Metabolism profiling of nevadensin in vitro and in vivo by UHPLC-Q-TOF-MS/MS

Comparative prototypes and metabolites of Du-zhi pill in normal and cerebral ischemia rats by UHPLC-Q-TOF-MS/MS method

Du-Zhi pill (DZP) is widely used as a Chinese medicine in treating cerebral ischemia. UHPLC-Q-TOF-MS/MS techniques were used to detect and identify the metabolites in rat brain samples of normal and middle cerebral artery occlusion (MCAO) model rats administered with DZP. It was tentatively found that 43 prototypes and 93 metabolites could be identified in rat brain samples. Normal and MCAO model rat brain samples contained 19 prototype components. Eight prototype components were only detected in normal rat brain samples, while 16 were found only in MCAO model rat brain samples. It was determined that 47 metabolites had been identified in the normal rats, while 86 had been placed in MCAO model rats. There were 40 common metabolites in both normal and MCAO model rat brain samples. Seven metabolites were only detected in normal rat brain samples, while 46 were found only in MCAO rat brain samples. The comparison of metabolites in brain samples of normal and MCAO rats showed apparent differences. It was discovered that glucuronidation, methylation, acetylation, and sulfation are phase II metabolic routes of DZP, while hydrogenation, hydroxylation, and dehydroxylation are phase I metabolic routes. Moreover, hydrogenation, glucuronidation, hydroxylation, and methylation were the main metabolic pathways because of the number of metabolites identified in these metabolic pathways. The results provide a valuable reference for further research into effective substances of DZP for treating cerebral ischemia.

Metabolite Profiling of Tartary Buckwheat Extracts in Rats Following Co-Administration of Ethanol Using UFLC-Q-Orbitrap High-Resolution Mass Spectrometry

Tartary buckwheat, a gluten-free pseudocereal, has received considerable attention owing to its unique nutritional ingredients and beneficial health effects such as anti-tumor, anti-oxidation, anti-inflammation and hepatoprotective activities. Pharmacokinetic and metabolite profiling have been preliminarily assessed for Tartary buckwheat extracts. However, its metabolites have not yet been characterized in vivo after co-administration with ethanol when Tartary buckwheat extracts are used for the treatment of alcoholic liver disease. In this paper, a Q-Exactive orbitrap high-resolution mass spectrometer was employed to identify the metabolites of Tartary buckwheat extracts in rat biological samples. Compared with previous metabolite profiling results, a total of 26 novel metabolites were found in rat biological samples, including 11, 10, 2 and 5 novel metabolites in rat plasma, bile, urine and feces, respectively, after oral co-administration of 240 mg/kg Tartary buckwheat extracts with ethanol (42%, v/v). The major metabolic pathways of the constituents in Tartary buckwheat extracts involved hydroxylation, methylation, glucuronidation, acetylation and sulfation. Quercetin and its metabolites may be the pharmacological material basis of Tartary buckwheat for the protective effect against alcoholic liver injury. The research enriched in vivo metabolite profiling of Tartary buckwheat extracts, which provided experimental data for a comprehensive understanding and rational use of Tartary buckwheat against alcoholic liver disease.

Rapid characterization and identification of the chemical constituents and the metabolites of Du-zhi pill using UHPLC coupled with quadrupole time-of-flight mass spectrometry

A reliable method using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was established to conduct a comprehensive analysis of the chemical constituents of Du-zhi pill (DZP) as well as their metabolites in rat plasma, urine and feces after gastric perfusion. The efficient on-line mass data acquisition modes combined the various off-line mass data mining strategy was applied. A full mass scan was performed, and then accurate MS/MS datasets were obtained through the use of a multiple mass defect filter (MMDF) and dynamic background subtraction (DBS)-dependent data acquisition method. Furthermore, post-acquisition data processing was conducted using various data-mining tools, including extracted ion chromatography (XIC), mass defect filtering (MDF), product ion filtering (PIF), and neutral loss filtering (NLF) (MetabolitePilot™). Finaly, a total of 176 compounds were identified or tentatively characterized in DZP. Moreover, a total of 233 components in vivo, which includes 92 prototype components and 141 metabolites, were unambiguously or tentatively identified in rat plasma, urine and feces. The metabolic pathways, including phase I reactions (hydroxylation, dehydroxylation and hydrogenation) and phase II reactions (acetylation, sulfation, glucuronidation and methylation), for the absorbed constituents, were explored and summarized. This is the first systematic study on the components of DZP and their metabolites in vivo. This study provide a valid analytical strategy for the characterization of chemical compounds and metabolites of TCM formulas. Moreover, an integrative strategy was proposed for the characterization and identification of chemical constituents and metabolites for additional TCM prescriptions.

