Comparative Pharmacokinetic Study of Taxifolin after Oral Administration of Fructus Polygoni Orientalis Extract in Normal and Fibrotic Rats by UPLC-MS/MS

The potential of flavonoids in hepatic fibrosis: A comprehensive review

BACKGROUND

Hepatic fibrosis is a pathophysiological process of extracellular matrix abnormal deposition induced by multiple pathogenic factors. Currently, there is still a lack of effective and non-toxic drugs for treating fibrosis in clinic. Flavonoids are polyphenolic compounds synthesized in plants and modern pharmacological studies confirmed flavonoids exhibit potent hepatoprotective effect.

PURPOSE

Summarize literature to elaborate the mechanism of HF and evaluate the potential of flavonoids in HF, aiming to provide a new perspective for future research.

METHODS

The literatures about hepatic fibrosis and flavonoids are collected via a series of scientific search engines including Google Scholar, Elsevier, PubMed, CNKI, WanFang, SciFinder and Web of Science database. The key words are "flavonoids", "hepatic fibrosis", "pharmacokinetic", "toxicity", "pathogenesis" "traditional Chinese medicine" and "mechanism" as well as combination application.

RESULTS

Phytochemical and pharmacological studies revealed that about 86 natural flavonoids extracted from Chinese herbal medicines possess significantly anti-fibrosis effect and the mechanisms maybe through anti-inflammatory, antioxidant, inhibiting hepatic stellate cells activation and clearing activated hepatic stellate cells.

CONCLUSIONS

This review summarizes the flavonoids which are effective in HF and the mechanisms in vivo and in vitro. However, fewer studies are focused on the pharmacokinetics of flavonoids in HF model and most studies are limited to preclinical studies, therefore there is no reliable data from clinical trials for the development of new drugs. Further in-depth research related it can be conducted to improve the bioavailability of flavonoids and serve the development of new drugs.

Effect and mechanism of quercetin or quercetin-containing formulas against COVID-19: From bench to bedside

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the global coronavirus disease 2019 (COVID-19) pandemic since 2019. Immunopathogenesis and thromboembolic events are central to its pathogenesis. Quercetin exhibits several beneficial activities against COVID-19, including antiviral, anti-inflammatory, immunomodulatory, antioxidative, and antithrombotic effects. Although several reviews have been published, these reviews are incomplete from the viewpoint of translational medicine. The authors comprehensively evaluated the evidence of quercetin against COVID-19, both basically and clinically, to apply quercetin and/or its derivatives in the future. The authors searched the PubMed, Embase, and the Cochrane Library databases without any restrictions. The search terms included COVID-19, SARS-CoV-2, quercetin, antiviral, anti-inflammatory, immunomodulatory, thrombosis, embolism, oxidative, and microbiota. The references of relevant articles were also reviewed. All authors independently screened and reviewed the quality of each included manuscript. The Cochrane Risk of Bias Tool, version 2 (RoB 2) was used to assess the quality of the included randomized controlled trials (RCTs). All selected studies were discussed monthly. The effectiveness of quercetin against COVID-19 is not solid due to methodological flaws in the clinical trials. High-quality studies are also required for quercetin-containing traditional Chinese medicines. The low bioavailability and highly variable pharmacokinetics of quercetin hinder its clinical applications. Its positive impact on immunomodulation through reverting dysbiosis of gut microbiota still lacks robust evidence. Quercetin against COVID-19 does not have tough clinical evidence. Strategies to improve its bioavailability and/or to develop its effective derivatives are needed. Well-designed RCTs are also crucial to confirm their effectiveness in the future.

Simultaneous Determination of Three Flavonoids in Rat Plasma of Masson Pinus Needles (Pinus massoniana L.) Extracts by UHPLC-MS/MS and Application to Pharmacokinetics Studies after Oral and Transdermal Administration

Pinus massoniana needles, a traditional herb, were applied to prevent hair loss in China. Studies available mainly focused on pine needle flavonoids with various biological activities. However, there has been no pharmacokinetics study of the flavonoids from Pinus needles extract. A selective and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously quantify taxifolin, quercetin and catechin in rat plasma. To separate the three constituents, an Agilent Extend-C18 column (2.1 mm × 100 mm, 1.8 μm) was used with a mobile phrase of (A) 0.1% formic acid and (B) acetonitrile. The analytes were measured by multiple reaction monitoring in the negative ionization mode. There was good linearity in the established UHPLC-MS/MS method, with a coefficient of determination (r2) of >0.99. The accuracy, intra-day and inter-day precision and recovery were all satisfactory and these 3 compounds were stable under the tested conditions. The validated method in this study was successfully applied to pharmacokinetic study in healthy rats after oral and transdermal administration of Pinus needles extract. The results could provide further research foundation for pine needle extract as external preparations.

