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At least 289 records · Page 16Linked to original sources
PubMed1995

Bioactive anthraquinone glycosides from Picramnia antidesma spp. fessonia.

A bioactivity guided fractionation, using KB cells and brine shrimp assays, of the methanolic extract from the leaves of Picramnia antidesma yielded two known anthraquinones, aloe-emodin and aloe-emodin anthrone, and three new aloe-emodin C-glycosides, named picramnioside A, picramnioside B and picramnioside C. Structures were established by spectroscopic methods (UV, IR, mass spectrometry, 1H and 13C and 2D NMR including COSY 45, HMQC, HMBC and ROESY). CD was used to establish the absolute configuration of the picramniosides.

Animals↗
PubMed1984

Acute effect of mercury toxicity on some enzymes in liver of teleost Sarotherodon mossambicus.

The effects of 1.5 ppm of mercuric chloride (LC50/48 hr) on some enzymes and organic substances of liver tissue of Sarotherodon mossambicus were studied. Significant decreases in the activities of succinate dehydrogenases, lactate dehydrogenases, glucose-6-phosphate dehydrogenase, alkaline phosphatase, and acid phosphatase and in the levels of organic substances like total anthrone-positive substances, glycogen, and total ninhydrin-positive substances were observed. The results indicate impaired oxidative and transphosphorylative activities and utilization of carbohydrates during acute mercury toxicosis in fish.

Animals↗
PubMed1981

The effect of orally administered prostaglandins on gastric mucus secretion in the rat.

The secretion of gastric mucus may play a role in the protective effect of prostaglandins against gastric ulcers. To investigate the effect of prostaglandins E1, E2, F1alpha, F2alpha, A1, A2 and 15 (S) 15 methyl prostaglandin E2-methyl ester on gastric mucus secretion, these prostaglandins were given orally to rats at doses of 0.1, 1.0 and 4.0 mg/kg. The anthrone method was used to analyze the amount of mucus washed from the stomach with 2 M Nacl. Gastric secretory volume effects were also observed. All of the compounds tested increased both gastric mucus and secretory volume. The most active compound was 15(S)15 methyl PGE2 Me ester. The mucus stimulating effect of these prostaglandins, when administered locally, may be relevant to the understanding of the anti-ulcer effect of prostaglandins.

Administration, Oral↗
PubMed1983

Mutagenicity of anthraquinones in the Salmonella preincubation test.

The mutagenicities of 15 naturally occurring anthraquinones were examined in Salmonella typhimurium strains TA98, TA100 and TA2637 by the preincubation method. 7 of the 15 compounds tested, i.e., chrysazin, emodin, islandicin, alizarin, chrysophanol, 2-hydroxyanthraquinone and emodic acid, were strong mutagens in strain TA2637 with metabolic activation. All of these compounds contain 1-3 hydroxyl groups, and some also have methyl groups. Cynodontin, an anthraquinone with 4 hydroxyl groups and 1 methyl group, was only slightly mutagenic in strain TA2637. 2-Hydroxyanthraquinone, alizarin, emodin, islandicin and chrysazin were also mutagenic in strain TA100 with S9 mix. All the bisanthraquinones tested, i.e., skyrin, (+)rugulosin, (-)luteoskyrin, (-)rubroskyrin and sennoside A, were non-mutagenic in this test system with or without metabolic activation. Unsubstituted anthraquinone and anthrone were also non-mutagenic. These results show that hydroxyl substituents are necessary for the mutagenicity of anthraquinones, the optimal substitutions being 1-3 hydroxyl groups per molecule. The 4th hydroxyl group, in the compound cynodontin reduces the mutagenicity considerably.

Anthraquinones↗
PubMed1990

Virucidal activity of hypericin against enveloped and non-enveloped DNA and RNA viruses.

Hypericin is a polycyclic anthrone first isolated from the plant St. Johnswort and was shown to have dramatic anti-retroviral activity against Friend leukemia virus and radiation leukemia virus in mice. Hypericin displayed marginal activity (IC50 = 6 micrograms/ml) against Moloney murine leukemia virus (Mo-MuLV) in vitro. Hypericin did not display selective antiviral activity against herpes simplex virus, influenza A, adenovirus, or poliovirus. The 50% cytotoxic concentration was approximately 25 micrograms/ml. When virus was incubated with hypericin before infecting cells, the drug was virucidal to all enveloped viruses tested (herpes simplex, influenza virus A, and Mo-MuLV) at concentrations of 1.56 micrograms/ml to 25 micrograms/ml. Hypericin was not virucidal to the non-enveloped viruses tested (adenovirus and poliovirus). These data indicate that the mechanism of viral inactivation for hypericin is dependent upon the presence of a viral lipid envelope. In vivo, hypericin (50 mg/ml) was effective against FLV or HSV-1 if incubated with the virus for 1 h at 37 degrees C before infecting mice, but was not effective if pre-incubated with virus for 1 h at 4 degrees C or if administered concurrently with virus.

