Therapeutic effects of Nimbolide, an autophagy regulator, in ameliorating pulmonary fibrosis through attenuation of TGF-β1 driven epithelial-to-mesenchymal transition

Nimbolide protects against diabetic cardiomyopathy by regulating endoplasmic reticulum stress and mitochondrial function via the Akt/mTOR pathway

Nimbolide has been demonstrated to possess protective properties against gestational diabetes mellitus and diabetic retinopathy. However, the role and molecular mechanism of nimbolide in diabetic cardiomyopathy (DCM) remain unknown. Diabetes was induced in rats via a single injection of streptozotocin (STZ) and then the diabetic rats were administered nimbolide (5 mg/kg and 20 mg/kg) or dimethyl sulfoxide daily for 12 weeks. H9c2 cardiomyocytes were exposed to high glucose (25 mM glucose) to mimic DCM in vitro. The protective effects of nimbolide against DCM were evaluated in vivo and in vitro. The potential molecular mechanism of nimbolide in DCM was further explored. We found that nimbolide dose-dependently decreased blood glucose and improved body weight of diabetic rats. Additionally, nimbolide dose-dependently improved cardiac function, alleviated myocardial injury/fibrosis, and inhibited endoplasmic reticulum (ER) stress and apoptosis in diabetic rats. Moreover, nimbolide dose-dependently improved mitochondrial function and activated the Akt/mTOR signaling. We consistently demonstrated the cardioprotective effects of nimbolide in an in vitro model of DCM. The involvement of ER stress and mitochondrial pathways were further confirmed by using inhibitors of ER stress and mitochondrial division. By applying a specific Akt inhibitor SC66, the cardioprotective effects of nimbolide were partially blocked. Our study indicated that nimbolide alleviated DCM by activating Akt/mTOR pathway. Nimbolide may be a novel therapeutic agent for DCM treatment.

Nimbolide: promising agent for prevention and treatment of chronic diseases (recent update)

Background

Nimbolide, a bioactive compound derived from the neem tree, has garnered attention as a potential breakthrough in the prevention and treatment of chronic diseases. Recent updates in research highlight its multifaceted pharmacological properties, demonstrating anti-inflammatory, antioxidant, and anticancer effects. With a rich history in traditional medicine, nimbolide efficacy in addressing the molecular complexities of conditions such as cardiovascular diseases, diabetes, and cancer positions it as a promising candidate for further exploration. As studies progress, the recent update underscores the growing optimism surrounding nimbolide as a valuable tool in the ongoing pursuit of innovative therapeutic strategies for chronic diseases.

Methods

The comprehensive search of the literature was done until September 2020 on the MEDLINE, Embase, Scopus and Web of Knowledge databases.

Results

Most studies have shown the Nimbolide is one of the most potent limonoids derived from the flowers and leaves of neem (Azadirachta indica), which is widely used to treat a variety of human diseases. In chronic diseases, nimbolide reported to modulate the key signaling pathways, such as Mitogen-activated protein kinases (MAPKs), Wingless-related integration site-β (Wnt-β)/catenin, NF-κB, PI3K/AKT, and signaling molecules, such as transforming growth factor (TGF-β), Matrix metalloproteinases (MMPs), Vascular Endothelial Growth Factor (VEGF), inflammatory cytokines, and epithelial-mesenchymal transition (EMT) proteins. Nimbolide has anti-inflammatory, anti-microbial, and anti-cancer properties, which make it an intriguing compound for research. Nimbolide demonstrated therapeutic potential for osteoarthritis, rheumatoid arthritis, cardiovascular, inflammation and cancer.

Conclusion

The current review mainly focused on understanding the molecular mechanisms underlying the therapecutic effects of nimbolide in chronic diseases.

Current and Novel Treatment Modalities of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) presents a clinical challenge characterized by progressive fibrosis and destruction of lung tissue. Despite recent advancements, including antifibrotic medications like pirfenidone and nintedanib, IPF remains a chronic and often fatal condition with limited treatment options. This article provides an overview of the current treatment modalities for IPF and explores the need for new therapeutic approaches. Antifibrotic medications have shown efficacy in slowing disease progression but are not curative and may not be suitable for all patients. Ongoing research focuses on emerging therapies such as stem cell therapy, immunomodulatory agents, and novel pharmacological targets like phosphodiesterase 4B (PDE4B) inhibitors. While these treatments offer promise, there remains an unmet need for effective therapies capable of halting or reversing fibrotic lung damage.

