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At least 109 records · Page 6Linked to original sources
PubMed2006

Cytotoxic activity of four xanthones from Emericella variecolor, an endophytic fungus isolated from Croton oblongifolius.

Four xanthones were isolated from mycelia of Emericella variecolor, an endophytic fungus isolated from the leaves of Croton oblongifolius. Their structures were elucidated by spectroscopic analysis to be shamixanthone, 14-methoxytajixanthone-25-acetate, tajixanthone methanoate, and tajixanthone hydrate. All compounds were tested for cytotoxic activity against various human tumor cell lines including gastric carcinoma, colon carcinoma, breast carcinoma, human hepatocarcinoma, and lung carcinoma. The antitumor activities of these xanthones were compared with that of doxorubicin hydrochloride, a chemotherapeutic substance. All of them showed moderate activities and were selective against gastric carcinoma, colon carcinoma, and breast carcinoma. Only tajixanthone hydrate exhibited moderate activity against all cancer cell lines. Furthermore, under the test conditions it was found that 14-methoxytajixanthone-25-acetate and tajixanthone hydrate are almost as active as doxorubicin hydrochloride against gastric carcinoma (KATO3) and breast carcinoma (BT474).

Antineoplastic Agents↗
PubMed1989

Novel inhibitory actions on platelet thromboxane and inositolphosphate formation by xanthones and their glycosides.

Xanthones and their glycosides were tested for their antiplatelet activities in washed rabbit platelets. Tripteroside acetate and norathyriol acetate were the most potent inhibitors. Tripteroside acetate inhibited platelet aggregation and ATP release induced by ADP, arachidonic acid, platelet-activating factor (PAF), collagen, ionophore A23187 and thrombin. The IC50 values of tripteroside acetate toward arachidonic acid- (100 microM) and collagen- (10 micrograms/ml) induced platelet aggregation were 10 and 30 micrograms/ml respectively. It inhibited thromboxane B2 formation of washed platelets caused by arachidonic acid, collagen, thrombin and ionophore A23187 and also that caused by the incubation of lysed platelet homogenate with arachidonic acid. Tripteroside acetate decreased the formation of inositolphosphate caused by thrombin, collagen and PAF, whereas it had no direct effect on fibrinogen-platelet interaction. It is concluded that xanthone derivatives inhibited platelet aggregation and release reaction by diminishing thromboxane formation and phosphoinositide breakdown.

Adenosine Diphosphate↗
PubMedDate not supplied

Mutagenicities of xanthone derivatives in Salmonella typhimurium TA100, TA98, TA97, and TA2637.

The mutagenicities of naturally occurring xanthones were tested in Salmonella typhimurium TA100, TA98, TA97, and TA2637 by the preincubation method. Xanthydrol, gentisein, gentisin, isogentisin, 1-hydroxy-3,7-dimethoxyxanthone, 1,3,7-trimethoxyxanthone, desmethylbellidifolin, bellidifolin and dimethylbellidifolin were mutagenic, but unsubstituted xanthone was not mutagenic to TA100, TA98, TA97 and TA2637 with or without a metabolic activation system. The beta-O-glucosides, norswertianolin and swertianolin, were only mutagenic when a metabolic activation system containing beta-glucosidase was used, and the C-glucoside mangiferin was not mutagenic even with this system.

Animals↗
PubMed1996

Cytotoxic xanthones from Garcinia hanburyi.

Eleven novel cytotoxic xanthones, gambogin, morellin dimethyl acetal, isomoreollin B, moreollic acid, gambogenic acid, gambogenin, isogambogenin, desoxygambogenin, gambogenin dimethyl acetal, gambogellic acid and hanburin were isolated together with four known xanthones, gambogic acid, isomorellin, morellic acid and desoxymorellin, from the dry latex of Garcinia hanburyi. The structures were elucidated by a detailed spectroscopic analysis.

Cell Line↗
PubMed1994

The effect of 3-[2-(cyclopropylamino)ethoxy]xanthone on platelet thromboxane formation.

