Pharmacokinetic comparison between quercetin and quercetin 3-O-β-glucuronide in rats by UHPLC-MS/MS

Pharmacokinetic Prediction and Cytotoxicity of New Quercetin Derivatives

Quercetin (QUE) possesses various pharmacological properties; however, its low bioavailability and solubility hinder its beneficial effects. Enzymatic glycosylation has been explored to improve these aspects. In the present study, we used a sucrose phosphorylase variant to catalyze the regioselective transglucosylation of QUE, predicted the pharmacokinetic properties and toxicity of these molecules using in silico tools, and evaluated their cytotoxicity compared to the original molecule and a β-glucosylated derivative of QUE. Three α-glucosylated derivatives were obtained, which demonstrated improved pharmacokinetics, including a higher volume of distribution and lower clearance rate, with minimal likelihood of cytochrome P450 enzyme inhibition compared to QUE. QUE and the β-glucosylated derivative exhibited cytotoxicity in both cell types evaluated, whereas their α-glucosylated derivatives were nontoxic. The results presented provide an insight into the predicted behavior of these molecules in the body and, combined with cytotoxicity evaluation, will serve as a foundation for investigating the biological effects and mechanisms of action of these new molecules.

Evaluation of Anti-Obesity Potential of Isolated Bioactive Fractions From Justicia Adhatoda Leaves: An In Vitro, In Vivo, and 3T3-L1 Cell Line Approach Using High-Performance Thin Layer Chromatography Coupled With Mass Spectrometry for Compound Identification

This study was conducted to investigate the anti-obesity effects of bioactive fractions JAF2 and JAF3 from Justicia adhatoda (JA) in vitro using enzymatic assays, 3T3-L1 cells, and in vivo using a monosodium glutamate-high-fat diet (MSG-HFD) model. High-performance thin-layer chromatography coupled with mass spectrometry (HPTLC-MS-MSn) was finally utilized to analyze bioactive fractions for the compounds responsible for the activity. In vitro, the anti-obesity effects of JAF2 and JAF3 were assessed in 3T3-L1 adipocytes, revealing that JAF2 significantly reduced lipid and triglyceride levels. In the in vivo MSG-HFD-induced obesity model, JAF2 improved hepatic profiles, countered oxidative stress, enhanced lipid profiles, and reduced pro-inflammatory cytokines. Overall, the assessment revealed a significant reduction in adipose tissue content in the treated groups, keeping other organ profiles safe. As per future perspectives, these cocktail fractions can be used in the context of genetically predisposed obesity in modern days.

Antioxidant Potential of Selected Apiaceae Plant Extracts: A Study Focused on the Chemical Composition and Neuroprotective Effect of Coriandrum sativum L. Extract Against Lead (Pb)-Induced Neurotoxicity in Rats

Lead is a common environmental pollutant. It can affect several body systems including the central nervous system (CNS). Lead can disrupt the nervous system by different mechanisms including oxidative stress, inflammation, disruption of neurotransmission, and aberrant autophagy. Apiaceous species have been used traditionally as food flavoring and medicine, representing a rich source of bioactive compounds. In the current study, the antioxidant power of four Apiaceous extracts (Foeniculum vulgare L., Pimpinella anisum L., Coriandrum sativum L., and Cuminum cyminum L.) was evaluated. Additionally, the metabolite profiles of the selected species were comprehensively investigated by untargeted liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) coupled to chemometry. Coriander (Coriandrum sativum L.) extract showed the highest radical scavenging activity and reducing power. Coriander was further subjected to in vivo evaluation of its protective effect against Lead (Pb)-induced neurotoxicity. Administration of coriander extracts improved the short- and long-term memory performance and decreased hippocampal Pb content in Pb-intoxicated rats. Moreover, it attenuated hippocampal oxidative stress, neurochemical changes, and exhibited anti-inflammatory effect in the hippocampal tissue. Further, coriander extracts attenuated Pb inhibitory effect on the mammalian target of Rapamycin (mTORC1) pathway resulting in upregulation of Phospho-p70 S6 Kinase (P-P70S6K) and Phospho-S6 Ribosomal Protein (PS6) and downregulation of Beclin-1. Additionally, some selected coriander ingredients were subjected to molecular docking to examine their regulatory effect on mTORC-1 and IκB kinase complex (Ikk-β). The present findings highlight the future pharmaceutical utilization of coriander extract as valuable source of phenolic compounds that can be used as antioxidant, anti-inflammatory, and neuroprotective agents against Pb-induced neurotoxicity.

Cranberry Extract Ameliorates Diabetic Cognitive Impairment in Rats Via LncRNA GAS-5 Downregulation and Pyroptosis Pathway Inhibition

The pathophysiology of diabetes-induced brain injury involves pyroptosis, an inflammatory programmed cell death. This study aimed to investigate the potential protective effect of cranberry extract (CE) against diabetes-induced brain injury. Type 1 diabetes was induced by intraperitoneal injection of streptozotocin in rats. Brain tissue samples were investigated for biochemical determination of the reduced glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA), and the quantitative RT-PCR for the gene expression of glial cell-derived neurotrophic factor (GDNF), lncRNA GAS-5, and pyroptosis markers. ELISA was used to determine the caspase-1 level and immunohistochemical staining for assessing IL-1β. Prophylactic dosing of the CE in diabetic rats improved cognitive behavior and significantly suppressed MDA concentration, pyroptosis genes expression (gasdermin D and caspase 1), and lncRNA GAS-5. In addition, CE significantly elevated GSH concentration, SOD activity, and gene expression of GDNF and markedly reduced IL-1β positive stained cells score in the brain. Phytochemical characterization of the CE by FT-IR and UPLC-PDA-MS/MS revealed cyanidin arabinoside, procyanidins, quercetin, and isorhamnetin as key components. CE protects against diabetes-induced cognitive dysfunction in rats by targeting redox-related signaling pathways and inducing an anti-inflammatory effect. LncRNA GAS-5 downregulation and pyroptosis pathway inhibition may contribute to its beneficial effects, suggesting its therapeutic potential.

Inhibitory Potential of the Drimane Sesquiterpenoids Isotadeonal and Polygodial in the NF-kB Pathway

Inflammation contributes to the onset and development of many diseases, including neurodegenerative diseases, caused by the activation of microglia, leading to neurological deterioration. Nuclear factor-κB (NF-κB) is one of the most relevant pathways for identifying anti-inflammatory molecules. In this study, polygodial and isotadeonal, two drimane sesquiterpene dialdehydes, were isolated from Drimys winteri, a medicinal tree of the Mapuche people in Chile. Isotadeonal, or epi-polygodial, was obtained from polygodial by epimerization in basic media (60% yield, Na2CO3, r/t, 24 h). Both sesquiterpenoids were evaluated on the NF-κB pathway, with the result that isotadeonal inhibited the phosphorylation of IκB-α at 10 μM with higher potency by Western blotting. The final inhibition of the pathway was evaluated using a SEAP reporter (secreted alkaline phosphatase) on THP-1 cells. Isotadeonal inhibited SEAP with higher potency than polygodial, quercetin, and CAPE (phenethyl ester of caffeic acid). In silico analysis suggests that the α-aldehyde of isotadeonal adopts a more stable conformation in the active pocket of IκB-α than polygodial.

Stone L, Haglund L. Senolytic treatment for low back pain

Senescent cells (SnCs) accumulate because of aging and external cellular stress throughout the body. They adopt a senescence-associated secretory phenotype (SASP) and release inflammatory and degenerative factors that actively contribute to age-related diseases, such as low back pain (LBP). The senolytics, o-vanillin and RG-7112, remove SnCs in human intervertebral discs (IVDs) and reduce SASP release, but it is unknown whether they can treat LBP. sparc-/- mice, with LBP, were treated orally with o-vanillin and RG-7112 as single or combination treatments. Treatment reduced LBP and SASP factor release and removed SnCs from the IVD and spinal cord. Treatment also lowered degeneration scores in the IVDs, improved vertebral bone quality, and reduced the expression of pain markers in the spinal cord. Together, our data suggest RG-7112 and o-vanillin as potential disease-modifying drugs for LBP and other painful disorders linked to cell senescence.

