Cell-based assays in combination with ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry for screening bioactive capilliposide C metabolites generated by rat intestinal microflora

Deciphering the metabolic profile and anti-colorectal cancer mechanism of Capilliposide A using ultra performance liquid chromatography mass spectrometry combined with non-targeted metabolomics studies

Colorectal cancer is a highly prevalent malignancy that threatens human health worldwide. Despite the availability of chemotherapy as a primary treatment option, individuals with CRC undergoing frequent chemotherapy are susceptible to developing drug resistance, which can result in poor treatment outcomes. Consequently, there is an urgent need to discover new bioactive compounds for the treatment of CRC. Capilliposide A is a triterpenoid saponin that is extracted from Lysimachia capillipes Hemsl. Although it has been reported that LC-A exhibits good bioactivity, its metabolic profile and potential mechanism underlying its anti-CRC effects remain unknown. In this study, the metabolic products of LC-A in rat plasma, feces, and urine were identified using an LC-MS platform. In addition, LC-MS-based metabolomics was employed to investigate the mechanism of LC-A against CRC. The results showed that LC-A significantly inhibited CRC cell proliferation, attenuated tumor growth, and alleviated metabolic abnormalities in CRC-bearing mice. Furthermore, the levels of p-cresol sulfate and phenylacetylglycine in CRC model plasma decreased, with an increment in sphingosine 1-phosphate, D-tryptophan, and L-2-aminoadipic acid. These metabolite levels can be reversed by LC-A treatment. These metabolite alterations were related to the sphingolipid and amino acid metabolic pathways, demonstrating that LC-A anti-CRC effects were regulated through the modulation of underlying metabolism. Additionally, seven metabolites of LC-A were characterized in rat feces, plasma, and urine. This study offers a scientific foundation for elucidating the metabolism of LC-A and its treatment of colorectal cancer.

Potential roles of gut microbes in biotransformation of natural products: An overview

Natural products have been extensively applied in clinical practice, characterized by multi-component and multi-target, many pharmacodynamic substances, complex action mechanisms, and various physiological activities. For the oral administration of natural products, the gut microbiota and clinical efficacy are closely related, but this relationship remains unclear. Gut microbes play an important role in the transformation and utilization of natural products caused by the diversity of enzyme systems. Effective components such as flavonoids, alkaloids, lignans, and phenols cannot be metabolized directly through human digestive enzymes but can be transformed by enzymes produced by gut microorganisms and then utilized. Therefore, the focus is paid to the metabolism of natural products through the gut microbiota. In the present study, we systematically reviewed the studies about gut microbiota and their effect on the biotransformation of various components of natural products and highlighted the involved common bacteria, reaction types, pharmacological actions, and research methods. This study aims to provide theoretical support for the clinical application in the prevention and treatment of diseases and provide new ideas for studying natural products based on gut biotransformation.

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.

In Vitro and In Situ Characterization of the Intestinal Absorption of Capilliposide B and Capilliposide C from Lysimachia capillipes Hemsl

The goal of this investigation was to determine the processes and mechanism of intestinal absorption for capilliposide B (CAPB) and capilliposide C (CAPC) from the Chinese herb, Lysimachia capillipes Hemsl. An analysis of basic parameters, such as drug concentrations, time, and behavior in different intestinal segments was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS). The susceptibility of CAPB and CAPC to various inhibitors such as P-glycoprotein (P-gp) inhibitor (verapamil); multidrug resistance-associated protein 2 (MRP2) inhibitor (indomethacin); cytochrome P450 protein 3A4 (CYP3A4) inhibitor (ketoconazole); and the co-inhibitor of P-gp, MRP2 and CYP3A4 (cyclosporine A) were assessed using both caco-2 cell monolayer and single-pass intestinal perfusion (SPIP) models. As a result, CAPB and CAPC are both poorly absorbed in the intestines and exhibited segment-dependent permeability. The intestinal permeability of CAPB and CAPC were significantly increased by the co-treatment of verapamil, indomethacin. In addition, the intestinal permeability of CAPB was also enhanced by ketoconazole and cyclosporine A. It can be concluded that the intestinal absorption mechanisms of CAPB and CAPC involve processes such as facilitated passive diffusion, efflux transporters, and enzyme-mediated metabolism. Both CAPB and CAPC are suggested to be substrates of P-gp and MRP2. However, CAPB may interact with the CYP3A4 system.