Animals↗
PubMed1988

Anthralin, a non-phorbol tumor promoter, fails to inhibit metabolic cooperation in mutant human fibroblasts, but inhibits phytohemagglutinin-induced lymphocyte blastogenesis in vitro.

Two (among many) of the hypotheses put forward to explain mechanisms of action of tumor promoters are: (1) immunosuppression of the host; and (2) inhibition of intercellular junctional communication. Murine spleen cells were exposed for 30 min to various concentrations of anthralin (1,8-dihydroxy-9-anthrone), a polyphenolic non-phorbol promoter, and 1,8-dihydroxyanthraquinone (1,8-DHAQ), an inactive congener. Phytohemagglutinin (PHA)-induced T cell blastogenesis, an indicator of lymphocyte function, was then assessed in vitro. Exposure to anthralin resulted in a concentration-dependent suppression of lymphocyte proliferation with complete suppression occurring at 1 microM. The inactive congener, 1,8-DHAQ, failed to suppress lectin-induced blastogenesis at concentrations up to 10 microM. Dithiothreitol (DTT), a sulfhydryl (SH) compound, failed to protect against the suppression of lymphocyte function by anthralin. In addition, anthralin failed to inhibit in vitro microtubule assembly, a SH-dependent process, in a crude rat brain extract. Finally, unlike 12-O-tetradecanoylphorbol-13-acetate (TPA), the most potent skin tumor promoter known, anthralin failed to inhibit metabolic cooperation between mutant human fibroblasts as assayed by [14C]citrulline incorporation. In summary, the data suggest that anthralin may act as a tumor promoter by suppressing immune parameters, a property which is shared by the phorbol esters.

Animals↗
PubMed1991

Isolation and purification of cell wall polysaccharide of Bacillus anthracis (delta Sterne).

A polysaccharide fraction was isolated form sodium-dodecyl-sulfate (SDS) treated cell walls of Bacillus anthracis (delta Sterne) by hydrofluoric acid (HF) hydrolysis and ethanolic precipitation. The polysaccharide fraction was subsequently purified by several washings with absolute ethanol. Purity of the isolated polysaccharide was tested using the anthrone assay and amino acid analyzer. The molecular mass of the polysaccharide fraction as determined by gel filtration chromatography was about 12000 Da. Preliminary analyses of the polysaccharide was done using thin layer chromatography and amino acid analyzer, and results obtained from these analyses were further confirmed by gas liquid chromatography and 13C-NMR spectroscopy. Results showed that the polysaccharide moiety contained galactose, N-acetylglucosamine, and N-acetylmannosamine in an approximate molar ratio of 3:2:1. This moiety was devoid of muramic acid, alanine, diaminopimelic acid, glutamic acid, and lipid, thus indicating that the isolated polysaccharide was of pure quality.

Acetylglucosamine↗
PubMed2004

Evaluation of Rhubarb using antioxidative activity as an index of pharmacological usefulness.

We attempted to estimate the pharmacological activity by measuring the concentrations of a composition ingredient using a multivariate statistical analysis method. Medicinal herb of Rhubarb has been many largely unrecognized biochemical and pharmacological effect components. Therefore, we attempted to estimate the antioxidative activity of Rhubarb on low-density lipoprotein (LDL) of its components. Thirty specimens of Rhubarb from various origins were used, chose nine components of anthraquinones, two components of anthrones, two components of flavan-3-ols, one component of procyanidin, one component of naphthalene, two components of phenylbutanones and one component of stilbene. Quantitative analysis of 18 components was performed with high-performance liquid chromatography (HPLC) and antioxidative activities were measured with plasma taken from spontaneous familial hypercholesterolemia model rabbits. There was considerable variation among the specimens in the concentration of components and antioxidative activities on LDL. As a result of multiple regression analysis, significant multiple correlation coefficient for antioxidative activities on LDL (R=0.914, P<0.01) was found in relation to the concentrations of five components: aloe-emodin, chrysophanol, emodin 1-O-beta-D-glucoside, lindleyin and 6-hydroxymusizin 8-O-beta-D-glucoside. Three of the five components were not active in promoting antioxidative activity and there was no significant correlation between the concentrations of the most active component and the activity. We consider this a useful method for selecting of Rhubarb and propose a new scientific approach for the selection of natural medicines.

