Alkylglycerols (1-O-alkyl-sn-glycerols) are microscale but critical lipids in foods. Conventional lipidomics analysis often loses sight of alkylglycerol analysis. In this study, we developed a high coverage pseudotargeted lipidomics method for analyzing alkylglycerols. The developed method integrated the advantages of GC-MS and LC-MS to profile alkylglycerol-type ether lipids comprehensively, with the help of a data processing Dart package termed FFIMA (Feature Fragments Information Matching Algorithm). The developed method exhibited competitive superiority to conventional lipidomics, such as wider coverage and higher accuracy. The validated method was assessed by three aquatic products and three milks. A total of 25 alkylglycerols, 107 diacylglycerol ethers, 21 monoacylglycerol ethers, 28 alkylglycerol-type ether phospholipids, and 35 plasmalogens were identified in the six foods. The results demonstrated that this method offers a comprehensive analysis of a wide spectrum of alkylglycerols.

BACKGROUND: Menispermi Rhizoma (MR), the dried rhizome of Menispermum dauricum DC. (Menispermaceae), has been used to treat sore throat, enteritis, dysentery, and rheumatic arthralgia. Despite extensive research on its pharmacological effects, the chemical components in vitro and in vivo have not been thoroughly studied.
OBJECTIVE: To establish an efficient method for rapid classification and identification of alkaloids in MR and its preparations, as well as metabolites in vivo after oral administration of MR.
METHODS: Rapid identification of alkaloids and absorbed components of MR was performed using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) coupled with UNIFI software. Moreover, the characteristic fragmentations and neutral losses of different types of alkaloids in MR were summarised to realise the rapid classification of alkaloids.
RESULTS: A total of 55 components were unambiguously or tentatively identified in MR. Among them, 37 and 31 components were found in MR capsules and tablets, respectively. Meanwhile, 109 compounds were tentatively identified in rat plasma, urine and faeces, including 55 prototypes and 54 metabolites. Hydrogenation, hydroxylation, methylation, glucuronic acid and sulphate conjugations were the dominating metabolic fates of alkaloids.
CONCLUSIONS: The data post-processing strategy established could greatly enhance the structural identification efficiency. The results obtained might lay the foundation for further interpretation of clinical effects, mechanism of action and quality control of MR.

This study aims to identify the chemical constituents of Simiao Yong\'an Decoction based on ultra-performance liquid chromatography coupled with linear quadrupole ion trap-orbitrap mass spectrometry(UPLC-LTQ-Orbitrap-MS). The elution was performed through a UPLC BEH C_(18) column(2.1 mm × 100 mm, 1.7 μm) with the mobile phase of water(containing 0.1% formic acid)-acetonitrile at a flow rate of 0.4 mL·min~(-1). LTQ-Orbitrap-MS with heat electrospray ion(HESI) source was employed to collect MS fragment information in the negative ion mode. A total of 72 compounds were identified based on reference substance comparison, fragmentation rules, accurate molecular weight, related reports and databases(MassBank and HMDB), including 30 iridoid glycosides, 9 organic acids, 15 flavonoids, 10 phenylpropanoids, 7 triterpenoids, and 1 saccharide. The method established in this study is comprehensive, rapid, and accurate, which can help summarize the fragmentation rules of constituents and provide reference for revealing the active constituents and pharmacodynamic mechanism of Simiao Yong\'an Decoction.

Lycium barbarum fruit (Goji berry) have been used as a traditional Chinese medicine (TCM) with its outstanding biological and pharmacological activities. Spermidine alkaloids are a major class of bioactive constituents in goji berry, nevertheless, detailed information related to its identification remains scarce. In this study, chemical profiling of spermidines in goji berry was carried out by ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Four structure types of standards were used to study the comprehensive fragmentation rules of spermidines. Different types of spermidines were identified by distinctive MS/MS fragment ions. Noticeably, it was first proposed that the co-existence of fragment ions at m/z 220 and 222 was the key characteristic for distinguishing spermidine isomers. According to the structural feature of spermidines, a quick, convenient, highly selective strong cation exchange solid-phase extraction (SCX-SPE) combined with RP-LC procedure was developed for selective enrichment and the MS detection compatibility. A total of 41 out of 58 spermidines were tentatively characterized using the established method, of which 26 were reported for the first time from goji berry. This study provides guidelines and references for the identification of spermidines in natural products.

