L-ascorbic Acid (l-ascorbic + acid)

Distribution by Scientific Domains

Selected Abstracts

Secoiridoid glucosides with free radical scavenging activity from the leaves of Syringa dilatata

Hyuncheol Oh
Abstract Activity-guided fractionation of the EtOAc and MeOH extract of the leaves of Syringa dilatata NAKAI furnished one free radical scavenger, the secoiridoid glucoside oleuropein together with ligstroside and an iridoid glucoside, syringopicroside. Oleuropein interacted with the stable free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and showed an IC50 value of 40.4 M. L-Ascorbic acid as a positive control showed an IC50 value of 50.3 M. Copyright 2003 John Wiley & Sons, Ltd. [source]

Optimum Dietary Level of L-ascorbic Acid for Japanese Eel, Anguilla japonica

Toncaun Ren
A feeding experiment was conducted to determine the optimum dietary level of ascorbic acid (AsA) for Japanese eel juveniles using L-ascorbic acid Ca based on growth, AsA content in tissues, hematology, and bactericidal activity of serum with Escherichia coli. Test diets with six levels of AsA (3, 10, 27,126, 645, and 3,135-mg/kg diet) as Ca ascorbate were fed to juvenile Japanese eels (11.0 0.2 g) once a day for 8 wk. High survival rates (> 80%) were observed among all dietary treatment groups. The specific growth rates of the fish fed diets containing 3 and 10-mg AsA/kg were significantly (P < 0.05) lower than those of other groups. Liver and brain AsA contents of the fish fed diets containing 3, 10, and 27-mg AsA/kg were significantly (P < 0.05) lower than those of the fish fed diets containing 645 and 3,135-mg AsA/kg. Hemoglobin content tended to be higher in the fish fed diets containing 645 and 3,135-mg AsA/kg than those of the fish fed other diets. Hematocrit value and total serum protein content of the fish fed diets containing 645 and 3135 mg AsA/kg were significantly (P < 0.05) higher than those of the other groups. The fish fed diets containing more than 27-mg AsAlkg showed a higher bactericidal activity of serum than the fish fed the diets containing 3-mg and 10-mg AsA/kg. The optimum dietary level of AsA for the Japanese eel juveniles growth was estimated to be more than 27-mg AsA/kg. Furthermore, the inclusion of 645-mg AsA/kg or more also increased the hematocrit, hemoglobin, total serum protein value, and liver and brain vitamin C concentrations. [source]

Targeted antitumoral dehydrocrotonin nanoparticles with L-ascorbic acid 6-stearate.

J Pharm Sci 98: 479
No abstract is available for this article. [source]

Loading of Bacterial Cellulose Aerogels with Bioactive Compounds by Antisolvent Precipitation with Supercritical Carbon Dioxide

Emmerich Haimer
Abstract Bacterial cellulose aerogels overcome the drawback of shrinking during preparation by drying with supercritical CO2. Thus, the pore network of these gels is fully accessible. These materials can be fully rewetted to 100% of its initial water content, without collapsing of the structure due to surface tension of the rewetting solvent. This rehydration property and the high pore volume of these material rendered bacterial cellulose aerogels very interesting as controlled release matrices. Supercritical CO2 drying, the method of choice for aerogel preparation, can simultaneously be used to precipitate solutes within the cellulose matrix and thus to load bacterial cellulose aerogels with active substances. This process, frequently termed supercritical antisolvent precipitation, is able to perform production of the actual aerogel and its loading in one single preparation step. In this work, the loading of a bacterial cellulose aerogel matrix with two model substances, namely dexpanthenol and L-ascorbic acid, and the release behavior from the matrix were studied. A mathematical release model was applied to model the interactions between the solutes and the cellulose matrix. The bacterial cellulose aerogels were easily equipped with the reagents by supercritical antisolvent precipitation. Loading isotherms as well as release kinetics indicated no specific interaction between matrix and loaded substances. Hence, loading and release can be controlled and predicted just by varying the thickness of the gel and the solute concentration in the loading bath. [source]

