Search results for "saccharide"
showing 10 items of 849 documents
Enhanced expression of haem oxygenase-1 by nitric oxide and antiinflammatory drugs in NIH 3T3 fibroblasts
2000
Haem oxygenase-1 (HO-1) can exert protective effects against oxidative stress and inflammation. Fibroblasts participate in inflammatory responses where they produce high levels of prostaglandins (PGs) and nitric oxide (NO). However, little is known of the presence of HO-1 in these cells and the possible interactions among these pathways. Incubation of cells with NO donors, spermine nonoate (SPNO) and S-nitroso-N-acetylpenicillamine (SNAP), induced a dose- and time-dependent expression of HO-1 protein. NO donors increased basal PGE2 release although they reduced PGE2 accumulated in the medium and cyclo-oxygenase (COX) activity when cells were stimulated with lipopolysaccharide (LPS). COX-2 p…
New Diosgenin Glycosides from Costus afer
1997
Two new steroidal saponins, aferosides B (1) and C (2), together with the known saponins, dioscin (3) and paryphyllin C (4), were isolated from the roots of Costus afer. The known flavonoid glycoside, kaempferol 3-O-α-l-rhamnopyranoside (5), was obtained from the aerial parts. The structures of the new compounds were elucidated principally by 2D NMR spectral methods. A structural revision of the sugar sequence was made for the previously reported saponin aferoside A (6) on the basis of detailed spectroscopic analysis. Saponins 1−4 and 6 did not show any ability to potentiate in vitro cisplatin cytotoxicity in a human colon cancer cell line.
Erythromycin exertsin vivoanti-inflammatory activity downregulating cell adhesion molecule expression
2005
1. Macrolides have long been used as anti-bacterial agents; however, there is some evidence that may exert anti-inflammatory activity. Therefore, erythromycin was used to characterize the mechanisms involved in their in vivo anti-inflammatory activity. 2. Erythromycin pretreatment (30 mg kg(-1) day(-1) for 1 week) reduced the lipopolysaccharide (LPS; intratracheal, 0.4 mg kg(-1))-induced increase in neutrophil count and elastase activity in the bronchoalveolar lavage fluid (BALF) and lung tissue myeloperoxidase activity, but failed to decrease tumor necrosis factor-alpha and macrophage-inflammatory protein-2 augmented levels in BALF. Erythromycin pretreatment also prevented lung P-selectin,…
Effects of γ-Butyrobetaine and Mildronate on Nitric Oxide Production in Lipopolysaccharide-Treated Rats
2008
Production of nitric oxide was measured in lipopolysaccharide-treated rats (10 mg/kg, 4 hr) using the electron paramagnetic resonance method. As compared to the control animals, the nitric oxide level in liver of lipopolysaccharide-treated rats increased from 27.6+/-4.7 to 1485+/-129 ng/g tissue, in heart from 4.8+/-0.7 to 271+/-26 ng/g tissue, in blood from 33.6+/-12.4 to 638+/-136 ng/g tissue, in kidney from 3.3+/-0.5 to 356+/-31 ng/g tissue, in brain cortex from 46.0+/-3.4 to 227+/-27 ng/g tissue, in cerebellum from 27.7+/-2.6 to 218+/-30 ng/g tissue, and in testes from 13.8+/-1.1 to 86+/-8 ng/g tissue. Administration of the antiischaemic drug, mildronate (120 mg/kg) caused a significant…
Inhibition of trehalose breakdown increases new carbon partitioning into cellulosic biomass in Nicotiana tabacum
2010
Abstract Validamycin A was used to inhibit in vivo trehalase activity in tobacco enabling the study of subsequent changes in new C partitioning into cellulosic biomass and lignin precursors. After 12-h exposure to treatment, plants were pulse labeled using radioactive 11 CO 2 , and the partitioning of isotope was traced into [ 11 C]cellulose and [ 11 C]hemicellulose, as well as into [ 11 C]phenylalanine, the precursor for lignin. Over this time course of treatment, new carbon partitioning into hemicellulose and cellulose was increased, while new carbon partitioning into phenylalanine was decreased. This trend was accompanied by a decrease in phenylalanine ammonia-lyase activity. After 4 d o…
Mycochemical investigation of Pleurotus eryngii var. eryngii
2017
The mycochemical composition and structural characterization of the whole aqueous and methanolic extracts from Pleurotus eryngii var. eryngii are investigated. Two water-soluble glucans were obtained from the fruiting bodies by hot water extraction, ethanol precipitation, dialysis and Sephadex G-200 gel filtration. On the basis of total hydrolysis, methylation analysis, and NMR studies (1H, 13C, DQF-COSY, TOCSY, HSQC and HMBC) two fractions PEPS-1 and PEPS-2 were characterized and the structure of the repeating unit of the glucan were determined as linear (1→6)--glucan and (1→6)--glucan, respectively. The methanolic extract of Pleurotus eryngii var. eryngii was also investigated and a com…
Ciprofloxacin releasing gellan gum/polydopamine based hydrogels with near infrared activated photothermal properties.
