LC-ESI-MS/MS method for the simultaneous determination of isoformononetin, daidzein, and equol in rat plasma: Application to a preclinical pharmacokinetic study

Predicting Pharmacokinetics of Active Constituents in Spatholobi caulis by Using Physiologically Based Pharmacokinetic Models

BACKGROUND/OBJECTIVES

Spatholobi Caulis (SPC) is a medicinal plant that mainly grows in China and Southeast Asian countries and commonly used in clinics; the pharmacokinetic characteristics in humans need to be determined. This study was to establish the physiologically based pharmacokinetic (PBPK) models of multiple active constituents from SPC in rats, and predict the pharmacokinetic properties of rats with different dosages and extrapolated to humans.

METHODS

The parameters were collected based on our previous study and by prediction using ADMET Predictor software predict. The PBPK models for 3'-methoxydadizein (1), 8-O-methylretusin (2), daidzin (3), and isolariciresinol (4) administered orally to rats were established using GastroPlus software. These models were employed to simulate the pharmacokinetic properties in rats across various dosages, and subsequently extrapolated to humans. The calculated parameters including Cmax, Tmax, and AUC were compared with observed values. The accuracy of the PBPK models was assessed using fold-error (FE) values.

RESULT

The FE values ranged from 1.03 to 1.52, meeting the PBPK model regulations where FE should be less than 2. The sensitivity analysis focusing on the absorption amount and AUC0→t of these four constituents in humans was also conducted. These results confirm the successful establishment of PBPK models of these four constituents from SPC in this study, and these models were applicable to predict pharmacokinetics across various doses and extrapolate across species.

CONCLUSIONS

The PBPK models of four constituents can be used to predict the pharmacokinetic characteristics in humans after oral administration of SPC and provide useful data for safe and rational medication in clinical practice.

Neuroprotective potential of formononetin, a naturally occurring isoflavone phytoestrogen

The increased prevalence of neurological illnesses is a burgeoning challenge to the public healthcare system and presents greater financial pressure. Formononetin, an O-methylated isoflavone, has gained a lot of attention due to its neuroprotective potential explored in several investigations. Formononetin is widely found in legumes and several types of clovers including Trifolium pratense L., Astragalus membranaceus, Sophora tomentosa, etc. Formononetin modulates various endogenous mediators to confer neuroprotection. It prevents RAGE activation that results in the inhibition of neuronal damage via downregulating the level of ROS and proinflammatory cytokines. Furthermore, formononetin also increases the expression of ADAM-10, which affects the pathology of neurodegenerative disease by lowering tau phosphorylation, maintaining synaptic plasticity, and boosting hippocampus neurogenesis. Besides these, formononetin also increases the expression of antioxidants, Nrf-2, PI3K, ApoJ, and LRP1. Whereas, reduces the expression of p65-NF-κB and proinflammatory cytokines. It also inhibits the deposition of Aβ and MAO-B activity. An inhibition of Aβ/RAGE-induced activation of MAPK and NOX governs the protection elicited by formononetin against inflammatory and oxidative stress-induced neuronal damage. Besides this, PI3K/Akt and ER-α-mediated activation of ADAM10, ApoJ/LRP1-mediated clearance of Aβ, and MAO-B inhibition-mediated preservation of dopaminergic neurons integrity are the major modulations produced by formononetin. This review covers the biosynthesis of formononetin and key molecular pathways modulated by formononetin to confer neuroprotection.

Preclinical pharmacokinetic exploration of a novel osteoporotic quinazolinone-benzopyran-indole hybrid (S019-0385) using LC-MS/MS

1. The current investigation was to develop and validate the LC-MS/MS method in order to analyse the various pharmacokinetic parameters of S019-0385. A sensitive, selective, and robust LC-MS/MS approach was established and validated for measuring S019-0385 in female mice plasma and tissue, using optimal multiple reaction monitoring (MRM) transition m/z 488.25/329.12 on positive mode. On a Waters Symmetry Shield C18 column, the analyte was separated using acetonitrile and deionised water with formic acid within 6 min at 0.7 mL/min. Linearity (R2 ≥ 0.99) was observed across 0.195-100 ng/mL concentration range using linear least-squares regression.2. Blood-to-plasma ratio and plasma protein drug binding (%) in mice and human was assessed and found to be less than 1 and >83%, respectively. Absolute bioavailability (%F) of S019-0385 in female Swiss mice was exhibited to be 6.90%. Percent dose excreted S019-0385 in unchanged form through urine and faecal was found to be less than 2% and 0.5%, respectively.3. Following oral administration at 5 mg/kg, the concentration of S019-0385 in tissue distribution was found to be in the order of C small intestine > C bone > C lung > C spleen > C kidney > C liver > C heart > C brain.

