Gamma irradiation can be performed alone or in combination with other preservatives such as dehydroacetic acid (DHA) and sodium dehydroacetate (DHA-Na) to achieve an enhanced level of food safety. Here, we studied the effect of gamma irradiation on the stability and degradation of DHA and DHA-Na in aqueous solution and pear juice. The degradation rate of DHA and DHA-Na was found to increase with increasing irradiation time and decreasing initial solute concentration in aqueous solution. The degradation rate of DHA-Na was higher than that of DHA under the same irradiation conditions. The degradation process of DHA and DHA-Na followed first-order reaction kinetics. The main radiolytic product of DHA and DHA-Na was identified as heptane-2,4,6-trione by GC-MS/MS, and the possible degradation pathway was proposed. Quantum chemical calculation results further confirmed that DHA-Na was much easier to be degraded than DHA. In addition, radiolytic degradation of DHA-Na happened in pear juice, but with a much lower degradation rate than that in aqueous solution.
In an effort to exploit the natural antifungal pogostone, its simplified scaffold dehydroacetic acid (DHA) was used as a lead compound to semi-synthesize 56 DHA derivatives ( I1 – 48 , II , III , and IV1 – 6 ). Among them, compound IV4 exhibited the most potent antifungal activity with 11.0 μM EC 50 against mycelial growth of Sclerotinia sclerotiorum (Lib.) de Bary whose sclerotia production was also completely suppressed at this concentration. Furthermore, IV4 could completely inhibit infection cushion formation of S. sclerotiorum on rape leaves and achieved a preventive efficacy of 90.2 % at 500 μM, which was on the same level as that of commercial boscalid at 30 μM (88.7 %). The results of physiological and ultrastructural studies indicated that IV4 might disrupt the cell membrane permeability or induce the imbalance of mitochondrial membrane potential homeostasis to exert the antifungal mode of action. Besides, the robust and predicative three-dimensional quantitative structure-activity relationship (3D-QSAR) models were developed and discussed herein.
危险品化学品经营许可证（带存储）