Natural plant products in treatment of pulmonary arterial hypertension

Carnosic acid, a novel food-source AT1R antagonist and its anti-hypertension mechanism

Hypertension is the most prevalent non-communicable disease, affecting billions of people worldwide. Discovery and development of natural antihypertensive lead compounds or drugs are important to resolve the limitations of existing antihypertensive drug safety and resistance. This investigation verified that carnosic acid (CA), an important active ingredient of rosemary, an edible spice plant, indicates a significant anti-hypertensive activity in spontaneous hypertension rats by targeting AT1R. Moreover, our research indicated that CA shared a comparable antagonistic mechanism with established synthetic angiotensin II receptor blockers (ARBs), as it occupies the binding sites of Angiotensin II (AngII) at His6 and Pro7 within the AT1R's ligand-binding pocket. Notably, CA exerted better anti-hypertensive activity since it could not break the Asn1113.35-Asn2957.46 hydrogen bond to stabilize the AT1R inactive state. As the first potent AT1R antagonist identified in a natural food source, CA is poised to become a novel anti-hypertensive lead compound, distinguished by its unique skeleton structure different from conventional ARBs. This research lays a valuable theoretical groundwork for the future exploration of CA and rosemary extract in both fundamental studies and clinical applications.

Pulmonary hypertension and the potential of 'drug' repurposing: A case for African medicinal plants

Abstract

Pulmonary hypertension (PH) is a haemodynamic disorder in which elevated blood pressure in the pulmonary circulation is caused by abnormal vascular tone. Despite advances in treatment, PH mortality remains high, and drug repurposing has been proposed as a mitigating approach. This article reviews the studies that have investigated drug repurposing as a viable option for PH. We provide an overview of PH and highlight pharmaceutical drugs with repurposing potential, based on limited evidence of their mechanisms of action. Moreover, studies have demonstrated the benefits of medicinal plants in PH, most of which are of Indian or Asian origin. Africa is a rich source of many medicinal plants that have been scientifically proven to counteract myriad pathologies. When perusing these studies, one will notice that some African medicinal plants can counteract the molecular pathways (e.g. proliferation, vasoconstriction, inflammation, oxidative stress and mitochondrial dysfunction) that are also involved in the pathogenesis of PH. We review the actions of these plants with actions applicable to PH and highlight that they could be repurposed as adjunct PH therapies. However, these plants have either never been tested in PH, or there is little evidence of their actions against PH. We therefore encourage caution, as more research is needed to study these plants further in experimental models of PH while acknowledging that the outcomes of such proof of-concept studies may not always yield promising findings. Regardless, this article aims to stimulate future research that could make timely contributions to the field.

Study synopsis

What the study adds. Pulmonary hypertension (PH) remains a fatal disease, and 80% of the patients live in developing countries where resources are scarce and specialised therapies are often unavailable. Drug repurposing is a viable option to try to improve treatment outcomes.Implications of the findings. We propose that another form of 'drug' repurposing is the use of medicinal plants, many of which have demonstrated benefits against pathological processes that are also key in PH, e.g. apoptosis, tumour-like growth of cells, proliferation, oxidative stress and mitochondrial dysfunction.

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.

Role of solid lipid nanoparticle for the delivery of Lipophilic Drugs and Herbal Medicines in the treatment of pulmonary hypertension

Pulmonary arterial hypertension (PAH) is an uncommon condition marked by elevated pulmonary artery pressure that leads to right ventricular failure. The majority of drugs are now been approved by FDA for PAH, however, several biopharmaceutical hindrances lead to failure of the therapy. Various novel drug delivery systems are available in the literature from which lipid-based nanoparticles i.e. solid lipid nanoparticle is widely investigated for improving the solubility and bioavailability of drugs. In this paper, the prototype phytoconstituents used in pulmonary arterial hypertension have limited solubility and bioavailability. We highlighted the novel concepts of SLN for lipophilic phytoconstituents with their potential applications. This paper also reviews the present state of the art regarding production techniques for SLN like High-Pressure Homogenization, Micro-emulsion Technique, and Phase Inversion Temperature Method, etc. Furthermore, toxicity aspects and in vivo fate of SLN are also highlighted in this review. In a nutshell, safer delivery of phytoconstituents by SLN added a novel feather to the cap of successful drug delivery technologies.

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.