Pharmacophylogenetic study of Scutellaria baicalensis and its substitute medicinal species based on the chloroplast genomics, metabolomics, and active ingredient

The genetic relationships among the species in Scutellaria genus remain unclear because of the variation in the number of species and complex trait. The usage of S. baicalensis and its four substitute medicinal species (S. amoena, S. hypericifolia, S. likiangensis, and S. viscidula) in traditional medicines make their specialized metabolism important in China, but interspecific genetic and chemical differences have rarely been reported for these species. In this study, the chloroplast genomes of four substitute species for S. baicalensis were assembled, and comparative and phylogenetic analyses were performed with these species and other Scutellaria relatives. In addition, metabolomics analyses were performed and the contents of the main active compounds were determined to reveal the interspecific chemical diversity of S. baicalensis and its four substitute species. The full lengths of their chloroplast genomes ranged from 151,574 to 151,816 bp with an average GC content of 38.34%, and a total of 113 genes were annotated. In the chloroplast genomes of S. baicalensis and its four substitutes, one hypervariable region (petA-psbL) is proposed as a potential DNA barcode. Phylogenetic analysis showed that the subdivision of the genus Scutellaria should be reconsidered. The metabolomics and content determination analyses showed that the four species exhibit a metabolism similar to that of S. baicalensis in different parts. Except for the roots of S. likiangensis, all parts of the substitute species showed high contents of baicalin. Genetic and chemical analyses of four substitute medicinal species for S. baicalensis were performed here for the first time, and their pharmacophylogenetic relationships were further explored, providing a scientific basis for the subsequent development of the medicinal value and resource utilization of Scutellaria.

Metabolic conjugation reduces in vitro toxicity of the flavonoid nevadensin

The present study focuses on the association between metabolic capacity and toxicity of the natural occurring flavonoid nevadensin in vitro. Human colon (HT29), liver (HepG2) and bone marrow (KG1) carcinoma cells were used and strong cell line dependent differences in toxic effect strength were found. HepG2 and KG1 cells were more sensitive against nevadensin treatment in comparison to HT29 cells. High resolution mass spectrometry experiments showed that nevadensin is rapidly glucuronidated in HT29 cells, whereas KG1 cells do not metabolize nevadensin, thus glucuronidation was supposed to be a crucial metabolic pathway in vitro. To proof this suggestion, nevadensin glucuronides were isolated from pig liver microsomes und structurally elucidated via NMR spectroscopy. In HepG2 cells a cellular enrichment of nevadensin itself as well as nevadensin-7-O-glucuronide was determined by tandem mass spectrometry. A proteomic screening of uridine 5'-diphospho (UDP)-glucuronosyltransferase (UGT) in HT29 and HepG2 cells provided first hints that the isoforms UGT1A6 and UGT1A1 are responsible for nevadensin glucuronidation. Additionally, nevadensin was found to be a potent SULT inhibitor in HepG2 cells. In sum, the present study clearly illustrates the importance of obtaining detailed information about metabolic competence of cell lines which should be considered in the evaluation of toxic endpoints.

Optimization of an ultrasonic-assisted aqueous two-phase extraction method for four flavonoids from Lysionotus pauciflorus

An effective approach to extracting four flavonoids (lysioside C, nevadensin-7-sambubioside, ikarisoside B, and nevadensin) from Lysionotus pauciflorus using ultrasonic-assisted aqueous two-phase extraction (UAATPE) technology was studied. Ethanol/K₂HPO₄ system was selected and the influence of several important parameters, including composition of the aqueous two-phase system (ATPS), extraction temperature and time, particle size, and solvent to material ratio, were investigated by single factor experimentss. Then three key parameters (ethanol concentration, solvent to material ratio and extraction temperature) were further optimized by response surface methodology (RSM). The optimal process was that 1 g 120 mesh herb powders were extracted with 45 g ATPS (made of 30% ethanol/18% K₂HPO₄) in 43 °C for 30 min, and yields of four flavonoids could reach 2.56, 2.06, 3.62, and 6.28 mg/g, respectively. Compared with ultrasonic-assisted extraction (UAE) in three conventional solvents (water, ethanol and 60% ethanol), the UAATPE displayed comparatively higher extraction capability. Therefore, UAATPE in ethanol/K₂HPO₄ system could be an alternative technology for integrated extraction of the flavonoids from L. pauciflorus.