Research advances in Pimpinella thellungiana: Nutrients, bioactive compounds, and functional properties benefitting livestock

Growth retardation affects the health and production of livestock, while overexertion can cause sudden cardiac arrest. Both cases are considered to be metabolic disorders and are detrimental to livestock production. Effective measures for relieving or treating these disorders are scarce. However, Pimpinella thellungiana H. Wolff (P. thellungiana), a medicinal herb, has been reported to relieve growth retardation and overexertion in ethnopharmacological clinical trials. This paper summarizes and classifies a total of 106 bioactive compounds that were isolated and identified from P. thellungiana, including flavonoids, simple phenylpropanoids, coumarins, volatile compounds, and simple polyphenols, and discusses its pharmaceutical benefits, including its growth-promoting, antioxidant, anti-inflammatory, anti-atherosclerotic, and hepatoprotective properties. The nutrition, metabolism, biological activities, and pharmacological effects of the principal compounds of P. thellungiana in livestock are reviewed, as well as their potential molecular targets and metabolic signaling pathways in which these compounds are involved. However, the pharmacological and toxicological effects of some compounds have not been well documented, and further investigations of the bioactive compounds are needed. Such studies are crucial for the development of natural drugs or feed additives from P. thellungiana to alleviate growth retardation and mitigate injuries from overexertion in livestock.

Double-Layer Microneedle Patch Loaded with HA-PBA-QCT for Management of Paclitaxel-Induced Peripheral Neuropathic Pain

Chemotherapy-induced neuropathic pain (CINP) is a common adverse effect of antineoplastic drugs, often leading to dose reduction, treatment delays, or cessation of chemotherapy. Chemotherapy agents, like paclitaxel (PTX), damage the somatosensory nervous system by inducing neuroinflammation and oxidative stress, resulting in the sensitization of sensory neurons. Quercetin (QCT), known for its anti-inflammatory, antioxidant, and neuroprotective properties, is investigated for various neurological disorders. This work creates phenylboronic acid-modified hyaluronic acid (HA-PBA) gels with incorporated QCT and fabricates a double-layer microneedle (MN) patch using an HA-PBA-QCT complex in the needles and HA/polyvinyl alcohol (PVA) as the substrate. The crosslinking between PVA and HA-PBA-QCT enables a controlled, sustained release of QCT upon application. This work applies these QCT-loaded microneedle (QMN) patches to the instep skin of PTX-treated mice, which exhibits mechanical allodynia and cold hyperalgesia. Biweekly applications of the QMN patches significantly reduce pain responses. This analgesic effect is associated with the modulation of satellite glial cell activity, decreased macrophage infiltration, and reduced TNF-α and IL-6 levels in dorsal root ganglia (DRGs). Additionally, the treatment improves cellular antioxidant capacity, indicated by upregulated Nrf2 and catalase in DRGs. Overall, these findings suggest that double-layer QMN patches offer long-term anti-inflammatory and antioxidant benefits, potentially alleviating CINP in patients.

Studying targeted oxidation in diabetic cognitive dysfunction based on scientometrics analysis: research progress of natural product approaches

PURPOSE

The aim is to provide new insights for researchers studying the pathogenesis of diabetic cognitive dysfunction and promoting the wider use of natural products in their treatment.

METHOD

First, the Web of Science Core Collection was selected as the data source for a computerized literature search on oxidative stress and diabetic cognitive dysfunction (DCD). Next, Biblimetrix and VOSviewer performed statistical analysis focusing on publication countries, institutions, authors, research hotspots, and emerging directions in the field. Then, through the analysis of keywords and key articles, the forefront of the field is identified. Finally, we discussed the pathogenesis of DCD, the influence of oxidative stress on DCD and the antioxidant effect of natural products on DCD.

RESULT

293 valid papers were obtained. Bibliometrics showed that oxidative stress, diabetes, Alzheimer's disease (AD), cognitive decline, insulin resistance and quercetin were the key words of the symbiotic network.

CONCLUSION

The antioxidant effects of natural products in improving DCD have been extensively studied in preclinical studies, providing potential for their treatment in DCD, but their evaluation in clinical trials is currently uncommon.

Pharmacodynamics (PD), Pharmacokinetics (PK) and PK-PD Modeling of NRF2 Activating Dietary Phytochemicals in Cancer Prevention and in Health

Purpose of Review

Dietary phytochemicals, bioactive compounds derived from plants, have gained increasing attention for their potential role in cancer prevention. Among these, NRF2 (nuclear factor erythroid 2-related factor 2) activating dietary phytochemicals such as curcumin, sulforaphane, ursolic acid, and cyanidin have demonstrated significant antioxidant and anti-inflammatory properties, making them promising agents in chemoprevention. This review examines the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of these dietary phytochemicals, with a focus on their NRF2-mediated effects in cancer prevention.

Recent Findings

Preclinical studies have highlighted the potential of these dietary phytochemicals to modulate oxidative stress and inflammation, key drivers of carcinogenesis. We explore the complexity of their PK/PD properties, influenced by factors such as bioavailability, metabolism, and drug interactions. While most of these phytochemicals follow two compartmental PK, their anti-oxidant and anti-inflammatory effects follow the indirect response (IDR) model. Furthermore, we discuss the application of physiologically based pharmacokinetic (PBPK) modeling to simulate the behavior of these compounds in humans, providing insights for clinical translation.

Summary

The integration of PK-PD analysis into the development of dietary phytochemical-based therapies offers a pathway to optimize dosing strategies, enhance therapeutic efficacy, and improve safety. This review underscores the importance of these compounds as part of cancer interception strategies, particularly in the early stages of cancer development, where they may offer a natural, less toxic alternative to conventional therapies.

Graphical Abstract

The role of quercetin in NLRP3-associated inflammation

Quercetin is a natural flavonoid that is widely found in fruits and vegetables. As an important flavonoid, it exhibits a wide range of biological activities, including antioxidant, anti-inflammatory, antiviral, immunomodulatory, and analgesic activities. Quercetin exerts powerful antioxidant activity by regulating glutathione, enzyme activity, and the production of reactive oxygen species (ROS). Quercetin exerts powerful anti-inflammatory effects by acting on the Nod-like receptor protein 3 (NLRP3) inflammasome. In diabetes, quercetin has been shown to improve insulin sensitivity and reduce high blood sugar level, while, in neurological diseases, it potentially prevents neuronal degeneration and cognitive decline by regulating neuroinflammation. In addition, in liver diseases, quercetin may improve liver inflammation and fibrosis by regulating the NLRP3 activity. In addition, quercetin may improve inflammation in other diseases based on the NLRP3 inflammasome. With this background, in this review, we have discussed the progress in the study on the mechanism of quercetin toward improving inflammation via NLRP3 inflammasome in the past decade. In addition, from the perspective of quercetin glycoside derivatives, the anti-inflammatory mechanism of hyperoside, rutin, and isoquercetin based on NLRP3 inflammasome has been discussed. Moreover, we have discussed the pharmacokinetics of quercetin and its nanoformulation application, with the aim to provide new ideas for further research on the anti-inflammatory effect of quercetin and its glycoside derivatives based on NLRP3 inflammasome, as well as in drug development and application.

A Systematic Review: Quercetin-Secondary Metabolite of the Flavonol Class, with Multiple Health Benefits and Low Bioavailability

The main goal of this systematic review on the flavonol class secondary metabolite quercetin is to evaluate and summarize the existing research on quercetin's potential health benefits, therapeutic properties, and effectiveness in disease prevention and treatment. In addition to evaluating quercetin's potential for drug development with fewer side effects and lower toxicity, this type of review attempts to collect scientific evidence addressing quercetin's roles as an antioxidant, anti-inflammatory, antibacterial, and anticancer agent. In the first part, we analyze various flavonoid compounds, focusing on their chemical structure, classification, and natural sources. We highlight their most recent biological activities as reported in the literature. Among these compounds, we pay special attention to quercetin, detailing its chemical structure, physicochemical properties, and process of biosynthesis in plants. We also present natural sources of quercetin and emphasize its health benefits, such as its antioxidant and anti-inflammatory effects. Additionally, we discuss methods to enhance its bioavailability, analyzing the latest and most effective delivery systems based on quercetin.

