A series of novel monoacylated vitamin C derivatives were chemically synthesized with a stable ascorbate derivative, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G), and acid anhydrides in pyridine. Their solubility in organic phase, thermal stability, radical scavenging activity, and in vitro skin permeability was evaluated. These monoacylated derivatives were identified as 6-O-acyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acids (6-Acyl-AA-2G) by UV spectra, elemental analyses, and nuclear magnetic resonance spectroscopy. The reactions afforded 6-Acyl-AA-2G in high yields (30-60%). 6-Acyl-AA-2G exhibited satisfactory stability in neutral solution comparable to that of a typical stable derivative, AA-2G, and also showed the radical scavenging activity. The lipid solubility of 6-Acyl-AA-2G was increased with increasing length of their acyl group. Increased skin permeability was superior to those of AA-2G and ascorbic acid (AsA). 6-Acyl-AA-2G that is susceptible to enzymatic hydrolysis by tissue esterase and/or alpha-glucosidase produces AA-2G and AsA, which is in the skin tissues. Thus, these findings indicate that the novel vitamin C derivatives presented here, 6-Acyl-AA-2G, may be effective antioxidants in skin care and medicinal use.

Contact between Helicobacter pylori and gastric epithelial cells results in activation of NF-kB followed by secretion of interleukin (IL)-8. However, host-cell receptor(s) and their ligands involved in H. pylori-related IL-8 production have yet to be fully defined. In this study, the interaction between Toll-like receptors (TLRs), which are host receptors for pathogens involved in the innate immune response, and heat-shock protein (HSP) 60, an immune-potent antigen of H. pylori, was examined during H. pylori-induced IL-8 secretion in vitro. Recombinant H. pylori HSP60 (rHpHSP60) was prepared and added to cultured KATO III human gastric epithelial cells with or without pre-incubation with mouse monoclonal anti-TLR2 or anti-TLR4 antibodies. IL-8 mRNA expression and IL-8 protein release were analysed by Northern blotting and immunoassay. Involvement of NF-kB activation was analysed immunocytochemically by anti-NF-kB p65 antibody and ammonium pyrrolidinedithiocarbamate (PDTC), an inhibitor of NF-kB-mediated transcriptional activation. rHpHSP60 induced IL-8 mRNA expression and IL-8 secretion in a dose-dependent manner in KATO III cells. Anti-TLR2 antibody inhibited rHpHSP60-induced IL-8 secretion by 75 %, and anti-TLR4 antibody inhibited it by 30 %. rHpHSP60 induced nuclear translocation of NF-kB p65, which was inhibited by pretreatment with anti-TLR2 antibody. Treatment with PDTC significantly decreased the secretion of IL-8 induced by rHpHSP60. These findings suggest that H. pylori HSP60 activates NF-kB and induces IL-8 production through TLR-triggered pathways in gastric epithelial cells. Thus, it is possible that H. pylori HSP60 and TLR interaction in host cells contributes to the development of gastric inflammation caused by H. pylori infection.

The radical scavenging activity of the stable derivatives, which are O-substituted at the C-2 position of ascorbic acid (AA), against 1,1-diphenyl-2-picrylhydrazyl (DPPH) was evaluated in buffer under different pH conditions, and compared with those of AA and alpha-tocopherol. AA was shown to have 50% radical scavenging ability (EC50) at a concentration of 2.2 x 10(-5) M against 0.1 mM DPPH in 60% ethanol. Ascorbyl 6-palmitate, a lipophilic AA derivative which has a free endiol group and is therefore unstable, also showed potent radical scavenging activity with EC50 of 2.9 x 10(-5) M. A typical lipophilic antioxidant, alpha-tocopherol gave a similar EC50 value as that of AA. In contrast, ascorbyl 2,6-dipalmitate, AA 2-phosphate and AA 2-sulfate exhibited negligible scavenging activity. On the other hand, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) and a series of 6-O-acyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acids (6-Acyl-AA-2G) themselves exhibited the radical scavenging activity of EC50: 6.1 x 10(-5) M and 4.4 x 10(-5)-5.9 x 10(-5) M, respectively, although their activities were lower than that of AA. Among 6-Acyl-AA-2G derivatives, the EC50 values tended to decrease with increasing length of their acyl carbon group. Increasing pH of the buffer resulted in decrease in the scavenging activity of all compounds tested as expected. We speculate that the difference in the radical scavenging activity of derivatives O-substituted at the C-2 position of AA may be ascribed to the linkage type of the substituent group to the endiol-lactone resonance system and the degree of dissociation of the C-3 proton.

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Molecular typing is an important tool in the surveillance and investigation of human Legionella infection outbreaks. In this study, two molecular typing methods, pulsed-field gel electrophoresis (PFGE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), were used to discriminate 23 Legionella pneumophila strains. The usefulness of MALDI-TOF-MS was demonstrated. The MALDI-TOF-MS fingerprinting with filtered small acid-soluble molecules gave different molecular profiles among strains, and the clustal analysis with MALDI-TOF-MS showed a high discrimination of strains the same as that with PFGE. In addition, MALDI-TOF-MS data could be generated within a few hours after the initial culture, although PFGE analyses took several days to complete. Thus, MALDI-TOF-MS offers a simple and rapid discrimination technique that could aid in the tracking of fast-spreading outbreaks of Legionella.