A Comparative Analysis of Neuroprotective Properties of Taxifolin and Its Water-Soluble Form in Ischemia of Cerebral Cortical Cells of the Mouse

Cerebral ischemia, and, as a result, insult, attacks up to 15 million people yearly in the world. In this connection, the development of effective preventive programs and methods of therapy has become one of the most urgent problems in modern angiology and pharmacology. The cytoprotective action of taxifolin (TAX) in ischemia is well known, but its limitations are also known due to its poor solubility and low capacity to pass through the hematoencephalic barrier. Molecular mechanisms underlying the protective effect of TAX in complex systems such as the brain remain poorly understood. It is known that the main cell types of the brain are neurons, astrocytes, and microglia, which regulate the activity of each other through neuroglial interactions. In this work, a comparative study of cytoprotective mechanisms of the effect of TAX and its new water-soluble form aqua taxifolin (aqTAX) was performed on cultured brain cells under ischemia-like conditions (oxygen-glucose deprivation (OGD)) followed by the reoxygenation of the culture medium. The concentration dependences of the protective effects of both taxifolin forms were determined using fluorescence microscopy, PCR analysis, and vitality tests. It was found that TAX began to effectively inhibit necrosis and the late stages of apoptosis in the concentration range of 30-100 µg/mL, with aqTAX in the range of 10-30 µg/mL. At the level of gene expression, aqTAX affected a larger number of genes than TAX; enhanced the basic and OGD/R-induced expression of genes encoding ROS-scavenging proteins with a higher efficiency, as well as anti-inflammatory and antiapoptotic proteins; and lowered the level of excitatory glutamate receptors. As a result, aqTAX significantly inhibited the OGD-induced increase in the Ca²⁺ levels in the cytosol ([Ca²⁺]_i) in neurons and astrocytes under ischemic conditions. After a 40 min preincubation of cells with aqTAX under hypoxic conditions, these Ca²⁺ signals were completely inhibited, resulting in an almost complete suppression of necrotic death of cerebral cortical cells, which was not observed with the use of classical TAX.

Diverse Galactooligosaccharides Differentially Reduce LPS-Induced Inflammation in Macrophages

The effects of natural and synthetic galactooligosaccharides (GOS) on inflammation were explored by investigating the structure-activity relationship between the degree of GOS polymerization and in vitro anti-inflammatory activity, together with the potential underlying mechanism of their anti-inflammatory effects. The results demonstrated that GOS had strong anti-inflammatory effects in lipopolysaccharide (LPS)-induced RAW264.7 macrophages, including the inhibition of nitric oxide production and the reduced expression of pro-inflammatory mediators (interleukin-1β, interleukin-6, and tumor necrosis factor α), induced nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and proteins related to the Toll-like receptor 4 (TLR4)/nuclear factor (NF)-κB signaling pathway. GOS4, which has the highest degree of polymerization, exerted the strongest anti-inflammatory activity among the GOS examined. More importantly, our findings confirmed the anti-inflammatory effects of GOS on RAW264.7 macrophages via the TLR4/NF-κB pathway. Our experimental results could provide further support for the exploration of GOS in human nutrition and health.

Ethyl acetate extract of Tibetan medicine Rhamnella gilgitica ameliorated type II collagen-induced arthritis in rats via regulating JAK-STAT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Rhamnella gilgitica Mansf. et Melch. (སེང་ལྡེང་།, RG) is a traditional Tibetan medicinal plant that is currently grown throughout Tibet. According to the theory of Tibetan medicine, RG is efficient for removing rheumatism, reducing swelling, and relieving pain. Hence, it has been used for the treatment of rheumatoid arthritis (RA) in Tibet for many years. However, there are no previous reports on the anti-RA activities of ethyl acetate extract of RG (RGEA).

AIM OF THE STUDY

This study aimed to explore the anti-RA effect and mechanism of RGEA on collagen-induced arthritis (CIA) in rats.

MATERIALS AND METHODS

The CIA model was established in male Wister rats by intradermal injection of bovine type II collagen and Complete Freund's Adjuvant at the base of the tail and left sole, respectively. The rats were orally administered with RGEA (9.71, 19.43, or 38.85 mg/kg) for 23 days. The body weight, swelling volume, arthritis index score, thymus and spleen indices, and pathological changes were observed to evaluate the effect of RGEA on RA. Furthermore, the inflammatory cytokines in serum, such as interleukin1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin6 (IL-6), interleukin17 (IL-17), interferon-γ (INF-γ), interleukin4 (IL-4), and interleukin10 (IL-10) were measured by enzyme linked immunosorbent assay (ELISA) to explore the anti-inflammatory effects of RGEA. The terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining was used to examine apoptosis. Finally, the protein and gene expression of B-cell lymphoma-2-associated X (Bax), B-cell lymphoma 2 (Bcl-2), Caspase3, janus-activated kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), suppressor of cytokine signaling1 (SOCS1), and 3 (SOCS3) in synovial tissue were detected using immunohistochemistry and real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

After the treatment with RGEA, the body weight of rats was restored, both the arthritis index and paw swelling were suppressed, and spleen and thymus indices were decreased. RGEA reduced the inflammatory cells and synovial hyperplasia in the synovial tissue of the knee joint, and suppressed bone erosion. Meanwhile, RGEA decreased the levels of IL-1β, IL-6, IL-17, TNF-α, and INF-γ, while increased the levels of IL-4 and IL-10. TUNEL fluorescence apoptosis results confirmed that RGEA obviously promoted the apoptosis of synovial cells. Further studies showed that RGEA inhibited the proteins and mRNAs expression of JAK2 and STAT3 as well as increased the proteins and mRNAs expression of SOCS1 and SOCS3. In addition, RGEA upregulated the expression of Bax and Caspase3, and downregulated the expression of Bcl-2.

CONCLUSION

The anti-RA effectof RGEA might be related to the promotion of apoptosis and inhibition of inflammation, which regulated the JAK-STAT pathway.