Isolation, characterization and structural determination of a unique type of arabinogalactan from an immunostimulatory extract of Chlorella pyrenoidosa

An arabinogalactan was isolated from a hot water extract of freeze-dried cells of the green microalga, Chlorella pyrenoidosa. This hot water extract is a proprietary immunomodulator, with the trademark Respondin™ (ONC-107). The arabinogalactan was recovered from the ethanol-soluble fraction of the supernatant resulting from a process that involved controlled ethanol precipitation followed by size exclusion chromatography on Sephadex G-100, then Cetavlon precipitation. Sugar analyses, GC–MS data for (S)-2-octyl glycosides, and 1D and 2D NMR experiments established unambiguously that the repeating unit was →2)-α-l-Araf-(1→3)-[α-l-Araf-(1→4)]-β-d-Galp-(1→. This structure does not fit into any of the known classes of arabinogalactans. SEC/MALS experiments gave a molecular mass for the arabinogalactan isolated as 47 ± 4 kDa but the original structure was probably larger.

AMP-activated protein kinase regulates GLUT4 transcription by phosphorylating histone deacetylase 5

Objective: Insulin resistance associated with obesity and diabetes is ameliorated by specific overexpression of GLUT4 in skeletal muscle. The molecular mechanisms regulating skeletal muscle GLUT4 expression remain to be elucidated. The purpose of this study was to examine these mechanisms.

Research Design and Methods and Results: Here, we report that AMP-activated protein kinase (AMPK) regulates GLUT4 transcription through the histone deacetylase (HDAC)5 transcriptional repressor. Overexpression of HDAC5 represses GLUT4 reporter gene expression, and HDAC inhibition in human primary myotubes increases endogenous GLUT4 gene expression. In vitro kinase assays, site-directed mutagenesis, and site-specific phospho-antibodies establish AMPK as an HDAC5 kinase that targets S259 and S498. Constitutively active but not dominant-negative AMPK and 5-aminoimidazole-4-carboxamide-1-β-d-ribonucleoside (AICAR) treatment in human primary myotubes results in HDAC5 phosphorylation at S259 and S498, association with 14-3-3 isoforms, and H3 acetylation. This reduces HDAC5 association with the GLUT4 promoter, as assessed through chromatin immunoprecipitation assays and HDAC5 nuclear export, concomitant with increases in GLUT4 gene expression. Gene reporter assays also confirm that the HDAC5 S259 and S498 sites are required for AICAR induction of GLUT4 transcription.

Conclusions: These data reveal a signal transduction pathway linking cellular energy charge to gene transcription directed at restoring cellular and whole-body energy balance and provide new therapeutic targets for the treatment and management of insulin resistance and type 2 diabetes.

Anthrone and oxanthrone C,O-diglycosides from Picramnia teapensis

Two C,O-diglycosylated compounds, the anthrone picramnioside F, and the oxanthrone mayoside C, were isolated from the stem bark of Picramnia teapensis, along with the previously reported anthraquinones, 1-O-beta -D- and 8-O-beta -D-glucopyranosyl emodin. The compounds were separated by recycling-HPLC, and their structures were determined on the basis of spectroscopic analysis. CD measurements were used to establish the absolute configuration of the anthrone and oxanthrone. The antifungal activity of 1-O-beta -D- and 8-O--D-glucopyranosyl emodin against Leucoagaricus gongilophorus was shown to be similar to that of the lignan sesamin. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Effect of soybean oil and Tween 80 on the production of botryosphaeran by Botryosphaeria rhodina MAMB-05

The addition of soybean oil and Tween 80 was evaluated with the objective of increasing the production of botryosphaeran, an exopolysaccharide (EPS) of the (1 -> 3 ;1 -> 6)-beta-D-glucan type produced by the fungus Botowsphaeria rhodina MAMB-05. Factorial design and analysis by response surface methodology was developed to select the main factors that would affect and enhance EPS production. The optimized culture conditions were: 40g l(-1) glucose with 10ml l(-1) soybean oil, and 4.5 ml l(-1) Tween 80, during 72h cultivation at 28 degrees C (180 rpm) and initial pH 5.7. The predicted result for botryosphaeran production was 8.22 +/- 1.36 g l(-1), and compared with the experimental value of 7.74 +/- 0.13 g l(-1) . Partial characterization of the botryosphaeran produced under the optimized conditions showed one type of polysaccharide with P-glycosidic linkages containing glucose as monosaccharide. (c) 2007 Elsevier Ltd. All rights reserved.