1,8-cineole Ameliorates Right Ventricle Dysfunction Associated With Pulmonary Arterial Hypertension by Restoring Connexin 43 and Mitochondrial Homeostasis

For the first time, the present study unravels a cardiospecific therapeutic approach for Pulmonary Arterial Hypertension (PAH), a disease with a very poor prognosis and high mortality rates due to right ventricle dysfunction. We first established a new in vitro model of high-pressure-induced hypertrophy that closely resembles heart defects associated with PAH and validated our in vitro findings on a preclinical in vivo model of monocrotaline (MCT)-induced PAH. Our results showed the in vitro antihypertrophic effect of 1,8-cineole, a monoterpene widely found in several essential oils. Also, a decrease in RV hypertrophy and fibrosis, and an improvement in heart function in vivo was observed, when 1,8-cineole was applied topically. Furthermore, 1,8-cineole restored gap junction protein connexin43 distribution at the intercalated discs and mitochondrial functionality, suggesting it may act by preserving cardiac cell-to-cell communication and bioenergetics. Overall, our results point out a promising therapeutic compound that can be easily applied topically, thus paving the way for the development of effective cardiac-specific therapies to greatly improve PAH outcomes.

Nanomedicine of Plant Origin for the Treatment of Metabolic Disorders

Metabolic disorders are major clinical challenges of health that are progressing globally. A concurrence of metabolic disorders such as obesity, insulin resistance, atherogenic dyslipidemia, and systematic hypertension leads to metabolic syndrome. Over the past years, the metabolic syndrome leads to a five- and two-fold rise in diabetes mellitus type II and cardiovascular diseases. Natural products specifically plant extracts have insulin-sensitizing, anti-inflammatory, and antioxidant properties and are also considered as an alternative option due to few adverse effects. Nanotechnology is one of the promising strategies, which improves the effectiveness of treatment and limits side effects. This review mainly focuses on plant extract-based nanosystems in the management of the metabolic syndrome. Numerous nano-drug delivery systems, i.e., liposomes, hydrogel nanocomposites, nanoemulsions, micelles, solid lipid, and core–shell nanoparticles, have been designed using plant extracts. It has been found that most of the nano-formulations successfully reduced oxidative stress, insulin resistance, chronic inflammation, and lipid profile in in vitro and in vivo studies as plant extracts interfere with the pathways of metabolic syndrome. Thus, these novel plant-based nanosystems could act as a promising candidate for clinical applications.

Bioactivities and mechanisms of natural medicines in the management of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive and rare disease without obvious clinical symptoms that shares characteristics with pulmonary vascular remodeling. Right heart failure in the terminal phase of PAH seriously threatens the lives of patients. This review attempts to comprehensively outline the current state of knowledge on PAH its pathology, pathogenesis, natural medicines therapy, mechanisms and clinical studies to provide potential treatment strategies. Although PAH and pulmonary hypertension have similar pathological features, PAH exhibits significantly elevated pulmonary vascular resistance caused by vascular stenosis and occlusion. Currently, the pathogenesis of PAH is thought to involve multiple factors, primarily including genetic/epigenetic factors, vascular cellular dysregulation, metabolic dysfunction, even inflammation and immunization. Yet many issues regarding PAH need to be clarified, such as the "oestrogen paradox". About 25 kinds monomers derived from natural medicine have been verified to protect against to PAH via modulating BMPR2/Smad, HIF-1α, PI3K/Akt/mTOR and eNOS/NO/cGMP signalling pathways. Yet limited and single PAH animal models may not corroborate the efficacy of natural medicines, and those natural compounds how to regulate crucial genes, proteins and even microRNA and lncRNA still need to put great attention. Additionally, pharmacokinetic studies and safety evaluation of natural medicines for the treatment of PAH should be undertaken in future studies. Meanwhile, methods for validating the efficacy of natural drugs in multiple PAH animal models and precise clinical design are also urgently needed to promote advances in PAH.

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.