This experiment was performed to analyze and identify the chemical constituents of Lycii Cortex by UPLC-LTQ-OrbitrapMS. The analysis was performed on a Waters Xbridge Shield RP18( 4. 6 mm×250 mm,5 μm) column with the mobile phase of 0. 1%formic acid( A)-acetonitrile( B) under gradient conditions at a flow rate of 1. 0 m L·min-1 and the temperature maintained at 35 ℃ ．Electrospray ionization ion trap time-off light multistage mass spectrometry was applied for qualitative analysis under positive and negative ion modes. The results indicated that 55 compounds consisted of 39 phenolic amides,6 organic acids,3 cyclic peptides,2 coumarins and 5 others. In conclusion,an UPLC-LTQ-Orbitrap-MS method was established to qualitative analysis of Lycii Cortex in this study,and the fragmentation rules of phenolic amides were summarized,which provides a good foundation for further study of Lycii Cortex.

In this study, a combination of quadrupole time-of-flight mass spectrometry (Q-TOF-MS) and linear trap quadrupole orbitrap mass spectrometry (LTQ-Orbitrap-MS) was performed to investigate the fragmentation behaviors of prenylated flavonoids (PFs) from Artocarpus plants. Fifteen PFs were selected as the model molecules and divided into five types (groups A-E) according to their structural characteristics in terms of the position and existing form of prenyl substitution in the flavone skeleton. The LTQ-Orbitrap-MSn spectra of the [M - H]- ions for these compounds provided a wealth of structural information on the five different types of compounds. The main fragmentation pathways of group A were the ortho effect and retro Diels-Alder (RDA), and common losses of C4H10, CO, and CO2. The compounds in group B easily lose C6H12, forming a stable structure of a 1,4-dienyl group, unlike those in group A. The fragmentation pathway for group C is characterized by obvious 1,4A-, 1,4B- cracking of the C ring. The diagnostic fragmentation for group D is obvious RDA cracking of the C ring and the successive loss of CH3 and H2O in the LTQ-Orbitrap-MSn spectra. Fragmentation with successive loss of CO or CO2, ·CH3, and CH4 in the LTQ-Orbitrap-MSn spectra formed the characteristics of group E. The summarized fragmentation rules were successfully exploited to identify PFs from Artocarpus heterophyllus, a well-known Artocarpus plant, which led to the identification of a total of 47 PFs in this plant.

Oligostilbenes have attracted much interest due to their intricate structures and diverse bioactivities. In this study, two stilbene dimers, (-)-7,8-cis-ε-viniferin (1) and carasiphenol A (2), and two trimers, suffruticosol A (3) and suffruticosol C (4), were investigated by electrospray ionization ion-trap time-of-flight multistage mass spectrometry (ESI-IT-TOF-MSn). Based on the MSn study, the fragmentation pathways and diagnostic ions of four oligostilbenes in both positive and negative modes were proposed. The consecutive elimination of phenol (C6H6O) and resorcinol (C6H6O2) moieties were the particular dissociation for oligostilbenes due to the presence of 1,2-diphenylethylene nucleus. The present MSn fragmentation study will provide valuable information for the fast characterization of oligostilbenes from complicated natural mixtures.