Parent-Metabolite Pharmacokinetic Modeling of Formononetin and Its Active Metabolites in Rats after Oral Administration of Formononetin Formulations

Formononetin is a major isoflavone contained in propolis and is reported to exhibit various pharmacological effects. However, the use of formononetin in pharmaceutical industry is limited due to its low bioavailability and solubility. There had been several efforts on formononetin formulation development, but further study is required to acquire optimal formulation. The aim of this study is to conduct pharmacokinetic (PK) evaluations after the oral administration of three formononetin formulations (20 mg/kg) in male Sprague Dawley rats. Then, a parent-metabolite PK model for formononetin was developed and evaluated for the first time. To do this, a simultaneous analysis method for formononetin and its active metabolites, daidzein, dihydrodaidzein and equol in rat plasma was developed using ultra-performance liquid chromatography tandem mass spectrometry. The separation was performed using a gradient elution of water and acetonitrile and a Kinetex C₁₈ column (2.1 mm × 100 mm, 1.7 µm particle size) at a temperature of 30 ± 5 °C. The simultaneous analytical method developed in this study was validated according to international guidance and was successfully applied for the pharmacokinetic study. The time-plasma concentrations of formononetin and daidzein were well described by a two-compartment model combined with a metabolite compartment. Additionally, plasma protein binding assay was conducted in male rat plasma. The findings from the study could be used as a fundamental for the future development of formononetin as a pharmaceutical product.

Simultaneous determination of daidzein, its prodrug and major conjugative metabolites in rat plasma and application in a pharmacokinetic study

The developed method successfully validated that the synthesized prodrug improved the bioavailability of DAN by reducing its phase II metabolites.

Dietary Isoflavones Alter Gut Microbiota and Lipopolysaccharide Biosynthesis to Reduce Inflammation

The etiopathogenesis of multiple sclerosis (MS) is strongly affected by environmental factors such as diet and the gut microbiota. An isoflavone-rich (ISO) diet was previously shown to reduce the severity of MS in the animal model experimental autoimmune encephalomyelitis (EAE). Translation of this concept to clinical trial where dietary isoflavones may be recommended for MS patients will require preliminary evidence that providing the isoflavone-rich diet to people with MS (PwMS) who lack phytoestrogen-metabolizing bacteria has beneficial effects. We have previously shown that the gut microbiota of PwMS resembles the gut microbiota of mice raised under a phytoestrogen-free (phyto-free) diet in that it lacks phytoestrogen-metabolizing bacteria. To investigate the effects of phytoestrogens on the microbiota inflammatory response and EAE disease severity we switched the diet of mice raised under a phyto-free (PF) diet to an isoflavone-rich diet. Microbiota analysis showed that the change in diet from one that is ISO to one that is PF reduces beneficial bacteria such as Bifidobacterium species. In addition we observed functional differences in lipopolysaccharide (LPS) biosynthesis pathways. Moreover LPS extracted from feces of mice fed an ISO diet induced increased production of anti-inflammatory cytokines from bone marrow-derived macrophages relative to fecal-LPS isolated from mice fed a PF diet. Eventually mice whose diet was switched from a PF diet to an ISO diet trended toward reduced EAE severity and mortality. Overall we show that an isoflavone-rich diet specifically modulates LPS biosynthesis of the gut microbiota imparts an anti-inflammatory response and decreases disease severity.

