Salvianolic Acid A, a Component of Salvia miltiorrhiza, Attenuates Endothelial-Mesenchymal Transition of HPAECs Induced by Hypoxia

Natural Products for the Treatment of Pulmonary Hypertension: Mechanism, Progress, and Future Opportunities

Pulmonary hypertension (PH) is a lethal disease due to the remodeling of pulmonary vessels. Its pathophysiological characteristics include increased pulmonary arterial pressure and pulmonary vascular resistance, leading to right heart failure and death. The pathological mechanism of PH is complex and includes inflammation, oxidative stress, vasoconstriction/diastolic imbalance, genetic factors, and ion channel abnormalities. Currently, many clinical drugs for the treatment of PH mainly play their role by relaxing pulmonary arteries, and the treatment effect is limited. Recent studies have shown that various natural products have unique therapeutic advantages for PH with complex pathological mechanisms owing to their multitarget characteristics and low toxicity. This review summarizes the main natural products and their pharmacological mechanisms in PH treatment to provide a useful reference for future research and development of new anti-PH drugs and their mechanisms.

Suppression of PFKFB3-driven glycolysis restrains endothelial-to-mesenchymal transition and fibrotic response

Endothelial-to-mesenchymal transition (EndoMT), the process wherein endothelial cells lose endothelial identity and adopt mesenchymal-like phenotypes, constitutes a critical contributor to cardiac fibrosis. The phenotypic plasticity of endothelial cells can be intricately shaped by alteration of metabolic pathways, but how endothelial cells adjust cellular metabolism to drive EndoMT is incompletely understood. Here, we identified 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) as a critical driver of EndoMT via triggering abnormal glycolysis and compromising mitochondrial respiration. Pharmacological suppression of PFKFB3 with salvianolic acid C (SAC), a phenolic compound derived from Salvia miltiorrhiza, attenuates EndoMT and fibrotic response. PFKFB3-haplodeficiency recapitulates the anti-EndoMT effect of SAC while PFKFB3-overexpression augments the magnitude of EndoMT and exacerbates cardiac fibrosis. Mechanistically, PFKFB3-driven glycolysis compromises cytoplasmic nicotinamide adenine dinucleotide phosphate (reduced form, NADPH) production via hijacking glucose flux from pentose phosphate pathway. Efflux of mitochondrial NADPH through isocitrate/α-ketoglutarate shuttle replenishes cytoplasmic NADPH pool but meanwhile impairs mitochondrial respiration by hampering mitochondrial iron-sulfur cluster biosynthesis. SAC disrupts PFKFB3 stability by accelerating its degradation and thus maintains metabolic homeostasis in endothelial cells, underlying its anti-EndoMT effects. These findings for the first time identify the critical role of PFKFB3 in triggering EndoMT by driving abnormal glycolysis in endothelial cells, and also highlight the therapeutic potential for pharmacological intervention of PFKFB3 (with SAC or other PFKFB3 inhibitors) to combat EndoMT-associated fibrotic responses via metabolic regulation.

Mechanistic and therapeutic perspectives of baicalin and baicalein on pulmonary hypertension: A comprehensive review

Pulmonary hypertension (PH) is a chronic and fatal disease, for which new therapeutic drugs and approaches are needed urgently. Baicalein and baicalin, the active compounds of the traditional Chinese medicine, Scutellaria baicalensis Georgi, exhibit a wide range of pharmacological activities. Numerous studies involving in vitro and in vivo models of PH have revealed that the treatment with baicalin and baicalein may be effective. This review summarizes the potential mechanisms driving the beneficial effects of baicalin and baicalein treatment on PH, including anti-inflammatory response, inhibition of pulmonary smooth muscle cell proliferation and endothelial-to-mesenchymal transformation, stabilization of the extracellular matrix, and mitigation of oxidative stress. The pharmacokinetics of these compounds have also been reviewed. The therapeutic potential of baicalin and baicalein warrants their continued study as natural treatments for PH.

