Abstract: A novel trehalase inhibitor having the following physicochemical properties:(1) Activity: a specific inhibitory activity to trehalase;(2) Form: white powder, water-soluble;(3) Somogy-Nelson test: negative(4) Rydon-Smith test: positive(5) Optical rotation [.alpha.].sub.D.sup.23 : 113.8.degree. (C, 0.1, H.sub.2 O)(6) Molecular weight: 335 ([M+H].sup.+ =336)(7) Ultraviolet absorption spectrum: 258.5 nm (max.)(8) .sup.13 C-NMR(ppm): 28.9, 41.0, 56.9, 58.4, 64.3, 65.0, 71.3, 74.0, 75.2, 75.8, 76.0, 77.1, 123.0, 144.

Abstract: This invention relates to a substance Trehalostatin which is a white powder soluble in water but hardly or only slightly soluble in hexane, benzene, ethers and petroleum ether, shows no absorption maxima at 220 nm or above in its ultraviolet visible light absorption spectrum, is positive in Rydon-Smith reaction and negative in ninhydrin reaction, 3,6-dinitrophthalic acid reaction and Elson-Morgan reaction, has an Rf value of 0.37 in Merk Kieselgal 60 G.sub.254 thin layer chromatography using a 3:1:2 mixture of n-butanol, acetic acid and water as a developing solvent, and Rt of 11.0 minutes in YMC PA03 (0.7.times.27 cm) high performance liquid chromatography using 65% v/v acetonitrile (in H.sub.2 O) as a solvent at a flow rate of 1.0 ml/min, has a molecular weight of 366 and a specific rotatory power [.alpha.].sub.D of +115.degree., and presents an NMR spectrum described below:H-NMR/D.sub.2 O 3.3 (ppm), dd, 1H, 3.5 (ppm), m, 1H, 3.5 (ppm), t, 1H, 3.6 (ppm), d, 1H, 3.6 (ppm), d, 1H, 3.7 (ppm), d, 1H, 3.