Searching for Novel Candidate Small Molecules for Ameliorating Idiopathic Pulmonary Fibrosis: a Narrative Review

Idiopathic pulmonary fibrosis (IPF) can be defined as a progressive chronic pulmonary disease showing scarring in the lung parenchyma, thereby resulting in increase in mortality and decrease in the quality of life. The pathophysiologic mechanism of fibrosis in IPF is still unclear. Repetitive microinjuries to alveolar epithelium with genetical predisposition and an abnormal restorative reaction accompanied by excessive deposition of collagens are involved in the pathogenesis. Although the two FDA-approved drugs, pirfenidone and nintedanib, are under use for retarding the decline in lung function of patients suffered from IPF, they are not able to improve the survival rate or quality of life. Therefore, a novel therapeutic agent acting on the major steps of the pathogenesis of disease and/or, at least, managing the clinical symptoms of IPF should be developed for the effective regulation of this incurable disease. In the present review, we tried to find a potential of managing the clinical symptoms of IPF by natural products derived from medicinal plants used for controlling the pulmonary inflammatory diseases in traditional Asian medicine. A multitude of natural products have been reported to exert an antifibrotic effect in vitro and in vivo through acting on the epithelial-mesenchymal transition pathway, transforming growth factor (TGF)-β-induced intracellular signaling, and the deposition of extracellular matrix. However, clinical antifibrotic efficacy of these natural products on IPF have not been elucidated yet. Thus, those effects should be proven by further examinations including the randomized clinical trials, in order to develop the ideal and optimal candidate for the therapeutics of IPF.

Landscape analysis and overview of the literature on oxidative stress and pulmonary diseases

Oxidative stress is caused by an imbalance in oxidant/antioxidant processes and is a critical process in pulmonary diseases. As no truly effective therapies exist for lung cancer, lung fibrosis and chronic obstructive pulmonary disease (COPD), at present, it is important to comprehensively study the relationship between oxidative stress and pulmonary diseases to identify truly effective therapeutics. Since there is no quantitative and qualitative bibliometric analysis of the literature in this area, this review provides an in-depth analysis of publications related to oxidative stress and pulmonary diseases over four periods, including from 1953 to 2007, 2008 to 2012, 2013 to 2017, and 2018 to 2022. Interest in many pulmonary diseases has increased, and the mechanisms and therapeutic drugs for pulmonary diseases have been well analyzed. Lung injury, lung cancer, asthma, COPD and pneumonia are the 5 most studied pulmonary diseases related to oxidative stress. Inflammation, apoptosis, nuclear factor erythroid 2 like 2 (NRF2), mitochondria, and nuclear factor-κB (NF-κB) are rapidly becoming the most commonly used top keywords. The top thirty medicines most studied for treating different pulmonary diseases were summarized. Antioxidants, especially those targeting reactive oxygen species (ROS) in specific organelles and certain diseases, may be a substantial and necessary choice in combined therapies rather than acting as a single "magic bullet" for the effective treatment of refractory pulmonary diseases.

From Basic Research to Clinical Practice: Considerations for Treatment Drugs for Silicosis

Silicosis, characterized by irreversible pulmonary fibrosis, remains a major global public health problem. Nowadays, cumulative studies are focusing on elucidating the pathogenesis of silicosis in order to identify preventive or therapeutic antifibrotic agents. However, the existing research on the mechanism of silica-dust-induced pulmonary fibrosis is only the tip of the iceberg and lags far behind clinical needs. Idiopathic pulmonary fibrosis (IPF), as a pulmonary fibrosis disease, also has the same problem. In this study, we examined the relationship between silicosis and IPF from the perspective of their pathogenesis and fibrotic characteristics, further discussing current drug research and limitations of clinical application in silicosis. Overall, this review provided novel insights for clinical treatment of silicosis with the hope of bridging the gap between research and practice in silicosis.