The development and validation of a sensitive HPLC-MS/MS method for the quantitative and pharmacokinetic study of the seven components of Buddleja lindleyana Fort

Buddleja lindleyana Fort., a traditional Chinese medicine, has demonstrated anti-inflammatory, immunomodulatory, antidementia, neuroprotective, antibacterial, and antioxidant effects. Its flowers, leaves, and roots have been used as traditional Chinese medicines. A simple and rapid high-performance liquid chromatography method coupled with mass spectrometry (HPLC-MS/MS) was applied in the multicomponent determination of Buddleja lindleyana Fort., and the discrepancies in the contents from ten different habitats were analyzed. The present study simultaneously determined the concentrations of seven chemical compounds of Buddleja lindleyana Fort. extract in rat plasma via HPLC-MS/MS, which was applied in the pharmacokinetic (PK) study of Buddleja lindleyana Fort. A C18 column was used for chromatographic separation, and ion acquisition was achieved by multiple-reaction monitoring (MRM) in negative ionization mode. The optimized mass transition ion-pairs (m/z) for quantization were 591.5/282.8 for linarin, 609.4/300.2 for rutin, 284.9/133.0 for luteolin, 300.6/151.0 for quercetin, 268.8/116.9 for apigenin, 283.0/267.9 for acacetin, 623.3/160.7 for acteoside, and 252.2/155.8 for sulfamethoxazole (IS). A double peak appeared in the drug–time curve of apigenin, which was associated with entero-hepatic recirculation. There were discrepancies in the contents of seven chemical compounds from 10 batches of Buddleja lindleyana Fort., which were associated with the growth environments. Herein, the pharmacokinetic parameters of seven analytes in Buddleja lindleyana Fort. extract are summarized. The maximum plasma concentration (C_max) of linarin, rutin, luteolin, quercetin, apigenin, acacetin and acteoside were 894.12 ± 9.34 ng mL⁻¹, 130.76 ± 18.33 ng mL⁻¹, 77.37 ± 25.72 ng mL⁻¹, 20.15 ± 24.85 ng mL⁻¹, 146.42 ± 14.88 ng mL⁻¹, 31.92 ± 17.58 ng mL⁻¹, and 649.78 ± 16.42 ng mL⁻¹, respectively. The time to reach C_max for linarin, rutin, luteolin, quercetin, apigenin, acacetin, and acteoside were 10, 5, 5, 5, 180, 10 and 10 min, respectively. This is the first report on the simultaneous determination of seven active components for 10 different growing environments and the pharmacokinetic studies of seven active components in rat plasma after the oral administration of Buddleja lindleyana Fort. extract. This study lays the foundation for a better understanding of the absorption mechanism of Buddleja lindleyana Fort., and the evaluation of its clinical application.

Quality control and pharmacokinetics of Buddleja lindleyana Fort by HPLC-MS/MS.

Nevadensin relieves food allergic responses and passive cutaneous anaphylaxis in mice through inhibiting the expression of c-Kit receptors

Nevadensin (NEV), a natural flavonoid compound derived from Lysionotus pauciflorus Maxim, has numerous biological activities. However, few researchers have examined its potential impact on alleviating allergies. In the present study, NEV was found to upregulate rectal temperature, suppress the development of diarrhea, and decrease the levels of serum specific immunoglobulin E, histamine and mouse MC protease-1 in ovalbumin-allergic mice. Moreover, NEV also alleviated passive cutaneous anaphylaxis reactions and inhibited the release of β-hexosaminidase and histamine in bone marrow-derived mast cells. Furthermore, we provide the first demonstration that NEV decreases the expression of c-Kit and suppresses the proliferation of bone marrow-derived mast cells and accelerates their apoptosis. These findings indicated that L. pauciflorus-derived NEV might have the potential to alleviate food hypersensitivity.

Metabolic profiling comparison of isovitexin in normal and kidney stone model rats by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

Isovitexin, a bioactive flavonoid constituent isolated from Desmodii Styracifolii, is considered an adjuvant for antiurolithiasis diseases. In this study, an ultra-high-performance liquid chromatography coupled with hybrid triple quadruple time-of-flight mass spectrometry method was developed to characterize and compare the metabolic profiling of isovitexin experimented on normal and kidney stone model rats. The comparative research indicated that 28 metabolites (18 phase I and 10 phase II) in normal rats and 33 metabolites (20 phase I and 13 phase II) in kidney stone model rats were initially identified. The results of relative quantitative determination reflected that the contents of metabolites produced by deglycosylation, reduction, and isomerization in kidney stone model rats were greater than those in healthy rats. Instead, the levels of oxidative and dehydrogenated metabolites in normal groups were higher than those in kidney stone model groups. The results of this study are valuable and important for understanding the metabolic process of isovitexin in clinical application, and especially the metabolism study in kidney stone model rats could provide a beneficial reference for the further search of effective substances associated with the treatment of kidney stones.