Animals↗
PubMed2005

2H NMR and X-ray diffraction studies of methyl rotation in crystals of ortho-methyldibenzocycloalkanones.

We have used (2)H NMR lineshape analyses and single crystal X-ray diffraction (XRD) to investigate the effects of molecular structure and crystalline environment on the rotational dynamics of methyl groups in four aromatic cycloalkanones. These include two methyl-substituted anthrones, one anthraquinone and one dibenzosuberone, which are known to undergo excited state H-atom tunneling from the ortho-methyl group to the carbonyl oxygen. With experiments conducted between 100 and 300K, samples 1,4-dimethylanthrone (DMAT) and 1,4-dimethylanthraquinone (DMAQ) were shown to enter the intermediate exchange regime (k(rot) approximately <10(7)s(-1)) at ca. 120K while samples of 1,4,10,10-tetramethylanthrone (TMAT) and 1,4-dimethyldibenzosuberone (DMDBS) remained in the fast exchange regime even at ca. 100K. Single crystal XRD analyses suggest that high intramolecular hindrance is avoided by molecular distortions, and that intermolecular contacts play an important role.

Journal Article↗
PubMedDate not supplied

Glucose transporter 1 expression in corneal wound repair under high serum glucose level.

PURPOSE: To determine glucose transporter (GLUT) 1 mRNA and protein expression during corneal epithelial wound healing in diabetic rat. METHODS: Diabetes mellitus was induced by intraperitoneal injection of streptozotocin. At 10 days after injection, unilateral 3-mm epithelial debridement was carried out in the central cornea. At 2, 4, 6, and 24 hours after wounding, whole corneal epithelium was collected and GLUT1 protein and mRNA levels were determined by Western blotting and reverse transcription-polymerase chain reaction, respectively. Sugar content in collected samples was measured by the Anthrone reaction. Normal rats were used as controls. RESULTS: Glucose transporter 1 protein and mRNA levels in unwounded cornea were similarly low in the diabetic and control groups. Healing of corneal wounds was slower in diabetic rats than in controls. After wounding, GLUT1 mRNA and protein expression in both groups were similarly enhanced compared to unwounded epithelium. Sugar content at all time points did not show significant alteration in any group, although in diabetic rats it was significantly higher than in controls throughout the time course. CONCLUSION: Glucose transporter 1 expression in diabetic rat cornea showed little difference from that in normal rat cornea, suggesting minimal influence of GLUT1 on the delayed healing of diabetic corneal wounds.

Animals↗
PubMed2003

Inhibition of collagenase and metalloproteinases by aloins and aloe gel.

The effects of Aloe barbadensis gel and aloe gel constituents on the activity of microbial and human metalloproteinases have been investigated. Clostridium histolyticum collagenase (ChC) results dose-dependently inhibited by aloe gel and the activity-guided fractionation led to an active fraction enriched in phenolics and aloins. Aloins have been shown to be able to bind and to inhibit ChC reversibly and non-competitively. Aloe gel and aloins are also effective inhibitors of stimulated granulocyte matrix metalloproteinases (MMPs). The remarkable structural resemblances between aloins and the pharmacophore structure of inhibitory tetracyclines, suggest that the inhibitory effects of aloins are via an interaction between the carbonyl group at C(9) and an adjacent hydroxyl group of anthrone (C(1) or C(8)) at the secondary binding site of enzyme, destabilizing the structure of granulocyte MMPs.

Aloe↗
PubMed1996

Pharmacokinetics of Dextran-70 in patients with cirrhosis and ascites undergoing therapeutic paracentesis.

BACKGROUND/AIM: Dextran-70 is frequently used as a plasma expander in patients with cirrhosis treated with large-volume paracentesis to prevent post-paracentesis hypovolemia, which is thought to develop after 24 h following the procedure. However, there are no studies on Dextran-70 pharmacokinetics in cirrhosis. METHODS: Nine patients with alcoholic cirrhosis and tense ascites treated with a 5-1 paracentesis were given 500 ml of Dextran-70. Blood samples to measure the plasma concentration of dextran were obtained 15 and 30 min, 1, 2, 3, 6, 12 and 24 h and 2 and 6 days after the end of the infusion. Nine healthy volunteers were studied in identical fashion after infusion of 100 ml of Dextran-70. The plasma concentration of dextran was determined by the anthrone method. A bicompartmental model was used to analyze the pharmacokinetic parameters. RESULTS: There were no significant differences between patients with cirrhosis and controls in the volume of distribution (7.7 +/- 0.6 vs. 7.3 +/- 1.21), half-life of the first and second component of plasma disappearance (2.96 +/- 0.69 and 80.3 5.9 h in patients with cirrhosis vs 2.82 +/- 0.69 and 67.1 +/- 10.7 h in controls). CONCLUSIONS: The pharmacokinetics of Dextran-70 in patients with cirrhosis and ascites after large-volume paracentesis is similar to that in controls. This may explain why Dextran-70 is less effective than albumin in preventing paracentesis-induced hypovolemia, which starts after most Dextran fraction has disappeared from plasma.