Targeting caveolae to pump bispecific antibody to TGF-β into diseased lungs enables ultra-low dose therapeutic efficacy

The long-sought-after "magic bullet" in systemic therapy remains unrealized for disease targets existing inside most tissues, theoretically because vascular endothelium impedes passive tissue entry and full target engagement. We engineered the first "dual precision" bispecific antibody with one arm pair to precisely bind to lung endothelium and drive active delivery and the other to precisely block TGF-β effector function inside lung tissue. Targeting caveolae for transendothelial pumping proved essential for delivering most of the injected intravenous dose precisely into lungs within one hour and for enhancing therapeutic potency by >1000-fold in a rat pneumonitis model. Ultra-low doses (μg/kg) inhibited inflammatory cell infiltration, edema, lung tissue damage, disease biomarker expression and TGF-β signaling. The prodigious benefit of active vs passive transvascular delivery of a precision therapeutic unveils a new promising drug design, delivery and therapy paradigm ripe for expansion and clinical testing.

Research progress of meliaceous limonoids from 2011 to 2021

Covering: July 2010 to December 2021Limonoids, a kind of natural tetranortriterpenoids with diverse skeletons and valuable insecticidal and medicinal bioactivities, are the characteristic metabolites of most plants of the Meliaceae family. The chemistry and bioactivities of meliaceous limonoids are a continuing hot area of natural products research; to date, about 2700 meliaceous limonoids have been identified. In particular, more than 1600, including thirty kinds of novel rearranged skeletons, have been isolated and identified in the past decade due to their wide distribution and abundant content in Meliaceae plants and active biosynthetic pathways. In addition to the discovery of new structures, many positive medicinal bioactivities of meliaceous limonoids have been investigated, and extensive achievements regarding the chemical and biological synthesis have been made. This review summarizes the recent research progress in the discovery of new structures, medicinal and agricultural bioactivities, and chem/biosynthesis of limonoids from the plants of the Meliaceae family during the past decade, with an emphasis on the discovery of limonoids with novel skeletons, the medicinal bioactivities and mechanisms, and chemical synthesis. The structures, origins, and bioactivities of other new limonoids were provided as ESI. Studies published from July 2010 to December 2021 are reviewed, and 482 references are cited.

Nuclear factor-kappa B (NF-κB) inhibition as a therapeutic target for plant nutraceuticals in mitigating inflammatory lung diseases

Nutraceuticals are dietary supplements that are used to improve health, postpone aging, prevent illnesses, and maintain the human body's correct functioning. Nutraceuticals are now garnering a lot of interest because of their nutritional and therapeutic benefits. The research indicating the relevance of nutraceuticals as a possible therapeutic candidate against inflammatory lung disease was covered in this review. Nowadays, inflammatory lung diseases such as chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, asthma, pneumonia, lung cancer, becoming highly dreadful because of their associated fatality. Inflammation is one of the cores and common factors of these diseases which is mainly associated with nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation, NF-κB p65 and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) phosphorylation, and initiation of the signaling pathway of the NF-κB. The secondary metabolites from natural sources are the active component that attenuates NF-κB and the associated pathway that inhibits inflammation in lung diseases. Nutraceuticals belonging to the chemical category polyphenols, alkaloids, terpenoids, flavonoids, tannins have the potential to combat the NF-κB pathway. Accordingly, this review discusses the medical value of nutraceuticals briefly and their ability to mitigate various inflammatory lung diseases through targeting inhibition of NF-κB.

Natural Product-Based Potential Therapeutic Interventions of Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a disease-refractive lung condition with an increased rate of mortality. The potential factors causing PF include viral infections, radiation exposure, and toxic airborne chemicals. Idiopathic PF (IPF) is related to pneumonia affecting the elderly and is characterized by recurring scar formation in the lungs. An impaired wound healing process, defined by the dysregulated aggregation of extracellular matrix components, triggers fibrotic scar formation in the lungs. The potential pathogenesis includes oxidative stress, altered cell signaling, inflammation, etc. Nintedanib and pirfenidone have been approved with a conditional endorsement for the management of IPF. In addition, natural product-based treatment strategies have shown promising results in treating PF. In this study, we reviewed the recently published literature and discussed the potential uses of natural products, classified into three types-isolated active compounds, crude extracts of plants, and traditional medicine, consisting of mixtures of different plant products-in treating PF. These natural products are promising in the treatment of PF via inhibiting inflammation, oxidative stress, and endothelial mesenchymal transition, as well as affecting TGF-β-mediated cell signaling, etc. Based on the current review, we have revealed the signaling mechanisms of PF pathogenesis and the potential opportunities offered by natural product-based medicine in treating PF.