Isoformononetin, a dietary isoflavone protects against streptozotocin induced rat model of neuroinflammation through inhibition of NLRP3/ASC/IL-1 axis activation

AIMS

Isoformononetin (IFN), a methoxyl isoflavone present in most of human dietary supplements. However, being a highly potent antioxidant and anti-inflammatory molecule, its activity against neuronal oxidative stress and neuroinflammation has not been explored till now. The present study was inquested to assess the antioxidant, anti-apoptotic and anti-inflammatory activity of IFN against streptozotocin induced neuroinflammation in different brain regions of rat.

MAIN METHODS

Four groups of animals were subjected to treatment as control, toxic control (STZ; single intracerebrovascular injection), third group (STZ + IFN; 20 mg/kg p.o.), fourth group (IFN) for 14 days. The different brain regions of rats were evaluated for inflammatory, apoptotic and biochemical antioxidant markers. The brain tissues were further assessed for gene expression, immunohistochemical and western blotting examination for localization of inflammasome cascade expression that plays a pivotal role in neuroinflammation.

KEY FINDINGS

The modulation in oxidant/antioxidant status after exposure of STZ was significantly balanced after administration of IFN to rats. Further, IFN was also found to be an apoptotic agent as it modulates the apoptotic gene (Bax) and anti-apoptotic gene (BcL₂) expression. IFN significantly curtailed the augmented protein expression of NLRP3, NLRP2, ASC, NFκBP65, IL-1β and caspase-1 due to STZ administration in cortex and hippocampus rat brain regions.

SIGNIFICANCE

The aforementioned results proclaim the neuroprotective functioning of IFN against STZ induced inflammation. IFN significantly prevents the neuroinflammation by decreasing the generation of ROS that reduces the activation of NLRP3/ASC/IL-1 axis thereby exerting neuroprotection as evidenced in rat model of STZ induced neuroninflammation.

Open sandwich fluorescence-linked immunosorbent assay for detection of soy isoflavone glycosides

To detect major soy isoflavone glycosides, namely daidzin (DZ) and genistin (GEN), novel open sandwich fluorescence-linked immunosorbent assay (os-FLISA) was developed by taking advantage of enhanced interactions between variable regions of heavy (VH) and light chain (VL) domains in the presence of an antigen. The VH and VL genes were expressed in Escherichia coli as a chimera protein with green fluorescence protein (AcGFP1) and maltose-binding protein (MBP), respectively. Comprehensive characterization of os-FLISA displayed nearly the same specificity as parental DZ- and GEN-specific monoclonal antibody, demonstrating the potential of the developed assay for detection of both DZ and GEN. Their detectable range in this system exhibited at 0.1-12.5 μg mL-1. Subsequent validation analysis revealed that os-FLISA was reliable and accurate system for detection of total soy isoflavone glycosides. Notably, this is the first FLISA based on an open sandwich system, which can be employed for the detection of small molecules.

A rapid ultra high performance liquid chromatography-tandem mass spectrometry method for the quantification of daidzein, its valine carbamate prodrug, and glucuronide in rat plasma samples: Comparison of the pharmacokinetic behavior of daidzine valine carbamate prodrugs

Two valine carbamate prodrugs of daidzein were designed to improve its bioavailability. To compare the pharmacokinetic behavior of these prodrugs with different protected phenolic hydroxyl groups of daidzein, a rapid and sensitive method for simultaneous quantification of daidzein, its valine carbamate prodrug, and daidzein-7-O-glucuronide in rat plasma was developed and validated in this study. The samples were processed using a fast one-step protein precipitation method with methanol added to 50 μL of plasma and were analyzed by ultra-high performance liquid chromatography with tandem mass spectrometry. To improve the selectivity, peak shape, and peak elution, several key factors, especially stationary phase and the composition of the mobile phase, were tested, and the analysis was performed using the Kinetex^® C18 column (100 × 2.1 mm, 2.6 μm) within only 2.6 min under optimal conditions. The established method exhibited good linearity over the concentration range of 2.0-1000 ng/mL for daidzein, and 8.0-4000 ng/mL for the prodrug and daidzein-7-O-glucuronide. The accuracy of the quality control samples was between 95.5 and 110.2% with satisfactory intra- and interday precision (relative standard deviation values < 10.85%), respectively. This sensitive, rapid, low-cost, and high-throughput method was successfully applied to compare the pharmacokinetic behavior of different daidzein carbamate prodrugs.