Natural ingredients from Chinese materia medica for pulmonary hypertension

Pulmonary hypertension (PH) is a severe pathophysiological condition characterized by pulmonary artery remodeling and continuous increases in pulmonary artery pressure, which may eventually develop to right heart failure and death. Although newly discovered and incredible treatment strategies in recent years have improved the prognosis of PH, limited types of effective and economical drugs for PH still makes it as a life-threatening disease. Some drugs from Chinese materia medica (CMM) have been traditionally applied in the treatment of lung diseases. Accumulating evidence suggests active pharmaceutical ingredients (APIs) derived from those medicines brings promising future for the prevention and treatment of PH. In this review, we summarized the pharmacological effects of APIs derived from CMM which are potent in treating PH, so as to provide new thoughts for initial drug discovery and identification of potential therapeutic strategies in alternative medicine for PH.

3'-Oxo-tabernaelegantine A (OTNA) selectively relaxes pulmonary arteries by inhibiting AhR

BACKGROUND

Pulmonary arterial hypertension (PAH), characterized by pulmonary artery constriction and vascular remodeling, has a high mortality rate. New drugs for the treatment of PAH urgently need to be developed.

PURPOSE

This study was designed to investigate the vasorelaxant activity of OTNA in isolated pulmonary arteries, and explore its molecular mechanism.

METHODS

Pulmonary arteries and thoracic aortas were isolated from mice, and vascular tone was tested with a Wire Myograph System. Nitric oxide levels were determined with DAF-FM DA and DAX-J2™ Red. Cellular thermal shift assays, microscale thermophoresis, and molecular docking were used to identify the interaction between OTNA and aryl hydrocarbon receptor (AhR). The levels of PI3K, p-PI3K, Akt, p-Akt, eNOS, p-eNOS, and AhR were analyzed by Western blotting.

RESULTS

OTNA selectively relaxed the isolated pulmonary artery rings in an endothelium-dependent manner. Mechanistic study showed that OTNA induced NO production through activation of the PI3K/Akt/eNOS pathway in endothelial cells. Furthermore, we also found that OTNA directly bound to AhR and activated the PI3K/Akt/eNOS pathway to dilate pulmonary arteries by inhibiting AhR.

CONCLUSIONS

OTNA relaxes pulmonary arteries by antagonizing AhR. This study provides a new natural antagonist of AhR as a promising lead compound for PAH treatment.

Anti-Inflammatory Effect of Allicin Associated with Fibrosis in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling. Recent evidence supports that inflammation plays a key role in triggering and maintaining pulmonary vascular remodeling. Recent studies have shown that garlic extract has protective effects in PAH, but the precise role of allicin, a compound derived from garlic, is unknown. Thus, we used allicin to evaluate its effects on inflammation and fibrosis in PAH. Male Wistar rats were divided into three groups: control (CON), monocrotaline (60 mg/kg) (MCT), and MCT plus allicin (16 mg/kg/oral gavage) (MCT + A). Right ventricle (RV) hypertrophy and pulmonary arterial medial wall thickness were determined. IL-1β, IL-6, TNF-α, NFκB p65, Iκβ, TGF-β, and α-SMA were determined by Western blot analysis. In addition, TNF-α and TGF-β were determined by immunohistochemistry, and miR-21-5p and mRNA expressions of Cd68, Bmpr2, and Smad5 were determined by RT-qPCR. Results: Allicin prevented increases in vessel wall thickness due to TNF-α, IL-6, IL-1β, and Cd68 in the lung. In addition, TGF-β, α-SMA, and fibrosis were lower in the MCT + A group compared with the MCT group. In the RV, allicin prevented increases in TNF-α, IL-6, and TGF-β. These observations suggest that, through the modulation of proinflammatory and profibrotic markers in the lung and heart, allicin delays the progression of PAH.

Nanophytomedicines for the Prevention of Metabolic Syndrome: A Pharmacological and Biopharmaceutical Review

Metabolic syndrome includes a series of metabolic abnormalities that leads to diabetes mellitus and cardiovascular diseases. Plant extracts, due to their unique advantages like anti-inflammatory, antioxidant, and insulin sensitizing properties, are interesting therapeutic options to manage MetS; however, the poor solubility and low bioavailability of lipophilic bioactive components in the herbal extracts are two critical challenges. Nano-scale delivery systems are suitable to improve delivery of herbal extracts. This review, for the first time, focuses on nanoformulations of herbal extracts in MetS and related complications. Included studies showed that several forms of nano drug delivery systems such as nanoemulsions, solid lipid nanoparticles, nanobiocomposites, and green-synthesized silver, gold, and zinc oxide nanoparticles have been developed using herbal extracts. It was shown that the method of preparation and related parameters such as temperature and type of polymer are important factors affecting physicochemical stability and therapeutic activity of the final product. Many of these formulations could successfully decrease the lipid profile, inflammation, oxidative damage, and insulin resistance in in vitro and in vivo models of MetS-related complications. Further studies are still needed to confirm the safety and efficacy of these novel herbal formulations for clinical application.