Azadirachta indica A. Juss bark extract and its Nimbin isomers restrict β-coronaviral infection and replication

Emerging mutations in the SARS-CoV-2 genome pose a challenge for vaccine development and antiviral therapy. The antiviral efficacy of Azadirachta indica bark extract (NBE) was assessed against SARS-CoV-2 and m-CoV-RSA59 infection. Effects of in vivo intranasal or oral NBE administration on viral load, inflammatory response, and histopathological changes were assessed in m-CoV-RSA59-infection. NBE administered inhibits SARS-CoV-2 and m-CoV-RSA59 infection and replication in vitro, reducing Envelope and Nucleocapsid gene expression. NBE ameliorates neuroinflammation and hepatitis in vivo by restricting viral replication and spread. Isolated fractions of NBE enriched in Nimbin isomers shows potent inhibition of m-CoV-RSA59 infection in vitro. In silico studies revealed that NBE could target Spike and RdRp of m-CoV and SARS-CoV-2 with high affinity. NBE has a triterpenoids origin that may allow them to competitively target panoply of viral proteins to inhibit mouse and different strains of human coronavirus infections, suggesting its potential as an antiviral against pan-β-Coronaviruses.

Small Molecule Drug Candidates for Managing the Clinical Symptoms of COVID-19: a Narrative Review

Towards the end of 2019, an atypical acute respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in Wuhan, China and subsequently named Coronavirus disease 2019 (COVID-19). The rapid dissemination of COVID-19 has provoked a global crisis in public health. COVID-19 has been reported to cause sepsis, severe infections in the respiratory tract, multiple organ failure, and pulmonary fibrosis, all of which might induce mortality. Although several vaccines for COVID-19 are currently being administered worldwide, the COVID-19 pandemic is not yet effectively under control. Therefore, novel therapeutic agents to eradicate the cause of the disease and/or manage the clinical symptoms of COVID-19 should be developed to effectively regulate the current pandemic. In this review, we discuss the possibility of managing the clinical symptoms of COVID-19 using natural products derived from medicinal plants used for controlling pulmonary inflammatory diseases in folk medicine. Diverse natural products have been reported to exert potential antiviral effects in vitro by affecting viral replication, entry into host cells, assembly in host cells, and release. However, the in vivo antiviral effects and clinical antiviral efficacies of these natural products against SARS-CoV-2 have not been successfully proven to date. Thus, these properties need to be elucidated through further investigations, including randomized clinical trials, in order to develop optimal and ideal therapeutic candidates for COVID-19.

TGF‑β1: Gentlemanly orchestrator in idiopathic pulmonary fibrosis (Review)

Idiopathic pulmonary fibrosis (IPF) is a worldwide disease characterized by the chronic and irreversible decline of lung function. Currently, there is no drug to successfully treat the disease except for lung transplantation. Numerous studies have been devoted to the study of the fibrotic process of IPF and findings showed that transforming growth factor‑β1 (TGF‑β1) plays a central role in the development of IPF. TGF‑β1 promotes the fibrotic process of IPF through various signaling pathways, including the Smad, MAPK, and ERK signaling pathways. There are intersections between these signaling pathways, which provide new targets for researchers to study new drugs. In addition, TGF‑β1 can affect the fibrosis process of IPF by affecting oxidative stress, epigenetics and other aspects. Most of the processes involved in TGF‑β1 promote IPF, but TGF‑β1 can also inhibit it. This review discusses the role of TGF‑β1 in IPF.

