0.92 microg/ml, an activity greater than that of the standard drug ellipticine (IC50 = 1.46 microg/ml). Compound 12 also showed the highest activity against KB cells, while gartanin (10) displayed the strongest activity against the NCI-H187 cells at the respective IC50 values of 2.08 microg/ml and 1.08 microg/ml.     

Potential of Xanthones from Tropical Fruit Mangosteen as Anti-cancer Agents: Caspase-Dependent Apoptosis Induction In Vitro and in Mice

The pericarp of mangosteen (Garcinia mangostana L.) is rich in various xanthones that are known to possess unique biological activities. In this work, we characterized the anti-proliferative and cytotoxic activities of mangosteen xanthones both in vitro and in mice. In vitro analysis with a human colorectal adenocarcinoma cell line, COLO 205, showed that mangosteen xanthones not only inhibit the proliferation of target cells but also induce their death by apoptosis that involves the activation of the caspase cascade. In vivo analysis using a mouse subcutaneous tumor model with COLO 205 cells showed that, at relatively low doses, the growth of tumors was repressed upon intratumoral administration of mangosteen xanthones. When a higher dose of mangosteen xanthones was administered, the size of tumors was reduced gradually, and, in some mice, the disappearance of tumors was seen. Histopathological evaluation and biochemical analysis of tumors that received mangosteen xanthones indicate the induction of apoptosis in tumors, which resulted in the repression of their growth and the reduction of their sizes. These results demonstrate the potential of mangosteen xanthones to serve as anti-cancer agents for the chemotherapy of cancer.     

Antimycobacterial activity of prenylated xanthones from the fruits of Garcinia mangostana

Prenylated xanthones, isolated from the fruit hulls and the edible arils and seeds of Garcinia mangostana, were tested for their antituberculosis potential. Alpha- and beta-mangostins and garcinone B exhibited strong inhibitory effect against Mycobacterium tuberculosis with the minimum inhibitory concentration (MIC) value of 6.25 microg/ml. Tri- and tetra-oxygenated xanthones with di-C5 units or with a C5 and a modified C5 groups are essential for high activities. Substitution in the A and C rings has been shown to modify the bioactivity of the compounds.     

Regiospecific synthesis of α-(phenylthio)ketones via rhodium(II) acetate catalysed addition of thiophenol to α-diazoketones

αα-Addition of thiophenol to α-diazoketones is catalysed efficiently by rhodium(II) acetate in benzene solution at room temperature, offering a convenient regio-specific route to a variety of α-(phenylthio)ketones.     

Prenylated Xanthone Composition of Garcinia mangostana (Mangosteen) Fruit Hull

Fourteen prenylated xanthones found in mangosteen fruit, Garcinia mangostana L., have been simultaneously separated by reversed-phase high-performance liquid chromatography with water–acetonitrile gradient elution and diode-array detection. The separated xanthones were detected at 254 nm. This new method was developed to establish a chemical fingerprint of the major constituents of mangosteen. It was also used for quantitative analysis of the two major xanthones in crude extracts of mangosteen fruit hull. This chemical fingerprint of G. mangostana extract can be used for comprehensive quality-control of mangosteen extract.