Rapid Identification of unstable acyl glucoside flavonoids of Oxytropis racemosa Turcz by high-performance liquid chromatography-diode array detection-electrospray ionisation/multi-stage mass spectrometry

Online identification of potential antioxidant components and evaluation of DNA oxidative damage protection ability in Prunus persica flowers

A high performance liquid chromatography-ultraviolet-visible detector-electrospray ionization-ion trap-time-of-flight-mass spectrometry-total antioxidant capacity determination (HPLC-UVD-ESI-IT-TOF-MS-TACD) new online technique was developed for efficient screening of potential antioxidant active components in Prunus persica flowers (PPF) from 4 origins. Through this online system, 46 compounds were initially identified, while 20 compounds with DPPH binding activity and 21 compounds with FRAP binding activity were detected. The antioxidant activities of 9 compounds obtained from the screening were then validated in DNA oxidative damage protection study. The results showed that this online system can cope well with the complexity of the samples. This also provides technical basis for rapid screening of antioxidant resources of PPF. In short, this study made the chemical composition of PPF more abundant and its potential antioxidant active compounds more explicit, which provided new ideas for the detection and development of natural antioxidants and provided scientific basis for PPF as functional food.

Discriminative Metabolomics Analysis and Cytotoxic Evaluation of Flowers, Leaves, and Roots Extracts of Matthiola longipetala subsp. livida

Matthiola longipetala subsp. livida is an annual herb in Brassicaceae that has received little attention despite the family's high reputation for health benefits, particularly cancer prevention. In this study, UPLC-HRMS-MS analysis was used for mapping the chemical constituents of different plant parts (i.e., flowers, leaves, and roots). Also, spectral similarity networks via the Global Natural Products Social Molecular Networking (GNPS) were employed to visualize their chemical differences and similarities. Additionally, the cytotoxic activity on HCT-116, HeLa, and HepG2 cell lines was evaluated. Throughout the current analysis, 154 compounds were annotated, with the prevalence of phenolic acids, glucosinolates, flavonol glucosides, lipids, peptides, and others. Predictably, secondary metabolites (phenolic acids, flavonoids, and glucosinolates) were predominant in flowers and leaves, while the roots were characterized by primary metabolites (peptides and fatty acids). Four diacetyl derivatives tentatively assigned as O-acetyl O-malonyl glucoside of quercetin (103), kaempferol (108 and 112), and isorhamnetin (114) were detected for the first time in nature. The flowers and leaves extracts showed significant inhibition of HeLa cell line propagation with LC50 values of 18.1 ± 0.42 and 29.6 ± 0.35 µg/mL, respectively, whereas the flowers extract inhibited HCT-116 with LC50 24.8 ± 0.45 µg/mL, compared to those of Doxorubicin (26.1 ± 0.27 and 37.6 ± 0.21 µg/mL), respectively. In conclusion, the flowers of M. longipetala are responsible for the abundance of bioactive compounds with cytotoxic properties.

Phenolamide and flavonoid glycoside profiles of 20 types of monofloral bee pollen

This study aimed at investigating phenolamides and flavonoid glycosides in 20 types of monofloral bee pollen. The plant origins of pollen samples were determined by DNA barcoding, with the purities to over 70 %. The 31 phenolamides and their 33 cis/trans isomers, and 25 flavonoid glycosides were identified; moreover, 19 phenolamides and 14 flavonoid glycosides as new-found compounds in bee pollen. All phenolics and flavonoids are present in the amidation or glycosylation form. The MS/MS cleavage modes of phenolamides and flavonoid glycosides were summarized. Isorhamnetin-3-O-gentiobioside presented the highest levels 23.61 mg/g in apricot pollen. Phenolamides in 11 types of pollen constituted over 1 % of the total weight, especially 3.9 % in rose and 2.8 % in pear pollen. Tri-p-coumaroyl spermidine and di-p-coumaroyl-caffeoyl spermidine respectively accounted for over 2.6 % of the total weight in pear and rose pollen. The richness in phenolamides and flavonoid glycosides can offer bee pollen more bioactivities as functional foods.