Dispersive liquid-liquid microextraction with high-performance liquid chromatography for the analysis of 1,4-benzodioxane-6-aldehyde in eliglustat tartrate active pharmaceutical ingredient

Potential genotoxic impurities (PGIs) are a series of compounds that could potentially damage DNA. Therefore, a sensitive method is needed for detection and quantification. The present work described and validated a method for the quantification of one PGI (namely 1,4-benzodioxane-6-aldehyde) in Eliglustat tartrate (EGT) active pharmaceutical ingredient (API) substances using dispersive liquid-liquid microextraction (DLLME) as sample preparation to remove matrix effect and detected by HPLC-UV. Parameters influencing the microextraction efficiency were systematically investigated. The combined application of DLLME and HPLC-UV provided the sensitivity of the method. The achieved limit of detection (LOD) and the limit of quantification (LOQ) were adequate for the specific purpose and found to be 1.29 μg g^-1 and 2.58 μg g^-1, respectively. This simple and effective methodology offers a key advantage in the ease of removing matrix effect and improves sensitivity obviously. In addition, no costly instrumentation and skilled personnel are needed when using this method, which is available and can be successfully implemented in routine factory drug quality control analysis.

A novel strategy for the characterization of glaucocalyxin A metabolites in vivo and in vitro by UHPLC-Q-TOF-MS based on DDA and DIA data acquisitions

Glaucocalyxin A (GLA) belongs to the natural ent-kauranoid diterpenoids family with antitumor, antifibrotic, anticoagulative, antioxidant, and anti-AD effects. In this study, ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) system was applied to observe probable metabolites of GLA in vitro and in vivo firstly. The mass data were respectively obtained by two typical acquisition methods, ‘data-dependent acquisition’ (DDA) and ‘data-independent acquisition’ (DIA) modes. The combinations can not only guarantee sensitivity but also capture more precursor ions and MS/MS spectra. Then, multiple data processing techniques were applied to hunt metabolites rapidly. As a result, 32 phase I metabolites of different structures and 6 phase II metabolites were identified, including 25, 18, 17 and 7 in rat urine, feces, bile, and plasma, respectively. Besides, under the action of rat intestinal flora (RIF), 7 metabolites were detected. In the study, the main bio-transformations were oxidation and demethylation. Conjugation with methylation, sulfate, and glucuronide produced phase II metabolites. This study laid the foundation for the further study of the pharmacological effects of GLA and was conducive to mechanism research.

The experimental process flow.

Capsaicin metabolites and GSH-associated detoxification and biotransformation pathways in human liver microsomes revealed by LC-HRMS/MS with data-mining tools

Capsaicin (CAP) is a principal pungent ingredient in hot peppers, it is also employed as a common food additive, an efficient pharmaceutical component, or even a riot control agent. CAP exerts various pharmacological activities as well as associated adverse physiological responses and causes moderate toxicity if overused. A full screening and identification of CAP metabolites in combination with its main detoxification pathways are crucial for the clear demonstration on its pharmacological and toxicological significance. Here, we employed a post-acquisition data-mining metabolic screening approach to rapidly find and identify a broad range of CAP metabolites generated from in vitro human liver microsomes, based on an ultra-performance liquid chromatography-quadrupole orbitrap high resolution tandem mass spectrometric method. First, we collected full scan MS and MS/MS data sets by a data-dependent acquisition method in positive ion mode, and then we employed a modified mass defect filter and a diagnostic ion filter to screen and identify all the probable CAP metabolites, combining with information including retention time, accurate mass, characteristic fragments, and relevant drug biotransformation patterns. In comparison with the stable isotope-labeled CAP involved biotransformation products, we confirmed 19 functionalized metabolites and 13 glutathione (GSH) conjugates of CAP, in which 13 metabolites are reported for the first time. We then briefly depicted an overview metabolic pathway of CAP from the GSH detoxification viewpoint, revealed that various metabolites of CAP can be generated from single or multiple biotransformation and metabolic reactions. Both CAP and its reactive metabolites produced relevant GSH conjugates, which indicates a wide and important detoxification value of GSH conjugation way.