Therapeutic Potential of Nutraceuticals against Drug-Induced Liver Injury

Drug-induced liver injury (DILI) continues to be a major concern in clinical practice, thus necessitating a need for novel therapeutic approaches to alleviate its impact on hepatic function. This review investigates the therapeutic potential of nutraceuticals against DILI, focusing on examining the underlying molecular mechanisms and cellular pathways. In preclinical and clinical studies, nutraceuticals, such as silymarin, curcumin, and N-acetylcysteine, have demonstrated remarkable efficacy in attenuating liver injury induced by diverse pharmaceutical agents. The molecular mechanisms underlying these hepatoprotective effects involve modulation of oxidative stress, inflammation, and apoptotic pathways. Furthermore, this review examines cellular routes affected by these nutritional components focusing on their influence on hepatocytes, Kupffer cells, and stellate cells. Key evidence highlights that autophagy modulation as well as unfolded protein response are essential cellular processes through which nutraceuticals exert their cytoprotective functions. In conclusion, nutraceuticals are emerging as promising therapeutic agents for mitigating DILI, by targeting different molecular pathways along with cell processes involved in it concurrently.

Antioxidant Mechanism, Spectroscopic and Pharmacological Properties of Four Flavonoids: DFT, Docking and Molecular Dynamics

Myricetin (1), Quercetin (2), Kaempferol (3) and Kaempferide (4) were flavonoids with phenolic hydroxyl groups. The antioxidant and pharmacological mechanisms of them were investigated in detail. The lowest hydroxyl dissociation enthalpies of 1, 2, 3 and 4 were calculated by DFT, respectively. The hydroxyl dissociation enthalpies of the four flavonoids at the O2 site are the highest. By analyzing the intramolecular hydrogen bonds and HOMO-LUMO orbitals of the four flavonoids, the reasons for their divergence of hydroxyl dissociation enthalpies and antioxidant mechanisms were further investigated. The UV-vis and IR spectra of four flavonoids were compared. The interactions about electrostatic attraction, p-π conjugation and hydrogen bond combined the flavonoid with the target protein closely. The root mean square deviation of peroxisome proliferator-activated receptor γ combined with 1, 2 and 3 increased, while that of PPARγ combined with 4 decreased.

Unraveling the therapeutic potential of quercetin and quercetin-3-O-glucuronide in Alzheimer's disease through network pharmacology, molecular docking, and dynamic simulations

Quercetin is a flavonoid with notable pharmacological effects and promising therapeutic potential. Quercetin plays a significant role in neuroinflammation, which helps reduce Alzheimer's disease (AD) severity. Quercetin (Q) and quercetin 3-O-glucuronide (Q3OG) are some of the most potent antioxidants available from natural sources. However, the natural form of quercetin converted into Q3OG when reacted with intestinal microbes. The study aims to ensure the therapeutic potential of Q and Q3OG. In this study, potential molecular targets of Q and Q3OG were first identified using the Swiss Target Prediction platform and pathogenic targets of AD were identified using the DisGeNET database. Followed by compound and disease target overlapping, 77 targets were placed in that AKT1, EGFR, MMP9, TNF, PTGS2, MMP2, IGF1R, MCL1, MET and PARP1 was the top-ranked target, which was estimated by CytoHubba plug-in. The Molecular docking was performed for Q and Q3OG towards the PDB:1UNQ target. The binding score of Q and Q3OG was - 6.2 kcal/mol and - 6.58 kcal/mol respectively. Molecular dynamics simulation was conducted for Q and Q3OG towards the PDB:1UNQ target at 200 ns. This study's results help identify the multiple target sites for the bioactive compounds. Thus, synthesizing new chemical entity-based quercetin on structural modification may aid in eradicating AD complications.

Revealing the potential bioactive components and mechanism of Qianhua Gout Capsules in the treatment of gouty arthritis through network pharmacology, molecular docking and pharmacodynamic study strategies

Recent clinical studies have confirmed the effectiveness of Qianhua Gout Capsules (QGC) in the treatment of gouty arthritis (GA). However, the specific regulatory targets and mechanisms of action of QGC are still unclear. To address this gap, we utilized network pharmacology, molecular docking, and pharmacodynamic approaches to investigate the bioactive components and associated mechanisms of QGC in the treatment of GA. By employing UPLC-Q Exactive-MS, we identified the compounds present in QGC, with active ingredients defined as those with oral bioavailability ≥30 % and drug similarity ≥0.18. Subsequently, the targets of these active compounds were determined using the TCMSP database, while GA-related targets were identified from DisGeNET, GeneCards, TTD, OMIM, and DrugBank databases. Further analysis including PPI analysis, GO analysis, and KEGG pathway enrichment was conducted on the targets. Validation of the predicted results was performed using a GA rat model, evaluating pathological changes, inflammatory markers, and pathway protein expression. Our results revealed a total of 130 components, 44 active components, 16 potential shared targets, GO-enriched terms, and 47 signaling pathways related to disease targets. Key active ingredients included quercetin, kaempferol, β-sitosterol, luteolin, and wogonin. The PPI analysis highlighted five targets (PPARG, IL-6, MMP-9, IL-1β, CXCL-8) with the highest connectivity, predominantly enriched in the IL-17 signaling pathway. Molecular docking experiments demonstrated strong binding of CXCL8, IL-1β, IL-6, MMP9, and PPARG targets with the top five active compounds. Furthermore, animal experiments confirmed the efficacy of QGC in treating GA in rats, showing reductions in TNF-α, IL-6, and MDA levels, and increases in SOD levels in serum. In synovial tissues, QGC treatment upregulated CXCL8 and PPARG expression, while downregulating IL-1β, MMP9, and IL-6 expression. In conclusion, this study applied a network pharmacology approach to uncover the composition of QGC, predict its pharmacological interactions, and demonstrate its in vivo efficacy, providing insights into the anti-GA mechanisms of QGC. These findings pave the way for future investigations into the therapeutic mechanisms underlying QGC's effectiveness in the treatment of GA.

Comparative Serum and Brain Pharmacokinetics of Quercetin after Oral and Nasal Administration to Rats as Lyophilized Complexes with β-Cyclodextrin Derivatives and Their Blends with Mannitol/Lecithin Microparticles

Quercetin (Que) is one of the most studied flavonoids with strong antioxidant properties ascribed to its ability to bind free radicals and inactivate them. However, the low solubility of the compound along with its inadequate absorption after oral administration limit its beneficial effects. Que's complexation with two different cyclodextrin (CD) derivatives (hydroxypropyl-β-CD and methyl-β-CD) via the neutralization/lyophilization method has been found to improve its physicochemical properties. Moreover, blends of the lyophilized powders with mannitol/lecithin microparticles (MLMPs) have been proposed as candidates for intranasal (IN) administration after in vitro and ex vivo evaluations. In this context, a comparative pharmacokinetic (PK) study of the IN vs oral administration of Que lyophilized powders and their blends with MLMPs (75:25 w/w) was performed on Wistar rats. The PK parameters estimated by a non-compartmental analysis using the sparse data methodology in Phoenix® 8.3 (Certara, Princeton, NJ, USA) illustrated the effectiveness of IN administration either in brain targeting or in reaching the bloodstream. Significant levels of the compound were achieved at both sites, compared to those after oral delivery which were negligible. These results favor the potential application of the prepared Que nasal powders for systemic and nose-to-brain delivery for the prevention and/or treatment of neuroinflammatory degenerative conditions, such as Parkinson's and Alzheimer's disease.