A synthetic xanthone derivative, 3-[2-(cyclopropylamino)ethoxy] xanthone (CPEX), was investigated for its antiplatelet activities in washed rabbit platelets and human platelet-rich plasma. CPEX inhibited concentration-dependently the aggregation and ATP release of rabbit platelets caused by arachidonic acid (AA; 100 microM) and collagen (10 micrograms/ml), but not those by thrombin (0.1 U/ml), PAF (2 ng/ml), and U46619 (1 microM). The IC50 value of CPEX on AA-induced aggregation was 10.9 +/- 2.1 microM (n = 7). Thromboxane B2 formations caused by AA, collagen, and thrombin were inhibited by CPEX (20 microM), and prostaglandin D2 formation caused by AA was also inhibited. In human platelet-rich plasma, CPEX specifically inhibited the secondary aggregation and the release reaction induced by epinephrine (5 microM) and ADP (3 microM). CPEX also inhibited AA- and collagen-induced inositol-phosphate formation in [3H]myo-inositol-labeled platelets and intracellular Ca2+ increase in fura-2/AM-loaded platelets, respectively, without affecting those induced by PAF, thrombin, and U46619 in the presence of indomethacin (5 microM). These data suggest that the antiplatelet effect of CPEX is due to an inhibitory effect on the cyclooxygenase and then leads to the decrease of thromboxane formation.

Adenosine Triphosphate↗
PubMed2006

Synthesis and pharmacological activities of xanthone derivatives as alpha-glucosidase inhibitors.

Considerable interest has been attracted in xanthone and its derivatives because of their large variety of pharmacological activities. In this project, a series of hydroxylxanthones and their acetoxy and alkoxy derivatives were synthesized and evaluated as alpha-glucosidase inhibitors, aimed at clarifying the structure-activity correlation. The results indicated that these xanthone derivatives were capable of inhibiting in vitro alpha-glucosidase with moderate to good activities. Among them, polyhydroxylxanthones exhibited the highest activities and thus may be exploitable as a lead compound for the development of potent alpha-glucosidase inhibitors.

Enzyme Inhibitors↗
PubMed2004

QSAR modeling of the MAO inhibitory activity of xanthones derivatives.

This work presents a study QSAR among the MAO A inhibitory activity (IMAO A) of a xanthones series correlated with descriptors like the E-state index (S(i)), molecular connectivity (chi) and shape (k) descriptors. The xanthones group (9-H-xanton-9-onas) are of natural or synthetic origin, they present eight positions for the substitution and their MAO A inhibitory activity is reported in the work from Gnerre et al. The descriptors included in the adjusted model were selected to describe the molecular structure of the compounds. The model was selected using the leave-one-out method, the cross-validation statistics indicate a model useful for prediction: r(2)=0.847 and s=8.069, calculated by multiple linear regression.

Molecular Structure↗
PubMed2004

Determination of dissociation constants of pharmacologically active xanthones by capillary zone electrophoresis with diode array detection.

In this article, the dissociation constants (pKa) of 10 pharmacologically active xanthones isolated from herbal medicine Securidaca inappendiculata were determined by capillary zone electrophoresis with diode array detection. The pKa values determined by the method based on the electrophoretic mobilities (calculated from migration times) have been proved by the method based on UV absorbance calculated from the online spectra corresponding peaks. No conspicuous difference was observed between the two methods with acceptable reproducibility. Two pKa values (pKa1 and pKa2) were found for four xanthones while generally the 10 compounds possess the pKa values ranging from 6.4 to 9.2.

Electrophoresis, Capillary↗
PubMed2005

Antibacterial activity of crude extracts from Mexican medicinal plants and purified coumarins and xanthones.

Thirty-two extracts from 22 Mexican medicinal plants of 15 different families were assayed to determine their antibacterial activity against Escherichia coli and Staphylococcus aureus. Seventeen plants showed antibacterial activity, while five plants showed no activity against both bacteria. All of the extracts showed higher activity against Staphylococcus aureus (methicillin-sensitive and methicillin-resistant) than against Escherichia coli, except one. Among the plants examined, Bursera simaruba (L.) Sarg. (Burseraceae), Haematoxylum brasiletto H. Karst. (Fabaceae), Calophyllum brasiliense Cambess. (Clusiaceae), and Mammea americana L. (Clusiaceae) were highly active against Staphylococcus aureus. Coumarins (mammea A/BA and mammea A/AA) and xanthones, namely jacareubin and 1,3,5,6-tetrahydroxy-2-(3,3-dimethylallyl) xanthone, were isolated as the principle compounds from the last two plants.

Anti-Bacterial Agents↗
PubMed2005

Inhibition of gastric H+,K+-ATPase activity by flavonoids, coumarins and xanthones isolated from Mexican medicinal plants.