Uncaria tomentosa (Willd. ex Schult.) DC.: A Review on Chemical Constituents and Biological Activities

Uncaria tomentosa (Willd. ex Schult.) DC. (Family: Rubiaceae), commonly known as cat’s claw, is a tropical medicinal vine originating at the Amazon rainforest and other areas of South and Central America. It has been traditionally used to treat asthma, abscesses, fever, urinary tract infections, viral infections, and wounds and found to be effective as an immune system rejuvenator, antioxidant, antimicrobial, and anti-inflammatory agent. U. tomentosa is rich in many phytoconstituents such as oxindole and indole alkaloids, glycosides, organic acids, proanthocyanidins, sterols, and triterpenes. Biological activities of U. tomentosa have been examined against various microorganisms and parasites, including pathogenic bacteria, viruses, and Plasmodium, Babesia and Theileria parasites. Several formulations of cat’s claw (e.g., tinctures, decoctions, capsules, extracts, and teas) are recently available in the market. The current review covers the chemical constituents, biological activities, pharmacokinetics, and toxic properties of U. tomentosa extracts.

Treatment Discontinuation or Interruption in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease, which can be potentially fatal. The management of a complex disease like PAH requires a multidisciplinary approach from a team consisting of physicians, nurses, social workers, and pharmacists. Adherence to PAH-specific therapy is one of the key factors in the management of this disease. Poor adherence to treatment is a common problem in PAH as it is in many chronic diseases. Management of medication interruptions is a challenge in patients with PAH that can lead to negative consequences. However, for most PAH-specific drugs, there are no clear guidelines on how to manage temporary or abrupt medication discontinuations. In this review, we summarized the available literature and provide suggestions on how to manage interruptions of PAH-specific therapies.

Chrysin ameliorates ANTU-induced pulmonary edema and pulmonary arterial hypertension via modulation of VEGF and eNOs

Alpha-naphthylthiourea (ANTU), a rodenticide induces lung toxicity. Chrysin a flavonoid possesses antioxidant, anti-inflammatory, and antihypertensive potential. The aim of this study was to evaluate the efficacy of chrysin against ANTU-induced pulmonary edema (PE) and pulmonary arterial hypertension (PAH) in laboratory rats. Sprague-Dawley rats were used to induce PE (ANTU, 10 mg/kg, ip) and PAH (ANTU, 5 mg/kg, ip, 4 weeks). Animals were treated with chrysin (10, 20, and 40 mg/kg) and various biochemical, molecular, and histological parameters were evaluated. Acute administration of ANTU induces PE revealed by significant (P < 0.05) increase in relative lung weight, pleural effusion volume, lung edema, bronchoalveolar lavage fluid cell counts, total protein, 5-hydroxytryptamine (5-HT), lactate dehydrogenase (LDH), and γ-glutamyl transferase (GGT), whereas pretreatment with chrysin (20 and 40 mg/kg, ip) significantly (P < 0.05) attenuated these ANTU-induced biochemical and histological alterations. Repeated administration of ANTU caused induction of PAH evaluated by significant (P < 0.05) alterations in electrocardiographic, hemodynamic changes, and left ventricular function, whereas chrysin (20 and 40 mg/kg, p.o.) treatment significantly (P < 0.05) attenuated these alterations. ANTU-induced hematological and serum biochemical (aspartate transaminase, alanine transaminase, LDH, and creatinine kinase MB) alterations were significantly (P < 0.05) inhibited by chrysin. It also significantly (P < 0.05) decreased elevated levels of oxido-nitrosative stress in the right ventricle (RV) and lung. Chrysin significantly (P < 0.05) attenuated downregulated endothelial nitric oxide synthase and upregulated vascular endothelial growth factor messenger RNA and protein expressions both in the RV and pulmonary artery. Chrysin inhibited ANTU-induced PE and PAH via modulation of inflammatory responses (5-HT, LDH, and GGT), oxido-nitrosative stress, and VEGF and eNOs levels.