Screening of metabolic markers present in Oxytropis by UHPLC-Q-TOF/MS and preliminary pharmacophylogenetic investigation

Plants belonging to the Oxytropis genus, family Leguminosae, are found throughout the world, with about 80 species mainly distributed in northwest and northeast China. The plants have medicinal properties and many plants have been used as folk medicine for the treatment of colds, inflammation of carbuncle swelling, pain, and different types of bleeding. In recent years, due to the reduced availability of wild resources and increased clinical demand, additional Oxytropis species have been used in Mongolian medicine. This study explored the medicinal potential of four Oxytropis species, investigating their phylogeny, chemical components, and pharmacological activities. Oxytropis myriophylla (Pall) DC., Oxytropis hirta Bunge, and Oxytropis bicolor Bge. were found to be closely related at the taxonomic level. While previous investigations on the bioactive constituents of Oxytropis have been limited and have concentrated largely on flavonoids and saponins, the present study established a novel UHPLC-Q-TOF/MS based on metabolite profiling to comprehensively analyze the chemical composition of the four Oxytropis species and to identify marker compounds. A total of 75 compounds were identified from the four species, with 23 identified as characteristic marker components. Twenty-six marker compounds were identified in O. myriophylla from different geographical regions. Analysis of pharmacological activity showed that extracts of O. myriophylla and O. hirta had stronger anti-inflammatory activity than the extracts from the other species. The relationships between the chemical components, traditional curative uses, and pharmacological activities were analyzed to provide a preliminary documentation of the pharmacophylogenetic characteristics of the Oxytropis family as a whole. Several marker compounds, including licoricesaponin G2, licoricesaponin J2, and glycyrrhizic acid found in O. hirta were found to have effective anti-inflammatory activity, consistent with the traditional application of reducing swelling and healing wounds. This preliminary investigation into the pharmacophylogeny of the genus Oxytropis will contribute to the conservation and exploitation of the medicinal resources of this genus.

Determination of phenolic profiles of Herniaria polygama and Herniaria incana fractions and their in vitro antioxidant and anti-inflammatory effects

The study is based on phytochemical profiling and in vitro evaluation of biological effects of phenolic acid derivatives-rich Herniaria fractions, isolated from two rupturewort (Herniaria L.) species, i.e. Herniaria incana Lam. (syn. H. besseri Fisch. ex Hornem) and H. polygama J. Gay (syn. H. odorata). For the first time, the composition of phenolic compounds of these species was extensively evaluated by both LC-HR-QTOF-ESI-MS and Nuclear Magnetic Resonance spectroscopy (NMR). LC-MS analyses of H. polygama revealed 72 tentatively identified compounds, while H. incana - 63. Only 8% of the metabolites reported in this work have been previously described for Herniaria spp. Most of the identified specialized metabolites were cinnamic and benzoic acid derivatives. Phenolic fraction of H. incana herb contained flavonoids as well. A multi-step chromatographic separation of phenolic fractions from H. polygama yielded three known cinnamic and one benzoic acid derivates, and from H. incana - 4 known flavonoids and one previously undescribed, i.e. rhamnocitrin-3-O-[3-hydroxy-3-methylglutaryl-(1 → 6'')]-[α-rhamnopyranosyl-(1 → 2'')]-β-glucopyranoside. Antioxidant properties of the examined fractions (1-50 μg/ml) were assessed in human blood plasma under the conditions of peroxynitrite-induced oxidative stress. Measurements of well-known biomarkers such as 3-nitrotyrosine, protein thiol groups, thiobarbituric acid-reactive substances and the ferric reducing ability of blood plasma revealed the protective effect of Herniaria fractions against oxidative damage to blood plasma components. Furthermore, the examined fractions effectively ameliorated the inflammatory response of the concanavalin A-stimulated human peripheral blood mononuclear cells (PBMCs). Additionally, cellular safety of the fractions was confirmed in PBMCs.