Preparation of caffeic acid grafted chitosan self-assembled micelles to enhance oral bioavailability and antibacterial activity of quercetin

Quercetin (QR) is a naturally occurring flavonoid organic compound that has poor solubility in water and highly unstable in alkaline conditions, resulting in limited absorption in poultry. Consequently, in our experiment, QR was employed as a model compound, encapsulated within the caffeic acid graft chitosan copolymer (CA-g-CS) self-assembled micelles to enhance its solubility, stability and exhibit a synergistic antibacterial effect. The optimization of the formula was carried out using a combination of single-factor experimentation and the response surface method. The in vitro release rate and stability of CA-g-CS-loaded QR micelles (CA-g-CS/QR) in various pH media were studied and the pharmacokinetics in white feather broiler chickens was evaluated in vivo. Additionally, the antibacterial activity was investigated using Escherichia coliCMCC44102 and Escherichia coli of chicken origin as the test strain. The results showed the optimized formula for the self-assembled micelles were 4 mL water, 0.02 mg/mL graft copolymer, and 1 mg QR, stirring at room temperature. The encapsulation efficiency was 72.09%. The resulting CA-g-CS/QR was uniform in size with an average diameter of 375.6 ± 5.9 nm. The release pattern was consistent with the Ritger-Peppas model. CA-g-CS/QR also significantly improved the stability of QR in alkaline condition. The relative bioavailability of CA-g-CS/QR was found to be 1.67-fold that of the reference drug, indicating a substantial increase in the absorption of QR in the broiler. Compared to the original drug, the antibacterial activity of CA-g-CS/QR was significantly enhanced, as evidenced by a reduction of half in the MIC and MBC values. These results suggest that CA-g-CS/QR improves the bioavailability and antibacterial activity of QR, making it a promising candidate for clinical use.

Pharmacokinetic Analysis of Zonarol, a Marine Algal Hydroquinone, in Mice Using HPLC with Fluorescence Detection

Zonarol, which was discovered in the brown algae Dictyopteris undulata, has antibiotic, antioxidative, anti-inflammatory, and neuroprotective hydroquinone properties. Additionally, a daily treatment of zonarol taken orally has been proven to prevent ulcerative colitis and nonalcoholic fatty liver disease in experimentally induced mice models. In this study, to elucidate the physiological behavior of zonarol in vivo, the establishment of quantitative methods for the determination of zonarol in biological samples and basic pharmacokinetics parameters after oral or intravenous administration with purified zonarol to mice were investigated. The zonarol (20-600 ng/mL) in this study was dose-dependently detected using an HPLC-FI system as a single peak on the ODS column with 80% aqueous methanol at 332 nm with an excitation of 293 nm. The pharmacokinetic parameters were derived from a non-compartment analysis of the plasma concentration of zonarol following oral or intravenous treatment in mice. The absolute bioavailability of zonarol was calculated as 25.0%. Interestingly, the maximal distribution of zonarol in the brain (2.525 ± 1.334 µg/g tissue) at 30 min was observed to be higher and slower than that in the liver and kidney at 15 min after bolus intravenous administrations to the mice (10 mg/kg BW). Based on these results, zonarol might be a candidate for a potential drug, an effective tool for drug delivery, or enhancing the treatment of cerebral disease.

Crop, Host, and Gut Microbiome Variation Influence Precision Nutrition: An Example of Blueberries

Epidemiological studies have shown associations between polyphenol-rich fruit intake and bone health, and preclinical studies have shown that blueberries improve bone health. To determine the genotype and dose of blueberries that are effective in ameliorating age-related bone loss, a multi-institutional team of investigators performed in vitro, preclinical, and clinical studies on blueberry varieties that differed in flavonoid profiles. Principal component analysis was used to select blueberry genotypes that varied in anthocyanin profiles. Total phenolic content did not predict the bioavailability of polyphenolic compounds in rats. A range in bioavailability was observed in individual polyphenolic compounds across genotypes. Both alpha and beta diversity analyses indicated that gut microbiome profiles varied with blueberry dose in rats. Additionally, the identification of specific taxa, such as Prevotellaceae_UCG-001 and Coriobacteriales, increasing after blueberry consumption adds to the mounting evidence of their role in polyphenol metabolism. All of the sources of variation can inform blueberry breeding practices to influence precision nutrition.

Profiling of chemical constituents of Matricarla chamomilla L. by UHPLC-Q-Orbitrap-HRMS and in vivo evaluation its anti-asthmatic activity

Matricarla chamomilla L. is native to European countries and widely cultivated in China, especially in Xinjiang. It has been used in Uygur medicine for the treatment of cough caused by asthma. In this study, UHPLC-Q-Orbitrap-MS was used to detect and identify the components from the active fraction of M. Chamomile, 64 compounds were identified by combining the standards, related literatures and mass spectrometry fragments, including 10 caffeoyl quinic acids, 38 flavonoids, 8 coumarins, 5 alkaloids and 3 other compounds. Furtherly, the anti-asthma activity of active fraction of M. Chamomile was investigated in OVA-induced allergic asthma rat model. The results showed that the number of EOS in Penh and bronchoalveolar lavage fluid (BALF) in the group of the active fraction of M. Chamomile was significantly lower than that in the model group. Besides, the active fraction of M. Chamomile can significantly reduce the IgE level and increased glutathione peroxidase (GSH-Px) in the serum of OVA-induced rats, and ameliorated OVA-induced lung injury. Hence, M. Chamomile could be used to treat asthma through their in vivo antioxidant and anti-inflammatory effects. This study explored the potential material basis of M. Chamomile for the treatment of asthma.

Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry Estimation of Quercetin-Loaded Nanoemulsion in Rabbit Plasma: In Vivo-In Silico Pharmacokinetic Analysis Using GastroPlus

In the present study, we developed and validated a rapid, specific, sensitive, and reproducible liquid chromatography-electrospray ionization tandem mass spectrometry method for quantifying quercetin (QT) in rabbit plasma using hydrochlorothiazide as the internal standard. Animals were orally administered with optimized QT-loaded nanoemulsion (QTNE) and QT suspension (QTS), equivalent to 30 mg/kg, to the test and control group, respectively. The blood samples were collected at pre-determined time points up to 48 h. The linearity range was from 5 to 5000 ng mL^-1 with R ² = 0.995. Further, we analyzed the various pharmacokinetic parameters and established the in vitro-in vivo correlation (IVIVC) of QTNE using GastroPlus software. The method was successfully developed and validated, and when applied for the determination of QT in rabbit plasma, it exhibited an increase in C _max from 122.56 ng mL^-1 (QTS) to 286.51 ng mL^-1 (QTNE) (2.34-fold) and AUC_0-48 from 976 ng h mL^-1 (QTS) to 4249 ng h mL^-1 (QTNE) (4.35-fold), indicating improved oral bioavailability QT when administered as QTNE. Statistical analysis revealed that the Loo-Riegelman method (two-compartmental method) best fitted the deconvolution approach (R ² = 0.998, SEP = 4.537, MAE = 2.759, and AIC = 42.38) for establishing the IVIVC. In conclusion, the established bioanalytical method and IVIVC studies revealed that QTNE is a potential carrier for the effective delivery of QT with enhanced oral bioavailability.

Pharmacokinetics and in vitro liver microsomal enzyme metabolism of Xylopic acid

Xylopic acid (XA) is a bioactive diterpene kaurene isolate of the Guinea pepper fruit, Xylopia aethiopica (Annonaceae) with numerous well-established biological effects. In this study, we aimed to fill certain scientific voids in terms of the scientific literature on XA, specifically, its pharmacokinetic (PK) parameters and in vitro liver microsomal enzyme metabolism. A new LC-MS/MS method was developed and validated for the determination of the plasma concentration-time profile of XA. The method was found to be accurate, precise, selective and repeatable with lowest limit of quantification (LLOQ) of 10 ng/mL and run time of 15 min. The maximum plasma concentration (C_max), time at which maximum plasma concentration was attained (T_max), half-life (t_1/2), clearance (CL) and mean residence time (MRT) of XA were 167.03 ± 6.18 ng/mL; 10 h; 13.03 ± 7.33 h; 0.04 ± 0.01 mL/h/kg and 23.83 ± 11.02 h respectively. Six metabolites (M1-M6) were tentatively identified after XA was subjected to in vitro liver microsomal enzyme metabolism. The metabolites were the products of methylation (M1), glucuronidation (M2), deacetylation (M3), glucosylation (M4), hydroxylation and glutamic acid addition (M5) and glutathionylation (M6). The outcome of this study provides useful insights that could guide further research on XA.

