Development of HPLC-EPR and HPLC-EPR-MS Techniques
We have been developing the hyphenated techniques in chromatography such as HPLC-EPR and HPLC-EPR-MS in order to solve problems concerning structures and reactions of the biological molecule-derived radicals.
In addition, we have been deveroping the HPLC-ECD-UV-EPR-MS system to detect and identify the ESR silent forms (the oxidized forms and the reduced forms) of radical adducts on EPR trace. An electrochemical detector (ECD) is placed as a reactor between the column and the UV detctor in the HPLC-ECD-UV-EPR-MS system.
Detection of the reduced forms of radical adducts on the ESR trace using HPLC-electrochemical detector-ultraviolet absorption detector-electron spin resonance-MS.
Hideyuki Ikeda and Hideo Iwahashi, J. Sep. Sci. 2010, 33: 1185-1191.
Inhibitory Effect of Naturally Occurring Antioxidants on the Formation of the Biomolecule-derived Radicals
We have been clarifying the mechanisms through which biomolecule-derived radicals form in the systems of photoreactions and microsomes. Inhibitory effect by natural occurring antioxidants such as polyphenols on the formation of free radicals has been investigated.
Identification of Radicals Formed in the Reaction Mixture of Bovine Kidney Microsomes with NADPH.
Kazumasa Kumamoto, Tomihiro Hirai, Shiroh Kishioka, Hideo Iwahashi, J Biochem, 2009, 146: 571-579.
Identification of a Radical Formed in the Reaction Mixtures of Ram Seminal Vesicle Microsomes with Arachidonic Acid Using High Performance Liquid Chromatography-Electron Spin Resonance Spectrometry and High Performance Liquid Chromatography-Electron Spin Resonance-Mass Spectrometry.
Katsuyuki Minakata and Hideo Iwahashi, J Clin Biochem Nutr. 2010, 46: 135-139.
Caffeic Acid Inhibits the Formation of 1-Hydroxyethyl Radical in the Reaction Mixture of Rat Liver Microsomes with Ethanol Partly through Its Metal Chelating.
Hideyuki Ikeda, Yuka Kimura, Miho Masaki and Hideo Iwahashi, J Clin Biochem Nutr. 2011, 48, 187-193.
Formation of 7-carboxyheptyl radical induced by singlet oxigen in the reaction mixture of oleic acid, riboflavin and ferrous ion under the UVA irradiation. Hiroko Mori and Hideo Iwahashi, J Clin Biochem Nutr. 2011, 49: 141-146.
Identification of the radicals formed in the reactions of some endogenous photosensitizers with oleic acid under the UVA irradiation. Hiroko Mori and Hideo Iwahashi, J. Clin. Biochem. Nutr. 2012, 51: 170-177.
Detection and identification of 1-methylethyl and methyl radicals generated by irradiating tea tree (Melaleuca alternifolia) oil with visible light (436 nm) in the presence of flavin mononucleotide and ferrous ion. H.-M. Mori and H. Iwahashi, Free Radical Research 2013, 47: 657?663.
Caffeic acid inhibits the formation of 7-carboxyheptyl radicals from oleic acid under flavin mononucleotide photosensitization by scavenging singlet oxygen and quenching the excited state of flavin mononucleotide. Marie Asano and Hideo Iwahashi, Molecules 2014, 19: 12486-12499.
Baicalin inhibits the Fenton reaction by enhancing electron transfer from Fe2+ to dissolved oxygen. Daisuke Nishizaki, Hideo Iwahashi, American Journal of Chinese Medicine 2015, 42: 87-101.
Detection and Identification of antimararial drug artemisinin-derived radicals
We have detected and identified radicals formed in the reaction of antimararial drug artemisin with ferrous ions.
Interaction between Biological Molecules
Interaction between biological molecules has been examined, focusing on non-Watson・Crick interactions of nucleic acid bases. We employ an ESI-mass spectrometer to perform the research.
Kazuaki Fukushima and Hideo Iwahashi, Chem Commun. 2000, 895-896.
Reaction of iron(IV)-oxo complex with several alkohols
We have examined the reactions of iron(IV)-oxo complex with several alkohols.
Radicals formed in the reactions of various unsaturated lipids with iron ions
We examined the formation of radicals in the reactions of various unsaturated lipids with iron ions.
Research on Reaction Mechanisms of Biological Molecules using Computational Chemistry
Reaction mechanisms of biological molecules have been revealed using molecular orbital theory and density functional theory calculations.