Lipase catalyzed synthesis of ester-based surfactants from biomass derivatives

Sanjib Kumar Karmee
Abstract Non-ionic surfactants find a unique place in pharmaceutical, detergent, food, and cosmetic industries because of their ready availability from biomass, low cost, and renewability. Generally these surfactants are esters obtained from the reaction of glycerol, L-ascorbic acid, and sugar, with long or medium chain fatty acids. Problems encountered during the synthesis of these surfactants are the immiscibility of highly polar substrates in organic solvents and non-regioselective reaction. Therefore, lipases as a catalyst and t -butanol or acetone, a mixture of solvent and ionic liquid as solvents, have been used for the synthesis of ester-based surfactants. This review focuses on the uses of lipases for the synthesis of surfactants obtained from biomass derivatives viz. fats and oils, sugar and vitamin-C. 2008 Society of Chemical Industry and John Wiley & Sons, Ltd [source]

The antioxidant effect of hydroxyl-substituent Schiff bases on the free-radical-induced hemolysis of human erythrocytes

You-Zhi Tang
Abstract The major objectives of the present work were focused on assessing the antioxidant capacities of two hydroxyl-substituent Schiff bases, 2-((o -hydroxylphenylimino)methyl)phenol (OSAP) and 2-((p -hydroxylphenylimino)methyl)phenol (PSAP) either used alone or in combination with some familiar water-soluble antioxidants i.e. 6-hydroxyl-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) and L-ascorbic acid (VC), and lipophilic ones i.e. ,-tocopherol (TOH) and L -ascorbyl-6-laurate (VC-12). 2,2'-Azobis(2-amidinopropane hydrochloride) (AAPH). Induced hemolysis of human erythrocytes functioned as the evaluation experimental system in this research. The present findings showed that either OSAP or PSAP not only was an antioxidant with high activity in protecting erythrocytes against AAPH-induced hemolysis concentration-dependently, but can also protect erythrocytes by acting with Trolox, TOH, VC and VC-12 synergistically. Based on chemical kinetic deduction, the number of trapping peroxyl radicals, n, of the above-mentioned antioxidants can be calculated in relation to Trolox that traps two peroxyl radicals; thus, TOH can trap 3.83 peroxyl radicals, VC-12 traps 2.87 and VC can only trap 1.08. As for OSAP and PSAP, 8.71 and 13.7 peroxyl radicals can be trapped, respectively, indicating that they were the most efficient inhibitors against AAPH-induced hemolysis. Moreover, the total number of peroxyl radicals trapped by OSAP+Trolox, OSAP+TOH, OSAP+VC and PSAP+VC were higher than the sum of the above individual antioxidant used alone, demonstrating that a mutual promotive effect existed in the above mixed antioxidants. In contrast, owing to the fact that the total number of peroxyl radicals trapped by OSAP+VC-12, PSAP+Trolox, PSAP+TOH and PSAP+VC-12 were less than the sum of the above individual antioxidant used alone, a mutual antagonistic effect was suggested in these combinative usages. This information may be helpful in the pharmaceutical application of two Schiff bases. Copyright 2005 John Wiley & Sons, Ltd. [source]

Early osteoblastic differentiation induced by dexamethasone enhances adenoviral gene delivery to marrow stromal cells

Jeremy S. Blum
Abstract We investigated the implications of induced osteogenic differentiation on gene delivery in multipotent rat marrow stromal cells (MSCs). Prior to genetic manipulation cells were cultured with or without osteogenic supplements (5 10,8 M dexamethasone, 160 ,M l-ascorbic acid 2-phosphate, and 10 mM ,-glycerophosphate). Comparison of liposome, retroviral, and adenoviral vectors demonstrated that all three vectors could mediate gene delivery to primary rat MSCs. When these vectors were applied in the absence or presence of osteogenic supplements, we found that MSCs differentiated prior to transduction with adenovirus type 5 vectors produced a 300% increase in transgene expression compared to MSCs that were not exposed to osteogenic supplements. This differentiation effect appeared specific to adenoviral mediated gene delivery, since there was minimal increase in retroviral gene delivery and no increase in liposome gene delivery when MSCs were treated with osteogenic supplements. In addition, we also determined this increase in transgene production to occur at a higher concentration of dexamethasone (5 10,8 M) in the culture medium of MSCs prior to adenoviral transduction. We found that this increased transgene production could be extended to the osteogenic protein, human bone morphogenetic protein 2 (hBMP-2). When delivered by an adenoviral vector, hBMP-2 transgene production could be increased from 1.4 ng/105 cells/3 days to 4.3 ng/105 cells/3 days by culture of MSCs with osteogenic supplements prior to transduction. These results indicate that the utility of MSCs as a therapeutic protein delivery mechanism through genetic manipulation can be enhanced by pre-culture of these cells with dexamethasone. 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source]