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Abstract: In present study, a capillary electrophoresis–mass spectrometry (CE–MS) method was developed for the simultaneous analysis of 12 nucleosides and nucleobases including cytosine, adenine, guanine, cytidine, cordycepin, adenosine, hypoxanthine, guanosine, inosine, 2′-deoxyuridine, uridine and thymidine in natural and cultured Cordyceps using 5-chlorocytosine arabinoside as an internal standard (IS). The CE separation conditions and MS parameters were optimized systematically for achieving good CE resolution and MS response of the investigated compounds. The optimum CE electrolyte was 100mM formic acid containing 10% (v/v) methanol. The optimum MS parameters were as follows: 75% (v/v) methanol containing 0.3% formic acid with a flow rate of 3μL/min was selected as the sheath liquid; the flow rate and temperature of drying gas were 6L/min and 350°C, respectively. The optimized CE–MS method was successfully applied for the simultaneous determination of 12 nucleosides and nucleobases in natural and cultured Cordyceps. On the basis of quantitative results, the total content of nucleosides is much higher in cultured Cordyceps (9138±4823μg/g for cultured C. sinensis; 3722±1446μg/g for C. militaris) than in natural ones (2167±412μg/g). However, the hypoxanthine (131±47μg/g) and inosine (335±90μg/g) are much higher in natural C. sinensis. Cordycepin, which is abundant in cultured C. militaris (2276.5±842.6μg/g), is only found in natural C. sinensis with very low content and cannot be detected in the cultured ones. [Copyright &y& Elsevier]

Nanomaterials with enzyme-like activity have been widely used in the construction of colorimetric and fluorescence sensors due to their advantages of cost-effectiveness, high stability, good biocompatibility, and ease of modification. Furthermore, the colorimetric and fluorescence sensors, which are effective approaches for detecting bioactive small-molecule compounds, have been extensively explored due to their simple operation and high sensitivity. Recent significant researches have focused on designing various sensors based on nanozymes with peroxidase- and oxidase-like activity for the colorimetric and fluorescence analysis of different analytes. In this review, recent developments (from 2018 to present) in the colorimetric and fluorescent analysis of bioactive small-molecule compounds based on the enzyme-like activity of nanomaterials were summarized. In addition, the challenges and design strategies in developing colorimetric and fluorescent assays with high performance and specific sensing were discussed. • Colorimetric and fluorescent analysis of bioactive small-molecule compounds are reviewed. • Nanomaterials with POD- and OXD-like activities are commonly used in the detections. • Strategy in developing high performance colorimetric and fluorescent assays are discussed. [ABSTRACT FROM AUTHOR]

• Summarize the applications of magnetic solid-phase extraction in phytochemical analysis. • Introduce different preparation methods for the functionalized magnetic nanoparticles. • Discuss the adsorption mechanism and performance of the material in the extraction Sample preparation such as isolation and pre-concentration is a crucial step for the phytochemical analysis. Magnetic solid-phase extraction (MSPE) has received considerable attention, mainly due to its phase separation more conveniently by facile magnetic decantation as compared to traditional SPE. This review focused on the recent applications of MSPE in sample preparation for the analysis of phytochemical compounds in plants, biological samples and Chinese herbal preparations. In addition, the enzymes immobilized on the magnetic materials and used for the biospecific extraction of enzyme inhibitors were also discussed. The information summarized in this article may provide a reference to the further applications of MSPE in phytochemical analysis. [ABSTRACT FROM AUTHOR]

• The covalently bonded liposome capillary column is prepared by a new three-step method. • The immobilized liposome capillary column (ILCC) has good repeatability and stability. • Retention factors of seventeen drugs are determined using ILCC and compared with other systems. • Partitions of drugs in ILCC are explained by linear free energy relationship analysis with seven solute descriptors. • This study provide reference information for evaluating the membrane permeability of drugs [Display omitted] Two liposomes, including 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) + 1,2-dimyristoyl- sn -glycero-3-phosphoethanolamine (PE) + cholesterol (Chol) (DSPC/PE/Chol liposomes) and soybean lecithin (SPC) + PE + Chol (SPC/PE/Chol liposomes), were prepared and fixed on the inner wall of capillary column by using the adhesion of polydopamine (PDA) membrane and the cross-linking property of glutaraldehyde (GA). The immobilized liposome capillary column (ILCC) has good repeatability and stability based on the electrophoretic mobility of analyte. A CE method based on the immobilized liposome capillary column chromatography (ILCCC) was successfully developed to study the retention behavior of drugs on ILCC, and the logarithm of retention factor (log k) of neutral and ionic drugs were determined. The results show that the log k measured by the ILCCC based on two liposomes have a good linear fitting (R2 = 0.86). Moreover, the linear relationship between ILCCC system and other related research systems (octanol-water system and immobilized artificial membrane (IAM)) was analyzed, and the results indicate that SPC/PE/Chol ILCCC, DSPC/PE/Chol ILCCC and IAM systems have good fitting results, R2 values are 0.86 and 0.78, respectively. In addition, the normalization coefficients of ILCCC and IAM systems obtained by the linear free energy relationship (LFER) analysis are close and the d value is small. In short, the ILCCC is a simple and feasible method for studying drug membrane permeability. [ABSTRACT FROM AUTHOR]

• The tyrosinase (TYR) is simply immobilized by an adsorb hollow fiber. • An enzyme inhibitor screening method is developed based on the immobilized TYR. • Three TYR inhibitors are identified from Pueraria lobata. In this study, a method based on adsorbed hollow fiber immobilized tyrosinase (TYR) was developed to screening potential TYR inhibitors from Pueraria lobate extract. Kojic acid and ranitidine were used as positive and negative control to verify the reliability of the proposed method, respectively. Several significant parameters of the screening process, including the amount of P. lobata extract, adsorption time and incubation time, were optimized. After investigating the repeatability of the developed method, seven potential active compounds in P. lobata extract were successfully detected and their chemical structures were tentatively identified by liquid chromatography – mass spectrometry analysis. Furthermore, the inhibitory activity of four identified compounds on TYR was tested in vitro, and three of them, namely, puerarin, puerarin-6″- O -xyloside and puerarin apioside were verified to have good TYR inhibitory activity with IC 50 value of 478.5, 513.8, and 877.3 μM, respectively. In addition, the molecular docking results indicated that these compounds could bind to the amino acid residues in TYR catalytic pocket. These results proved that the proposed method is a feasible approach for screening of TYR inhibitors from plant extract. [ABSTRACT FROM AUTHOR]