Target Nuclear Factor Erythroid 2-Related Factor 2 in Pulmonary Hypertension: Molecular Insight into Application

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor involved in maintaining redox balance and activates the expression of downstream antioxidant enzymes. Nrf2 has received wide attention considering its crucial role in oxidative and electrophilic stress. Large amounts of studies have demonstrated the protective role of Nrf2 activation in various pulmonary hypertension (pH) models. Additionally, various kinds of natural phytochemicals acting as Nrf2 activators prevent the development of pH and provide a novel and promising therapeutic insight for the treatment of pH. In the current review, we give a brief introduction of Nrf2 and focus on the role and mechanism of Nrf2 in the pathophysiology of pH and then review the relevant research of Nrf2 agonists in pH in both experimental research and clinical trials.

Traditional Herbal Medicine Discovery for the Treatment and Prevention of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is characterized by pulmonary artery remodeling that may subsequently culminate in right heart failure and premature death. Although there are currently both non-pharmacological (lung transplantation, etc.) and pharmacological (Sildenafil, Bosentan, and new oral drugs on trial) therapies available, PAH remains a serious and fatal pulmonary disease. As a unique medical treatment, traditional herbal medicine (THM) treatment has gradually exerted its advantages in treating PAH worldwide through a multi-level and multi-target approach. Additionally, the potential mechanisms of THM were deciphered, including suppression of proliferation and apoptosis of pulmonary artery smooth muscle cells, controlling the processes of inflammation and oxidative stress, and regulating vasoconstriction and ion channels. In this review, the effects and mechanisms of the frequently studied compound THM, single herbal preparations, and multiple active components from THM are comprehensively summarized, as well as their related mechanisms on several classical preclinical PAH models. It is worth mentioning that sodium tanshinone IIA sulfonate sodium and tetramethylpyrazine are under clinical trials and are considered the most promoting medicines for PAH treatment. Last, reverse pharmacology, a strategy to discover THM or THM-derived components, has also been proposed here for PAH. This review discusses the current state of THM, their working mechanisms against PAH, and prospects of reverse pharmacology, which are expected to facilitate the natural anti-PAH medicine discovery and development and its bench-to-bedside transformation.

Puerarin attenuates the endothelial-mesenchymal transition induced by oxidative stress in human coronary artery endothelial cells through PI3K/AKT pathway

Endothelial-mesenchymal transition (EndMT) is a process in which endothelial cells lose their specific morphology/markers and undergo a dramatic remodeling of the cytoskeleton. It has been implicated in the progression of cardiovascular diseases such as cardiac fibrosis and cardiac dysfunction. Recent study indicated that puerarin could inhibit EndMT against cardiac fibrosis. However, the precise role of puerarin in EndMT and the underlying molecular mechanisms remain unclear. EndMT was induced by H₂O₂ (150 μM) in human coronary artery endothelial cells (HCAECs). HCAECs were exposed to H₂O₂ for six days with or without puerarin pretreated 2 h. The protein changes of EndMT markers (CD31, VE-cadherin, FSP1 and α-SMA) in HCAECs were detected. The levels of phosphoinositide-3-kinase (PI3K) and protein kinase B (AKT) proteins were analyzed by Western Blot. Wound healing and transwell assay were carried out to examine cell chemotaxis. Puerarin mitigated H₂O₂-induced EndMT as indicated by alleviating the reduced expression of CD31 and VE-cadherin and inhibiting the upregulation of α-SMA and FSP1. Furthermore, the mechanisms study showed that puerarin activated the PI3K/AKT pathway by inhibiting reactive oxygen species and further attenuated EndMT. On the other hand, PI3K inhibitor LY294002 reversed this effect imposed by puerarin. Puerarin alleviated the migration of mesenchymal-like cells through reducing MMPs protein expression. These results implicated that puerarin exhibited cytoprotective effects against H₂O₂-induced EndMT in HCAECs through alleviating oxidative stress, activating the PI3K/AKT pathway and limiting cell migration.

