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PubMed2002

New and antifungal xanthones from Calophyllum caledonicum.

Two new xanthones, namely caledonixanthones E (1) and F (2), were isolated from the stem bark of Calophyllum caledonicum (Guttiferae). The structural elucidation of these compounds was mainly established on the basis of 1D, 2D NMR and HRMS spectroscopic analysis. Among the isolated compounds, eight other known xanthones were also identified in the course of this phytochemical study. In addition to this report, a preliminary evaluation of the antifungal properties of these polyphenolic compounds against Aspergillus fumigatus and Candida albicans is presented.

Antifungal Agents↗
PubMed2004

Cytotoxic xanthones and biphenyls from the root of Garcinia linii.

Three new xanthones, linixanthones A-C, two new biphenyls, garcibiphenyls A and B, and a new benzopyran, garcibenzopyran, together with twelve known xanthones and a known biphenyl have been isolated from the root of Garcinia linii. The structures of these new compounds were determined through spectral analyses. Among the isolates, five compounds exhibited cytotoxicities (ED50 values < 4 microg/mL) against P-388 and HT-29 cell lines in vitro.

Antineoplastic Agents, Phytogenic↗
PubMed2005

Cytotoxic and antifungal isoprenylated xanthones and flavonoids from Cudrania fruticosa.

A new isoprenylated xanthone, cudrafrutixanthone A, was isolated from the roots of Cudrania fruticosa, together with 18 known compounds. Their structures were elucidated by spectroscopic methods. Most isoprenylated xanthones exhibited cytotoxicity against HCT-116, SMMC-7721, SGC-7901, and BGC-823 cell lines with IC (50) values of 1 - 5 microg/mL. Toxyloxanthone C and wighteone showed antifungal activity against Candida albicans with MICs of 25 and 12.5 microg/mL, respectively.

Antifungal Agents↗
PubMed2006

Prenylated xanthones as potential antiplasmodial substances.

Mangostin, the major xanthone of Garcinia mangostana, and a series of synthetic derivatives were investigated for their in vitro antiplasmodial activity against Plasmodium falciparum. Mangostin itself showed moderate activity, but prenylated xanthones containing alkylamino functional groups exhibited quite potent antiplasmodial activity. Some structure-activity relationships are proposed.

Animals↗
PubMed1996

Polymethoxylated xanthones from the herb of Centaurium erythraea with strong antimutagenic properties in Salmonella typhimurium.

Two methoxylated xanthone derivatives, eustomin and demethyleustomin, were isolated from the aerial parts of Centaurium erythraea Rafn. Both compounds were identified by spectral analysis. They showed strong antimutagenic properties in Salmonella typhimurium strains TA98, TA100, and TA102, when tested against 2-nitrofluorene, 2-aminoanthracene, ethyl methanesulfonate, and nalidixic acid. The bioantimutagenic character of the compounds was supported by the strong effects shown in post-treatment experiments as well as by results obtained with rec A- mutants of E. coli and Bacillus subtilis. From this it follows that the xanthone derivatives probably interfere mainly with the process of post-replication repair.

Antimutagenic Agents↗
PubMed2005

Xanthone glycosides from Swertia franchetiana.

A new xanthone glycoside (1) has been isolated from Swertia franchetiana together with five known xanthone glycosides. Their structures were elucidated as 7-O-[beta-D-xylopyranosyl-(1-->2)-beta-D-xylopyranosyl]-1,7,8-trihydroxy-3-methoxyxanthone (1), 7-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl]-1,7,8-trihydroxy-3-methoxyxanthone (2), 8-O-beta-D-glucopyranosyl-1,3,5,8-tetrahydroxyxanthone (3), 1-O-beta-D-glucopyranosyl-1-hydroxy-3,7,8-trimethoxyxanthone (4), 1-O-[beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranosyl]-1-hydroxy-2,3,5-trimethoxyxanthone (5) and 1-O-[beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyranosyl]-1-hydroxy-3,5-dimethoxyxanthone (6) on the basis of spectroscopic evidence.

Chromatography, Gel↗
PubMed2006

Daphnifolin, a new xanthone from Mesua daphnifolia (Guttiferae).