In Vitro-In Vivo Study of the Impact of Excipient Emulsions on the Bioavailability and Antioxidant Activity of Flavonoids: Influence of the Carrier Oil Type

The influence of the carrier oil type on the bioavailability and bioactivity of flavonoids (quercetin, kaempferol, and apigenin) was examined using in vitro digestion, in situ intestinal perfusion, and pharmacokinetic studies. Here, medium-chain triglycerides (MCTs), long-chain triglycerides (LCTs), or MCT/LCT mixtures (1:1, w/w) served as the oil phase of excipient emulsions. Overall, the bioavailability and antioxidant activity of flavonoids increased when they were coingested with excipient emulsions. The in vitro bioaccessibility of flavonoids was affected by the carrier oil: LCT (17.9-22.8%) > MCT/LCT (12.1-13.7%) > MCT (9.2-12.6%). These differences were mainly attributed to the fact that the mixed micelles formed after the digestion of LCTs had larger hydrophobic domains to solubilize more flavonoids. However, in vivo pharmacokinetic experiments showed that the flavonoid concentrations in rat serum were comparable for all carrier oils (p > 0.05). Our results assist in formulating excipient emulsions to enhance the efficacy of flavonoids.

Natural Blockers of PD-1/PD-L1 Interaction for the Immunotherapy of Triple-Negative Breast Cancer-Brain Metastasis

The limited treatment options for triple-negative breast cancer with brain metastasis (TNBC-BM) have left the door of further drug development for these patients wide open. Although immunotherapy via monoclonal antibodies has shown some promising results in several cancers including TNBC, it cannot be considered the most effective treatment for brain metastasis. This is due to the protective role of the blood-brain barrier (BBB) which limits the entrance of most drugs, especially the bulky ones such as antibodies, to the brain. For a drug to traverse the BBB via passive diffusion, various physicochemical properties should be considered. Since natural medicine has been a key inspiration for the development of the majority of current medicines, in this paper, we review several naturally-derived molecules which have the potential for immunotherapy via blocking the interaction of programmed cell death protein-1 (PD-1) and its ligand, PD-L1. The mechanism of action, physicochemical properties and pharmacokinetics of these molecules and their theoretical potential to be used for the treatment of TNBC-BM are discussed.

Polyphenolic promiscuity, inflammation-coupled selectivity: Whether PAINs filters mask an antiviral asset

The Covid-19 pandemic has elicited much laboratory and clinical research attention on vaccines, mAbs, and certain small-molecule antivirals against SARS-CoV-2 infection. By contrast, there has been comparatively little attention on plant-derived compounds, especially those that are understood to be safely ingested at common doses and are frequently consumed in the diet in herbs, spices, fruits and vegetables. Examining plant secondary metabolites, we review recent elucidations into the pharmacological activity of flavonoids and other polyphenolic compounds and also survey their putative frequent-hitter behavior. Polyphenols, like many drugs, are glucuronidated post-ingestion. In an inflammatory milieu such as infection, a reversion back to the active aglycone by the release of β-glucuronidase from neutrophils and macrophages allows cellular entry of the aglycone. In the context of viral infection, virions and intracellular virus particles may be exposed to promiscuous binding by the polyphenol aglycones resulting in viral inhibition. As the mechanism's scope would apply to the diverse range of virus species that elicit inflammation in infected hosts, we highlight pre-clinical studies of polyphenol aglycones, such as luteolin, isoginkgetin, quercetin, quercetagetin, baicalein, curcumin, fisetin and hesperetin that reduce virion replication spanning multiple distinct virus genera. It is hoped that greater awareness of the potential spatial selectivity of polyphenolic activation to sites of pathogenic infection will spur renewed research and clinical attention for natural products antiviral assaying and trialing over a wide array of infectious viral diseases.

Bioactivity and Therapeutic Potential of Kaempferol and Quercetin: New Insights for Plant and Human Health

Plant secondary metabolites, especially flavonoids, are major metabolites widely found in plants that play several key roles in plant defence and signalling in response to stress conditions. The most studied among these flavonoids are kaempferol and quercetin due to their anti-oxidative potential and their key roles in the defence system, making them more critical for plant adaptation in stress environments. Kaempferol and quercetin in plants have great therapeutic potential for human health. Despite being well-studied, some of their functional aspects regarding plants and human health need further evaluation. This review summarizes the emerging potential of kaempferol and quercetin in terms of antimicrobial activity, bioavailability and bioactivity in the human body as well as in the regulation of plant defence in response to stresses and as a signalling molecule in terms of hormonal modulation under stress conditions. We also evaluated the safe use of both metabolites in the pharmaceutical industry.

Targeting Oxidative Stress in Intracerebral Hemorrhage: Prospects of the Natural Products Approach

Intracerebral hemorrhage (ICH), the second most common subtype of stroke, remains a significant cause of morbidity and mortality worldwide. The pathological mechanism of ICH is very complex, and it has been demonstrated that oxidative stress (OS) plays an important role in the pathogenesis of ICH. Previous studies have shown that OS is a therapeutic target after ICH, and antioxidants have also achieved some benefits in the treatment of ICH. This review aimed to explore the promise of natural products therapy to target OS in ICH. We searched PubMed using the keywords "oxidative stress in intracerebral hemorrhage" and "natural products in intracerebral hemorrhage". Numerous animal and cell studies on ICH have demonstrated the potent antioxidant properties of natural products, including polyphenols and phenolic compounds, terpenoids, alkaloids, etc. In summary, natural products such as antioxidants offer the possibility of treatment of OS after ICH. However, researchers still have a long way to go to apply these natural products for the treatment of ICH more widely in the clinic.

Potential Pharmaceutical Applications of Quercetin in Cardiovascular Diseases

Quercetin, as a member of flavonoids, has emerged as a potential therapeutic agent in cardiovascular diseases (CVDs) in recent decades. In this comprehensive literature review, our goal was a critical appraisal of the pathophysiological mechanisms of quercetin in relation to the classical cardiovascular risk factors (e.g., hyperlipidemia), atherosclerosis, etc. We also assessed experimental and clinical data about its potential application in CVDs. Experimental studies including both in vitro methods and in vivo animal models mainly outline the following effects of quercetin: (1) antihypertensive, (2) hypolipidemic, (3) hypoglycemic, (4) anti-atherosclerotic, and (5) cardioprotective (suppressed cardiotoxicity). From the clinical point of view, there are human studies and meta-analyses implicating its beneficial effects on glycemic and lipid parameters. In contrast, other human studies failed to demonstrate consistent favorable effects of quercetin on other cardiometabolic risk factors such as MS, obesity, and hypertension, underlying the need for further investigation. Analyzing the reason of this inconsistency, we identified significant drawbacks in the clinical trials’ design, while the absence of pharmacokinetic/pharmacodynamic tests prior to the studies attenuated the power of clinical results. Therefore, additional well-designed preclinical and clinical studies are required to examine the therapeutic mechanisms and clinical efficacy of quercetin in CVDs.