Identification of Metabolites of Eupatorin in Vivo and in Vitro Based on UHPLC-Q-TOF-MS/MS

Eupatorin is the major bioactive component of Java tea (Orthosiphon stamineus), exhibiting strong anticancer and anti-inflammatory activities. However, no research on the metabolism of eupatorin has been reported to date. In the present study, ultra-high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) combined with an efficient online data acquisition and a multiple data processing method were developed for metabolite identification in vivo (rat plasma, bile, urine and feces) and in vitro (rat liver microsomes and intestinal flora). A total of 51 metabolites in vivo, 60 metabolites in vitro were structurally characterized. The loss of CH2, CH2O, O, CO, oxidation, methylation, glucuronidation, sulfate conjugation, N-acetylation, hydrogenation, ketone formation, glycine conjugation, glutamine conjugation and glucose conjugation were the main metabolic pathways of eupatorin. This was the first identification of metabolites of eupatorin in vivo and in vitro and it will provide reference and valuable evidence for further development of new pharmaceuticals and pharmacological mechanisms.

A Systematic Study of the Metabolites of Dietary Acacetin in Vivo and in Vitro Based on UHPLC-Q-TOF-MS/MS Analysis

Acacetin, a dietary component, is abundant in acacia honey and has superior anticancer activities. To date, no research on the metabolism of acacetin has been reported. In the current research, an online detection strategy of ultra-high-performance liquid chromatography connected to a quadrupole time-of-flight mass spectrometer (UHPLC-Q-TOF-MS/MS) was utilized for metabolite identification in vivo (rat plasma, bile, urine, and feces) and in vitro (rat liver microsomes). A total of 31 metabolites were structurally characterized in rats, and 25 metabolites were detected in rat liver microsomes, among which, 4 metabolites were compared with standards. Oxidation, the loss of CH₂, reduction, hydrolysis, glucuronide conjugation, sulfate conjugation, methylation, and N-acetylation were the main metabolic pathways of acacetin. This study is the first to characterize acacetin metabolites in vivo and in vitro, and the results of this study offer novel and valuable evidence for a comprehensive understanding of the safety and efficacy of acacetin.

Metabolites study on 5-O-methylvisammioside in vivo and in vitro by ultra high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

5-O-Methylvisammioside is one of major chromones of Radix Saposhnikoviae possessing definite pharmacological activities, but there are few reports with respect to the metabolism of 5-O-methylvisammioside. In this work, metabolites in vivo were explored in male Sprague-Dawley rats and in vitro investigated on rat intestinal bacteria incubation model and were identified by using ultra high performance liquid chromatography/quadrupole time-of-flight mass spectrometry. An online data acquisition method based on a multiple mass defect filter and dynamic background subtraction was developed to trace all probable metabolites. As a result, 26 metabolites in vivo (including 18, 15, 10, and 10 in rat urine, faece, bile, and blood) and 7 metabolites in vitro were characterized, respectively. Additionally, the main metabolic pathways in vivo and in vitro, including deglycosylation, deglycosylation + demethylation, deglycosylation + oxidation, N-acetylation, and sulfate conjugation, were summarized by calculating the relative content of each metabolite. The obtained results significantly enriched our knowledge about 5-O-methylvisammioside metabolism and will lead to a better understanding of its safety and efficacy.

Use of UHPLC-QTOF-MS/MS with combination of in silico approach for distributions and metabolites profile of flavonoids after oral administration of Niuhuang Shangqing tablets in rats

Niuhuang Shangqing tablet (NHSQT), a well-known traditional Chinese medicine preparation, has been used as an over- the- counter drug for the treatment of headache, dizziness in China. The flavonoids are the main active components in NHSQT, however, there have no reports about their distribution and metabolic fate in vivo after oral administration of NHSQTs so far. An novel UHPLC-QTOF-MS/MS method combined with in silico approach was applied to identify the flavonoids and metabolites profiling in biological samples following oral administration NHSQTs for the first time. As a result, 127 compounds including 34 original compounds of flavonoids and 93 metabolites were identified. There were 20 flavones, 9 flavonols, 4 flavanones and 1 flavan-3, 4-diol found in biological samples. Rutin, wogonoside, apigenin, baicalein, wogonin, oroxylin A, quercetin and acacetin were considered as the potential flavonoids in NHSQT against brain diseases. The docking-based metabolism models were established and applied to propose the sites of hydroxylation of flavonoids, which indicated baicalin was engaged in dihydroxylation at C2', C3', tilianin was engaged in hydroxylation at C3, wogonin and wogonside were engaged in dihydroxylation at C3', C4'. Some novel metabolic pathways were discovered for oroxylin A, acacetin, diosmetin, tilianin. The metabolic spots and pathways of flavonoids vary as much between flavones, flavonols and flavanones. The results presented here would be helpful for the further study of pharmacokinetics and quality control of NHSQT.