Pulmonary fibrosis: Therapeutic and mechanistic insights into the role of phytochemicals

Pulmonary fibrosis (PF) is the devastating consequence of various inflammatory diseases of the lung. PF leads to a reduction of lung function, respiratory failure, and death. Several molecular pathways are involved in PF, such as inflammatory cytokines including tumor necrosis factor α (TNFα), tumor necrosis factor β1 (TNFβ1), interleukin 6 (IL-6), and interleukin 4 (IL-4), reactive oxygen species, matrix metalloproteases, and transforming growth factor-beta (TGF-β). Targeting these processes involved in the progression of PF is essential for the treatment of this disease. Natural products, including plant extracts and active compound that directly target the processes involved in PF, could be suitable therapeutic options with less adverse effects. In the present study, we reviewed the protective effects and the therapeutic role of various bioactive compounds from plants in PF management.

Nimbolide, a Neem Limonoid, Is a Promising Candidate for the Anticancer Drug Arsenal

Nimbolide, a major limonoid constituent of Azadirachta indica, commonly known as neem, has attracted increasing research attention owing to its wide spectrum of pharmacological properties, predominantly anticancer activity. Nimbolide is reported to exert potent antiproliferative effects on a myriad cancer cell lines and chemotherapeutic efficacy in preclinical animal tumor models. The potentiality of nimbolide to circumvent multidrug resistance and aid in targeted protein degradation broaden its utility in enhancing therapeutic modalities and outcome. Accumulating evidence indicates that nimbolide prevents the acquisition of cancer hallmarks such as sustained proliferation, apoptosis evasion, invasion, angiogenesis, metastasis, and inflammation by modulating kinase-driven oncogenic signaling networks. Nimbolide has been demonstrated to abrogate aberrant activation of cellular signaling by influencing the subcellular localization of transcription factors and phosphorylation of kinases in addition to influencing the epigenome. Nimbolide, with its ever-expanding repertoire of molecular targets, is a valuable addition to the anticancer drug arsenal.

Nimbolide exerts protective effects in complete Freund's adjuvant induced inflammatory arthritis via abrogation of STAT-3/NF-κB/Notch-1 signaling

AIM

Activation of transmembrane Notch-1 receptors through inflammatory cytokines is highly regulated by STAT-3 and NF-κB phosphorylation. Nimbolide (NMB) exhibits potent anti-inflammatory, anti-fibrotic, anticancer activities by targeting various pathways. Here, we have investigated the effect of NMB in regulation of STAT-3/NF-κB/Notch-1 axis in complete Freund's adjuvant (CFA) induced inflammatory arthritis (IA) model.

MAIN METHODS

The anti-inflammatory and anti-arthritic activity of NMB was evaluated both in vitro (IL-1β stimulated HIG-82 synovial fibroblasts) and in vivo (CFA induced rat model of IA) models. In vitro anti-arthritic activity was assessed by anti-migratory effect, while in vivo effects were evaluated through radiological and histological analysis. The effect of NMB on STAT-3, NF-κB, Notch-1 signaling pathways and proinflammatory cytokines were studied using western blot, immunohistochemistry and ELISA methods. Key findings NMB attenuated the migration of synovial fibroblasts in vitro. It reduced the progression of arthritis as evidenced from the improved radiological and histological abnormalities in arthritic rats. NMB significantly suppressed the nitrosooxidative stress and levels of pro-inflammatory cytokines. NMB also exhibited remarkable protective activity against upregulation of MAPK, STAT-3 and NF-κB phosphorylation mediated Notch-1 signaling pathway in synovial tissue of arthritic rats.

SIGNIFICANCE

NMB may have clinical therapeutic value in rheumatoid arthritis by inhibiting STAT-3/NF-κB/Notch-1 axis and also by reducing the levels of proinflammatory cytokines.

Nimbolide ameliorates pancreatic inflammation and apoptosis by modulating NF-κB/SIRT1 and apoptosis signaling in acute pancreatitis model