Medicinal plants are commonly used in Latin American folk medicine for the treatment of gastric problems. In order to understand the properties of some of their chemical constituents, four natural xanthones, an acetylated derivative, two coumarins (mammea A/BA and mammea C/OA) isolated from Calophyllum brasiliense Cambess and two flavonoids (minimiflorin and mundulin) isolated from Lonchocarpus oaxacensis Pittier, and the chalcone lonchocarpin isolated from Lonchocarpus guatemalensis Benth were tested for their activities on gastric H+,K+-ATPase isolated from dog stomach. All the compounds tested inhibited H+,K+-ATPase activity with varied potency. The xanthones inhibited the H+,K+-ATPase with IC50 values ranging from 47 microM to 1.6 mM. Coumarins inhibited H+,K+-ATPase with IC50 values of 110 and 638 microM. IC50 values for the flavonoids ranged from 9.6 to 510 microM among which minimiflorin was the most potent. The results suggest that H+,K+-ATPase is sensitive to inhibition by several types of structurally different natural compounds. The potency of the effects on gastric H+,K+-ATPase depends on the presence, position and number of hydroxyls groups in the molecule. Collectively, these results suggest a potential for important pharmacological and toxicological interactions by these types of natural products at the level of H+,K+-ATPase which may explain, at least in part, the gastroprotective properties, indicated by traditional medicine, of the plants from which these compounds were isolated.

Animals↗
PubMed2005

Neuropharmacological evaluation of diethylether extract and xanthones of Gentiana kochiana.

Diethylether extract of aerial parts of Gentiana kochiana mostly consists of two tetraoxygenated xanthones: gentiacaulein (1,7-dihidroxy-3,8-dimethoxyxanthone; 76.1%) and gentiakochianin (1,7,8-trihidroxy-3-methoxyxanthone; 14.2%). The extract and these xanthones were evaluated for the CNS pharmacological activity in rodents. In vitro assays on rat brain preparations revealed insignificant interaction of the compounds with the specific dopamine and serotonin receptors or synaptosomal uptake of serotonin. However, the extract and gentiacaulein strongly inhibited rat microsomal MAO A (IC50=0.22 microg/ml and 0.49 microM, respectively). Their effects on MAO B and a gentiakochianin blocking potential on both MAO enzymes were moderate. Behavioral examinations on mice showed that 10 day s.c. administration of the extract (20 mg/kg) significantly decreased immobility score in a forced swimming test and strongly inhibited ambulation and stereotypy in an open-field test. These effects resembled those induced by 10 mg/kg imipramine. The ex vivo MAO A activity in crude brain mitochondrial fraction of mice treated with 20 mg/kg of the extract was significantly elevated, whilst that outside brain nerve terminals was declined. This study suggests some antidepressant therapeutic potential of G. kochiana, particularly of gentiacaulein, with an ambiguity whether pharmacological mechanism could be related only to the central inhibition of MAO A.

Animals↗
PubMed2005

Antimicrobial activity of isoprenoid-substituted xanthones from Cudrania cochinchinensis against vancomycin-resistant enterococci.

Ten xanthones with one or two isoprenoid groups and a prenylated benzophenone isolated from roots of Cudrania cochinchinensis (Moraceae) were tested for their antimicrobial activities against vancomycin-resistant enterococci (VRE). Among these compounds, gerontoxanthone H exhibited considerable antibacterial activity against five VRE strains (VanA, VanB and VanC) (MICs = 1.56 microg/ml). Four xanthones, 1,3,7-trihydroxy-2-prenylxanthone, gerontoxanthone I, alvaxanthone and isoalvaxanthone, showed weaker antibacterial activity against these VREs (MICs = 3.13-6.25 microg/ml). .

Anti-Bacterial Agents↗
PubMed2005

Xanthones from Garcinia cowa Roxb. latex.

Five xanthones named cowagarcinone A-E and six previously reported xanthones were isolated from the latex of Garcinia cowa Roxb. Their structures were determined on the basis of spectroscopic analysis. The crude latex and the isolated compounds were investigated for their radical scavenging activities.

Garcinia↗
PubMed2005

Xanthones and benzophenones from Garcinia griffithii and Garcinia mangostana.

A new polyisoprenylated benzophenone, guttiferone I, together with the known compounds cambogin, 1,7-dihydroxyxanthone, 1,3,6,7-tetrahydroxyxanthone and 1,3,5,6-tetrahydroxyxanthone were isolated from the stem bark of Garcinia griffithii. The acetone extract of the heartwood of Garcinia mangostana contained one new diprenylated xanthone (mangoxanthone) and a new benzophenone (3',6-dihydroxy-2,4,4'-trimethoxybenzophenone) as well as the known xanthones dulxanthone D, 1,3,7-trihydroxy-2-methoxyxanthone, 1,3,5-trihydroxy-13,13-dimethyl-2H-pyran[7,6-b]xanthen-9-one. Their structures were established on the basis of spectroscopic studies and chemical correlation.

