Systematic Strategy for Metabolites of Amentoflavone In Vivo and In Vitro Based on UHPLC-Q-TOF-MS/MS Analysis

Exploring the quality marker of Curcumae kwangsiensis radix from different production regions using the spectrum-effect relationship, serum metabolism, and molecular docking integrated with chemometrics

ETHNOPHARMACOLOGICAL RELEVANCE

Curcuma kwangsiensis radix (CKR) is one of the most important herbs in traditional Chinese medicine. It effectively enhances blood circulation and eliminates stasis, which is highly associated with thrombosis. Furthermore, CKR is primarily produced in the Guangxi and Yunnan provinces of China. However, the quality control indicators of CKR in different production regions remain controversial.

AIM

To explore the quality marker (Q-Marker) of CKR in different production regions.

MATERIALS AND METHODS

First, we determined the UPLC fingerprints of CKR from different production regions. Second, in vitro, antiplatelet aggregation biopotency (AAB) was measured using a parallel-line assay based on the quantitative response method of the bioassay. We identified CKR components and their serum metabolism using UPLC-Q-TOF-MSE. Subsequently, molecular docking technology was used for Q-Marker analysis. Finally, we established a method for the quantitative analysis of Q-Marker.

RESULTS

We observed significant differences of CKR between the Guangxi and Yunnan provinces according to the UPLC fingerprint and AAB results. Eight quality control-relevant components were screened using orthogonal partial least squares based on the spectrum-effect relationship. UPLC-Q-TOF-MSE identified 57 CKR components, and 10 prototype components and 11 metabolites, respectively, were detected during serum metabolism. Ultimately, curcumenone was screened as a Q-Marker using the spectrum-effect relationship integrated with serum metabolism, which positively correlated with the quality. The AAB results of the Q-Marker indicated that curcumenone exhibited significant anti-platelet aggregation activity. The results of the Q-Marker molecular docking revealed the strongest binding effect between curcumenone and the GP-IIb/IIIa receptor, whereas that between the P2Y12 receptor and the P2Y1 receptor was the weakest. In addition, quantitative analysis of the Q-Marker indicated that there were significant differences in the contents of the Q-Marker from different production regions.

CONCLUSIONS

We identified a Q-Marker for CKR that can provide a foundation for quality evaluation research from different production regions.

Metabolite Profiling Analysis of the Tongmai Sini Decoction in Rats after Oral Administration through UHPLC-Q-Exactive-MS/MS

Tongmai Sini decoction (TSD), the classical prescriptions of traditional Chinese medicine, consisting of three commonly used herbal medicines, has been widely applied for the treatment of myocardial infarction and heart failure. However, the absorbed components and their metabolism in vivo of TSD still remain unknown. In this study, a reliable and effective method using ultra-performance liquid chromatography coupled with hybrid quadrupole-Orbitrap mass spectrometry (UHPLC-Q-Exactive-MS/MS) was employed to identify prototype components and metabolites in vivo (rat plasma and urine). Combined with mass defect filtering (MDF), dynamic background subtraction (DBS), and neutral loss filtering (NLF) data-mining tools, a total of thirty-two major compounds were selected and investigated for their metabolism in vivo. As a result, a total of 82 prototype compounds were identified or tentatively characterized in vivo, including 41 alkaloids, 35 phenolic compounds, 6 saponins. Meanwhile, A total of 65 metabolites (40 alkaloids and 25 phenolic compounds) were tentatively identified. The metabolic reactions were mainly hydrogenation, demethylation, hydroxylation, hydration, methylation, deoxylation, and sulfation. These findings will be beneficial for an in-depth understanding of the pharmacological mechanism and pharmacodynamic substance basis of TSD.

Microbial-Transferred Metabolites and Improvement of Biological Activities of Green Tea Catechins by Human Gut Microbiota

Green tea catechins (GTCs) are dietary polyphenols with broad bioactivities that undergo extensive microbial metabolism in the human gut. However, microbial-transferred metabolites and their health benefits are not fully understood. Herein, the microbial metabolism of GTCs by human fecal microbiota and dynamic alteration of the microbiota were integrally investigated via in vitro anaerobic fermentation. The results showed that the human gut microbiota exhibited a strong metabolic effect on GTCs via UHPLC-MS/MS analysis. A total of 35 microbial-transferred metabolites were identified, far more than were identified in previous studies. Among them, five metabolites, namely EGCG quinone, EGC quinone, ECG quinone, EC quinone, and mono-oxygenated EGCG, were identified for the first time in fermented GTCs with the human gut microbiota. Consequently, corresponding metabolic pathways were proposed. Notably, the antioxidant, α-amylase, and α-glucosidase inhibitory activities of the GTCs sample increased after fermentation compared to those of the initial unfermented sample. The results of the 16S rRNA gene sequence analysis showed that the GTCs significantly altered gut microbial diversity and enriched the abundancy of Eubacterium, Flavonifractor, etc., which may be further involved in the metabolisms of GTCs. Thus, these findings contribute to a better understanding of the interactions between GTCs and gut microbiota, as well as the health benefits of green tea consumption.

