Biological synthesis of L-Ascorbyl Palmitate in organic system were studied in this text. The contradiction between conversion of vitamin C and concentration of L-Ascorbyl Palmitate were resolved. High conversion of vitamin C and concentration of L-Ascorbyl Palmitate were obtained by Novo435. A series of solvents(log P from -0.24 to 3.5 )were investigated for the reaction,and acetone was found to be the most suitable from the standpoint of the enzyme activity and solubility of L-ascorbic. And the equilibrium of the reaction was affected by the addition of the molecular sieves and temperature. Reaction carried out at 60 degrees C and with 20% 0.4nm molecular sieves is good for the enzyme to keep its activity and for making the equilibrium go to the product. With 1.094 g palmitic acid, 0.107 g vitamin C and 0.020 g Novo435, rotate rate of 200 r/min, the conversion of ascorbic reached 80% and the concentration of L-ascorbyl palmitate is 20 g/L after 48 h. Furthermore, reaction batch of Novo435 and substrates recycle were observed, the result indicated that Novo435 may used 4-5 times continuously with high conversion. And 6-O-unsaturated acyl L-ascorbates were synthesized through Novo435 condensation of ascorbic acid and various unsaturated fatty acids with high conversion in this text.
Ascorbic Acid ; analogs & derivatives ; biosynthesis ; Catalysis ; Enzymes, Immobilized ; chemistry ; metabolism ; Lipase ; chemistry ; metabolism

By engineering the subsite +1 of cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans, we improved its maltodextrin specificity for 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G) synthesis. Specifically, we conducted site-saturation mutagenesis on Leu194, Ala230, and His233 in subsite +1 separately and gained 3 mutants L194N (leucine --> asparagine), A230D (alanine --> aspartic acid), and H233E (histidine --> glutamic acid) produced higher AA-2G yield than the wild-type and the other mutant CGTases. Therefore, the 3 mutants L194N, A230D, and H233E were further used to construct the double and triple mutations. Among the 7 obtained combinational mutants, the triple mutant L194N/A230D/H233E produced the highest AA-2G titer of 1.95 g/L, which was increased by 62.5% compared with that produced by the wild-type CGTase. Then, we modeled the reaction kinetics of all the mutants and found a substrate inhibition by high titer of L-AA for the mutants. The optimal temperature, pH, and reaction time of all the mutants were also determined. The structure modeling indicated that the enhanced maltodextrin specificity may be related with the changes of hydrogen bonding interactions between the side chain of residue at the three positions (194, 230 and 233) and the substrate sugars.
Ascorbic Acid ; analogs & derivatives ; chemistry ; Glucosyltransferases ; genetics ; metabolism ; Hydrogen Bonding ; Kinetics ; Mutagenesis, Site-Directed ; Paenibacillus ; enzymology ; Polysaccharides ; chemistry ; Protein Engineering ; Substrate Specificity ; Temperature

In peripheral blood hematopoietic stem cell transplantation (PBHSCT) , the mobilization and circulating of bone marrow hematopoietic stem cells in blood with higher oxygen concentration all increase reactive oxygen species(ROS) production, which has negative effect on the biological function of BMHSC. In order to investigate the protective effect of antioxidant on hematopoietic stem cells (HSC), the ascorbic acid 2-phosphate (AA2P), an ascorbic acid derivative of vitamin C, was added in HSC culturing by imitating oxygen conditions which BMHSC experienced in peripheral blood stem cell transplantation. The protective effect of above-mentioned culture methods on the biologic functions of BMHSC was evaluated by vitro amplification assay, committed division assay, reactive oxygen species (ROS) measurement, CD34(+) HSC engraftment. The results showed that the ROS level in HSC from in vitro cultures was much higher than that freshly separated BMHSC, and the amplified AC133(+)CD34(+) HSC, BFU-E, CFU-GM, CFU-GEMM colonies, migration rate and severe combined immunodeficiency (SCID)-repopulating cells (SRC) were all much more than HSC cultured without AA2P. It is concluded that antioxidant intervention may be an effective methods for protecting the biological function of PBHSC and improving the therapeutic effect of PBHSCT.
Antigens, CD34 ; metabolism ; Antioxidants ; pharmacology ; Ascorbic Acid ; analogs & derivatives ; pharmacology ; Cells, Cultured ; Hematopoietic Stem Cells ; cytology ; drug effects ; Humans ; Reactive Oxygen Species ; metabolism

OBJECTIVETo evaluate the efficacy of free-radical scavenger in the treatment of chronic bacterial prostatitis (CBP).

