Novel synergistic cross-linking ameliorate ready-to-eat sea cucumber deterioration and its quantum chemical analysis.

Synergistic cross-linkers could improve the taste acceptability of ready-to-eat sea cucumber (RSC). Besides, the hardness of RSC was increased by 331.00% and 266.87% after synergistic cross-linking. Synergistic cross-linking treatment could ameliorate the non-enzymatic degradation of RSC collagen and polysaccharides. Gaussian calculations results showed that dipeptides containing asparagine residues may have different reaction pathways. The main cleavage pathways of CH3CO-Asn-Gly-NHCH3 (NG) might be water-assisted side chain cyclization, stepwise cyclamide hydrolysis via a Gemdiol Intermediate, deamination, and peptide bond breakage. The relative free energy of cyclamide hydrolysis process of NG was increased by 8.2 kcal/mol after synergistic cross-linking. The mass spectrometry results showed that typical peptides could cleavage at NG, CH3CO-Asn-Lys-NHCH3 (NK) and CH3CO-Asn-Leu-NHCH3 (NL) sites after heating, which justified the breakage pattern of peptides in Gaussian calculations. It can offer a comprehensive theoretical basis for the processing of the ready-to-eat sea cucumber with storage stability.

[Chemical profiling from water extract of Wikstroemia indica by UPLC-Q-TOF-MS/MS].

In this study,a method using ultra performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry( UPLC-Q-TOF-MS/MS) was established to identify complicated chemical constituents of Wikstroemia indica. Chromatographic separation was performed on an AcclaimTMRSLC 120-C18 column( 2. 1 mm×100 mm,2. 2 µm) using gradient elution with 0. 2% ammonium formate buffer salt solution( A)-0. 2% ammonium formate buffer salt solution methanol( B) as mobile phase. The column temperature was maintained at 30 ℃. The analytes were determined by positive and negative ion modes with electro-spray ionization source. A total of 52 compounds( including eleven coumarins,thirteen flavonoids,ten lignans,two amides,four phenolic acids,six sesquiterpenes and six other compounds) were identified or tentatively characterized from the water extract of W. indica by comparing their retention times and MS spectra with those of authentic standards or literature datas. Three compounds were found for the first time from W.indica namely isomer of indicanone,ß-hydroxypropiovanillone and epiprocurcumenol. Furthermore,the fragmentation rules of some compounds were speculated and summarized. In addition,the cleavage pathways of guaiane sesquiterpenes were described for the first time,which can provide reference for studying the fragmentation pathways of similar compounds. This study provides an easy way to identify chemical constituents of traditional Chinese medicine and a basis for the further study on chemical fundamentals of W. indica.

Chemical profiling from water extract of Wikstroemia indica by UPLC-Q-TOF-MS/MS / 中国中药杂志

In this study,a method using ultra performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry( UPLC-Q-TOF-MS/MS) was established to identify complicated chemical constituents of Wikstroemia indica. Chromatographic separation was performed on an AcclaimTMRSLC 120-C18 column( 2. 1 mm×100 mm,2. 2 μm) using gradient elution with 0. 2% ammonium formate buffer salt solution( A)-0. 2% ammonium formate buffer salt solution methanol( B) as mobile phase. The column temperature was maintained at 30 ℃. The analytes were determined by positive and negative ion modes with electro-spray ionization source. A total of 52 compounds( including eleven coumarins,thirteen flavonoids,ten lignans,two amides,four phenolic acids,six sesquiterpenes and six other compounds) were identified or tentatively characterized from the water extract of W. indica by comparing their retention times and MS spectra with those of authentic standards or literature datas. Three compounds were found for the first time from W.indica namely isomer of indicanone,β-hydroxypropiovanillone and epiprocurcumenol. Furthermore,the fragmentation rules of some compounds were speculated and summarized. In addition,the cleavage pathways of guaiane sesquiterpenes were described for the first time,which can provide reference for studying the fragmentation pathways of similar compounds. This study provides an easy way to identify chemical constituents of traditional Chinese medicine and a basis for the further study on chemical fundamentals of W. indica.

Identification on chemical constituents of aqueous extract of Scrophulariae Radix by UPLC-LTQ-Orbitrap HRMS combined with cleavage pathways / 中草药

Objective: To rapidly identify the chemical constituents from the aqueous extract of Scrophulariae Radix by UPLC-LTQ- Orbitrap HRMS combined with cleavage pathways of different chemical constituent cluster. Methods: The analysis was performed on an Acquity UPLC® BEH C18 column (100 mm ×2.1 mm, 1.7 μm). The mobile phase consisted of methanol and 0.1% formic acid aqueous solution was used for gradient elution, with a flow rate of 0.20 mL/min. ESI ion source was applied for mass spectra under positive mode. Results: The cleavage pathways of iridoids and phenylpropanoids were summarized based on mass data of standards. The constituents of the aqueous extract of Scrophulariae Radix were further analyzed by using the mass data and element compositions analysis, and referring with the cleavage pathways, literatures and ClogP value. A total of 61 constituents were identified, including 28 iridoids, 27 phenylpropanoids, and six others. Among them, three acetylangoroside C and methoxylscrophuloside B4 were new compounds, and stegioside III was identified from Scrophulariae Radix for the first time. Conclusion: UPLC-LTQ-Orbitrap HRMS can rapidly and comprehensively characterize the chemical constituents of the aqueous extract of Scrophulariae Radix, which provides a reference for the clarification of efficacy material basis and quality control of Scrophulariae Radix.