A mass defect filtering combined background subtraction strategy for rapid screening and identification of metabolites in rat plasma after oral administration of Yindan Xinnaotong soft capsule

The absorbed prototypes and metabolites of traditional Chinese medicines (TCMs) serves an important part in pharmacological action and clinical effects. However, the comprehensive characterization of which is facing actual or possible rigorous challenges due to the lack of data mining methods and the complexity of metabolite samples. Yindan Xinnaotong soft capsule (YDXNT), a typical traditional Chinese medicine prescription consisting of extracts from 8 herbal medicines, is widely used for the treatment of angina pectoris and ischemic stroke in the clinic. This study established a systematic data mining strategy based on ultra-high performance liquid chromatography tandem quadrupole-time-of-fight mass spectrometry (UHPLC-Q-TOF MS) for comprehensive metabolite profiling of YDXNT in rat plasma after oral administration. The multi-level feature ion filtration strategy was primarily conducted through the full scan MS data of plasma samples. All potential metabolites were rapidly fileted out from the endogenous background interference based on the background subtract and the chemical type specifically mass defect filter (MDF) windows including flavonoids, ginkgolides, phenolic acids, saponins, and tanshinones. As the MDF windows of certain types were overlapped, the screened-out potential metabolites were deeply characterized and identified according to their retention times (RT), integrating neutral loss filtering (NLF), diagnostic fragment ions filtering (DFIF), and further confirmed by reference standards. Thus, a total of 122 compounds, consisting of 29 prototype components (16 confirmed with reference standards) and 93 metabolites had been identified. This study provides a rapid and robust metabolite profiling method for researching complicated traditional Chinese medicine prescriptions.

Chemopreventive mechanisms of amentoflavone: recent trends and advancements

In parallel to the continuous rise of new cancer cases all over the world, the interest of scientific community in natural anticancer agents has steadily been increased. In the past decades, numerous phytochemicals have been shown to possess a strong anticancer potential in preclinical conditions. One of such interesting compounds, derived from different plants such as ginkgo, hinoki, and St. John`s wort, is amentoflavone. In this review article, a wide range of anticancer properties of this natural biflavone are described, revealing its ability to suppress the malignant growth and lead tumor cells to apoptotic death, besides impeding also angiogenic and metastatic processes. Therefore, amentoflavone can be considered a potential lead compound for the development of novel anticancer drug candidates, definitely deserving further in vivo studies and also initiation of clinical trials. It is expected that this plant biflavone might be important, either alone or in combination with the current standard chemotherapeutics, in providing some alleviation for the continuous rise of global cancer burden.

Gender differences pharmacokinetics, bioavailability, hepatic metabolism and metabolism studies of Pinnatifolone A, a sesquiterpenoid compound, in rats by LC-MS/MS and UHPLC-Q-TOF-MS/MS

BACKGROUND

Pinnatifolone A is a typical sesquiterpenoid and the primary active ingredient of Syringa oblata Lindl., has potent anti-inflammatory activity. However, Pinnatifolone A pharmacokinetic and metabolites analysis investigations in male and female rats, as well as its in vitro stability in male and female rat liver microsomes, have not been evaluated and compared.

PURPOSE

To investigate preclinical pharmacokinetic and metabolite in both genders, confirm gender differences, and provide usable information for the development of clinical applications.

METHODS

A quick, precise, and sensitive LC-MS/MS method was created and effectively used to determine the pharmacokinetics of oral (140 mg/kg) and intravenous (6.3 mg/kg) Pinnatifolone A in male and female rats, in vitro Pinnatifolone A elimination studies in male and female rat liver microsomes. Following that, a UHPLC-Q-TOF-MS/MS technique was established to identify the metabolic profiles of Pinnatifolone A obtained from rat plasma and excreta.