METHODSFifty-eight healthy male rats were randomly divided into a control group and four model groups (Groups A, B, C and D). The chronic prostatitis model was established in the latter groups through injecting E. coli into the ventral robe of the prostate according to document. Group A was untreated, Group B treated with free-radical scavenger vitamin C, Group C with salicylazosulfapyridine (SASP), Group D with SASP and vitamin C. Superoxide dismutase (SOD) and malondialdehyde (MDA) examinations were conducted in each group 2 months later.

RESULTSVitamin C could significantly increase the level of SOD and decrease the level of MDA. There was significant difference between the model groups and the control one, as well as between the treated groups and the untreated one, but none among the treated groups.

CONCLUSIONFree-radical scavenger may be useful for the treatment of chronic bacterial prostatitis.

Animals ; Ascorbic Acid ; therapeutic use ; Chronic Disease ; Free Radical Scavengers ; therapeutic use ; Male ; Malondialdehyde ; metabolism ; Prostatitis ; drug therapy ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sulfasalazine ; analogs & derivatives ; therapeutic use ; Superoxide Dismutase ; metabolism

Pro-oxidant properties of ascorbate have been studied with uses of brain tissues and neuronal cells. Here we address potential mechanism of ascorbate coupling with glutamate to generate oxidative stress, and the role which oxidized ascorbate (dehydroascorbate) transport plays in oxidative neuronal injury. Ascorbate in neurones can be depleted by adding glutamate in culture medium since endogenous ascorbate can be exchanged with glutamate, which enhances ascorbate/ dehydroascorbate transport by depleting ascorbate in the neurons with the glutamate-heteroexchange. However, ascorbate is known readily being oxidized to dehydroascorbate in the medium. Glutamate enhanced the dehydroascorbate uptake by cells via a glucose transporter (GLUT) from extracellular region, and cytosolic dehydroascorbate enhanced lipid peroxide production and reduced glutathione (GSH) concentrations. Iso-ascorbate, the epimer of ascorbate was ineffective in generating the oxidative stress. These observations support the current concept that the high rates of dehydroascorbate transport via a GLUT after the release of ascorbate by glutamate leads to peroxidation, the role of glutamate on ascorbate/ dehydroascorbate recycling being critical to induce neuronal death via an oxidative stress in the brain injury.
Animals ; Ascorbic Acid/analogs & derivatives/pharmacology ; Biological Transport/drug effects ; Cerebral Cortex/*drug effects/*metabolism ; Cytochalasin B/pharmacology ; Dehydroascorbic Acid/*metabolism ; Glutamic Acid/*pharmacology ; Glutathione/metabolism ; In Vitro ; Lipid Peroxidation/*drug effects ; Male ; Oxidation-Reduction/drug effects ; Oxidative Stress/drug effects ; Rats ; Rats, Sprague-Dawley ; Thiobarbituric Acid Reactive Substances/metabolism

We report a case of regression of multiple pulmonary metastases, which originated from hepatocellular carcinoma after treatment with intravenous administration of high-dose vitamin C. A 74-year-old woman presented to the clinic for her cancer-related symptoms such as general weakness and anorexia. After undergoing initial transarterial chemoembolization (TACE), local recurrence with multiple pulmonary metastases was found. She refused further conventional therapy, including sorafenib tosylate (Nexavar). She did receive high doses of vitamin C (70 g), which were administered into a peripheral vein twice a week for 10 months, and multiple pulmonary metastases were observed to have completely regressed. She then underwent subsequent TACE, resulting in remission of her primary hepatocellular carcinoma.
Aged ; Antineoplastic Agents/administration & dosage/*therapeutic use ; Ascorbic Acid/*administration & dosage/therapeutic use ; Carcinoma, Hepatocellular/*drug therapy/pathology ; Chemoembolization, Therapeutic ; Combined Modality Therapy ; Female ; Humans ; Liver Neoplasms/pathology/*therapy ; Lung Neoplasms/*drug therapy/pathology ; Neoplasm Recurrence, Local ; Niacinamide/analogs & derivatives/therapeutic use ; Phenylurea Compounds/therapeutic use ; Treatment Outcome