Chemical profiling and antidiabetic potency of Paeonia delavayi: Comparison between different parts and constituents

Paeonia delavayi (Paeoniaceae), an endemic plant mainly distributed in southwest China, is always used as the substitute of P. suffruticosa due to their morphological and pharmacological similarity. In the previous study, P. suffruticosa was revealed with antidiabetic potency, whereas the chemical difference and antidiabetic property between different parts of P. delavayi has not yet been studied. This paper was designed to clarify the chemical constituents and antidiabetic potency of P. delavayi by LCMS analysis and enzyme inhibition on α-glucosidase, PTP1B, TCPTP, and DPP4. By interpretation of their UV absorptions and MS fragmentations, and/or comparison with reference samples, 57 constituents comprising 15 flavonoids, 10 monoterpene glycosides, eight triterpenoids, seven galloyl glucoses, six N-containing compounds, five gallic acids, two acetophenones, and four other types of compounds were identified from the different parts of P. delavayi. Moreover, two new monoterpene aglycones (42 and 47) and one new noroleanane triterpenoid (51) were speculated by their MS/MS fragmentation rules. Principal component analysis (PCA) suggested the chemical resemblance between root core and root bark which could be well differentiated with the leaves and stems by their characteristic constituents (monoterpene glycosides, flavonoids, and acetophenones). All the four parts (200 μg/mL) showed obvious inhibition on α-glucosidase and PTP1B (81.2%-98.5%), but moderate to weak inhibition on TCPTP and DPP4 (19.5%-34.9%). Nine compounds representing five main types of constituents in Paeonia plants were assayed for their antidiabetic effects, indicating flavonoids and triterpenoids were the main active substances regarding to the four enzymes. Luteolin displayed obvious activity on α-glucosidase, PTP1B, and TCPTP with IC₅₀ values of 94.6, 136.3, and 157.3 μM, and akebonic acid could inhibit α-glucosidase and PTP1B with IC₅₀ values of 73.5 and 57.8 μM. Luteolin and akebonic acid were recognized as competitive inhibitors of α-glucosidase, but anticompetitive and mix-type inhibitors of PTP1B, respectively. Docking study demonstrated akebonic acid as PTP1B (over TCPTP) selective inhibitor by bonding to the catalytic sites (B/C) of PTP1B. This LCMS combined with enzymatic comparison opens new sights for recognizing the chemical profiles and antidiabetic potency of P. delavayi.

Comprehensive Phytochemical Characterization of Herbal Parts from Kidney Vetch (Anthyllis vulneraria L.) by LC/MSn and GC/MS

Extracts of kidney vetch (Anthyllis vulneraria L.) are becoming increasingly interesting as ingredients for the health and cosmetics industry. However, comprehensive phytochemical investigations of this plant are scant in the literature. Thus, the aim of the present work was an in-depth characterization of semi-polar constituents from A. vulneraria. To capture a broad spectrum of compounds, the aerial parts of A. vulneraria were extracted with EtOH/water and the resulting crude extracts fractionated by partition between AcOEt and BuOH. Secondary plant metabolites were analyzed by HPLC-ESI-MSⁿ and GC/MS. In a fraction obtained from the BuOH extract via Amberlite® XAD-7 purification glycosides of kaempferol, quercetin, isorhamnetin and rhamnocitrin were detected by LC/MSⁿ , besides flavonoids acylated with meglutol (3-hydroxy-3-methylglutaric acid), acetic and ferulic acids. Moreover, aglycons were analyzed in extracts after 1 N HCl hydrolysis and derivatization with BSTFA. GC/MS analysis of the hydrolysates revealed the incidence of compounds like meglutol, OH/OMe-substituted benzoic acids, ferulic and fatty acids, flavonoids, sugars and the triterpenoid medicagenic acid. Furthermore, a hemolytic activity was detected in the AcOEt extract using a blood-agar assay, and this was ascribed to the occurrence of saponins. In a saponin fraction, obtained from the AcOEt extract by chromatographic purification, two main saponins were characterized by LC/MSⁿ and HR-ESI-MSⁿ . A pure sapogenin could be isolated via VLC and CC purification upon acid hydrolysis of the saponins and assigned to saikogenin D by NMR analysis.