2021
Abstract In this work, with the aim to obtain a wound dressing hydrogel, an amine derivative of gellan gum was crosslinked in the presence of 4arm-polyethylenglycole-vinylsulfone. Through this easy and reproducible chemical procedure, a hydrogel with advanced elastic properties and hydrolytic resistance under physiological conditions was obtained. The incorporation of different quantities of polydopamine in the gelling solutions allows to obtain different hydrogels with marked photothermal properties when irradiated with a laser in the near infrared at 810 nm. The organic nanoparticles, reacting with the amino groups of the polysaccharide derivative, contribute to increase the storage modul…
Polygalacturonate hydrogels using Fe2+ as cross-linkers : impact of the local association mode on gelation mechanisms, control of the multiscale stru…
2018
This pHD thesis describes the design of polygalacturonate hydrogels (polyGal) cross-linked by the Fe2+ cations, and their experimental characterization from the molecular scales up to the macroscopic scales, by combining EXAFS spectroscopy, Small Angle Neutron Scattering (SANS) and rheological measurements. We designed a robust gelling protocol that allowed to obtain reproducible cylindrical gels with controlled concentration gradients from the lower side to the upper side of the gel. The ratio [Fe]/[Gal] has a constant value all along the gel, which demonstrate that the Fe2+ cations are associated with 4 galacturonate units. The comparison of EXAFS measurements and molecular dynamics simul…
Polysaccharide-Based pH-Responsive Nanocapsules Prepared with Bio-Orthogonal Chemistry and Their Use as Responsive Delivery Systems.
2020
Bio-orthogonal reactions have become an essential tool to prepare biomaterials; for example, in the synthesis of nanocarriers, bio-orthogonal chemistry allows circumventing common obstacles related to the encapsulation of delicate payloads or the occurrence of uncontrolled side reactions, which significantly limit the range of potential payloads to encapsulate. Here, we report a new approach to prepare pH-responsive nanocarriers using dynamic bio-orthogonal chemistry. The reaction between a poly(hydrazide) crosslinker and functionalized polysaccharides was used to form a pH-responsive hydrazone network. The network formation occurred at the interface of aqueous nanodroplets in miniemulsion …
Production and physicochemical characterization of a new amine derivative of gellan gum and rheological study of derived hydrogels
2020
The production of an amine derivative of gellan gum, named GG-EDA, was here obtained by functionalizing the polysaccharide backbone with pendant ethylenediamine moieties. The obtained derivative was characterized by spectroscopic, colorimetric, chromatographic and rheological analyses to study the effect of the free amino groups on the physicochemical properties of the macromolecule. A titration experiment was conducted to study the acid-base dissociation constants in aqueous media for the carboxylic and amino groups in the GG-EDA and to shed light on the possibility that the derivative shows a polyampholyte structure under physiological conditions. The rheological analysis conducted on bot…