Plant-derived flavonoids are a potential source of drugs for the treatment of liver fibrosis

Liver fibrosis is a dynamic pathological process that can be triggered by any chronic liver injury. If left unaddressed, it will inevitably progress to the severe outcomes of liver cirrhosis or even hepatocellular carcinoma. In the past few years, the prevalence and fatality of hepatic fibrosis have been steadily rising on a global scale. As a result of its intricate pathogenesis, the quest for pharmacological interventions targeting liver fibrosis has remained a formidable challenge. Currently, no pharmaceuticals are exhibiting substantial clinical efficacy in the management of hepatic fibrosis. Hence, it is of utmost importance to expedite the development of novel therapeutics for the treatment of this condition. Various research studies have revealed the ability of different natural flavonoid compounds to alleviate or reverse hepatic fibrosis through a range of mechanisms, which are related to the regulation of liver inflammation, oxidative stress, synthesis and secretion of fibrosis-related factors, hepatic stellate cells activation, and proliferation, and extracellular matrix synthesis and degradation by these compounds. This review summarizes the progress of research on different sources of natural flavonoids with inhibitory effects on liver fibrosis over the last decades. The anti-fibrotic effects of natural flavonoids have been increasingly studied, making them a potential source of drugs for the treatment of liver fibrosis due to their good efficacy and biosafety.

Exploration of the Potential Targets and Molecular Mechanism of Carthamus tinctorius L. for Liver Fibrosis Based on Network Pharmacology and Molecular Docking Strategy

Carthamus tinctorius L. (Honghua, HH) is an herbal medicine and functional food widely used to treat chronic liver diseases, including liver fibrosis. By using network pharmacology and molecular docking experiments, the present study aims to determine the bioactive components, potential targets, and molecular mechanisms of HH for treating liver fibrosis. The components of HH were screened from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and literature, and the SwissTargetPrediction database was used to predict the treatment targets of HH. Genecards and DisGeNET databases contained targets for liver fibrosis, and the STRING database provided networks of protein–protein interactions. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed using the Database of Annotation, Visualization and Integrated Discovery. The protein–protein interactive network and drug–component–major target–pathway interactive network were visualized and analyzed by Cytoscape software. Finally, Autodock Vina and Discovery Studio software were used for molecular docking Validation. A total of 23 candidate bioactive compounds with 187 treatment targets of HH were acquired from the databases and literature. A total of 121 overlapping targets between HH and liver fibrosis were found to provide the molecular basis for HH on liver fibrosis. Quercetin, beta carotene, and lignan were identified as key components with targeting to ESR1, PIK3CA, and MTOR. HH is engaged in the intervention of various signaling cascades associated with liver fibrosis, such as PI3K/AKT/mTOR pathway, MAPK pathway, and PPAR pathway. In conclusion, HH treats liver fibrosis through multi-component, multi-target, and multi-pathway mechanisms.

Bioactive Substances in Safflower Flowers and Their Applicability in Medicine and Health-Promoting Foods

Safflower flowers (Carthamus tinctorius) contain many natural substances with a wide range of economic uses. The most famous dye isolated from flower petals is hydroxysafflor A (HSYA), which has antibacterial, anti-inflammatory, and antioxidant properties. This review is aimed at updating the state of knowledge about their applicability in oncology, pulmonology, cardiology, gynecology, dermatology, gastrology, immunology, and suitability in the treatment of obesity and diabetes and its consequences with information published mainly in 2018-2020. They were also effective in treating obesity and diabetes and its consequences. The issues related to the possibilities of using HSYA in the production of health-promoting food were also analyzed.

A Comprehensive Review of Natural Products against Liver Fibrosis: Flavonoids, Quinones, Lignans, Phenols, and Acids

Liver fibrosis resulting from continuous long-term hepatic damage represents a heavy burden worldwide. Liver fibrosis is recognized as a complicated pathogenic mechanism with extracellular matrix (ECM) accumulation and hepatic stellate cell (HSC) activation. A series of drugs demonstrate significant antifibrotic activity in vitro and in vivo. No specific agents with ideally clinical efficacy for liver fibrosis treatment have been developed. In this review, we summarized the antifibrotic effects and molecular mechanisms of 29 kinds of common natural products. The mechanism of these compounds is correlated with anti-inflammatory, antiapoptotic, and antifibrotic activities. Moreover, parenchymal hepatic cell survival, HSC deactivation, and ECM degradation by interfering with multiple targets and signaling pathways are also involved in the antifibrotic effects of these compounds. However, there remain two bottlenecks for clinical breakthroughs. The low bioavailability of natural products should be improved, and the combined application of two or more compounds should be investigated for more prominent pharmacological effects. In summary, exploration on natural products against liver fibrosis is becoming increasingly extensive. Therefore, natural products are potential resources for the development of agents to treat liver fibrosis.