Antioxidant, Gastroprotective, Cytotoxic Activities and UHPLC PDA-Q Orbitrap Mass Spectrometry Identification of Metabolites in Baccharis grisebachii Decoction

The decoction of the local plant Baccharis grisebachii is used as a digestive, gastroprotective, external cicatrizing agent and antiseptic in Argentine. A lyophilized decoction (BLD) from the aerial parts of this plant was evaluated regarding its anti-ulcer, antioxidant and cytotoxic activities and the bioactivities were supported by UHPLC-MS metabolome fingerprinting which revealed the presence of several small bioactive compounds. The antioxidant properties were evaluated by DPPH, TEAC, FRAP and lipoperoxidation inhibition in erythrocytes methods, and the antibacterial activity was evaluated according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The BLD showed a moderate free radical scavenging activity in the DPPH (EC₅₀ = 106 µg/mL) and lipid peroxidation in erythrocytes assays (67%, at 250 µg/mL). However, the BLD had the highest gastroprotective effect at a dose of 750 mg/kg with a ninety-three percent inhibition of damage through a mechanism that involve NO and prostaglandins using the ethanol-induced gastric damage in a standard rat model. On the other hand, BLD does not induce cytotoxic changes on human tumor and no-tumor cell lines at the concentrations assayed. Regarding the metabolomic analysis, thirty-one compounds were detected and 30 identified based on UHPLC-OT-MS including twelve flavonoids, eleven cinnamic acid derivatives, one coumarin, one stilbene and two other different phenolic compounds. The results support that the medicinal decoction of Baccharis grisebachii is a valuable natural product with gastroprotective effects and with potential to improve human health that opens a pathway for the development of important phytomedicine products.

UHPLC-Q-TOF-MS/MS method based on four-step strategy for metabolites of hinokiflavone in vivo and in vitro

Hinokiflavone (HF), belonging to biflavonoids, possesses excellent pharmacological activities, including anti-inflammatory, antioxidant and antitumor activity. Nevertheless, its metabolism in vivo (rats) and in vitro (rat liver microsomes and intestinal flora) is presently not characterized. In this study, ultra-high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) based on four-step strategy was a rapid method for the detection of HF metabolites. A total of 41 metabolites in vivo, 49 metabolites in vitro were characterized. It also verified that intestinal tract exceeds the liver in the biotransformation of HF. More significant, the main metabolic pathways for HF were mainly bio-transformed to various mono-flavone resulting from the rupture of connective CO bonds, which exhibited a large distinction with other biflavones. Noteworthily, glutamine conjugation and glycine conjugation were considered as unique metabolic pathways of HF. The information obtained from this study contributes to better understanding of pharmacological mechanism of HF.

A comprehensive study of eriocitrin metabolism in vivo and in vitro based on an efficient UHPLC-Q-TOF-MS/MS strategy

Eriocitrin, a main flavonoid in lemons, possesses strong antioxidant, lipid-lowering and anticancer activities and has long been used in food, beverages and wine. However, its metabolism in vivo and in vitro is still unclear. In this study, an efficient strategy was developed to detect and identify metabolites of eriocitrin by using ultra-high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) based on online data acquisition and multiple data processing techniques. A total of 32 metabolites in vivo and 27 metabolites in vitro were obtained based on the above method. Furthermore, the main metabolic pathways of eriocitrin included reduction, hydrogenation, N-acetylation, ketone formation, oxidation, methylation, sulfate conjugation, glutamine conjugation, glycine conjugation, desaturation and demethylation to carboxylic acid. This study will lay a foundation for further studies on the metabolic mechanisms of eriocitrin.

41 metabolites of eriocitrin in vivo and in vitro was identified based on the efficient UHPLC-Q-TOF-MS/MS strategy.

Non-volatile natural products in plant glandular trichomes: chemistry, biological activities and biosynthesis

The investigation methods, chemistry, bioactivities, and biosynthesis of non-volatile natural products involving 489 compounds in plant glandular trichomes are reviewed.