RESULTS

In the current study, we established for the first time an LC-MS/MS method for the quantitation of Pinnatifolone A with acceptable linearity and selectivity, recovery and matrix effect, accuracy and precision. The absolute oral bioavailability of Pinnatifolone A was approximately 30.36% in female rats, the clearance (CL) was 20.99±3.33 l/h/kg in female rats and 472.37±437.31 l/h/kg in male rats. This difference in rat genders may pertain to the sex-specific expression of hepatic enzymes as demonstrated in the metabolic stability evaluation in the present research; the male rats exhibited higher CL_int(mic) (158.83±9.57 μl/min/mg protein) than female rats (76.47±7.90 μl/min/mg protein) liver microsomes, indicating higher Pinnatifolone A clearance in male rats. Twenty-four metabolites were detected and identified in female and male rats; N-acetylcysteine conjugation metabolite was the most abundant metabolites in both rat feces and urine. Furthermore, male and female rats had significantly different levels of the N-acetylcysteine conjugation metabolite. Hydrogenation metabolite was particular to female rats both in rat fecal and urine. Glucuronide conjugation metabolite was the predominant metabolite in rat plasma, and its amount in female rats was double that of male rats.

CONCLUSIONS

The present research is the first to report the preclinical pharmacokinetics and metabolites of Pinnatifolone A in male and female rats, confirming the gender-based differences. The findings provide a comprehensive overview for further understanding of the pharmacokinetic and metabolic characteristics of Pinnatifolone A and serve as a guide for its future development and utilization.

Amentoflavone-Enriched Selaginella rossii Protects against Ultraviolet- and Oxidative Stress-Induced Aging in Skin Cells

Selaginellaceae plants are used in cosmetics to limit skin aging. This study is the first to investigate the anti-aging effects of Selaginella rossii (SR) on ultraviolet B (UVB)- and oxidative stress-induced skin cells. The 95% ethanol extract of Selaginella rossii (SR95E) contained much higher amounts of amentoflavone (AMF), an active compound, than other Selaginellaceae plants and was more effective in inhibiting matrix metalloproteinase (MMP)-1 expression in CCD-986sk fibroblasts. SR95E significantly decreased UVB-induced MMP-1, MMP-2, MMP-3 and MMP-9 expression and enhanced procollagen type I C-peptide content and mRNA expression of collagen type I alpha (COL1A)1 and COL1A2 in CCD-986sk fibroblasts. In HaCaT keratinocytes, SR95E treatment also dose-dependently decreased UVB-induced MMP-1 concentration and MMP-1, MMP-2, MMP-3 and MMP-9 mRNA expression. Moreover, SR95E treatment markedly inhibited UVB-induced c-Jun N-terminal kinase and p38 mitogen-activated protein kinase signaling and nuclear factor kappa-B signaling in HaCaT cells. Furthermore, SR95E and AMF markedly regulated the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced expression of cellular senescence-related markers, including p16, p21 and LMNB1, in HaCaT cells. Overall, this study indicates that SR may have potential as a functional material on preventing UVB- and AAPH-induced skin aging and wrinkles.

A Systematic Strategy for the Characterization of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-glucoside Metabolites In Vivo by Ultrahigh Performance Liquid Chromatography Coupled with a Q Exactive-Orbitrap Mass System

2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-glucoside (THSG), a polyphenol stilbene compound, is the main active constituent in Polygonum multiflorum. In this study, a comprehensive analytical strategy was developed for the characterization of THSG metabolites in vivo (rat plasma, bile, urine, heart, liver, spleen, lung, kidney, and stomach) utilizing ultrahigh performance liquid chromatography coupled with Q Exactive hybrid quadrupole-Orbitrap mass spectrometry (UHPLC-Q Exactive-Orbitrap MS) based on multiple data-processing techniques. As a result, a total of 75 metabolites were characterized in bio-samples, and calculated Clog P values were further employed to assign the chemical structures of some isomers. Glucoside hydrolysis, hydrogenation, hydroxylation, glucuronide conjugation, and sulfate conjugation would be the major metabolic pathways of THSG. It appeared that most metabolites would generally undergo phase I reactions followed by phase II reactions. These results provided valuable information for in-depth understanding of the safety and efficacy of THSG and showed a valuable methodology for metabolic characterization.

