Structural characterization and cytotoxic properties of a 4-O-methylglucuronoxylan from Castanea sativa

1 - ArticleA glucuronoxylan was purified from a delignified holocellulose alkaline extract of Castanea sativa (Spanish chestnut) and its structure analyzed by means of FT-IR, GC of the per-trimethylsilylated methylglycoside derivatives, and H-1 and C-13 NMR spectroscopy. The results supported a structure based on a linear polymer of xylopyranose units linked with beta(1 -> 4) bonds in which, on average, one out of every six units is substituted at C-2 by a 4-O-methylglucuronic acid unit; this structure is typical of a hardwood acidic 4-O-methylglucuronoxylan (MGX) with an estimated degree of polymerization of 200. The MGX from C. sativa inhibited the proliferation of A431 human epidermoid carcinoma cells with an IC50 value of 50 mu M. In addition, this xylan inhibited A431 cell migration and invasion. Preliminary experiments showing that secretion of metalloproteinases MMP2 and MMP9 by A431 tumor cells was inhibited by the purified C. sativa MGX strongly suggest that this mechanism of action may play a role in its antimigration and anti-invasive properties

Biosorption of lead (II) on modified barks explained by the hard and soft acids and bases (HSAB) theory

Astier, Cedric Chaleix, Vincent Faugeron, Celine Ropartz, David Krausz, Pierre Gloaguen, Vincent15NORTH CAROLINA STATE UNIV DEPT WOOD & PAPER SCI[Astier, Cedric; Chaleix, Vincent; Faugeron, Celine; Krausz, Pierre; Gloaguen, Vincent] Fac Sci & Tech, Lab Chim Subst Nat, EA1069, F-87060 Limoges, France. [Ropartz, David] INRA, Plate Forme BIBS, Biopolymeres Interact Assemblages UR1268, F-44300 Nantes, [email protected] audienceChemical modification of Douglas fir bark and its subsequent utilization in adsorption of Pb(II) from aqueous solutions was investigated. The polysaccharidic moiety of barks was functionalized by periodate oxidation and derivatized after reductive amination in the presence of aminated oligo-carrageenans. Pb(II) adsorption isotherms of derivatized barks were then determined and compared to the capabilities of crude barks using the Langmuir adsorption model in terms of affinity (b) and maximum binding capacity (q(max)). Compared to crude barks, the derivatization of barks by oligo-carrageenans resulted in significant enhancements of q(max) and b by up to x8 and x4, respectively. The results obtained from crude barks on chemically grafted carboxylic and sulfated barks are discussed and interpreted through the Hard and Soft Acids and Bases (HSAB) theory

Antibacterial activity of a photosensitive hybrid cellulose fabric

We report the preparation of a cellulose fabric bearing derivative protoporphyrin IX units covalently attached to the cellulose backbone of a fabric. Ce-(IV) redox system radical polymerization was used to polymerize methacrylic acid (MAA) onto a cotton material and to obtain cotton-g-polyMAA. Attachment of the photosensitizer, a protoporphyrin IX (PpIX) amino derivative, on cotton-g-polyMAA was realized successfully by a classical peptidic covalent link. The modified surfaces were characterized by ATR-FTIR, DRUV, TGA, and SEM methods. Under visible light irradiation, protoporphyrinic cotton showed antibacterial activity against Staphyloccoccus aureus. This concept is very promising in the field of bacterial decontamination (sterile area, hospital equipment, etc.)

Perspectives de valorisation des co-produits de Pinus caribaea : composition phytochimique et activités anti-oxydantes et antimicrobiennes

International audienc

Synthesis and biological activity of chloroethyl pyrimidine nucleosides

1 - ArticleThe synthesis and biological activity of chloroethyl pyrimidine nucleosides is presented. One of these new nucleosides analogues significantly inhibited cell proliferation, migration and invasion as tested in vitro on the A431 vulvar epidermal carcinoma cell line

Functionalisation of silicon substituted hydroxyapatite bioceramics by BMP-2 for bone tissue engineering

International audienc

Synthesis and biological activity of mustard derivatives of thymine

1 - ArticleThe synthesis and biological activity of a novel DNA cross-linking antitumor agent is presented. The new alkylating agent significantly inhibited cell proliferation, migration and invasion as tested in vitro on the A431 vulvar epidermal carcinoma cell line

Perspectives de valorisation des co-produits de Pinus caribaea : composition phytochimique et activités anti-oxydantes et antimicrobiennes

International audienc

Diagnosis and therapy of precocious tumors with inkjet-printed mesoporous silica microdots

International audienc