Mechanical Proofreading: A General Mechanism to Enhance the Fidelity of Information Transfer Between Cells

The cells and receptors of the immune system are mechanically active. Single molecule force spectroscopy, traction force microscopy, and molecular tension probe measurements all point to the importance of piconewton (pN) molecular forces in immune function. For example, forces enhance the ability of a T cell to discriminate between nearly identical antigens. The role of molecular forces at these critical immune recognition junctions is puzzling because mechanical forces generally facilitate bond dissociation, potentially increasing the difficulty for a receptor to recognize its cognate antigen. The advantage molecular forces confer in the process of immune recognition is not clear. Why would cells expend energy to exert force on the critical, but tenuous bonds that mediate immune surveillance? Do molecular forces provide some advantage to the immune system? The premise of this review is that molecular forces provide a specificity advantage to immune cells. Inspired by the recent discovery that receptor forces regulate immune signaling in T cells and B cells, we dub this notion "mechanical proofreading," akin to more classic kinetic proofreading models. During the process of mechanical proofreading, cells exert pN receptor forces on receptor-ligand interactions, deliberately increasing the energy cost of the immune recognition process in exchange for increased specificity of signaling. Here, we review the role of molecular forces in the immune system and suggest how these forces may facilitate mechanical proofreading to increase the specificity of the immune response.

Metabolic Stability and Metabolite Characterization of Capilliposide B and Capilliposide C by LC⁻QTRAP⁻MS/MS

Capilliposide B (LC-B) and Capilliposide C (LC-C), two new triterpenoid saponins extracted from Lysimachia capillipes Hemsl, exhibit potential anticancer activity both in vitro and in vivo. However, their metabolic process remains unclear. In this study, the metabolic stability of LC-B, LC-C, and Capilliposide A (LC-A, a bioactive metabolite of LC-B and LC-C) was investigated in human, rat, and mouse liver microsomes, respectively. Thereafter, their metabolites were identified and characterized after oral administration in mice. As a result, species difference was found in the metabolic stability of LC-B and LC-C. All three compounds of interest were stable in human and rat liver microsomes, but LC-B and LC-C significantly degraded in mouse liver microsomes. The metabolic instability of LC-B and LC-C was mainly caused by esterolysis. Moreover, 19 metabolites were identified and characterized in mouse biological matrices. LC-B and LC-C mainly underwent deglycosylation and esterolysis, accompanied by dehydration, dehydrogenation, and hydroxylation as minor metabolic reactions. Finally, the metabolic pathway of LC-B and LC-C in mice was proposed. Our results updated the preclinical metabolism and disposition process of LC-B and LC-C, which provided additional information for better understanding efficacy and safety.

Capilliposide C Sensitizes Esophageal Squamous Carcinoma Cells to Oxaliplatin by Inducing Apoptosis Through the PI3K/Akt/mTOR Pathway

BACKGROUND Although platinum-based chemotherapy is the most effective strategy for esophageal cancer, toxicity and drug resistance limit the dose administration and the application of chemotherapy. Capilliposide C (CPS-C) is isolated from the Chinese herb Lysimachia capillipes Hemsl and is approved to be effective against carcinomas. However, the activity of CPS-C against esophageal cancer remains unclear. The present study was conducted to assess the chemosensitizing effects of CPS-C for enhancing the therapeutic efficacy of oxaliplatin in esophageal squamous carcinoma cells and explore the underlying mechanism. MATERIAL AND METHODS Human esophageal squamous cell carcinoma (ESCC) TE-1 and TE-2 were used. Several in vitro and in vivo analyses were carried out, including MTT, Annexin V/PI, Western blot, and TUNEL and immunohistochemistry in a xenograft model. RESULTS CPS-C significantly enhanced the proliferative inhibition and apoptotic effect of oxaliplatin in ESCC cells. Oxaliplatin combined with CPS-C decreased the expressions of PI3K, phospho-Akt, phospho-mTOR, Bcl-2, and Bcl-XL, and increased the expression of Bax and caspase-3 significantly compared to oxaliplatin-only treatment. Furthermore, in the ESCC xenograft model, CPS-C significantly enhanced the anti-cancer effects and apoptosis of oxaliplatin. CONCLUSIONS The results indicated that CPS-C enhanced the anti-proliferative and apoptotic effect of oxaliplatin by modulating the PI3K/Akt/mTOR pathway on ESCC in vitro and in vivo.

Tissue distribution of capilliposide B, capilliposide C and their bioactive metabolite in mice using liquid -tandem mass spectrometry

Lysimachia capillipes Hemsl (Primulaceae), a folk medicinal plant in China, showed significant anti-tumor activities in vivo and in vitro. Capilliposide B (LC-B) and capilliposide C (LC-C) are the main bioactive components in this plant. To explore their tissue distribution, a reliable bioanalytical method for the quantification of LC-B, LC-C and their bioactive metabolite, capilliposide A (LC-A), in mouse tissues was developed and validated. In this study, the tissue distribution profiles of the three compounds were examined after intravenous administration of pure LC-B and oral administration of total saponins of L. capillipes Hemsl extract (LCE) for 10 days. Method validation was conducted over the curve range 10.0-5000 ng/mL for all three analytes in various tissue homogenates. The relative standard deviation of intra-day and inter-day precision of the QC samples was <14.7%, and the accuracy ranged from 85.9 to 114.0%. The results indicated that LC-B was rapidly and widely distributed throughout the whole body except for muscle following intravenous administration of LC-B. In addition, LC-A was only in liver, intestine, lung and stomach. After oral administration of LCE, LC-B and LC-C were distributed into various tissues. The highest levels were observed in stomach and intestine.