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.

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.

Natural Products as Sources of Novel Drug Candidates for the Pharmacological Management of Osteoarthritis: A Narrative Review

Osteoarthritis is a chronic degenerative articular disorder. Formation of bone spurs, synovial inflammation, loss of cartilage, and underlying bone restructuring have been reported to be the main pathologic characteristics of osteoarthritis symptoms. The onset and progression of osteoarthritis are attributed to various inflammatory cytokines in joint tissues and fluids that are produced by chondrocytes and/or interact with chondrocytes, as well as to low-grade inflammation in intra-articular tissues. Disruption of the equilibrium between the synthesis and degradation of the cartilage of the joint is the major cause of osteoarthritis. Hence, developing a promising pharmacological tool to restore the equilibrium between the synthesis and degradation of osteoarthritic joint cartilage can be a useful strategy for effectively managing osteoarthritis. In this review, we provide an overview of the research results pertaining to the search for a novel candidate agent for osteoarthritis management via restoration of the equilibrium between cartilage synthesis and degradation. We especially focused on investigations of medicinal plants and natural products derived from them to shed light on the potential pharmacotherapy of osteoarthritis.

Effect of Pyunkang-tang on Inflammatory Aspects of Chronic Obstructive Pulmonary Disease in a Rat Model

We investigated the anti-inflammatory effect of Pyunkang-tang extract (PGT), a complex herbal extract based on traditional Chinese medicine that is used in Korea for controlling diverse pulmonary diseases, on cigarette smoke-induced pulmonary pathology in a rat model of chronic obstructive pulmonary disease (COPD). The constituents of PGT were Lonicerae japonica, Liriope platyphylla, Adenophora triphilla, Xantium strumarinum, Selaginella tamariscina and Rehmannia glutinosa. Rats were exposed by inhalation to a mixture of cigarette smoke extract (CSE) and sulfur dioxide for three weeks to induce COPD-like pulmonary inflammation. PGT was administered orally to rats and pathological changes to the pulmonary system were examined in each group of animals through measurement of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels in bronchoalveolar lavage fluid (BALF) at 21 days post-CSE treatment. The effect of PGT on the hypersecretion of pulmonary mucin in rats was assessed by quantification of the amount of mucus secreted and by examining histopathologic changes in tracheal epithelium. Confluent NCI-H292 cells were pretreated with PGT for 30 min and then stimulated with CSE plus PMA (phorbol 12-myristate 13-acetate), for 24 h. The MUC5AC mucin gene expression was measured by RT-PCR. Production of MUC5AC mucin protein was measured by ELISA. The results were as follows: (1) PGT inhibited CSE-induced pulmonary inflammation as shown by decreased TNF-α and IL-6 levels in BALF; (2) PGT inhibited the hypersecretion of pulmonary mucin and normalized the increased amount of mucosubstances in goblet cells of the CSE-induced COPD rat model; (3) PGT inhibited CSE-induced MUC5AC mucin production and gene expression in vitro in NCI-H292 cells, a human airway epithelial cell line. These results suggest that PGT might regulate the inflammatory aspects of COPD in a rat model.

Effects of Nodakenin, Columbianadin, and Umbelliferone Isolated from the Roots of Angelica decursiva on the Gene Expression and Production of MUC5AC Mucin from Human Airway Epithelial NCI-H292 Cells

Angelica decursiva has been utilised as remedy for controlling the airway inflammatory diseases in folk medicine. We investigated whether nodakenin, columbianadin, and umbelliferone isolated from the roots of Angelica decursiva inhibit the gene expression and production of MUC5AC mucin from human airway epithelial cells. Confluent NCI-H292 cells were pretreated with nodakenin, columbianadin or umbelliferone for 30 min and then stimulated with epidermal growth factor (EGF), phorbol 12-myristate 13-acetate (PMA) or tumor necrosis factor-α (TNF-α) for 24 h. The MUC5AC mucin gene expression was measured by reverse transcription - polymerase chain reaction (RT-PCR). Production of MUC5AC mucin protein was measured by enzyme-linked immunosorbent assay (ELISA). The results were as follows: (1) Nodakenin did not affect the expression of MUC5AC mucin gene induced by EGF, PMA or TNF-α. Columbianadin inhibited the expression of MUC5AC mucin gene induced by EGF or PMA. However, umbelliferone inhibited the expression of MUC5AC mucin gene induced by EGF, PMA or TNF-α; (2) Nodakenin also did not affect the production of MUC5AC mucin protein induced by EGF, PMA or TNF-α. Columbianadin inhibited the production of MUC5AC mucin protein induced by PMA. However, umbelliferone inhibited the production of MUC5AC mucin protein induced by EGF, PMA or TNF-α. These results suggest that, among the three compounds investigated, umbelliferone only inhibits the gene expression and production of MUC5AC mucin stimulated by various inducers, by directly acting on airway epithelial cells, and the results might explain the traditional use of Angelica decursiva as remedy for diverse inflammatory pulmonary diseases.

Pyunkang-hwan (Pyunkang-Tang) ameliorates air pollutant-induced inflammatory hypersecretion of airway mucus and bleomycin- induced pulmonary fibrosis in rats.