A new tetraoxygenated xanthone, daphnifolin (1,3,5-trihydroxy-4-methoxyxanthone), along with three other xanthones, were isolated from the stem bark extracts of Mesua daphnifolia. Their structures were characterized on the basis of 1D and 2D NMR spectral data.

Magnetic Resonance Spectroscopy↗
PubMed2003

First 2-hydroxy-3-methylbut-3-enyl substituted xanthones isolated from plants: structure elucidation, synthesis and antifungal activity.

Two new 2-hydroxy-3-methylbut-3-enyl substituted xanthones, (+/-)-caledol 1 and (+/-)-dicaledol 2 were isolated from a dichloromethane extract of the leaves of Calophyllum caledonicum (Clusiaceae). Compounds 1 and 2 are the first 2-hydroxy-3-methylbut-3-enyl substituted xanthones isolated from natural source. Their structures were elucidated by means of combined analytical methods including HRFABMS, 1D and 2D NMR spectroscopies and also confirmed by total synthesis using biomimetic ortho-prenylphenols photooxygenation (1O2) as a key step. The antifungal activity against Aspergillus fumigatus is reported.

Aspergillus fumigatus↗
PubMed2000

Inhibition of lipoprotein oxidation by prenylated xanthones derived from mangostin.

Oxidative damage is thought to play a critical role in cardiovascular and other chronic diseases. This has led to considerable interest in the antioxidant activity of dietary compounds. Flavonoids have received the most attention and much is known about the structural requirements for antioxidant activity. However, little is known about the antioxidant activity of other plant derived phenolic compounds such as the xanthones. We have previously shown that the prenylated xanthone, mangostin, can inhibit the oxidation of low density lipoprotein. In order to examine the effects of structure modification on antioxidant activity of this class of compound we have prepared a number of derivatives of mangostin and tested antioxidant activity in an isolated LDL and plasma assay. The results of this study show that structural modification of mangostin can have a profound effect on antioxidant activity. Derivatisation of the C-3 and C-6 hydroxyl groups with either methyl, acetate, propane diol or nitrile substantially reduces antioxidant activity. In contrast, derivatisation of C-3 and C-6 with aminoethyl derivatives enhanced antioxidant activity, which may be related to changes in solubility. Cyclisation of the prenyl chains had little influence on antioxidant activity.

Antioxidants↗
PubMed2003

A new xanthone from Hedychium gardnerianum.

A new xanthone (2), 3-(2-hydroxyethoxy)xanthone, and three known compounds, 1-hydroxyxanthone, salicylic acid and the sesquiterpene oplopanone, were isolated for the first time from the rhizomes of Hedychium gardnerianum Rosc. The structures of these compounds were elucidated on the basis of detailed spectral analysis, including 2D NMR experiments.

Anti-Infective Agents↗
PubMed2005

Antioxidant activities of Swertia decussata xanthones.

The lipid peroxidation inhibitory activities of four hydroxyxanthones, isolated from the whole plant Swertia decussata, were evaluated for the first time. The most promising antioxidant among the xanthones, 1,7,8-trihydroxy-3-methoxyxanthone (swertianine, 4) was also tested for its scavenging potential against DPPH and superoxide radicals. The data clearly revealed good antioxidant activity of the xanthones, especially 4 which also showed strong protection against y-ray induced pBR322 DNA damage. A comparison of the radioprotecting activities of the monomethylated tetrahydroxyxanthone 4 with that of its congener, 1,3,7-trihydroxy-8-methoxyxanthone (5) revealed that the radioprotecting activity was not affected by the position of methylation.

Animals↗
PubMed2006

Two new xanthones from Hypericum japonicum.

Two new xanthones, 1,6-dihydroxyisojacereubin-5-O-beta-D-glucoside (1) and 3,6,7-tri-hydroxy-1-methoxy-xanthone (2), were isolated from Hypericum japonicum. The structural elucidation of the isolated compounds were primarily based on HREIMS, EIMS, UV, IR, 1D-, and 2D-NMR analyses, including COSY, HMQC, HMBC, and NOESY correlations.

China↗
PubMed2002

Optimization of xanthones for antimalarial activity: the 3,6-bis-omega-diethylaminoalkoxyxanthone series.