Ascites↗
PubMed1998

Glycogen content in the gastric mucosa of partially resected stomach; a possible relationship with the development of cancer.

Since gastric carcinoma, unlike uninvaded mucosa, has a relatively high glycogen content and the risk of gastric carcinoma is especially high in patients with a partially resected stomach, the aim of this study was to follow glycogen storage in both uninvaded gastric stump mucosa and carcinoma developing in the stump postsurgery performed for benign and malignant conditions. One hundred patients were recruited, including controls with non-operated stomachs (duodenal ulcer or gastric cancer patients). In endoscopically taken biopsies glycogen was determined by the anthrone method. It was found that the glycogen content in the gastric remnants was higher than in non-operated stomachs and increased with the time after surgery. It is possible that the risk of gastric cancer, which increases with the time from surgery, may be related to glycogen storage.

Adult↗
PubMed1999

Antiherpetic activities of various protein bound polysaccharides isolated from Ganoderma lucidum.

To investigate antiherpetic substances from Ganoderma lucidum, various protein bound polysaccharides, GLhw, GLhw-01, GLhw-02, GLhw-03, were isolated by activity-guided isolation from water soluble substances of the carpophores. These substances were examined for their antiviral activities against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) by plaque reduction assay in vitro. Among them, the acidic protein bound polysaccharide, GLhw-02 of a brownish substance, exhibited the most potent antherpetic activity with 50% effective concentrations (EC50) of 300 approximately 520 microg/ml in Vero and HEp-2 cells, and its selectivity indices (SI) were more than 20. GLhw-02 was identified to consist mainly of polysaccharide (approximately 40.6%) and protein (approximately 7.80%) by anthrone test and Lowry-Folin test, and showed the usual molar ratio (C:H:O = 1:2:1) of carbohydrates by elemental analysis. These results suggest that GLhw-02 possesses the possibility of being developed from a new antiherpetic agent.

Acyclovir↗
PubMed1993

Tetracenomycin F2 cyclase: intramolecular aldol condensation in the biosynthesis of tetracenomycin C in Streptomyces glaucescens.

Tetracenomycin (Tcm) F2 cyclase, which catalyzes the cyclization of the anthrone Tcm F2 to the naphthacenone Tcm F1 in the biosynthesis of the anthracycline antibiotic Tcm C in Streptomyces glaucescens, has been purified to homogeneity and characterized. The N-terminal sequence of the enzyme establishes that it is encoded by the tcmI gene, whose deduced product has a molecular weight of 12,728. SDS-PAGE analysis gave a single band with a molecular weight of 12,500, whereas gel-filtration chromatography yielded a molecular weight of 37,500, indicating that the Tcm F2 cyclase is a homotrimer in solution. Under pH > or = 8.0, the enzyme catalyzes the cyclization of Tcm F2 to Tcm F1 and has a Km of 121 +/- 18.2 microM and Vmax of 704 +/- 62.3 nmol.min-1.mg-1. In contrast, under pH < or = 6.5, it catalyzes the cyclization of Tcm F2 to 9-decarboxy Tcm F1, a known shunt metabolite of the Tcm C biosynthetic pathway. Tcm F2 cyclase represents the first discrete enzyme for carbon-carbon bond formation via an intramolecular aldol condensation-dehydration mechanism, a key biochemical operation proposed in the early steps of the biosynthesis of all aromatic polyketides.

Aldehyde-Lyases↗
PubMed1996

Oxidation of 9-alkylanthracenes by cytochrome P450 2B1, horseradish peroxidase, and iron tetraphenylporphine/iodosylbenzene systems: anaerobic and aerobic mechanisms.