Comparison of Botryosphaeran production by the ascomyceteous fungus Botryosphaeria sp., grown on different carbohydrate carbon sources, and their partial structural features

The influence of glucose concentration and other carbohydrates (monosaccharides: fructose, galactose, mannose; polyols: mannitol and sorbitol; disaccharides: lactose, sucrose and commercial sucrose; and industrial sugarcane molasses) were compared as sole carbon sources for the production of Botryosphaeran, an exopolysaccharide (EPS) produced by Botryosphaeria sp. The optimum glucose concentration for EPS production was 50 g 1(-1). With the exception of mannitol, the fungus produced EPS on all carbon sources studied, with highest yields occurring with sucrose followed by glucose. All EPS showed exclusively glucose after acid hydrolysis and monosaccharide analysis. FTIR spectroscopy demonstrated the presence of beta-anomers indicating that all the EPS produced by Botryosphaeria sp. on the different carbon sources were essentially of the beta-D-glucan type.

Caracterização química de glucanas fúngicas e suas aplicações biotecnológicas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of Byrsonima crassa and Phenolic Constituents on Helicobacter pylori-Induced Neutrophils Oxidative Burst

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemical Composition and Antioxidant and Antimycobacterial Activities of Bromelia balansae (Bromeliaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Phenolic compounds in leaves of Alchornea triplinervia: anatomical localization, mutagenicity, and antibacterial activity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Flavonoids and a naphthopyranone from Eriocaulon ligulatum and their mutagenic activity

A new acylated flavonoid, 6,4'-dimethoxyquereetin-3-O-beta-D-6 ''[3,4,5-trihydroxy (E)-cinnamoyl]glucopyranoside, and a naphthopyranone dimer, named eriocauline, together with 2 other known flavonoids, 6-methoxyapigenin-7-O-beta-D-glucopyranoside and 6-methoxyapigenin-7-O-beta-D-allopyranoside, have been isolated from the capitulae of Eriocaulon ligulatum. The compounds were identified using spectroscopic methods (HR-ESI-MS, and 1-D and 2-D NMR). The methanol extract exhibited mutagenic activity in the Salmonella/microsome assay, in strains TA100, TA97a and TA102 and for dichloromethane extract tested in strain TA98.

Mutagenicity of paepalantine dimer and glycoside derivatives from Paepalanthus bromelioides

The first isocoumarin isolated from the methylene chloride extract of Paepalanthus bromelioides, named paepalantine (isocoumarin 1), was found to have antimicrobial activity; but, it is mutagenic clastogenic and cytotoxic. Two other isocoumarins, paepalantine-9-O-beta-D-glucopyranoside (isocoumarin 2) and paepalantine-9-O-beta-D-allopyranosyl(1-->6) glucopyranoside (isocoumarin 3) were isolated from the ethanolic extract. A fourth new isocoumarin, also isolated from the methylene chloride extract of the capitula of P. bromelioides, was characterized as an 8-8' dimer of paepalantine and denominated isocoumarin 4. The abilities of isocoumarins 2, 3 and 4 to induce mutations in Salmonella typhimurium strains TA97a, TA98, TA100 and TA102 were investigated. Mutagenic activity was observed in strain TA97a treated with isocoumarin 2 in the presence of S9 mixture. The substitution of H at position 9 by glucose or glucose-allose caused reductions in the mutagenic activities of paepalantine, indicating this to be an important site for these properties. (C) 2003 Elsevier Ltd. All rights reserved.