Hydroxysafflor Yellow A: A Promising Therapeutic Agent for a Broad Spectrum of Diseases

Hydroxysafflor yellow A (HSYA) is one of the major bioactive and water-soluble compounds isolated from Carthami Flos, the flower of safflower (Carthamus tinctorius L.). As a natural pigment with favorable medical use, HSYA has gained extensive attention due to broad and effective pharmacological activities since first isolation in 1993. In clinic, the safflor yellow injection which mainly contains about 80% HSYA was approved by the China State Food and Drug Administration and used to treat cardiac diseases such as angina pectoris. In basic pharmacology, HSYA has been proved to exhibit a broad spectrum of biological effects that include, but not limited to, cardiovascular effect, neuroprotection, liver and lung protection, antitumor activity, metabolism regulation, and endothelium cell protection. Although a great number of studies have been carried out to prove the pharmacological effects and corresponding mechanisms of HYSA, a systemic review of HYSA has not yet been seen. Here, we provide a comprehensive summarization of the pharmacological effects of HYSA. Together with special attention to mechanisms of actions, this review can serve as the basis for further researches and developments of this medicinal compound.

Emodin suppresses activation of hepatic stellate cells through p38 mitogen-activated protein kinase and Smad signaling pathways in vitro

The aim of this study was to evaluate the hypothesis that emodin inhibits extracellular matrix (ECM)-related gene expression in activated hepatic stellate cells (HSCs) by blocking canonical or/and noncanonical components of transforming growth factor β1 (TGFβ1) intracellular signaling. Here, we demonstrate that emodin suppressed the gene expression of HSCs activation markers type I collagen, fibronectin, and α-smooth muscle actin, as well as HSCs proliferation. Mechanistically, emodin suppresses TGFβ1, TGFβ receptor II, TGFβ receptor I, and Smad4 gene expression, as well as Smad luciferase activity. Simultaneously, emodin reduced p38 mitogen-activated protein kinase (p38^MAPK ) activity but not c-Jun N-terminal kinases and extracellular signal-regulated kinases 1 and 2 phosphorylation in HSC-T6 cells. Interestingly, deprivation of TGFβ using a neutralizing antibody abolished emodin-mediated inhibitions of the both Smad transcriptional activity and p38^MAPK phosphorylation. Furthermore, emodin-mediated inhibition of HSCs activation could be partially blocked by PD98059 inhibition of p38^MAPK or short hairpin RNA-imposed knockdown of Smad4. Conversely, simultaneous inhibition of Smad4 and p38^MAPK pathways completely reverses the effects of emodin, suggesting that Smad and p38^MAPK locate downstream of TGFβ1 and regulate collagen genes expression in HSCs. Collectively, these data suggest that emodin is a promising candidate for the treatment of hepatic fibrosis.

Hydroxysafflor Yellow A Suppresses MRC-5 Cell Activation Induced by TGF-β1 by Blocking TGF-β1 Binding to TβRII

Hydroxysafflor yellow A (HSYA) is an active ingredient of Carthamus tinctorius L.. This study aimed to evaluate the effects of HSYA on transforming growth factor-β1 (TGF-β1)-induced changes in proliferation, migration, differentiation, and extracellular matrix accumulation and degradation in human fetal lung fibroblasts (MRC-5), to explore the mechanisms whereby HSYA may alleviate pulmonary fibrosis. MRC-5 cells were incubated with various doses of HSYA and/or the TGF-β receptor type I kinase inhibitor SB431542 and then stimulated with TGF-β1. Cell proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfo-phenyl)-2H-tetrazolium inner salt assay. Cell migration was detected by wound-healing assay. Protein levels of α-smooth muscle actin (α-SMA), collagen I α 1 (COL1A1), and fibronectin (FN) were measured by immunofluorescence. Protein levels of matrix metalloproteinase-2, tissue inhibitor of matrix metalloproteinase-1, tissue inhibitor of matrix metalloproteinase-2, TGF-β type II receptor (TβRII), and TGF-β type I receptor were detected by western blotting. TβRII knockdown with siRNA interfered with the inhibitory effect of HSYA on α-SMA, COL1A1, and FN expression, and TGF-β1-induced Sma and Mad protein (Smad), and extracellular signal-regulated kinase/mitogen-activated protein kinase signaling pathway activation. The antagonistic effect of HSYA on the binding of fluorescein isothiocyanate-TGF-β1 to MRC-5 cell cytoplasmic receptors was measured by flow cytometry. HSYA significantly suppressed TGF-β1-induced cell proliferation and migration. HSYA could antagonize the binding of FITC-TGF-β1 to MRC-5 cell cytoplasmic receptors. Also HSYA inhibited TGF-β1-activated cell expression of α-SMA, COL1A1, and FN and phosphorylation level of Smad2, Smad3, and ERK by targeting TβRII in MRC-5 cells. These findings suggest that TβRII might be the target responsible for the inhibitory effects of HSYA on TGF-β1-induced pathological changes in pulmonary fibrosis.

