Xiujun Cao,Qiyue Xie,Song Zhang,Hanlin Xu,Jie Su,Jiabin Zhang,Chunhui Deng,Guoxing Song
Monodispersed magnetic microspheres were synthesized by the magnetization of the aminized polystyrene cores and the subsequent polymerization of allyl glycidyl ether, divinylbenzene and N-vinyl-2-pyrrolidone, which exhibited excellent monodispersity in aqueous solution and high efficiency for allyl-benzodioxoles extraction. Various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM) were employed to characterize the composites. Coupled with gas chromatography-mass spectrometry (GC–MS), a sensitive and simple magnetic solid phase extraction (MSPE) procedure based on the prepared microspheres was established for determination of allyl-benzodioxoles in cola-flavoured drinks. The factors affecting the extraction procedure, such as pH value, adsorbent amount, adsorption time, desorption solution and desorption time were optimized. The developed method was characterized by a high recovery (spiked at 5 μg L −1 , 25 μg L −1 and 250 μg L −1 ), a low detection limit (0.05 μg L −1 for safrole and 0.08 μg L −1 for myristicin), a good linearity (correlation coefficients higher than 0.9990 for both) and a satisfactory repeatability (relative standard deviation below 3.7% for both, n = 3). The approach proposed here was confirmed to be fast and reliable for quantitative analysis of allyl-benzodioxoles in cola samples, especially at a trace level.
Guoyu Wei,Wei Zhao,Huayang Xu,Guangming Wang,Hualei Wang,Anlong Hu
Polygonatum cyrtonema (giant Chinese Solomon's seal) is a perennial herb belonging to the family Liliaceae, with significant medicinal and dietary value. However, a severe rhizome rot has led to a decline in the yield and quality of this species. In this study, a fungus was isolated from symptomatic rhizome samples and identified as Fusarium commune through molecular and morphological analyses. In pathogenicity tests, the identification of F. commune as the causative agent of rhizome rot was confirmed by fulfilling Koch's postulates. Biological characteristics indicated that the optimal growth conditions for F. commune were a temperature of 25°C, pH of 8, carbon source of soluble starch, nitrogen source of peptone and a photoperiod of 24 h light. In order to reduce the use of chemical fungicides and explore natural substances to control the disease, the sensitivity of F. commune to seven phytochemicals was studied. Four phytochemicals (honokiol, 2-allylphenol, magnolol and carvacrol) showed inhibitory activity, with honokiol having a 50% of the maximal effect concentration (EC 50 ) of 9.99 ± 0.14 mg/L. The results of pot experiment showed that the four phytochemicals had significant control efficacy on the rhizome rot of P. cyrtonema , and the highest control efficacy was observed with honokiol. These findings provide a scientific basis for the control of rhizome rot in P. cyrtonema .
Asymmetric epoxidation is a green route to enantiopure epoxides, but often suffers from low enantioselectivity toward unconjugated terminal alkenes. Mining of the NCBI non-redundant protein sequences with a reconstructed ancestral sequence based on six styrene monooxygenases identified a monooxygenase (HhMo) from Herbaspirillum huttiense with 29.6–32.3% sequence identity with styrene monooxygenases, which was previously annotated as an alanine phosphoribitol ligase. HhMo catalyzed the epoxidation of allylbenzenes with moderate to excellent enantioselectivity yielding the corresponding epoxides in up to 99% ee. The HhMo-catalyzed epoxidation could also achieve the kinetic resolution of racemic secondary allylic alcohols, yielding the corresponding epoxides with up to 50% yields, as well as excellent enantio- and diastereoselectivity (up to >99% ee and >99% de) within 20–60 min, making a greener strategy for the production of valuable enantiopure glycidol derivatives in the fine chemical and pharmaceutical industries.
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