The University of Shiga Prefecture · Faculty of Engineering · 講師

Research keywordsnatural products chemistry・anthraquinones・microwave isomerization・lycopene・SPCA2 inhibitors・calcium ATPase inhibitors

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• Characterization of an L-α,β-diaminopropionic acid polymer with comb-like structure isolated from a poly(ε-L-lysine)-producing Streptomyces sp.2021 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： Springer 参加形態： 共同（主担当） Polymers of basic amino acids function as polycationic compounds under physiological conditions and exhibit intriguing biological properties, such as antimicrobial and antiviral activities, immunopotentiating ability, and DNA binding activity. Poly(ε-L-lysine) (ε-PL) produced by some strains of Streptomyces spp. is a cationic homopolymer of L-lysine linking between ε-amino and α-carboxylic acid functional groups, and has been used as a food preservative based on its biocompatibility and biodegradability. An ε-PL producing strain of Streptomyces sp. USE-33 was found to secrete a novel polycationic substance into its culture broth along with ε-PL. High-performance liquid chromatography analyses and one- and two-dimensional 1H and 13C nuclear magnetic resonance (NMR) experiments, accompanied by NMR titration studies, revealed that the secreted substance was poly[β-(L-diaminopropionyl-L-diaminopropionic acid)], PAP, characterized by an isopeptide backbone linking between the β-amino and α-carboxylic acid groups of L-α,β-diaminopropionic acid (L-Dpr) with pendent L-Dpr residues. PAP had a molecular weight of 500 to 1400, and copolymers composed of the two amino acids L-Dpr and L-lysine were not detected in the producer strain USE-33. The strain coproduced high levels of the two poly(amino acid)s in the presence of glycerol, citrate, and ammonium sulfate at pH 4.0 in a two-stage cultivation procedure. PAP exhibited strong inhibitory activities against several yeasts and weaker activities against bacteria than ε-PL. PAP may share a number of biological functions with ε-PL, and the use of PAP along with ε-PL has potential as a specific and advanced material for technical applications in various fields. DOI： 10.1007/s00253-021-11257-3 その他リンク： https://pubmed.ncbi.nlm.nih.gov/33846822/
• Microwave-Accelerated Z-Isomerization of (all-E)-Lycopene in Tomato Oleoresin and Enhancement of the Conversion by Vegetable Oils Containing Disulfide Compounds2018 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： European Journal of Lipid Science and Technology © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The effect of microwave irradiation on Z-isomerization of (all-E)-lycopene contained in tomato oleoresin is investigated, and the Z-isomerization efficiency is compared to that of the conventional oil-bath heating method. With a 4-min microwave treatment at 2450 MHz frequency and 500 W power, the total Z-isomer content of lycopene increased to approximately 70%, almost without decomposition, and the efficiency, at the same temperature, is higher than that with conventional heating. In both treatments, the (9Z)- and (13Z)-isomers are mainly formed. Moreover, the effect of addition of vegetable oils to the oleoresin on the Z-isomerization by microwave irradiation is examined. When roasted seed oils and garlic oil are added, the production of (5Z)-lycopene, an isomer having higher functionality and storage stability among the Z-isomers, is significantly increased. This work reveals that the promoting effect is probably caused by the presence of disulfide compounds existing commonly in the above oils: Thiyl radicals, produced from disulfide compounds by microwave irradiation, would act as a catalyst for the Z-isomerization reaction. Practical Applications: Z-Isomers of lycopene, which are the predominant forms in the human body, have higher bioavailability and antioxidant capacity than the all-E-isomer, which is the major configuration form in raw tomatoes. Thus, appropriate methods are required to achieve the efficient Z-isomerization of (all-E)-lycopene. This study has developed an efficient production method for lycopene Z-isomers by microwave irradiation of (all-E)-lycopene in edible vegetable oils containing disulfide compounds, in which neither organic solvents nor food additives are used. It would be practically feasible to utilize this procedure not only for food, drink, and dietary supplement manufacturing, but also for daily cooking. (all-E)-Lycopene in tomato oleoresin is efficiently isomerized to the Z-isomers by microwave irradiation and the Z-isomerization is accelerated by adding vegetable oils containing disulfide compounds. DOI： 10.1002/ejlt.201800060 Scopus その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85046735985&origin=inward
• Isolation and spectral characterization of thermally generated multi-Z-isomers of lycopene and the theoretically preferred pathway to di-Z-isomers2016 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） 参加形態： 共同（主担当） Lycopene has a large number of geometric isomers caused by E/Z isomerization at arbitrary sites within the eleven conjugated double bonds, offering varying characteristics related to features such as antioxidant capacity and bioavailability. However, the geometric structures of only a few lycopene Z-isomers have been thoroughly identified from natural sources. In this study, seven multi-Z-isomers of lycopene, (9Z,13′Z)-, (5Z,13Z,9′Z)-, (9Z,9′Z)-, (5Z,13′Z)-, (5Z,9′Z)-, (5Z,9Z,5′Z)-, and (5Z,9Z)-lycopene, were obtained from tomato samples by thermal isomerization, and then isolated by elaborate chromatography, and fully assigned using proton nuclear magnetic resonance. Moreover, the theoretically preferred pathway from (all-E)-lycopene to di-Z-isomers was examined with a computational approach using a Gaussian program. Fine-tuning of the HPLC separation conditions led to the discovery of novel multi-Z-isomers, and whose formation was supported by advanced theoretical calculations. DOI： 10.1080/09168451.2016.1249454
• 1,4-Dihydroxy-2,3-dinitro-9,10-anthraquinone2016 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） 参加形態： 共同（副担当） In the title compound, C14 H6 N2 O8 , the anthraquinone unit is essentially planar [maximum deviation = 0.0645 (10) Å ], and there are two intramolecular O—H⋯ O hydrogen bonds forming S (6) motifs. The planes of the two nitro substituents make dihedral angles of 54.77 (8) and 55.60 (3)° with the anthraquinone ring system. In the crystal, molecules are linked by short intermolecular O⋯ O contacts, leading to a three-dimensional network structure

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