Hydroxyxanthones have been identified as novel antimalarial agents. The compounds are believed to exert their activity by complexation to heme and inhibition of hemozoin formation. Modification of the xanthone structure was pursued to improve their antimalarial activity. Attachment of R-groups bearing protonatable nitrogen atoms was conducted to enhance heme affinity through ionic interactions with the propionate side chains of the metalloporphyrin and to facilitate drug accumulation in the parasite food vacuole. A series of 3,6-bis-omega-diethylaminoalkoxyxanthones with side chains ranging from 2 to 8 carbon atoms were prepared and evaluated. Measurement of heme affinity for each of the derivatives revealed a strong correlation (R(2) = 0.97) between affinity and antimalarial potency. The two most active compounds in the series contained 5- and 6-carbon side chains and exhibited low nanomolar 50% inhibitory concentration (IC(50)) values against strains of chloroquine-susceptible and multidrug-resistant Plasmodium falciparum in vitro. Both of these xanthones exhibit stronger heme affinity (8.26 x 10(5) and 9.02 x 10(5) M(-1), respectively) than either chloroquine or quinine under similar conditions and appear to complex heme in a unique manner.

Alkanes↗
PubMed2003

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.

Anti-Bacterial Agents↗
PubMed2005

Antibacterial caged-tetraprenylated xanthones from the fruits of Garcinia hanburyi.

A new caged-tetraprenylated xanthone, hanburinone (1), was isolated from the fresh fruits of Garcinia hanburyi together with four known caged-tetraprenylated xanthones; isomoreollin B (2), morellin (3), moreollic acid (4) and morellic acid (5). Their structures were elucidated by analysis of spectroscopic data and comparison of the NMR data with those reported previously. Compounds 4 and 5 showed moderately antibacterial activity against methicillin-resistant Staphylococcus aureus with a MIC value of 25 microg/ml.

Anti-Bacterial Agents↗
PubMed2006

Afzeliixanthones A and B, two new prenylated xanthones from Garcinia afzelii ENGL. (Guttiferae).

Two new prenylated xanthones, afzeliixanthones A (1) and B (2), together with three known xanthones (3-5) and two phytosterols, beta-sitosterol and stigmasterol, were isolated from the CH2Cl2/MeOH (1:1) extract of the stem bark of Garcinia afzelii ENGL. collected in the South West Province of Cameroon. Structures were mainly established using one and two-dimensional NMR and mass spectroscopies. The antioxidant activities of the crude extracts as well as the new compounds (1) and (2) were evaluated.

Antioxidants↗
PubMed2006

Cytotoxic and antimalarial prenylated xanthones from Cratoxylum cochinchinense.

A new prenylated xanthone, 5-O-methylcelebixanthone (1), together with six known compounds; celebixanthone (2), 1,3,7-trihydroxy-2,4-di(3-methylbut-2-enyl)xanthone (3), cochinchinone A (4), alpha-mangostin (5), beta-mangostin (6) and cochinchinone C (7) were isolated from roots of Cratoxylum cochinchinense. Their structures were elucidated by spectroscopic methods. Compounds 2 and 4-7 showed cytotoxic activity against the human lung cancer cell line (NCI-H187) with IC(50) values ranging from 0.65 to 5.2 microg/ml. Compounds 1, 2, 6 and 7 also showed antimalarial activity against Plasmodium falciparum with IC(50) values of 3.2, 4.9, 7.2 and 2.6 microg/ml, respectively.

Animals↗
PubMed2007

Xanthones from stems of Hypericum chinense.

Six new xanthones, 4,6-dihydroxy-2,3-dimethoxyxanthone (1), 2,6-dihydroxy-3,4-dimethoxyxanthone (2), 6-hydroxy-2,3,4-trimethoxyxanthone (3), 3,6-dihydroxy-1,2-dimethoxyxanthone (4), 4,7-dihydroxy-2,3-dimethoxyxanthone (5), and 3,7-dihydroxy-2,4-dimethoxyxanthone (6) were isolated from the stems of Hypericum chinense, together with four known xanthones. Their structures were established based on spectroscopic studies.

Chromatography, High Pressure Liquid↗