Ultra performance liquid chromatography-tandem mass spectrometeric analysis of ethyl acetate fraction from saudi Lavandula coronopifolia Poir and evaluation of its cytotoxic and antioxidant activities

Introduction: The ethyl acetate fraction of the Saudi Lavandula coronopifolia Poir has been previously reported to have hepatoprotective activity against ethanol-induced oxidative stress. The aim of the current study was to investigate the chemical composition, cytotoxic effect, and antioxidant activities of ethyl acetate fraction of the aerial parts of Saudi L. coronopifolia Poir. Methods: Air dried aerial parts of L. coronopifolia were extracted using 90% ethyl alcohol. The dried extract was suspended in water, defatted with light petroleum and then fractionated with ethyl acetate. The ethyl acetate fraction was subjected to ultra performance liquid chromatography-tandem mass spectrometeric (UPLC-ESI/MS/MS) analysis in a negative ionization mode. The antioxidant activity of the fraction was determined using free radical 2,2-diphyenyl-picrylhydrazyl (DPPH) scavenging assay and its cytotoxic effect against HepG2 (human hepatocarcinoma) and MCF-7 (human breast carcinoma) cells were determined using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium (MTT) cell viability assay. Results: The major components of the ethyl acetate fraction included carvacrol-O-diglucoside, (34.98%) and trihydroxy ursolic acid (12.07%). Moreover, the DPPH radical scavenging activity of ethyl acetate fraction was measured. The ethyl acetate fraction revealed an antioxidant potential with EC50 17.8 ± 1.3 µg/mL. Additionally, he ethyl acetate fraction showed cytotoxic activity against HepG-2 and MCF-7 cells with IC50=29.3 ± 0.9 µg/mL and 14.6 ± 0.3 µg/mL, respectively. Conclusion: The ethyl acetate fraction of the Saudi L. coronopifolia has antioxidant activity and also cytotoxic activity against breast and liver cancer cells.

Pharmacokinetics of Active Ingredients of Salvia miltiorrhiza and Carthamus tinctorius in Compatibility in Normal and Cerebral Ischemia Rats: A Comparative Study

BACKGROUND AND OBJECTIVE

Dan-Hong injection, which comprises extracts of Salvia miltiorrhiza and Carthamus tinctorius, promotes blood circulation and reduces blood stasis. Combination of S. miltiorrhiza and C. tinctorius is more effective in treating cerebral ischemia than S. miltiorrhiza alone. This study aimed to examine the pharmacokinetic characteristics of four active ingredients of S. miltiorrhiza and C. tinctorius, namely danshensu (DSS), hydroxysafflor yellow A (HSYA), and salvianolic acid A (SAA) and B (SAB) in normal and cerebral ischemia rats.

METHODS

Normal and cerebral ischemia rats were injected via the tail vein with each active ingredient, and blood was collected through the jaw vein at different time points. The plasma concentration of the compatibility group was analyzed by high-performance liquid chromatography, and pharmacokinetic parameters were determined using Pharmacokinetic Kinetica 4.4 software.

RESULTS

The pharmacokinetics of the four active ingredients in the normal and cerebral ischemia rats were consistent with a two-compartment model. The area under the concentration-time curve was higher in normal rats than in cerebral ischemia rats, with a highly significant difference for SAA (P < 0.01). Clearance rates were lower in normal rats than in cerebral ischemia rats, with DSS showing the most significant difference (P < 0.01). Furthermore, there were significant differences between normal and cerebral ischemia rats in the distribution phase-elimination half life for DSS, SAA, and HSYA, as well as in the apparent volume of distribution for the central compartment for DSS and HSYA (P < 0.01). The plasma concentrations of the four active ingredients were higher in normal rats than in cerebral ischemia rats.

CONCLUSION

Cerebral ischemia rats showed higher drug clearance rates and longer retention times than normal rats, which may be due to destruction of the blood-brain barrier during cerebral ischemia-reperfusion. The four active ingredients likely integrated and interacted with each other to affect target sites in the brain to protect against cerebral ischemic injury.