Hydroxysafflor yellow A inhibits TGF-β1-induced activation of human fetal lung fibroblasts in vitro

Objective

Hydroxysafflor yellow A (HSYA) is one of the chemical component isolated from Chinese medicine Carthamus tinctorius L. Our preliminary study confirmed that HSYA attenuated bleomycin-induced pulmonary fibrosis in mice. In this study, we evaluated the effect of HSYA on TGF-β1-induced activation of human fetal lung fibroblasts (MRC-5) and explored the underlying mechanisms of its activity.

Method

MRC-5 cells activated by TGF-β1 were incubated with HSYA and/or the TGF-β type I receptor inhibitor, SB431542. TGF-β1-induced cell proliferation, α-smooth muscle actin, collagen I alpha 1 and fibronectin expression, Smad, mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3 kinase/Akt signalling pathway activation were observed.

Key findings

Hydroxysafflor yellow A significantly inhibited TGF-β1-induced cell proliferation and the expression, both mRNA and protein, of α-smooth muscle actin, collagen I alpha 1 and fibronectin. HSYA also suppressed TGF-β1 activation of Smad signal transduction via inhibition of Smad2 and Smad3 phosphorylation, their nuclear translocation and the binding activity of Smad3 to type I collagen promoter in MRC-5 cells. In addition, HSYA inhibited TGF-β1-induced phosphorylation of extracellular signal-regulated kinase (ERK). The inhibitory effects of HSYA were similar to SB431542.

Conclusion

These findings suggest that HSYA inhibits TGF-β1-induced activation of MRC-5 cells associated with TGF-β1/Smad and ERK/MAPK signalling pathways.

Strategies to prevent and reverse liver fibrosis in humans and laboratory animals

Liver fibrosis results from chronic damage to the liver in conjunction with various pathways and is mediated by a complex microenvironment. Based on clinical observations, it is now evident that fibrosis is a dynamic, bidirectional process with an inherent capacity for recovery and remodeling. The major mechanisms involved in liver fibrosis include the repetitive injury of hepatocytes, the activation of the inflammatory response after injury stimulation, and the activation and proliferation of hepatic stellate cells (HSCs), which represents the major extracellular matrix (ECM)-producing cells, stimulated by hepatocyte injury and inflammation. The microenvironment in the liver is synergistically regulated abnormal ECM deposition, scar formation, angiogenesis, and fibrogenesis. Moreover, recent studies have clarified novel mechanism in fibrosis such as epigenetic regulation of HSCs, the leptin and PPARγ pathways, the coagulation system, and even autophagy. Uncovering the mechanisms of liver fibrogenesis provides a basis to develop potential therapies to reverse and treat the fibrotic response, thereby improving the outcomes of patients with chronic liver disease. Although both scientific and clinical challenges remain, emerging studies attempt to reveal the ideal anti-fibrotic drug that could be easily delivered to the liver with high specificity and low toxicity. This review highlights the mechanisms, including novel pathways underlying fibrogenesis that may be translated into preventive and treatment strategies, reviews both current and novel agents that target specific pathways or multiple targets, and discusses novel drug delivery systems such as nanotechnology that can be applied in the treatment of liver fibrosis. In addition, we also discuss some current treatment strategies that are being applied in animal models and in clinical trials.

Pharmacokinetic profiles of hydroxysafflor yellow A following intravenous administration of its pure preparations in healthy Chinese volunteers

ETHNOPHARMACOLOGICAL RELEVANCE

Hydroxysafflor yellow A (HSYA), the major active marker compound isolated from Carthamus tinctorius L., has been demonstrated to possess various attractive pharmacological activities. However, there is a lack of information about the complete clinical pharmacokinetic profiles of HSYA following the administration of its pure preparations. The purpose of this study was to fully characterize the pharmacokinetic (PK) properties of HSYA in healthy Chinese volunteers following drip intravenous infusion of injectable powder of pure HSYA (IPPH), a new drug recently approved for the phase I clinical study by China Food and Drug Administration.

MATERIALS AND METHODS

36 healthy subjects of either sex were recruited in this single-center, and open-label, single doses (25, 50, and 75 mg) and multiple doses (50 mg, once daily, 7 consecutive days) study. Plasma samples were analyzed with a validated LC-MS/MS method. Various PK parameters were estimated from the plasma concentration versus time data using non-compartmental methods.