Chemical profiling and total quality assessment of Isodon japonica using data-independent acquisition mode combined with superimposed multiple product ion UHPLC-Q-TOF-MS and chemometric analysis

In this paper, an analytical strategy combined data acquisition with a practical mining strategy aimed at rapid characterization and quantitation of ent-kaurane diterpenoids in Isodon japonica using ultra high-performance liquid chromatography-triple time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS). First, an effective self-built filter template based on drug phase I/II metabolic reaction theory and a components library data set were established. Second, the mass spectra of ent-kaurane diterpenoid standards were studied and their mass spectrum cleavage pathways were summarized. Next, the methanol extract of this herb was studied by data-independent acquisition mode (DIA). With the aid of a self-built filter template, the peaks of ent-kaurane diterpenoids were easily picked out and rapidly classified as ent-kaurane diterpenoids from a complex matrix. A total of 24 ent-kaurane diterpenoids were structurally identified. Meanwhile, the self-built filter template provided a convenient and fast method for the structural characterization and Isodon japonica was used to illustrate this approach for the first time. Furthermore, eight major bioactive diterpenoids were simultaneously quantified by a newly developed superimposed multiple product ion (SMPI) with UPLC-Q-TOF-MS/MS method. Principal component analysis (PCA) revealed significant differences in different batches of samples. These combined qualitative and quantitative methods were used to provide a potential approach for the holistic quality evaluation of traditional Chinese medicine (TCM) and its preparations.

Chemiluminescence of off-line and on-line gold nanoparticle-catalyzed luminol system in the presence of flavonoid

It was found that flavonoids could remarkably inhibit the chemiluminescence (CL) intensity of an off-line gold nanoparticle (AuNP)-catalyzed luminol-H₂ O₂ CL system. By contrast, flavonoids enhanced the CL intensity of an on-line AuNP-catalyzed luminol-H₂ O₂ CL system. In the off-line system, the AuNPs were prepared beforehand, whereas in the on-line system, AuNPs were produced by on-line mixing of luminol prepared in a buffer solution of NaHCO₃  - Na₂ CO₃ and HAuCl₄ with no need for the preliminary preparation of AuNPs. The on-line system had prominent advantages over the off-line system, namely a lowering of the background noise and improvements in the stability of the CL system. The results show that differences in the signal suppression effect of flavonoids on the off-line AuNP-catalyzed CL system are influenced by the combined action of a free radical scavenging effect and occupy-sites function; the latter was proved to be predominant using controlled experiments. Enhancement of the on-line system was ascribed to the presence of flavonoids promoting the on-line formation of AuNPs, which better catalyzed the luminol-H₂ O₂ CL reaction, and the enhancement activity of the six flavonoids increased with the increase in reducibility. This work broadens the scope of practical applications of an AuNP-catalyzed CL system.

Neutral Loss Ion Mapping Experiment Combined with Precursor Mass List and Dynamic Exclusion for Screening Unstable Malonyl Glucoside Conjugates