Discrimination of Salvia miltiorrhiza Bunge from Different Geographical Locations Employing High-Performance Liquid Chromatography, Near-Infrared Fingerprinting Combined with Chemometrics

To evaluate the quality of Salvia miltiorrhiza Bunge, high-performance liquid chromatography-diode array detector (HPLC/UV-PAD), near infrared (NIR) spectroscopy, and chemometrics were used to discriminate nine components of samples from four different geographical locations. HPLC was performed with a C18 (5 μm, 4.6 mm × 250 mm) column and 0.1% formic acid aqueous solution-acetonitrile with a gradient elution system. Orthogonal partial least squares discriminant analysis was used to identify the amounts of salvianolic acid B. NIR was used to distinguish rapidly S. miltiorrhiza Bunge samples from different geographical locations. In this assay, discriminant analysis was performed, and the accuracy was found to be 100%. The combination of these two methods can be used to quickly and accurately identify S. miltiorrhiza Bunge from different geographical locations.

Chemical and pharmacological research on the polyphenol acids isolated from Danshen: A review of salvianolic acids

Danshen, the dried root of Salvia miltiorrhiza Bge, is a common medicinal herb in Traditional Chinese Medicine, which has been used for the treatment of a number of diseases for thousands of years. More than 2000 years ago, the Chinese early pharmacy monograph "Shennong Materia Medica" recorded that Danshen could be used for the treatment of gastrointestinal diseases, cardiovascular diseases, certain gynecological diseases, etc. Since then, Danshen has been widely used clinically in many different prescriptions for many different diseases, especially for the treatment of cardiovascular diseases. Nowadays, many pharmacological studies about the water-soluble components from Danshen have been reported, especially salvianolic acids. It turned out that salvianolic acids showed strong anti-lipid peroxidation and anti-thrombic activities, and among them, SalAA and SalAB were the most potent. This review focused on the achievements in research of salvianolic acids regarding their bioactivities and pharmacological effects. These studies not only shed light on the water-soluble active components of Danshen and their mechanisms at the molecular level, but also provided theoretical information for the development of new medicines from Danshen for the treatment of cardiovascular and cerebrovascular diseases, inflammatory diseases, metabolic diseases, etc.

Study on Biological Activity of Bread Enriched with Natural Polyphenols in Terms of Growth Inhibition of Tumor Intestine Cells

A complex plant polyphenolic preparation (PP) was produced from chokeberry, raspberry, wild strawberry, peach, bilberry, apricot, cranberry, and parsley, using ultrafiltration and C18 preparative chromatography. Thirty main compounds were identified in PP (LC-MS), with the highest contribution of cyanidin 3-O-glucoside, p-coumaroyl glucoside, chlorogenic acid, neochlorogenic acid, and isoquercetin. PP was used (at 0.16% m/m) for the production of a sourdough bread (based on rye flour, water, and salt), followed by in vitro digestion. Fluid obtained after PP-enriched bread digestion (EBD fluid) was tested in terms of cytotoxicity, growth inhibition, antioxidant activity, and morphological changes in cancerous intestinal epithelial cells (HT-29) and normal (CCD 841 CoTr). Results show that EBD fluid concentration over 125 μg/mL significantly decreased activity of succinate dehydrogenase in HT-29 cells and reduced their viability of 25%. At this concentration of EBD fluid, modification in cellular morphology was also observed. DPPH analysis revealed that the highest antioxidant activity was observed at concentration of 75 μg/mL, both PP and EBD fluid. Our results show that an introduction of PP into relatively low-polyphenolic, baking products should be carefully considered because polyphenols still retain its biological activity. Antioxidant activity of polyphenols is one of the mechanisms that explains the observed effect of inhibiting the growth of colon cancer cells.

