Simultaneous determination of glaucocalyxin A and glaucocalyxin B in rat plasma by LC-MS/MS and its application to a pharmacokinetic study after oral administration of Rabdosia japonica extract

Potential clinical applications of phytopharmaceuticals for the in-patient management of coagulopathies in COVID-19

Thrombotic complications occur in many cardiovascular pathologies and have been demonstrated in COVID‐19. The currently used antithrombotic drugs are not free of adverse reactions, and COVID‐19 patients in particular, when treated with a therapeutic dose of an anticoagulant do not receive mortality benefits. The clinical management of COVID‐19 is one of the most difficult tasks for clinicians, and the search for safe, potent, and effective antithrombotic drugs may benefit from exploring naturally bioactive molecules from plant sources. This review describes recent advances in understanding the antithrombotic potential of herbal drug prototypes and points to their future clinical use as potent antithrombotic drugs. Although natural products are perceived to be safe, their clinical and therapeutic applications are not always apparent or accepted. More in‐depth studies are necessary to demonstrate the clinical usefulness of plant‐derived, bioactive compounds. In addition, holistic approaches in systematic investigations and the identification of antithrombotic mechanisms of the herbal bioactive molecule(s) need to be conducted in pre‐clinical studies. Moreover, rigorous studies are needed to compare the potency of herbal drugs to that of competitor chemical antithrombotic drugs, and to examine their interactions with Western antithrombotic medicines. We have also proposed a road map to improve the commercialization of phytopharmaceuticals.

Glycoproteins From Rabdosia japonica var. glaucocalyx Regulate Macrophage Polarization and Alleviate Lipopolysaccharide-Induced Acute Lung Injury in Mice via TLR4/NF-κB Pathway

Background and Aims:Rabdosia japonica var. glaucocalyx is a traditional Chinese medicine (TCM) for various inflammatory diseases. This present work aimed to investigate the protective effects of R. japonica var. glaucocalyx glycoproteins on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the potential mechanism.

Methods: Glycoproteins (XPS) were isolated from R. japonica var. glaucocalyx, and homogeneous glycoprotein (XPS5-1) was purified from XPS. ANA-1 cells were used to observe the effect of glycoproteins on the secretion of inflammatory mediators by enzyme-linked immunosorbent assay (ELISA). Flow cytometry assay, immunofluorescence assay, and Western blot analysis were performed to detect macrophage polarization in vitro. The ALI model was induced by LPS via intratracheal instillation, and XPS (20, 40, and 80 mg/kg) was administered intragastrically 2 h later. The mechanisms of XPS against ALI were investigated by Western blot, ELISA, and immunohistochemistry.

Results:In vitro, XPS and XPS5-1 downregulated LPS-induced proinflammatory mediators production including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and nitric oxide (NO) and upregulated LPS-induced IL-10 secretion. The LPS-stimulated macrophage polarization was also modulated from M1 to M2. In vivo, XPS maintained pulmonary histology with significantly reducing protein concentration and numbers of mononuclear cells in bronchoalveolar lavage fluid (BALF). The level of IL-10 in BALF was upregulated by XPS treatment. The level of cytokines including TNF-α, IL-1β, and IL-6 was downregulated. XPS also decreased infiltration of macrophages and polymorphonuclear leukocytes (PMNs) in lung. XPS suppressed the expression of key proteins in the TLR4/NF-κB signal pathway.

Conclusion: XPS was demonstrated to be a potential agent for treating ALI. Our findings might provide evidence supporting the traditional application of R. japonica var. glaucocalyx in inflammation-linked diseases.

Natural Terpenoids as Neuroinflammatory Inhibitors in LPS-stimulated BV-2 Microglia

Neuroinflammation is a typical feature of many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Microglia, the resident immune cells of the brain, readily become activated in response to an infection or an injury. Uncontrolled and overactivated microglia can release pro-inflammatory and cytotoxic factors and are the major culprits in neuroinflammation. Hence, research on novel neuroinflammatory inhibitors is of paramount importance for the treatment of neurodegenerative diseases. Bacterial lipopolysaccharide, widely used in the studies of brain inflammation, initiates several major cellular activities that critically contribute to the pathogenesis of neuroinflammation. This review will highlight the progress on terpenoids, an important and structurally diverse group of natural compounds, as neuroinflammatory inhibitors in lipopolysaccharidestimulated BV-2 microglial cells over the last 20 years.

Validation of an UHPLC-MS/MS Method for the Determination of Glaucocalyxin A, a Novel Potent Negative Akt Regulator in Rat Plasma, Lung and Brain Tissues: Application to a Pharmacokinetic Study

Glaucocalyxin A, a novel potent negative Akt regulator, is a major active constituent of Rabdosia japonica. A simple, specific and sensitive ultra-high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the quantification of glaucocalyxin A in rat plasma, lung and brain tissues after intravenous administration. Sample preparation was carried out through a simple liqiud-liquid extraction with ethyl acetate using bullatine A as internal standard. The chromatographic separation was achieved by using an Agilent ZORBAX Eclipse Plus C18 column (3.0 mm × 100 mm, 1.8 μm) with a mobile phase of acetonitrile and water containing 0.1% formic acid in a gradient elution. Mass spectrometry analysis was conducted in positive ionization mode with multiple reaction monitoring transitions at m/z 333.2 → 157.1 for glaucocalyxin A and m/z 344.2 → 128.1 for IS. Calibration curves were linear over the ranges of 20.0-4000 ng/mL for both plasma and tissue samples (r2 > 0.99). The Lower limit of quantification (LLOQ) was 0.284 ng/mL. The intra-day and inter-day precision relative standard deviation (RSD%) were <14.9%, while the accuracy ranged from -12.5 to 17.0% for LLOQ and quality control samples. This UHPLC-MS/MS method was successfully applied in the pharmacokinetics, lung and brain tissue distributions of glaucocalyxin A after intravenous administration.

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

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

The experimental process flow.