Sex-related deposition and metabolism of vanisulfane, a novel vanillin-derived pesticide, in rats and its hepatotoxic and gonadal effects

A series of vanillin derivatives have recently been synthesized as effective candidate antiviral agents, with vanisulfane exhibiting pronounced curative and protective activities against cucumber mosaic virus and potato virus Y. However, research on some new pesticides usually ignores their various metabolites and sex-related toxicity. Assisted by ¹⁴C labeling, a trial was conducted to investigate the tissue distribution, excretion, and metabolism of vanisulfane in male and female rats for the first time. The results showed that 83.30-87.51% of applied ¹⁴C activity was excreted in urine and feces within 24 h of oral administration, and ¹⁴C was most abundant in the liver and kidney in both sexes. Interestingly, sex differences were observed in the experiment, with lower body clearance in males than in females 24 h after treatment and preferences for biliary and renal excretion of the pesticide in male and female rats, respectively. A high degradation rate was found for vanisulfane in the plasma; thus, the metabolites of vanisulfane were investigated using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) combined with ¹⁴C labeling. One glucuronic acid conjugate and two oxidation metabolites were detected, supporting the monitoring of vanisulfane in vivo. Additionally, rats exposed to vanisulfane exhibited hepatic steatosis in both sexes, along with mild gonadal effects in males. This research offers an effective method for conducting environmental behavioral research and provides new insights for evaluating the potential risks of novel pesticides in mammals from a sex perspective.

Characterization of the chemical constituents and in vivo metabolic profile of Scutellaria barbata D. Don by ultra-high performance liquid chromatography-high resolution mass spectrometry

Scutellaria barbata D. Don (S. barbata) is one of the most frequently used anticancer herb medicine in China. Mechanistic understanding of the biological activities of S. barbata is hindered by limited knowledge regarding its components and metabolic profile. In this study, ultra-high-performance liquid chromatography coupled with high resolution mass spectrometry (quadrupole time-of-flight mass spectrometry,) was used to identify the chemical constituents in S. barbata and their metabolic profiles in rats. By applying cleavage rules and comparison with reference substances, 89 components were identified, which included 45 flavonoids, 28 diterpenoids, 10 phenolics, and 6 others. A total of 110 compounds, including 32 prototype compounds and 78 metabolites, were identified or tentatively characterized in vivo. Methylation, sulfonation, and glucuronidation were the main metabolic pathways, which could be attributed to the fact that several of the compounds in S. barbata have phenolic hydroxyl groups. This is the first systematic study on the chemical constituents and in vivo metabolic profile of S. barbata. The analytical method features a quick and comprehensive dissection of the chemical composition and metabolic profile of S. barbata and provides a basis for exploring its various biological activates. This article is protected by copyright. All rights reserved.

Evaluation of amentoflavone metabolites on PARP-1 inhibition and the potentiation on anti-proliferative effects of carboplatin in A549 cells

The present study aims to determine the major metabolites of amentoflavone (AMF) and further evaluate their inhibitory effects on PARP-1. First, different fractions (Frs. 1-9), which were collected according to retention time of AMF metabolites based on UHPLC-QTOF-MS/MS qualitative analysis, were evaluated on their inhibitory effects against PARP-1. Then, two mono-sulfate metabolites in the fractions with potent PARP-1 inhibitory effect were targetedly semi-synthesized. Moreover, three mono-sulfate conjugates (compound 8, 9 and 10), including one disulfate conjugate (compound 10), were isolated and their structures were fully elucidated by UHPLC-QTOF-MS/MS and NMR. Finally, the binding mode of compound 8 (amentoflavone-4‴-O-sulfate) toward PARP-1 and its potentiation on carboplatin (CBP) in A549 cells were investigated. This study was the first report on bioactivity evaluation of AMF metabolites in rat bile on PARP-1 and the potentiation of compound 8 on carboplatin (CBP) in A549 cells in vitro. This paper also provided scientific basis for the AMF metabolites on PARP-1 inhibition and chemosensitization.

Evaluation on absorption risks of amentoflavone after oral administration in rats

The present study was aimed to systemically assess the absorption risks of amentoflavone (AMF). Physicochemical properties of AMF were evaluated using in vitro assays including water solubility and stability in both simulated gastric and intestinal fluids, as well as logD, pka and permeability studies in a monolayer Caco-2 model. The results together suggested that AMF was a compound with moderate intestinal absorption and the poor solubility was the key rate-limiting step for the oral absorption of AMF, and PVP-K30 were thus used as a solubilizer to improve its solubility and oral bioavailability. Furthermore, studies on pharmacokinetics and biliary excretion of AMF with tween 80 or PVP-K30 were performed after oral administration, and the results showed that the percentage of AMF conjugates in bile was determined up to be 96.73% and no AMF conjugates were detected in rat plasma. The above results revealed that the poor oral absorption of AMF may probably be attributed to the low solubility, high level of metabolism and hepatic first-pass effects. The relative bioavailability of AMF solubilized by PVP-K30 was about 2-fold than that of AMF suspended in 1% tween 80. The present study may help provide scientific insights to guide the rational design of AMF into more efficient formulation systems.