Natural Plants Compounds as Modulators of Epithelial-to-Mesenchymal Transition

Epithelial-to-mesenchymal transition (EMT) is a self-regulated physiological process required for tissue repair that, in non-controled conditions may lead to fibrosis, angiogenesis, loss of normal organ function or cancer. Although several molecular pathways involved in EMT regulation have been described, this process does not have any specific treatment. This article introduces a systematic review of effective natural plant compounds and their extract that modulates the pathological EMT or its deleterious effects, through acting on different cellular signal transduction pathways both in vivo and in vitro. Thereby, cryptotanshinone, resveratrol, oxymatrine, ligustrazine, osthole, codonolactone, betanin, tannic acid, gentiopicroside, curcumin, genistein, paeoniflorin, gambogic acid and Cinnamomum cassia extracts inhibit EMT acting on transforming growth factor-β (TGF-β)/Smads signaling pathways. Gedunin, carnosol, celastrol, black rice anthocyanins, Duchesnea indica, cordycepin and Celastrus orbiculatus extract downregulate vimectin, fibronectin and N-cadherin. Sulforaphane, luteolin, celastrol, curcumin, arctigenin inhibit β-catenin signaling pathways. Salvianolic acid-A and plumbagin block oxidative stress, while honokiol, gallic acid, piperlongumine, brusatol and paeoniflorin inhibit EMT transcription factors such as SNAIL, TWIST and ZEB. Plectranthoic acid, resveratrol, genistein, baicalin, polyphyllin I, cairicoside E, luteolin, berberine, nimbolide, curcumin, withaferin-A, jatrophone, ginsenoside-Rb1, honokiol, parthenolide, phoyunnanin-E, epicatechin-3-gallate, gigantol, eupatolide, baicalin and baicalein and nitidine chloride inhibit EMT acting on other signaling pathways (SIRT1, p38 MAPK, NFAT1, SMAD, IL-6, STAT3, AQP5, notch 1, PI3K/Akt, Wnt/β-catenin, NF-κB, FAK/AKT, Hh). Despite the huge amount of preclinical data regarding EMT modulation by the natural compounds of plant, clinical translation is poor. Additionally, this review highlights some relevant examples of clinical trials using natural plant compounds to modulate EMT and its deleterious effects. Overall, this opens up new therapeutic alternatives in cancer, inflammatory and fibrosing diseases through the control of EMT process.

Endothelial-to-mesenchymal transition: Pathogenesis and therapeutic targets for chronic pulmonary and vascular diseases

Endothelial-to-mesenchymal transition (EndoMT) is a process of transdifferentiation where endothelial cells gradually adopt the phenotypic characteristics of mesenchymal cells. This phenomenon was first discovered in embryonic heart development. The mechanisms underlying EndoMT are due to the activation of transforming growth factor-β, bone morphogenetic protein, Wingless/Integrated, or Notch signaling pathways. The EndoMT can be modulated by pathological processes, including inflammation, disturbed shear stress, vascular stiffness, and metabolic dysregulation. Recent studies have shown that EndoMT is implicated in the pathogenesis of chronic lung diseases, including pulmonary hypertension and lung fibrosis. Lung pathology of bronchopulmonary dysplasia can be mimicked in rodents exposed to hyperoxia as neonates. Although hyperoxic exposure reduces an endothelial cell marker platelet and endothelial cell adhesion molecule but increases a mesenchymal cell biomarker α-smooth muscle actin in vitro in human pulmonary endothelial cells, there is no direct evidence showing EndoMT in the development of bronchopulmonary dysplasia. Both pulmonary hypertension and lung fibrosis occur in long-term survivors with bronchopulmonary dysplasia. In this review, we discuss the EndoMT and its modulation by pathological processes. We then focus on the role of EndoMT in the pathogenesis of these chronic lung diseases, and discuss therapeutic approaches targeting the EndoMT using its negative regulators.

MicroRNA‑30a‑5p promotes proliferation and inhibits apoptosis of human pulmonary artery endothelial cells under hypoxia by targeting YKL‑40