Developing the liquid chromatography-mass spectrometry method for simultaneously quantifying five components in rat serums after oral administration of hawthorn aqueous extracts and its application to a pharmacokinetic study

Hawthorn, one of the widely-used traditional Chinese medicines, has been used to treat dyspepsia, hyperlipidemia, and cardiovascular disease in the clinic. Our previous study revealed that gallic acid, neochlorogenic acid, cryptochlorogenic acid, vitexin, and quercetin were active components of hawthorn. In this study, a simple, precise, and reliable liquid chromatography-mass spectrometry method was developed for the simultaneous quantification of five components in rat serums. The separation was achieved on the Hypersil GOLD C₁₈ column, and the mobile phases consisted of 0.1% acetic acid water and methanol at a flow rate of 0.3 mL/min. The mass spectrometry data acquisition was performed on Q-Extractive-Orbitrap mass spectrometry with an electrospray ionization source in negative ion mode. The proposed liquid chromatography-mass spectrometry method was validated in terms of linearity, intra- and inter-precision, accuracy, recoveries, matrix effects, and stability. Then this newly proposed liquid chromatography-mass spectrometry method was successfully applied to a pharmacokinetic study on rats after oral administration of hawthorn aqueous extracts. This study provided relevant information on the pharmacokinetics of active components of hawthorn and explained the underlying mechanism of their bioactivity.

Protective Effect of Quercetin 3-O-Glucuronide against Cisplatin Cytotoxicity in Renal Tubular Cells

Quercetin, a flavonoid with promising therapeutic potential, has been shown to protect from cisplatin nephrotoxicity in rats following intraperitoneal injection, but its low bioavailability curtails its prospective clinical utility in oral therapy. We recently developed a micellar formulation (P-quercetin) with enhanced solubility and bioavailability, and identical nephroprotective properties. As a first aim, we herein evaluated the oral treatment with P-quercetin in rats, which displayed no nephroprotection. In order to unravel this discrepancy, quercetin and its main metabolites were measured by HPLC in the blood and urine after intraperitoneal and oral administrations. Whilst quercetin was absorbed similarly, the profile of its metabolites was different, which led us to hypothesize that nephroprotection might be exerted in vivo by a metabolic derivate. Consequently, we then aimed to evaluate the cytoprotective capacity of quercetin and its main metabolites (quercetin 3-O-glucoside, rutin, tamarixetin, isorhamnetin and quercetin 3-O-glucuronide) against cisplatin toxicity, in HK-2 and NRK-52E tubular cell lines. Cells were incubated for 6 h with quercetin, its metabolites or vehicle (pretreatment), and subsequently 18 h in cotreatment with 10-300 μM cisplatin. Immediately after treatment, cell cultures were subject to the MTT technique as an index of cytotoxicity and photographed under light microscopy for phenotypic assessment. Quercetin afforded no direct cytoprotection and quercetin-3-O-glucuronide was the only metabolite partially preventing the effect of cisplatin in cultured tubule cells. Our results identify a metabolic derivative of quercetin contributing to its nephroprotection and prompt to further explore exogenous quercetin-3-O-glucuronide in the prophylaxis of tubular nephrotoxicity.

Anti-Inflammatory, Antioxidant, Moisturizing, and Antimelanogenesis Effects of Quercetin 3-O-β-D-Glucuronide in Human Keratinocytes and Melanoma Cells via Activation of NF-κB and AP-1 Pathways

Quercetin 3-O-β-D-glucuronide (Q-3-G), the glucuronide conjugate of quercetin, has been reported as having anti-inflammatory properties in the lipopolysaccharide-stimulated macrophages, as well as anticancer and antioxidant properties. Unlike quercetin, which has been extensively described to possess a wide range of pharmacological activities including skin protective effects, the pharmacological benefits and mechanisms Q-3-G in the skin remained to be elucidated. This study focused on characterizing the skin protective properties, including anti-inflammatory and antioxidant properties, of Q-3-G against UVB-induced or H₂O₂-induced oxidative stress, the hydration effects, and antimelanogenesis activities using human keratinocytes (HaCaT) and melanoma (B16F10) cells. Q-3-G down-regulated the expression of the pro-inflammatory gene and cytokine such as cyclooxygenase-2 (COX-2) and tumor necrosis factor (TNF)-α in H₂O₂ or UVB-irradiated HaCaT cells. We also showed that Q-3-G exhibits an antioxidant effect using free radical scavenging assays, flow cytometry, and an increased expression of nuclear factor erythroid 2- related factor 2 (Nrf2). Q-3-G reduced melanin production in α-melanocyte-stimulating hormone (α-MSH)-induced B16F10 cells. The hydration effects and mechanisms of Q-3-G were examined by evaluating the moisturizing factor-related genes, such as transglutaminase-1 (TGM-1), filaggrin (FLG), and hyaluronic acid synthase (HAS)-1. In addition, Q-3-G increased the phosphorylation of c-Jun, Jun N-terminal kinase (JNK), Mitogen-activated protein kinase (MAPK) kinase 4 (MKK4), and TAK1, involved in the MAPKs/AP-1 pathway, and the phosphorylation of IκBα, IκB kinase (IKK)-α, Akt, and Src, involved in the NF-κB pathway. Taken together, we have demonstrated that Q-3-G exerts anti-inflammatory, antioxidant, moisturizing, and antimelanogenesis properties in human keratinocytes and melanoma cells through NF-κB and AP-1 pathways.

Trans-ε-Viniferin Encapsulation in Multi-Lamellar Liposomes: Consequences on Pharmacokinetic Parameters, Biodistribution and Glucuronide Formation in Rats

Trans-ε-viniferin (εVin) is a resveratrol dimer exhibiting promising biological activities for human health. Its bioavailability being low, the development of encapsulation methods would be used to overcome this issue. The aim of this study was to measure the consequences of the encapsulation of εVin in multilamellar liposomes on its pharmacokinetic parameters, metabolism and tissue distribution in rats. After oral administration of εVin (20 mg/kg body weight), either as free or encapsulated forms, plasmas were sequentially collected (from 0 to 4 h) as well as liver, kidneys and adipose tissues (4 h after administration) and analyzed by LC-HRMS. The glucuronide metabolites (εVG) were also produced by hemisynthesis for their quantification in plasma and tissues. The encapsulation process did not significantly modify the pharmacokinetic parameters of εVin itself. However, a significant increase of the T1/2 was noticed for εVG after administration of the encapsulated form as compared to the free form. An accumulation of εVin and εVG in adipose tissues was noticed, and interestingly a significant increase of the latter in the mesenteric one after administration of the encapsulated form was highlighted. Since adipose tissues could represent storage depots, and encapsulation allows for prolonging the exposure time of glucuronide metabolites in the organism, this could be of interest to promote their potential biological activities.

Integrated Phytochemical Analysis Based on UPLC-MS/MS and Network Pharmacology Approaches to Explore the Effect of Odontites vulgaris Moench on Rheumatoid Arthritis

Odontites vulgaris Moench has the effect of clearing away heat, detoxification, dispelling wind, and clearing dampness. In this study, the potential anti-inflammatory compounds of O. vulgaris were investigated using ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) combined with the network pharmacology approach and further confirmed on an LPS-activated RAW 264.7 macrophage model. Monomer compounds were prepared from the active fraction using modern advanced separation and purification methods. UPLC-Q-Exactive HRMS was used to identify the chemical compounds in the active fractions of O. vulgaris. D-mannitol, geniposidic acid, salidroside, shanzhiside methyl ester, eleutheroside B, geniposide, 7,8-dihydroxycoumarin, gardoside methyl ester, arenarioside, vanillic acid, p-hydroxy-cinnamic acid, melampyroside, syringaresinol, tricin, and diosmetin were isolated from O. vulgaris for the first time. A compound database of O. vulgaris was established based on the existing literature to predict the mechanism of O. vulgaris in the treatment of rheumatoid arthritis. The results suggest that the PI3K-Akt pathway mediates O. vulgaris and deserves more attention in the treatment of RA. Finally, the anti-rheumatoid arthritis effects of the four target compounds were validated with the decreased levels of NO, TNF-α, IL-6 and IL-1β in RAW 264.7 macrophage cells treated with LPS. The present study explored the potential targets and signaling pathways of O. vulgaris in the treatment of RA, which may help to illustrate the mechanisms involved in the action of O. vulgaris and may provide a better understanding of the relationship between O. vulgaris and RA. This study provides novel insights into the development of new drugs and utilization of Mongolian traditional Chinese medicine resources.