RESULTS

After single dose administration of IPPH, the values of AUC(0-t), AUC(0-∞) and C(max) for HSYA were statistically proportional over the dose range of 25-75 mg. After 7 repeated doses of 50 mg IPPH, both C(max) and AUC(0-∞) were significantly decreased, from 3207 to 2959 μg L(-1), and from 12,811 to 12,135 µg h L(-1) respectively, while t(1/2) was significantly prolonged from 3.912 to 4.414 h. The minimum plasma concentrations on day 5, 6 and 7 showed good stability with no significant difference. Both Cmax and AUC of HSYA in male volunteers were generally lower than that in females. IPPH was generally well tolerated in healthy volunteers by either single or multiple dosing.

CONCLUSION

HSYA displayed moderately linear PK properties over the doses ranging from 25 to 75 mg of IPPH. Repeated administration of IPPH once daily could not lead to the in-vivo drug accumulation, but significantly affect PK behavior of HSYA. Gender difference should be considered for dosage recommendation in the clinic.

Measurement of hydroxysafflor yellow A in human urine by liquid chromatography-tandem mass spectrometry

A rapid and specific high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the quantification of hydroxysafflor yellow A (HSYA) in human urine with isorhamnetin-3-O-neohespeidoside as internal standard (IS). HSYA and IS were extracted from urine samples by simple solid-phase extraction and separated on an Agilent Zorbax SB C18 column (4.6 mm × 150 mm, 5 μm) with the mobile phase of 0.2 mM ammonium acetate: methanol (30/70, v/v) at a flow rate of 0.4 mL/min. Polar endogenous interferences eluted in 0.1-2.5 min were switched into waste channel by the Valve Valco, to reduce the possible matrix effect for MS detection in each run. The MS detection of analytes was performed on a tandem mass spectrometer equipped with an electrospray ionization source in negative mode using multiple-reaction monitoring. The MS/MS ion transitions monitored were m/z 611.3→491.2 for HSYA and m/z 623.2→299.2 for IS. The method was fully validated for selectivity, sensitivity, linearity, precision, accuracy, recovery, matrix effect and stability, and then was applied to the urinary excretion study of injectable powder of pure HSYA in healthy Chinese volunteers for the first time. The results suggested that urine was the main excretion way of HSYA in healthy volunteers, further demonstrating the feasibility and necessity of our current method.

Alteration of the ERK5 pathway by hydroxysafflor yellow A blocks expression of MEF2C in activated hepatic stellate cells in vitro: Potential treatment for hepatic fibrogenesis

Abstract Context: Hepatic fibrosis ultimately leads to cirrhosis if not treated effectively. Hepatic stellate cells (HSC) are a main mediator of hepatic fibrosis through the accumulation of extracellular matrix proteins. Suppression activation of passaged HSC has been proposed as therapeutic strategies for the treatment and prevention of hepatic fibrosis. Objective: To evaluate the effect of hydroxysafflor yellow A (HSYA), an active chemical compound derived from the flowers of Carthamus tinctorius L. (Compositae), on HSC inhibition, and to begin elucidating underlying mechanisms. Materials and methods: Primary HSCs were isolated from rats by in situ pronase/collagenase perfusion. Culture-activated HSCs were treated with or without HSYA at 30 μM in the presence or absence of PD98059 for 48 h, and then cell proliferation was measured by MTS assays. Messenger RNA (mRNA) expression was quantified by polymerase chain reaction, and protein was quantified by Western blots or enzyme-linked immunosorbent assays. Results: HSYA significantly inhibits culture-activated HSC proliferation in a dose-dependent and time-dependent manner with an IC50 value of 112.79 μM. HSYA (30 μM) induce the suppression of HSC activation, as indicated by decreases in contents of type I alpha collagen in HSC-cultured media and expression of α-smooth muscle actin protein in culture-activated HSC by 55 and 71%, respectively. HSYA (30 μM) also caused significant decreases in mRNA expression of type III alpha collagen in HSC by 28%. HSYA (30 μM) suppresses myocyte enhancer factor 2 C (MEF2C) expression both at its mRNA and protein levels by 60 and 61%, respectively. Further study demonstrated that HSYA (30 μM) caused significant decreases in p-ERK5 by 49%. Blocking extracellular signal-regulated protein kinase 5 (ERK5) activity by XMD 8--92, an ERK5 inhibitor, markedly abrogated the inhibitive effects of HSYA on HSC activation, and blocked the HSYA-mediated MEF2C down-regulation. Conclusions: HSYA suppress HSC activation by ERK5-mediated MEF2C down-regulation and makes it a potential candidate for prevention and treatment of hepatic fibrogenesis.