Mutagenic evaluation and chemical investigation of Byrsonima intermedia A. Juss. leaf extracts

Byrsonima intermedia is a native species of the cerrado formation (tropical American savannah). In Brazil, this plant has been used for the treatment of fever, in ulcers, as a diuretic, as antiasthinatics and in skin infections. Members of the genus Byrsonima (Malpighiaceae) are employed not only in the folk medicine but also as food to make juice, jellies and liquor. The aim of this work was to evaluate the mutagenic effects of Byrsonima intermedia, common name 'murici'. Phytochernical analysis of methanol extract furnished (+)catechin, (-)-epicatechin, quercetin-3-O-beta-D-galactopyranoside, methyl gallate, gallic acid, quercetin-3-O-alpha-L-arabinopyranoside, amentoflavone, quercetin, querceti n-3-O-(2-O-galloyl)-beta-galactopyranoside and quei-eetin-3-O-(2-O-galloyl)-alpha-arabinopyranoside. Methanol, hydromethanol and chloroform extracts were evaluated in inutagenic assay with Salmonella typhimurium (Ames test) and mice (Micronucleus test). The methanolic extract presented signs of mutagenic activity for the strains TA98 and TA100 in the Ames assay. Mutagenicity was not observed in vivo. (c) 2007 Elsevier B.V.. All rights reserved.

Structure-antimicrobial activity of some natural isocoumarins and their analogues

Three naturally occurring isocoumarins (paepalantine, paepalantine 9-O-beta-D-glucopyranoside and paepalantine 90-beta-D-allopyranosyl(1 -> 6) glucopyranoside) and two semi-synthetic analogues, 9,10-acylated compound and 9-OH-10-methylated compound,. structurally similar to paepalantine, were evaluated for antimicrobial activity using a spectrophotometric microdilution technique. The paepalantine was active against S. aureus, S. epidermidis, and E faecalis. while the other four compounds proved ineffective against all microorganisms tested at concentrations of 500 mu g/ml. Variations in phenolic substitution at OH-9 and/or OH-10 in the paepalantine molecule resulted in compounds without antimicrobial activity. A combination of structural features, two phenolic groups as cathecolic system, forms an oxygenated system arrangement that may reflect the potentially antimicrobial properties of paepalantine. (c) 2004 Elsevier GmbH. All rights reserved.

Mutagenic activity promoted by amentoflavone and methanolic extract of Byrsonima crassa Niedenzu

Byrsonima crassa is a plant pertaining to the Brazilian central savannah-like belt of vegetation and popularly used for the treatment of gastric dysfunctions and diarrhoea. The methanol extract contains catechin, tannins, terpenes and flavonoids; both mutagenic potential and antioxidant properties have been ascribed to flavonoids. The mutagenicity of some flavonoids is believed to be associated with the formation of reactive oxygen species and seems to depend on the number and position of hydroxyl groups. In the present study the mutagenic activity of the methanol, chloroform and 80% aqueous methanol extracts, as well as acetate and aqueous sub-fractions, of this medicinal plant were evaluated by Salmonella typhimurium assay, using strains 100, TA98, TA102 and TA97a, and in mouse reticulocytes. The results showed mutagenic activity of the methanolic extract in the TA98 strain without S9, but no mutagenicity to mouse cells in any of the extracts. The acetate fraction showed strong signs of mutagenicity without S9, suggesting that in this enriched fraction were concentrated the compounds that induced mutagenic activity. The aqueous fraction showed no mutagenic activity. The TLC and HSCCC analyses of the acetate fraction with some standard compounds permitted the isolation of the quercetin-3-O-beta-D-galactopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, amentoflavone, methyl gallate and (+)-catechin, of which only the amentoflavone exhibited positive mutagenicity to TA98 (+S9, -S9). (c) 2006 Elsevier B.V.. All rights reserved.

Oleanane Saponins and Glycerogalactolipids from the Leaves of Guapira graciliflora

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)