Pulmonary arterial hypertension (PAH) is a fatal and currently incurable cardiopulmonary disease. Numerous microRNAs (miRNAs) serve important roles in the development of PAH. While the expression of miR-30a-5p was downregulated in the lung tissue of rats in a pulmonary hypertension rat model, the expression pattern and function of miR-30a-5p in human PAH remain unclear. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was used to examine miR-30a-5p and chitinase-3-like protein 1 (YKL-40) mRNA expression levels. The expression levels of YKL-40 and apoptosis-associated proteins were measured by western blot analysis. Cell proliferation assays and flow cytometry analysis were performed to examine cell proliferation and apoptosis, respectively. The association between miR-30a-5p and YKL-40 was determined by a luciferase reporter assay, RT-qPCR and western blot analysis. The relative expression levels of miR-30a-5p in plasma were increased in patients with PAH [median=13.23 (25th percentile=6.388, 75th percentile=21.91)] compared with normal controls [median=2.25 (25th percentile=1.4, 75th percentile=3.7). The expression of miR-30a-5p was significantly downregulated while the protein expression of YKL-40 was significantly upregulated in hypoxia-induced human pulmonary artery endothelial cells (HPAECs) when compared with the hypoxia-induced group at 0 h. miR-30a-5p overexpression promoted HPAEC growth and inhibited apoptosis of HPAECs under hypoxia. A miR-30a-5p mimic decreased the luciferase activity of a luciferase reporter construct containing YKL-40 3′-untranslated region and also decreased YKL-40 protein expression. YKL-40 overexpression partly alleviated the effects of miR-30a-5p upregulation on proliferation and apoptosis of HPAECs under hypoxia. In conclusion, the data indicated that miR-30a-5p promoted cell growth and inhibited apoptosis of HPAECs under hypoxia by targeting YKL-40. Therefore, the miR-30a-5p/YKL-40 axis may provide a potential target for the development of novel PAH therapies.

Salvia miltiorrhizaBurge (Danshen): a golden herbal medicine in cardiovascular therapeutics

Salvia miltiorrhiza Burge (Danshen) is an eminent medicinal herb that possesses broad cardiovascular and cerebrovascular protective actions and has been used in Asian countries for many centuries. Accumulating evidence suggests that Danshen and its components prevent vascular diseases, in particular, atherosclerosis and cardiac diseases, including myocardial infarction, myocardial ischemia/reperfusion injury, arrhythmia, cardiac hypertrophy and cardiac fibrosis. The published literature indicates that lipophilic constituents (tanshinone I, tanshinone IIa, tanshinone IIb, cryptotanshinone, dihydrotanshinone, etc) as well as hydrophilic constituents (danshensu, salvianolic acid A and B, protocatechuic aldehyde, etc) contribute to the cardiovascular protective actions of Danshen, suggesting a potential synergism among these constituents. Herein, we provide a systematic up-to-date review on the cardiovascular actions and therapeutic potential of major pharmacologically active constituents of Danshen. These bioactive compounds will serve as excellent drug candidates in small-molecule cardiovascular drug discovery. This article also provides a scientific rationale for understanding the traditional use of Danshen in cardiovascular therapeutics.

In Silico Identification and In Vitro Evaluation of Natural Inhibitors of Leishmania major Pteridine Reductase I

In a continuation of our computational efforts to find new natural inhibitors of a variety of target enzymes from parasites causing neglected tropical diseases (NTDs), we now report on 15 natural products (NPs) that we have identified as inhibitors of Leishmania major pteridine reductase I (LmPTR1) through a combination of in silico and in vitro investigations. Pteridine reductase (PTR1) is an enzyme of the trypanosomatid parasites’ peculiar folate metabolism, and has previously been validated as a drug target. Initially, pharmacophore queries were created based on four 3D structures of LmPTR1 using co-crystallized known inhibitors as templates. Each of the pharmacophore queries was used to virtually screen a database of 1100 commercially available natural products. The resulting hits were submitted to molecular docking analyses in the substrate binding site of the respective protein structures used for the pharmacophore design. This approach led to the in silico identification of a total of 18 NPs with predicted binding affinity to LmPTR1. These compounds were subsequently tested in vitro for inhibitory activity towards recombinant LmPTR1 in a spectrophotometric inhibition assay. Fifteen out of the 18 tested compounds (hit rate = 83%) showed significant inhibitory activity against LmPTR1 when tested at a concentration of 50 µM. The IC₅₀ values were determined for the six NPs that inhibited the target enzyme by more than 50% at 50 µM, with sophoraflavanone G being the most active compound tested (IC₅₀ = 19.2 µM). The NPs identified and evaluated in the present study may represent promising lead structures for the further rational drug design of more potent inhibitors against LmPTR1.