Variously substituted alkylanthracenes were studied as models for polycyclic hydrocarbon oxidations. 9-Methylanthracene was oxidized to 9-(hydroxymethyl)anthracene, 10-methyl-10-hydroxy-9-anthrone, and anthraquinone in several systems, including (i) NADPH- and O2-fortified rat liver microsomes, (ii) cytochrome P450 (P450) 2B1 Supported by either iodosylbenzene (PhIO) or a mixture of NADPH-P450 reductase, NADPH, and O2, (iii) horseradish peroxidase and either H2O2 or ethyl hydroperoxide, and (iv) a mixture of iron tetraphenylporphine (FeTPP) and PhIO (in anhydrous CH2Cl2/MeOH). The microsomal system also formed dihydrodiols from 9-methyl- and 9-ethylanthracenes. The formation of the three oxidized products by the P450/NADPH/O2 system was dependent upon O2 label from 18O2 was incorporated into the products, and no label from H2(18O) was incorporated. No label from 18O2 was incorporated into the three products in the FeTPP/PhIO system. In the horseradish peroxidase/H2O2 system, the formation of the three products was decreased when O2 was omitted, and label from both H2(18)O and 18O2 was incorporated into all three products. The results are interpreted in terms of three mechanisms. One is used by the FeTPP and P450 systems, with all oxygen transfers coming from an FeO entity. The other two pathways are utilized by horseradish peroxidase and begin with formation of a radical cation, which can undergo reactions either with H2O or with O2 to form the products detected here. The involvement of a 9-methylanthracene radical cation in the P450 and FeTPP pathways is a possibility, but rapid rearrangement and oxygen rebound must be invoked. Comparisons of products from various 9-alkylanthracenes do not provide evidence that one-electron oxidation is an integral part of the epoxidation process with these compounds. The significance of the lack of trapping of radical (by H2(18O) in the P450 reactions to DNA adduct formation is considered.

Aerobiosis↗
PubMed2001

Synthesis and lectin recognition of polystyrene core-glycopolymer corona nanospheres.

Polymeric nanospheres with a polystyrene core and a glucosyloxyethyl methacrylate (GEMA) oligomer corona were synthesized by the free radical coplymerization of styrene (M(1)) plus a GEMA macromonomer (M(2)) at various molar ratios (M(1)/M(2) = 50-150) in the presence of AIBN (1 mol % to the total monomer) in an ethanol/water (3/2, v/v) solvent. The size of the nanospheres was controlled from 300 to 620 nm by altering the monomer ratio. The size distributions were significantly narrow. The amount of glucose conjugated per unit surface area of the nanosphere, which was analyzed by the anthron-sulfuric acid method, was 1.01-2.28 microg cm(-1), which increased with an increase in size. The transmittance of a solution of dispersed nanospheres (the corresponding glucose concentration was 73 microM) increased by the addition of the glucose-binding protein concanavalin A (Con A) (1-50 microM), indicating that the nanospheres were being precipitated by the cross-linking of ConA. An enzyme-linked lectin assay (ELLA) revealed that Con A bound to the glucose on the nanospheres 250-700-fold more than to monomeric glucose. The binding activity to the nanospheres was less than that to a GEMA oligomer, and decreased with an increase in the amount of GEMA oligomer grafted onto the nanosphere, possibly because of steric hindrance of the lectin binding to the glucose on the nanospheres. The polystyrene core-glycopolymer corona nanosphere is a useful material for studying sugar-biomolecule recognition.

Concanavalin A↗
PubMedDate not supplied

Immobilization of dextransucrase from Leuconostoc mesenteroides NRRL B-512F on Eupergit C supports.

Dextransucrase from Leuconostoc mesenteroides B-512F was immobilized on epoxy-activated acrylic polymers with different textural properties (Eupergit C and Eupergit C 250L). Prior to immobilization, dextransucrase was treated with dextranase to remove the dextran layer covering the enzyme surface, thus increasing the accessibility of its reactive groups to the epoxide centers of the support. Elimination of 99% of the initial carbohydrate content was determined by the anthrone method. To prevent enzyme inactivation, the immobilization was carried out at pH 5.4, at which the coupling to the support took place through the carboxylic groups of the enzyme. The effects of the amount (mg) of dextransucrase added per gram of support (from 0.2:1 to 30:1), temperature and contact time were studied. Maximum activity recovery of 22% was achieved using Eupergit C 250L. Using this macroporous support, the maximum specific activity (710 U/g biocatalyst) was significantly higher than that obtained with the less porous Eupergit C (226 U/g biocatalyst). The dextransucrase immobilized on Eupergit C 250L showed similar optimal temperature (30 degrees C) and pH (5-6) compared with the native enzyme. In contrast, a notable stabilization effect at 30 degrees C was observed as a consequence of immobilization. After a fast partial inactivation, the dextransucrase immobilized on Eupergit C 250L maintained more than 40% of the initial activity over the following 2 days. The features of this immobilized system are very attractive for its application in batch and fixed-bed bioreactors.

Bioreactors↗