Benzophenones↗
PubMed2002

Inhibition of cyclooxygenase and prostaglandin E2 synthesis by gamma-mangostin, a xanthone derivative in mangosteen, in C6 rat glioma cells.

The fruit hull of mangosteen, Garcinia mangostana L., has been used for many years as a medicine for treatment of skin infection, wounds, and diarrhea in Southeast Asia. In the present study, we examined the effect of gamma-mangostin, a tetraoxygenated diprenylated xanthone contained in mangosteen, on arachidonic acid (AA) cascade in C6 rat glioma cells. gamma-Mangostin had a potent inhibitory activity of prostaglandin E2 (PGE2) release induced by A23187, a Ca2+ ionophore. The inhibition was concentration-dependent, with the IC50 value of about 5 microM. gamma-Mangostin had no inhibitory effect on A23187-induced phosphorylation of p42/p44 extracellular signal regulated kinase/mitogen-activated protein kinase or on the liberation of [14C]-AA from the cells labeled with [14C]-AA. However, gamma-mangostin concentration-dependently inhibited the conversion of AA to PGE2 in microsomal preparations, showing its possible inhibition of cyclooxygenase (COX). In enzyme assay in vitro, gamma-mangostin inhibited the activities of both constitutive COX (COX-1) and inducible COX (COX-2) in a concentration-dependent manner, with the IC50 values of about 0.8 and 2 microM, respectively. Lineweaver-Burk plot analysis indicated that gamma-mangostin competitively inhibited the activities of both COX-1 and -2. This study is a first demonstration that gamma-mangostin, a xanthone derivative, directly inhibits COX activity.

Animals↗
PubMed1997

Antinociceptive properties of the hydroalcoholic extract and preliminary study of a xanthone isolated from Polygala cyparissias (Polygalaceae).

Polygala cyparissias (Polygalaceae) grows abundantly on Brazil's Atlantic coast, belonging to the typical underbrush vegetation of dunes and have been used in folk medicine for treatment of several diseases, such as disturbances of bowel and kidney. The hydroalcoholic extract of P. cyparissias (HE, 3 to 60 mg kg(-1), i.p. or 25 to 200 mg kg(-1), p.o.) produced significant and graded inhibition of acetic acid-induced abdominal constrictions, with mean ID50 values of 6 and 72 mg kg(-1), respectively. The HE (at this same range of doses) also produced dose-related inhibition of both the early and the late phase of formalin-induced licking. The calculated mean ID50 values for the early phase were: >60 and >200 mg kg(-1), while for the late phase they were 11 and 101 mg kg(-1), respectively, by i.p. and p.o. routes. The HE also caused dose-related inhibition of formalin-induced edema formation (P<0.01). The HE (3 to 60 mg kg(-1), i.p. or 50 to 200 mg kg(-1), p.o.) produced significant and dose-related inhibition of the neurogenic nociception caused by topical injection of capsaicin, with mean ID50 values of 12 and 71 mg kg(-1), respectively. Given orally, the HE (50 to 200 mg kg(-1)) prevented in a dose-dependent manner, bradykinin (3 nmol/paw) and substance P (10 nmol/paw)-induced hyperalgesia in the rat paw, with mean ED50 values of 122 and 121 mg kg(-1), respectively, but was ineffective in the hot-plate model of nociception. The antinociception caused by the HE, in contrast to that of morphine (5 mg kg(-1), s.c.), was not reversed by naloxone (5 mg kg(-1), i.p.) when assessed in the acetic acid writhing test. The HE, at antinociceptive doses, did not affect motor coordination of animals when assessed in the rota-rod model. The xanthone isolated from P. cyparissias, identified as 1,7-dihydroxy-2,3-dimethoxy xanthone (0.3 to 30 mg kg(-1), i.p.), produced dose-related inhibition of acetic acid-induced abdominal constriction, with mean ID50 value of 1.5 mg kg(-1). These data show that the active principle(s) present in the HE of P. cyparissias, elicited pronounced antinociception when assessed by i.p. or p.o. routes, against both inflammatory and neurogenic nociception, and was able to prevent bradykinin and substance P-induced hyperalgesia. Its precise mechanism of action still remains unclear.

Abdominal Pain↗