Effects of Nelumbo nucifera Leaf Extract on Obesity

The two main components from a Nelumbo nucifera leaf extract (NnEx) were investigated for their ability to prevent triglyceride accumulation and promoting lipolysis. Sun-dried Nelumbo nucifera leaves were immersed in hot water to extract the soluble components, and the resulting solution was analyzed by LC-MS and nuclear magnetic resonance. The results showed that quercetin-3-O-ß-glucuronide (Q3GA) and quercetin were the key components of the NnEx. In vitro experiments confirmed that quercetin and Q3GA functioned in lipid metabolism by promoting triglyceride degradation through inhibition of the cAMP pathway. In vivo experiments showed that NnEx ingestion inhibited the accumulation of neutral fats in ICR mice and transitioned the hepatocytes of type II diabetic KK-Ay mice out of glycogenosis. These results highlight the ability of NnEx to control metabolism by modulating fat and sugar absorption and may provide an interesting novel treatment for obesity and related lifestyle diseases such as type II diabetes.

Spontaneous conversion of prenyl halides to acids: application in metal-free preparation of deuterated compounds under mild conditions

Here we reveal a simple generation of deuterium halide (DX) from common and inexpensive reagents readily available in a synthetic chemistry laboratory, i.e. prenyl-, allyl-, and propargyl halides, under mild conditions. We envisaged that in situ generation of an acid, deuterium halide, would be useful for acid-catalyzed reactions and could be employed for organocatalytic deuteration. The present work reports a metal-free method for deuterium labeling covering a broad range of substrate including phenolic compounds (i.e. flavonoids and stilbenes), indoles, pyrroles, carbonyl compounds, and steroids. This method was also applied for commonly used drugs such as loxoprofen, haloperidol, stanolone, progesterone, androstenedione, donepezil, ketorolac, adrenosterone, cortisone, pregnenolone, and dexamethasone. A gram-scale chromatography-free synthesis of some deuterated compounds is demonstrated in this work. This work provides a simple, clean and by-product-free, site-selective deuteration, and the deuterated products are obtained without chromatographic separation. When applying these initiators for other acid-catalyzed reactions, the deuterium isotope effects of DX may provide products which are different from those obtained from reactions using common acids. Although the mechanism of the spontaneous transformation of prenyl halides to acid is unclear, this overlooked chemistry may be useful for many reactions.

Transit and Metabolic Pathways of Quercetin in Tubular Cells: Involvement of Its Antioxidant Properties in the Kidney

Quercetin is a flavonoid with antioxidant, antiviral, antimicrobial, and anti-inflammatory properties. Therefore, it has been postulated as a molecule with great therapeutic potential. The renoprotective capacity of quercetin against various toxins that produce oxidative stress, in both in vivo and in vitro models, has been shown. However, it is not clear whether quercetin itself or any of its metabolites are responsible for the protective effects on the kidney. Although the pharmacokinetics of quercetin have been widely studied and the complexity of its transit throughout the body is well known, the metabolic processes that occur in the kidney are less known. Because of that, the objective of this review was to delve into the molecular and cellular events triggered by quercetin and/or its metabolites in the tubular cells, which could explain some of the protective properties of this flavonoid against oxidative stress produced by toxin administration. Thus, the following are analyzed: (1) the transit of quercetin to the kidney; (2) the uptake mechanisms of quercetin and its metabolites from plasma to the tubular cells; (3) the metabolic processes triggered in those cells, which affect the accumulation of metabolites in the intracellular space; and (4) the efflux mechanisms of these compounds and their subsequent elimination through urine. Finally, it is discussed whether those processes that are mediated in the tubular cells and that give rise to different metabolites are related to the antioxidant and renoprotective properties observed after the administration of quercetin.

Assessment of Metabolic Interaction between Repaglinide and Quercetin via Mixed Inhibition in the Liver: In Vitro and In Vivo

Repaglinide (RPG), a rapid-acting meglitinide analog, is an oral hypoglycemic agent for patients with type 2 diabetes mellitus. Quercetin (QCT) is a well-known antioxidant and antidiabetic flavonoid that has been used as an important ingredient in many functional foods and complementary medicines. This study aimed to comprehensively investigate the effects of QCT on the metabolism of RPG and its underlying mechanisms. The mean (range) IC₅₀ of QCT on the microsomal metabolism of RPG was estimated to be 16.7 (13.0–18.6) μM in the rat liver microsome (RLM) and 3.0 (1.53–5.44) μM in the human liver microsome (HLM). The type of inhibition exhibited by QCT on RPG metabolism was determined to be a mixed inhibition with a K_i of 72.0 μM in RLM and 24.2 μM in HLM as obtained through relevant graphical and enzyme inhibition model-based analyses. Furthermore, the area under the plasma concentration versus time curve (AUC) and peak plasma concentration (C_max) of RPG administered intravenously and orally in rats were significantly increased by 1.83- and 1.88-fold, respectively, after concurrent administration with QCT. As the protein binding and blood distribution of RPG were observed to be unaltered by QCT, it is plausible that the hepatic first-pass and systemic metabolism of RPG could have been inhibited by QCT, resulting in the increased systemic exposure (AUC and C_max) of RPG. These results suggest that there is a possibility that clinically significant pharmacokinetic interactions between QCT and RPG could occur, depending on the extent and duration of QCT intake from foods and dietary supplements.

Method Development and Validation for Simultaneous Determination of Six Flavonoids in Rat Eyes after Oral Administration of Diospyros kaki Leaves Extract by UPLC-MS/MS

A robust ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technique was proven effective for simultaneous characterization of six flavonoids including quercetin-3-O-beta-galactoside (Q3GAL), quercetin-3-O-beta-glucoside (Q3GLU), quercetin-3-(2-galloylglucoside) (Q3GG), kaempferol-3-O-beta-galactoside (K3GAL), kaempferol-3-O-beta-glucoside (K3GLU), and kaempferol-3-(2-galloylglucoside) (K3GG) in rat eyes. By investigation of corresponding validation parameters (linearity, selectivity, precision, accuracy, matrix effect, extraction recovery, and stability), the method was verified to be within current acceptable criteria. Thereafter, the validated method enabled quantification of the six compounds successful in rat eyes after oral administration of ethanol extract Diospyros kaki (EEDK) at 0, 3, 15, 35, 60, 120 min.

HPLC coupled with quadrupole time of flight tandem mass spectrometry for analysis of glycosylated components from the fresh flowers of two congeneric species: Robinia hispida L. and Robinia pseudoacacia L

Developing methods for the systematic and rapid identification of the chemical compositions of fresh plant tissues has long attracted the attention of phytochemists and pharmacologists. In the present study, based on highly efficient sample pretreatment and high-throughput analysis of high-performance liquid chromatography coupled with quadrupole time of flight tandem mass spectrometry data using molecular networks, a method was developed for systematically analyzing the chemical constituents of the fresh flowers of Robinia hispida L. and Robina pseudoacacia L., two congeneric ornamental species that lack prior consideration. A total of 44 glycosylated structures were characterized. And on the basis of establishing of the fragmentation pathways of 11 known flavonoid glycosides, together with the molecular networking analysis, 18 other ions of flavonoid glycosides in five classes were clustered. Moreover, 15 soyasaponins/triterpenoid glycosides were tentatively identified by comparison of their tandem mass spectrometry characteristic ions with those reported in the literature or the online Global Natural Product Social Molecular Networking database. The water extracts were separated by flash chromatography, which resulted in the discovery of one new compound, named rohispidascopolin, along with five known entities. The pharmacological targets were predicted by SwissTargetPrediction.