Analysis of chemical variations between raw and wine-processed Ligustri Lucidi Fructus by ultra-high-performance liquid chromatography-Q-Exactive Orbitrap/MS combined with multivariate statistical analysis approach

Ligustri Lucidi Fructus (LLF) is the dried and mature fruit of Ligubtrum lucidum Ait., which has the effect of nourishing the liver and kidney, brightening the eyes and promoting the growth of black hair. Wine-processed LLF is commonly used in traditional Chinese medicine; however, the processing mechanisms are still unclear. Herein, a system data acquisition and mining strategy was designed to investigate the chemical profile differences between the raw and wine-processed LLF, based on high-performance liquid chromatography-Orbitrap high resolution mass spectrometry coupled with multivariate statistical analysis including principal component analysis and partial least square analysis. Afterwars, a total of 55 components were found to be the main contributors to the significant difference between raw and wine-processed LLF by comparison with chromatographic behaviors, intact precursor ions, and characteristic MS fragmentation patterns. In addition, 10 main constituents of raw and wine-processed LLF were simultaneously determined by UHPLC-MS/MS for analyzing the content variations. Some structural transformation mechanisms during wine processing were deduced from the results. The results may provide a scientific foundation for deeply elucidating the wine-processing mechanism of LLF.

Rapid Characterizaiton of Chemical Constituents of the Tubers of Gymnadenia conopsea by UPLC-Orbitrap-MS/MS Analysis

Gymnadenia conopsea R. Br. is a traditional Tibetan medicinal plant that grows at altitudes above 3000 m, which is used to treat neurasthenia, asthma, coughs, and chronic hepatitis. However, a comprehensive configuration of the chemical profile of this plant has not been reported because of the complexity of its chemical constituents. In this study, a rapid and precise method based on ultra-high performance liquid chromatography (UPLC) combined with an Orbitrap mass spectrometer (UPLC–Orbitrap–MS/MS) was established in both positive- and negative-ion modes to rapidly identify various chemical components in the tubers of G. conopsea for the first time. Finally, a total of 91 compounds, including 17 succinic acid ester glycosides, 9 stilbenes, 6 phenanthrenes, 19 alkaloids, 11 terpenoids and steroids, 20 phenolic acid derivatives, and 9 others, were identified in the tubers of G. conopsea based on the accurate mass within 3 ppm error. Furthermore, many alkaloids, phenolic acid derivates, and terpenes were reported from G. conopsea for the first time. This rapid method provides an important scientific basis for further study on the cultivation, clinical application, and functional food of G. conopsea.

A Simple and Rapid LC-MS/MS Method for Quantification of Total Daidzein, Genistein, and Equol in Human Urine

Isoflavones and isoflavandiols have shown many health benefits, such as reducing cardiovascular disease, cancer, age-related disease, and osteoporosis. However, to investigate the relationships between consumption of isoflavones and their health benefits, it is important to be able to accurately quantify exposure in the large numbers of samples typically produced in association studies (i.e., several thousands). Current methods rely on solid-phase extraction protocols for sample cleanup, resulting in protracted extraction and analysis times. Here, we describe a fast and easy sample preparation method of human urine samples for subsequent quantification of daidzein, genistein (isoflavones), and equol (isoflavandiol) using LC-MS/MS. Sample preparation involves only the addition of dimethylformamide (DMF) and formic acid (FA) after enzymatic hydrolysis of their metabolites by a β-glucuronidase and sulfatase mixture. The method was validated by precision, linearity, accuracy, recoveries, limit of detection (LOD), and limit of quantification (LOQ). Linear calibration curves have been shown by daidzein, genistein, and equol. The correlation coefficients values are r ² > 0.99 for daidzein, genistein, and equol. LOD for daidzein and genistein was 1 ng/ml and equol was 2 ng/ml. Recoveries were >90%, and the relative standard deviation for intraday (<10%) and interday (≤20% over 10 days) was good. This method is suitable for quantification of isoflavones and the microbial metabolite equol in human urine and is particularly useful where large numbers of samples require analysis.