Swerilactones H-K (1-4) as four unprecedented secoiridoid trimers represent a new type of natural product, which has attracted much interest of natural chemists due to their novel skeletons and promising bioactivity. In order to well understand their MS fragmentation behaviors, they were investigated by electrospray ionization ion-trap time-of-flight multistage product ion mass spectrometry (ESI-IT-TOF-MS n ) for the first time. The protonated molecules ([M+H]+) of swerilactones J and K, and deprotonated molecules ([M-H]-) of swerilactones H, J and K were readily observed in the conventional single-stage mass spectra (MS); however only the [M+Cl]- ion for swerilactone I was obtained in negative mode. Based on the MS n study, the fragmentation pathways of swerilactones H and I in negative mode, and swerilactones J and K in both positive and negative modes were proposed. The neutral losses of H2O, CO, CO2 and C2H4O moieties are the particular elimination from the precursor ions due to the presence of hydroxyl, δ-lactone and 1-O-ethyl moieties in their structures, of which the retro-Diels-Alder cleavage was the most particular dissociation. The fragment ions at m/z 341 and 291 in negative mode can be considered as the diagnostic ions for secoiridoid trimers. This investigation will provide valuable information for their fast characterization from complicated natural mixtures and extensive understanding their structural architectures.

More than 80 aristolochic acids (AAs) and aristololactams (ALs) have been found in plants of the Aristolochiaceae family, but relatively few have been fully studied. The present study aimed at developing and validating a liquid chromatography tandem mass spectrometry (LC/MS(n)) for the analysis of these compounds. We characterized the fragmentation behaviors of 31 AAs, ALs, and their analogues via high performance liquid chromatography coupled with electrospray ionization mass spectrometry. We summarized their fragmentation rules and used these rules to identify the constituents contained in Aristolochia contorta, Ar. debilis, Ar. manshurensis, Ar. fangchi, Ar. cinnabarina, and Ar. mollissima. The AAs and ALs showed very different MS behaviors. In MS(1) of AAs, the characteristic pseudomolecular ions were [M + NH4](+), [M + H](+), and [M + H - H2O](+). However, only [M + H](+) was found in the MS(1) of ALs, which was simpler than that of AAs. Distinct MS(n)fragmentation patterns were found for AAs and ALs, showing the same skeleton among the different substituent groups. The distribution of the 31 constituents in the 6 species of Aristolochia genus was reported for the first time. 25 Analogues of AAs and ALs were detected in this genus. A hierarchical schemes and a calculating formula of the molecular formula of these nitrophenanthrene carboxylic acids and their lactams were proposed. In conclusion, this method could be applied to identification of similar unknown constituents in other plants.

High-resolution electrospray ionization ion-trap time-of-flight tandem mass spectrometry (HR-ESI-IT-TOF-MS(n)) in positive-ion mode was used to determine the accurate masses and fragmentation pathways of four C(19)-diterpenoid alkaloids, aconitine (1), yunnaconitine (2), crassicauline A (3), and benzoylmesaconine (4). The [M+H](+) ions of compounds 1-4 were readily observed in conventional single-stage mass spectrometry. Based on the MS(1-6) analyses, detailed fragmentation rules of the four compounds were proposed. The neutral losses of AcOH, MeOH, H(2)O, CO, C(2)H(4), PhCOOH and p-OMePhCOOH segments were the characteristic eliminations from the precursor ions due to the presence of acetyl, methoxyl, hydroxyl, N-ethyl, benzoyl and p-methoxyl-benzoyl units in the structures. Benefited from the high resolution of the mass analyzer, the loss of 28 Da corresponding to CO or CH(4) segment in product ions was unambiguously distinguished. The losing sequence of the main substituent groups was summarized as: C(8)-acetyl>C(16)-methotyl>C(15)-hydroxyl>C(6)-methoxyl>C(1)-methoxyl/C(3)-hydroxyl>C(18)-methoxyl>>C(13)-hydroxyl. The sequential loss of (16)-methoxyl moiety and CO (generating from enol-ketone tautomerism) groups could be recognized as the characteristic eliminations for the compounds with C(16)-methoxyl and C(15)-hydroxyl groups simultaneously. The application of HR-ESI-IT-TOF-MS(n) technique to investigate the fragmentation of C(19)-diterpenoid alkaloids provided useful information to understand their fragmentation behaviors.