Water Extract of Lotus Leaf Alleviates Dexamethasone-Induced Muscle Atrophy via Regulating Protein Metabolism-Related Pathways in Mice

Muscle atrophy is an abnormal condition characterized by loss of skeletal muscle mass and function and is primarily caused by injury, malnutrition, various diseases, and aging. Leaf of lotus (Nelumbo nucifera Gaertn), which has been used for medicinal purposes, contains various active ingredients, including polyphenols, and is reported to exert an antioxidant effect. In this study, we investigated the effect of water extract of lotus leaf (LL) on muscle atrophy and the underlying molecular mechanisms of action. Amounts of 100, 200, or 300 mg/kg/day LL were administered to dexamethasone (DEX)-induced muscle atrophy mice for 4 weeks. Micro-computed tomography (CT) analysis revealed that the intake of LL significantly increased calf muscle volume, surface area, and density in DEX-induced muscle atrophy mice. Administration of LL recovered moving distance, grip strength, ATP production, and body weight, which were decreased by DEX. In addition, muscle damage caused by DEX was also improved by LL. LL reduced the protein catabolic pathway by suppressing gene expression of muscle atrophy F-Box (MAFbx; atrogin-1), muscle RING finger 1 (MuRF1), and forkhead box O (FoxO)3a, as well as phosphorylation of AMP-activated kinase (AMPK). The AKT-mammalian target of the rapamycin (mTOR) signal pathway, which is important for muscle protein synthesis, was increased in LL-administered groups. The HPLC analysis and pharmacological test revealed that quercetin 3-O-beta-glucuronide (Q3G) is a major active component in LL. Thus, Q3G decreased the gene expression of atrogin-1 and MuRF1 and phosphorylation of AMPK. This compound also increased phosphorylation levels of mTOR and its upstream enzyme AKT in DEX-treated C2C12 cells. We identified that LL improves muscle wasting through regulation of muscle protein metabolism in DEX-induced muscle atrophy mice. Q3G is predicted to be one of the major active phenolic components in LL. Therefore, we propose LL as a supplement or therapeutic agent to prevent or treat muscle wasting, such as sarcopenia.

Quercetin metabolites from Hibiscus sabdariffa contribute to alleviate glucolipotoxicity-induced metabolic stress in vitro

Polyphenols from Hibiscus sabdariffa (HS) alleviate obesity-related metabolic complications but the metabolites responsible for such effects are unknown. We aimed to elucidate which of the potential plasma metabolites from a polyphenol-enriched HS (PEHS) extract contributed for the reversion of glucolipotoxicity-induced metabolic stress using 3T3-L1 adipocyte and INS 832/13 pancreatic β-cell models under glucolipotoxic conditions. PEHS extract, quercetin (Q) and quercetin-3-O-glucuronide (Q3GA) showed stronger capacity to decrease glucolipotoxicity-induced ROS generation than ascorbic acid or chlorogenic acid. PEHS extract, Q and Q3GA decreased secretion of cytokines (leptin, TNF-α, IGF-1, IL-6, VEGF, IL-1α, IL-1β and CCL2) and reduced CCL2 expression at transcriptional level. In addition, PEHS extract, Q and Q3GA reduced triglyceride accumulation, which occurred through fatty acid synthase (FASN) downregulation, AMPK activation and mitochondrial mass and biogenesis restoration via PPARα upregulation. Electron microscopy confirmed that PEHS extract and Q3GA decreased mitochondrial remodeling and mitophagy. Virtual screening leads us to postulate that Q and Q3GA might act as agonists of these protein targets at specific sites. These data suggest that Q and Q3GA may be the main responsible compounds for the capacity of PEHS extract to revert glucolipotoxicity-induced metabolic stress through AMPK-mediated decrease in fat storage and increase in fatty acid oxidation, though other compounds of the extract may contribute to this capacity.

Traditional uses, phytochemistry, and pharmacology of Ficus hispida L.f.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Ficus hispida L.f. (Moraceae) has long been used as a traditional medicine in India, China, Sri Lanka, Australia, and Myanmar in the treatment of diarrhea, ulcer, anemia, diabetes, inflammation, and cancer.

AIM OF THE REVIEW

This review provides a systematic comment on the botany, traditional uses, and phytochemical and pharmacological studies of F. hispida, with an aim to make critical update of the current knowledge and obtain opportunities for further therapeutic potential.

MATERIALS AND METHODS

The information was derived from scientific literature databases including PubMed, Baidu Scholar, Google Scholar, Web of Science, and Science Direct. Additional information was gathered from books, Ph.D. and M.Sc. dissertations, and unpublished materials.

RESULTS AND DISCUSSION

F. hispida is used especially in Chinese and Indian traditional medical systems as a remedy for skin disorders, respiratory diseases, and urinary diseases. Wound healing, anti-inflammatory, antinociceptive, sedative, antidiarrheal, antiulcer, antimicrobial, antioxidant, hepatoprotective, antineoplastic, and antidiabetic activities have been reported for crude extracts and isolated metabolites, but the methodologies in these studies often have inadequate design and low technical quality. More than 76 compounds have been isolated from F.hispida, including sesquiterpenoids and triterpenoids, flavonoids, coumarins, phenylpropionic acids, benzoic acid derivatives, alkaloids, steroids, other glycosides, and alkanes, but the method of bioassay-guided fractionation is seldom applied in the isolation from F. hispida.

CONCLUSION

F. hispida is used widely in traditional medicines and has multiple pharmacological effects that could support traditional uses. However, pharmacological studies should be viewed with caution because of the inappropriate experimental design. More in vitro and in vivo research is urgently needed to study the molecular mechanisms and assess the effective and safe dose of F. hispida.

Haemodynamic effects of the flavonoid quercetin in rats revisited

Background and Purpose

The flavonoid quercetin increased the in vitro potency of the α₁‐antagonist tamsulosin to reduce phenylephrine‐dependent arterial contractions by 10‐fold. To examine if this supplement–drug interaction luxates hypotensive and orthostatic events in vivo, several set of studies were conducted in spontaneously hypertensive (SHR) and normotensive (Wistar Kyoto [WKY]) rats.

Experimental Approach

First, in rats pretreated with quercetin or its vehicle, responses to phenylephrine and tamsulosin were examined. Second, tamsulosin‐induced changes in renal, mesenteric, hindquarter and carotid conductance were compared in quercetin‐ and vehicle‐treated rats instrumented with Doppler flow probes. Animals were also placed on a tilt table to record regional haemodynamic changes to orthostatic challenges. Third, adult SHR were instrumented with telemeters to measure 24‐hr patterns of BP. Recordings were made before and during a 5‐week oral treatment of quercetin. Finally, pre‐hypertensive SHR were treated with quercetin from 4 to 8 weeks of age and arterial pressure was measured at 8 and 12 weeks.

Key Results

Pretreatment with quercetin did not influence the responses to phenylephrine and tamsulosin, in neither WKY nor SHR. While tamsulosin treatment and tilting lowered BP and increased conductance in all vascular beds, effect size was not influenced by pretreatment with quercetin. Prolonged treatment with quercetin, in either prehypertensive SHR or adult SHR with established hypertension did not lower BP.

Conclusions and Implications

Cumulatively, these data demonstrate that quercetin does not amplify haemodynamic effects of tamsulosin or tilting in vivo in rats and has no effect on BP development in SHR.

An Innovative Approach to the Preparation of Plasma Samples for UHPLC-MS Analysis

A new sample processing method for analyzing flavonol metabolites in plasma using enzymatic proteolysis was developed and validated. Four endopeptidases were examined regarding their influence on the analyte recovery of quercetin-3- O-glucuronide (Q3GlcA). Methanol was added to inactivate and precipitate the enzymes, and samples were concentrated via evaporation prior to UHPLC-MS analysis. Quercetin-3- O-rutinoside (Q3Rut) was used as an internal standard. The selectivity and accuracy of the established UHPLC-ESI-MS ⁿ method showed a coefficient of variation (CV) of the repeatability of the measuring instrument of 1.7% for Q3GlcA. The average recovery of Q3GlcA was approximately 67% with an interday method precision of 24% and r = 46.9 as its repeatability. Therefore, enzymatic proteolysis has proven to be a suitable alternative to the methods previously described in the literature, such as solid-phase extraction (SPE). Still, the method has only been validated for Q3GlcA, but its applicability to other substance classes seems possible.