Satoru Mihara

The role of flavor and fragrance chemicals in TRPA1 (transient receptor potential cation channel, member A1) activity associated with allergies

TRPA1 has been proposed to be associated with diverse sensory allergic reactions, including thermal (cold) nociception, hearing and allergic inflammatory conditions. Some naturally occurring compounds are known to activate TRPA1 by forming a Michael addition product with a cysteine residue of TRPA1 through covalent protein modification and, in consequence, to cause allergic reactions. The anti-allergic property of TRPA1 agonists may be due to the activation and subsequent desensitization of TRPA1 expressed in sensory neurons. In this review, naturally occurring TRPA1 antagonists, such as camphor, 1,8-cineole, menthol, borneol, fenchyl alcohol and 2-methylisoborneol, and TRPA1 agonists, including thymol, carvacrol, 1’S-1’- acetoxychavicol acetate, cinnamaldehyde, α-n-hexyl cinnamic aldehyde and thymoquinone as well as isothiocyanates and sulfides are discussed.

Study of configuration and conformation of N-nitroso-2-methylthiazolidine

Abstract The configuration and conformation of N-nitroso-2-methylthiazolidine (1) were assigned from analysis of NMR spectra. The lanthanide-induced shifts (LIS) for 1 could reasonably be explained by assuming coordination of tris(dipivalomethanato)europium(III) [Eu(DPM)3] to the oxygen lone pair of the nitroso group. As a result of the stereospecific association (CT comples) between 1 and benzene, the C4H protons experienced a greater upfield shift than the C2H protons for the Z isomer and vice versa for the E isomer when the solvent was changed from aliphatic to aromatic. Both the coordination of Eu(DPM)3 to the oxygen lone pair of the nitroso group and the formation of the CT complex between 1 and benzene were hindered by the methyl group. The Z/E ratios were increased in polar solvents. The barrier to rotation about the NN bond, which was calculated from the temperature dependence of the NMR spectra of 1, was 20 kcal/mol.

Stirring continuous extraction of aqueous organic compounds with fluororesin as a water/organic solvent separator

This work describes a new stirring continuous-extraction system equipped with a fluororesin in a water/organic solvent separation chamber to make the method effective and simple. Recovery of the pure compounds and the losses associated with this method were quantitatively investigated on experiments with model systems. This method has been applied to the separation of flavors from wine