Malonates are one type of the acylation conjugates and found abundantly in ginseng and soybean. Malonyl conjugates of ginsenosides and isoflavone glycosides were often considered as the characteristic components to evaluate various species and different forms of ginseng and soybean products because of their thermal instability. Another famous isoflavonoid-rich leguminous traditional Chinese medicine (TCM), named Puerarin lobata (Gegen), has also been reported to contain malonyl daidzin and malonyl genistin. However, the conjugates were found to present in very low amount and particularly unstable in the negative ion mode scan using LTQ Orbitrap mass spectrometry with electrospray ionization (ESI). In order to screen and characterize the malonyl conjugates in Gegen, a specific method was designed and developed combining neutral loss ion mapping (NLIM) experiment and precursor mass list (PL) triggered data dependent acquisition (DDA). Along with the activation of dynamic exclusion (DE), the method was proven to be specific and efficient for searching the malonate derivatives from Gegen. Two samples were examined by the established method. A total of 66 compounds were found, and 43 of them were malonates of isoflavone glycoside. Very few compounds were reported previously in Gegen. The results are helpful to understand the constituents of Gegen with more insight. The study not only provided a method for analyzing the malonyl conjugates from complex matrices but also explored a way to trace other low amount components in TCMs.

Comparative study of lanostane-type triterpene acids in different parts of Poria cocos (Schw.) Wolf by UHPLC-Fourier transform MS and UHPLC-triple quadruple MS

Poria cocos (Schw.) Wolf is widely used as a traditional Chinese medicine, and approximately 10% of traditional Chinese medicinal preparations contain this material, according to the Chinese Pharmacopoeia (2010 edition). Although the epidermis (fulingpi in Chinese, or FLP) and the inner parts (baifuling in Chinese, or BFL) of P. cocos had different therapeutic applications in history, studies pertaining to a comparative analysis of their chemical constituents have been scarce. UHPLC-DAD-FT/MS(n) has been used in the current study to identify the triterpene acids present in fungus based on a detailed analysis of the fragmentation behavior of 13 standard compounds. This analysis allowed for the identification of 27 triterpene acids, including five groups of isomers and four potential new compounds. Furthermore, a UHPLC-MS/MS method has been developed for quantifying the amounts of nine bioactive triterpene acids in samples of the FLP and BFL, including three 3,4-seco-lanostane-type triterpene acids. These results revealed significant differences in the amounts of these compounds in the FLP and BFL samples. Principal component analysis and partial least squares discriminant analysis of the results for the FLP and BFL samples clearly demonstrated that dehydrotumulosic acid, trametenolic acid, dehydrotrametenolic acid and poricoic acid A were the main compounds contributing to the clusters in FLP and BFL. The observed differences in the chemical compositions of FLP and BFL could provide some explanation of the differences in their clinic applications. This study represents the first reported comprehensive analysis of lanostane-type triterpene acids in FLP and BFL parts of P. cocos.

Identification of multiple constituents from seed of Vaccaria segetalis with an adsorbent-separation strategy based on liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

RATIONALE

Seeds of Vaccaria segetalis (Wang-Bu-Liu-Xing in Chinese) are mainly used in traditional Chinese medicine for the treatment of amenorrhea, breast infections, and edema. The study was designed to identify the components and metabolites of Wang-Bu-Liu-Xing.

METHODS

A novel methodology combining an adsorbent-separation strategy with analysis by liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (LC/QTOF-MS/MS) was established to identify the components of Wang-Bu-Liu-Xing. The adsorbent-separation technique was applied on macroporous resin (adsorbents). Different concentrations of ethanol (30%, 60%, and 95%), which covered high-to-low polarity ranges, were chosen as the elution solvent, respectively. The QTOF mass spectrometer was operated in negative ion mode with an electrospray ionization source.

RESULTS

A total of 52 components were successfully identified in the Wang-Bu-Liu-Xing decoction based on the fragmentation pathways and QTOF high-accuracy mass spectral analysis. To the best of our knowledge, several new saponins were reported for the first time. A total of 20 compounds, which included 10 prototypes and 10 metabolites, were also identified in rat plasma and urine after oral administration of Wang-Bu-Liu-Xing decoction.

CONCLUSIONS

An integrated adsorbent-separation strategy is powerful and reliable for global detection and identification of complex components in herbal prescriptions. The components identified in rat biofluids may also provide helpful chemical information for further pharmacology and active mechanism study on this herb.