OBJECTIVE: To investigate the effect of Pyunkanghwan (Pyunkang-tang) extract (PGT) on secretion of airway mucin in an experimental animal model involving hyperplasia of goblet cells and mucus hypersecretion, and to test its effects on bleomycin (BLM)-induced pulmonary fibrosis in vivo. METHODS: The protective activity of orally administered PGT was assessed in two rat pulmonary disease models. Effects on hypersecretion of pulmonary mucin in sulfur dioxide (SO2)-induced bronchitis in rats were assessed by quantifying the amount of mucus secreted and examining histopathology in the tracheal epithelium. In a rat model for BLMinduced pulmonary fibrosis, toxicity to the pulmonary system was examined by measuring levels of malondialdehyde and hydroxyproline, indicators of lipid peroxides and collagen, respectively, in lung tissue 28 days post-BLM treatment. Serial sections of lung tissue were stained with Masson trichrome to visualize collagen deposition. Effects of PGT on collagen synthesis were also assessed in vitro, in a cell culture model. RESULTS: PGT inhibited mucin secretion and normalized SO2-induced increased muco- substances in goblet cells. In the BLM- induced model, PGT decreased the characteristic histopathological features of lung fibrosis and inhibited fibrotic lesions, as indicated by decreased hydroxyproline content. PGT also inhibited the BLM-induced increase in malondialdehyde levels, demonstrating its protective effect against lipid peroxidation in cell membranes of the lung. In MLg 2908 mouse lung fibroblast cells, PGT decreased transforming growth factor (TGF)-ß-stimulated type I collagen synthesis. CONCLUSION: PGT can inhibit both hypersecretion of airway mucins and pulmonary fibrosis.

Effects of Caffeic Acid, Myristicin and Rosemarinic Acid on the Gene Expression and Production of Airway MUC5AC Mucin

Perilla frutescens was empirically used for controlling airway inflammatory diseases in folk medicine. We investigated whether caffeic acid, myristicin and rosemarinic acid derived from Perilla frutescens significantly affect the gene expression and production of mucin from airway epithelial cells. Confluent NCI-H292 cells were pretreated with caffeic acid, myristicin or rosemarinic acid for 30 min and then stimulated with phorbol 12-myristate 13-acetate (PMA) for 24 h. The MUC5AC mucin gene expression and production were measured by reverse transcription - polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Additionally, we examined whether caffeic acid, myristicin or rosemarinic acid affects MUC5AC mucin production indued by epidermal growth factor (EGF) and tumor necrosis factor-α (TNF-α), the other two stimulators of production of airway mucin. The results were as follows: (1) Caffeic acid, myristicin and rosemarinic acid inhibited the gene expression and production of MUC5AC mucin induced by PMA from NCI-H292 cells, respectively; (2) Among the three compounds derived from Perilla frutescens, only rosemarinic acid inhibited the production of MUC5AC mucin induced by EGF or TNF-α, the other two stimulators of production of airway mucin. These results suggest that rosemarinic acid derived from Perilla frutescens can regulate the production and gene expression of mucin, by directly acting on airway epithelial cells and, at least in part, explains the traditional use of Perilla frutescens as remedies for diverse inflammatory pulmonary diseases.

Effects of Lupenone, Lupeol, and Taraxerol Derived from Adenophora triphylla on the Gene Expression and Production of Airway MUC5AC Mucin / 결핵및호흡기질환

BACKGROUND: Adenophora triphylla var. japonica is empirically used for controlling airway inflammatory diseases in folk medicine. We evaluated the gene expression and production of mucin from airway epithelial cells in response to lupenone, lupeol and taraxerol derived from Adenophora triphylla var. japonica. METHODS: Confluent NCI-H292 cells were pretreated with lupenone, lupeol or taraxerol for 30 minutes and then stimulated with tumor necrosis factor alpha (TNF-alpha) for 24 hours. The MUC5AC mucin gene expression and production were measured by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Additionally, we examined whether lupenone, lupeol or taraxerol affects MUC5AC mucin production induced by epidermal growth factor (EGF) and phorbol 12-myristate 13-acetate (PMA), the other 2 stimulators of airway mucin production. RESULTS: Lupenone, lupeol, and taraxerol inhibited the gene expression and production of MUC5AC mucin induced by TNF-alpha from NCI-H292 cells, respectively. The 3 compounds inhibited the EGF or PMA-induced production of MUC5AC mucin in NCI-H292 cells. CONCLUSION: These results indicated that lupenone, lupeol and taraxerol derived from Adenophora triphylla var. japonica regulates the production and gene expression of mucin, by directly acting on airway epithelial cells. In addition, the results partly explain the mechanism of of Adenophora triphylla var. japonica as a traditional remedy for diverse inflammatory pulmonary diseases.

Effects of Morus alba L. and Natural Products Including Morusin on In Vivo Secretion and In Vitro Production of Airway MUC5AC Mucin / 결핵및호흡기질환

BACKGROUND: It is valuable to find the potential activity of regulating the excessive mucin secretion by the compounds derived from various medicinal plants. We investigated whether aqueous extract of the root bark of Morus alba L. (AMA), kuwanon E, kuwanon G, mulberrofuran G, and morusin significantly affect the secretion and production of airway mucin using in vivo and in vitro experimental models. METHODS: Effect of AMA was examined on hypersecretion of airway mucin in sulfur dioxide-induced acute bronchitis in rats. Confluent NCI-H292 cells were pretreated with ethanolic extract, kuwanon E, kuwanon G, mulberrofuran G, or morusin for 30 minutes and then stimulated with phorbol 12-myristate 13-acetate (PMA) for 24 hours. The MUC5AC mucin secretion and production were measured by enzyme-linked immunosorbent assay. RESULTS: AMA stimulated the secretion of airway mucin in sulfur dioxide-induced bronchitis rat model; aqueous extract, ethanolic extract, kuwanon E, kuwanon G, mulberrofuran G and morusin inhibited the production of MUC5AC mucin induced by PMA from NCI-H292 cells, respectively. CONCLUSION: These results suggest that extract of the root bark and the natural products derived from Morus alba L. can regulate the secretion and production of airway mucin and, at least in part, explains the folk use of extract of Morus alba L. as mucoregulators in diverse inflammatory pulmonary diseases.