Extensive metabolism of flavonoids relevant to their potential efficacy on Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disorder, the incidence of which is climbing with ever-growing aged population, but no cure is hitherto available. The epidemiological studies unveiled that chronic intake of flavonoids was negatively associated with AD risk. Flavonoids, a family of natural polyphenols widely distributed in human daily diets, were readily conjugated by phase II drug metabolizing enzymes after absorption in vivo, and glucuronidation could occur in 1 min following intravenous administration. Recently, as many as 191 metabolites were obtained after intragastric administration of a single flavonoid, indicating that other bioactive metabolites, besides conjugates, might be formed and account for the contradiction between efficacy of flavonoids in human or animal models and low systematic exposure of flavonoid glycosides or aglycones. In this review, metabolism of complete 68 flavonoid monomers potential for AD treatment, grouped in flavonoid O-glycosides, flavonoid aglycones, flavonoid C-glycosides, flavonoid dimers, flavonolignans and prenylated flavonoids according to their common structural elements, respectively, has been systematically retrospected, summarized and discussed, including their unequivocally identified metabolites, metabolic interconversions, metabolic locations, metabolic sites (regio- or stereo-selectivity), primarily involved metabolic enzymes or intestinal bacteria, and interspecies correlations or differences in metabolism, and their bioactive metabolites and the underlying mechanism to reverse AD pathology were also reviewed, providing whole perspective about advances on extensive metabolism of diverse potent flavonoids in vivo and in vitro up to date and aiming at elucidation of mechanism of actions of flavonoids on AD or other central nervous system (CNS) disorders.

Discovery of Novel Apigenin-Piperazine Hybrids as Potent and Selective Poly (ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors for the Treatment of Cancer

Poly (ADP-ribose) polymerase-1 (PARP-1) is a potential target for the discovery of chemosensitizers and anticancer drugs. Amentoflavone (AMF) is reported to be a selective PARP-1 inhibitor. Here, structural modifications and trimming of AMF have led to a series of AMF derivatives (9a-h) and apigenin-piperazine/piperidine hybrids (14a-p, 15a-p, 17a-h, and 19a-f), respectively. Among these compounds, 15l exhibited a potent PARP-1 inhibitory effect (IC50 = 14.7 nM) and possessed high selectivity to PARP-1 over PARP-2 (61.2-fold). Molecular dynamics simulation and the cellular thermal shift assay revealed that 15l directly bound to the PARP-1 structure. In in vitro and in vivo studies, 15l showed a potent chemotherapy sensitizing effect against A549 cells and a selective cytotoxic effect toward SK-OV-3 cells through PARP-1 inhibition. 15l·2HCl also displayed good ADME characteristics, pharmacokinetic parameters, and a desirable safety margin. These findings demonstrated that 15l·2HCl may serve as a lead compound for chemosensitizers and the (BRCA-1)-deficient cancer therapy.

Accurate Quantification of Sulfonamide Metabolites in Goat Meat: A New Strategy for Minimizing Interaction between Sheep Serum Albumin and Sulfonamide Metabolites

To date, the determination of sulfonamide metabolites in animal-derived food has universal disadvantages of low throughput and no integrated metabolites involved. In this study, a powerful and reliable strategy for high-throughput screening of sulfonamide metabolites in goat meat was proposed based on an aqueous two-phase separation procedure (ATPS) combined with ultrahigh-performance liquid chromatography quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap). Noncovalent interactions including van der Waals force, hydrogen bonding, and hydrophobic effect were determined to be staple interactions between the sulfonamide metabolites and sheep serum albumin by fluorescence spectroscopy and molecular docking technology, and an 80% acetonitrile-water solution/(NH₄)₂SO₄ was used as ATPS in order to release combined sulfonamide metabolites and minimize the influence of sheep serum albumin. Sulfonamide metabolites in the matrix were screened based on a mechanism of mass natural loss and core structure followed by identification combined with the pharmacokinetic. The developed strategy was validated according to EU standard 2002/657/EC with CCα ranging from 0.07 to 0.98 μg kg^-1, accuracy recovery with 84-107%, and RSDs lower than 8.9%. Eighty seven goat meat samples were used for determination of 26 sulfonamides and 8 potential metabolites. On the basis of the established innovative process, this study has successfully implemented the comprehensive detection of sulfonamide metabolites, including N⁴-acetylated substitution, N⁴-hydroxylation, 4-nitroso, azo dimers, oxidized nitro, N⁴ monoglucose conjugation, β-d-glucuronide, and N-4-aminobenzenesulfonyl metabolites, which were shown to undergo oxidation, hydrogenation, sulfation, glucuronidation, glucosylation, and O-aminomethylation.