Acute pancreatitis (AP) is a potential gastrointestinal problem most commonly associated with pancreatic inflammation and acinar cells injury. Nimbolide (NB), isolated from the tree Azadirachta indica, possesses antioxidant and anti-inflammatory effects. Here, we aimed to investigate the pancreatic protective effects of NB in ameliorating cerulein-induced pancreatic inflammation and apoptosis in AP model and evaluate the potential mechanism of action. AP was induced in Swiss albino mice by six-hourly intraperitoneal exposures of cerulein (50 µg/kg/hr) and pre-treatment of NB (0.3 and 1 mg/kg) 7 days prior to the cerulein exposure. Various parameters associated with AP in plasma and pancreatic tissues were evaluated. Severity of AP was effectively ameliorated by NB as shown by reducing pancreatic edema, plasma amylase and lipase levels, MPO levels and in cerulein-induced histological damage. Further, the antioxidant effect of NB was associated with a significant inhibition of oxidative-nitrosative stress in Raw 264.7 cells and cerulein-induced AP mice. Moreover, NB suppressed proinflammatory cytokines, iNOS and nitrotyrosine expression. In addition, NB inhibited NF-κB activation and increased SIRT1 expression in cerulein challenged mice. Furthermore, NB also inhibited pancreatic apoptosis by downregulating cleaved caspase 3 and Bax while upregulating Bcl2 expression in cerulein-treated mice. Inhibition of pancreatic inflammation and apoptosis resulted in attenuation of cerulein-induced AP. These results suggest that NB exerts strong anti-pancreatitis effects against cerulein-induced AP by combating inflammatory and apoptosis signaling via SIRT1 activation.

Natural products as home-based prophylactic and symptom management agents in the setting of COVID-19

Coronavirus disease (COVID‐19) caused by the novel coronavirus (SARS‐CoV‐2) has rapidly spread across the globe affecting 213 countries or territories with greater than six million confirmed cases and about 0.37 million deaths, with World Health Organization categorizing it as a pandemic. Infected patients present with fever, cough, shortness of breath, and critical cases show acute respiratory infection and multiple organ failure. Likelihood of these severe indications is further enhanced by age as well as underlying comorbidities such as diabetes, cardiovascular, or thoracic problems, as well as due to an immunocompromised state. Currently, curative drugs or vaccines are lacking, and the standard of care is limited to symptom management. Natural products like ginger, turmeric, garlic, onion, cinnamon, lemon, neem, basil, and black pepper have been scientifically proven to have therapeutic benefits against acute respiratory tract infections including pulmonary fibrosis, diffuse alveolar damage, pneumonia, and acute respiratory distress syndrome, as well as associated septic shock, lung and kidney injury, all of which are symptoms associated with COVID‐19 infection. This review highlights the potential of these natural products to serve as home‐based, inexpensive, easily accessible, prophylactic agents against COVID‐19.

The protective effect of Hederagenin on pulmonary fibrosis by regulating the Ras/JNK/NFAT4 axis in rats

As a respiratory disease with high morbidity and mortality, pulmonary fibrosis (PF) has been a serious threat to people's health. Hederagenin (HDG) is a pentacyclic triterpenoid saponin widely distributed in various plants. This study explored the role of HDG in Bleomycin (BLM)-induced PF and the molecular mechanism. The results showed that HDG reduced BLM-induced pulmonary dysfunction, pathological damage in a dose-dependent manner. Besides, HDG reduced BLM-induced collagen deposition by decreasing the levels of α-SMA, Collagen I and hydroxproline. Furthermore, HDG reduced the levels of inflammatory cytokines (TNF-α and IL-6), TGF-β1 and connective tissue growth factor (CTGF) in bronchoalveolar lavage fluid (BALF) or serum. Further mechanism analysis indicated that HDG inhibited the expression of Ras and phosphorylation of JNK and NFAT4 in a dose-dependent manner. However, the JNK pathway activator Anisomycin reversed this inhibitory effect. In conclusion, these findings suggest that HDG may be a potential target drug for PF therapy.

Autophagy and pulmonary disease

Autophagy is a process of cell self-renewal that is dependent on the degradation of the cytoplasmic proteins or organelles of lysosomes. Many diseases, such as metabolic diseases, cancer, neurodegenerative diseases, and lung diseases, have been confirmed to be associated with elevated or impaired levels of autophagy. At present, studies have found that autophagy participates in the regulation of chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, pulmonary hypertension, acute lung injury, lung cancer, and other pulmonary diseases. Using recent literature on the signal transduction mechanisms of autophagy and the effects of autophagy signalling on lung diseases, this review intends to clarify the mechanisms of lung disease to guide the treatment of related diseases. The reviews of this paper are available via the supplemental material section.