Selaginella uncinata flavonoids ameliorated ovalbumin-induced airway inflammation in a rat model of asthma

Evaluation of Urtica dioica Phytochemicals against Therapeutic Targets of Allergic Rhinitis Using Computational Studies

Allergic rhinitis (AR) is a prevalent inflammatory condition affecting millions globally, with current treatments often associated with significant side effects. To seek safer and more effective alternatives, natural sources like Urtica dioica (UD) are being explored. However, UD's mechanism of action remains unknown. Therefore, to elucidate it, we conducted an in silico evaluation of UD phytochemicals' effects on known therapeutic targets of allergic rhinitis: histamine receptor 1 (HR1), neurokinin 1 receptor (NK1R), cysteinyl leukotriene receptor 1 (CLR1), chemoattractant receptor-homologous molecule expressed on type 2 helper T cells (CRTH2), and bradykinin receptor type 2 (BK2R). The docking analysis identified amentoflavone, alpha-tocotrienol, neoxanthin, and isorhamnetin 3-O-rutinoside as possessing a high affinity for all the receptors. Subsequently, molecular dynamics (MD) simulations were used to analyze the key interactions; the free energy of binding was calculated through Generalized Born and Surface Area Solvation (MMGBSA), and the conformational changes were evaluated. Alpha-tocotrienol exhibited a high affinity while also inducing positive conformational changes across all targets. Amentoflavone primarily affected CRTH2, neoxanthin targeted NK1R, CRTH2, and BK2R, and isorhamnetin-3-O-rutinoside acted on NK1R. These findings suggest UD's potential to treat AR symptoms by inhibiting these targets. Notably, alpha-tocotrienol emerges as a promising multi-target inhibitor. Further in vivo and in vitro studies are needed for validation.

Water extract of Pingchuan formula ameliorated murine asthma through modulating metabolites and gut microbiota

BACKGROUND

Pingchuan formula is a traditional Chinese herbal prescription for asthma, but its components and underlying mechanisms remain unclear. Here, we evaluated its anti-asthmatic actvity and regulatory effects on the gut microbiota in mice based on the traditional Chinese medicine Zang-Fu theory, which proposed the exterior-interior relationship between the lung and the large intestine.

METHODS

Mouse model withovalbumin (OVA)-induced asthma was used to assess the protective effect of the water extract of Pingchuan formula (PC). The chemical compounds of PC and mouse serum metabolites were identified by Ultraperformance liquid chromatography-Q Exactive HF-X spectrometry. Gut microbiota was evaluated by 16 S rRNA gene sequencing. The gut microbiota was depleted with a broad-spectrum antibiotic mixture (Abx) to explore whether it plays a role in the protective effects of PC.

RESULTS

PC mainly contains phenols, flavonoids, alkaloids, carboxylic acids, and their derivatives. PC attenuated OVA-induced asthma in mice by alleviating inflammatory infiltration, indicated by decreased levels of IL-18, IL-6, IL-4, and Eotaxin in lung tissues. PC treatment altered the serum metabolites and affected the pyrimidine pathway. In addition, our results showed that acacetin and abscisic acid were the key serum metabolites PC treatment changed the composition of gut microbiota by increasing the relative abundance of Clostridia_UCG_014 and Akkermansia while decreasing Blautia, Barnesiella, and Clostridium_Ⅲ at the genus level. Importantly, the Abx treatment partly abolished the anti-asthmatic effect of PC.

CONCLUSION

We demonstrated that PC could alleviate OVA-induced asthma in mice and protect against inflammatory infiltration in lungs via modulating the serum metabolites and gut microbiota, thereby providing a new reference for the therapeutic effect of PC.

Role of bZIP transcription factors in the regulation of plant secondary metabolism

MAIN CONCLUSION

This study provides an overview of the structure, classification, regulatory mechanisms, and biological functions of the basic (region) leucine zipper transcription factors and their molecular mechanisms in flavonoid, terpenoid, alkaloid, phenolic acid, and lignin biosynthesis. Basic (region) leucine zippers (bZIPs) are evolutionarily conserved transcription factors (TFs) in eukaryotic organisms. The bZIP TFs are widely distributed in plants and play important roles in plant growth and development, photomorphogenesis, signal transduction, resistance to pathogenic microbes, biotic and abiotic stress, and secondary metabolism. Moreover, the expression of bZIP TFs not only promotes or inhibits the accumulation of secondary metabolites in medicinal plants, but also affects the stress response of plants to the external adverse environment. This paper describes the structure, classification, biological function, and regulatory mechanisms of bZIP TFs. In addition, the molecular mechanism of bZIP TFs regulating the biosynthesis of flavonoids, terpenoids, alkaloids, phenolic acids, and lignin are also elaborated. This review provides a summary for in-depth study of the molecular mechanism of bZIP TFs regulating the synthesis pathway of secondary metabolites and plant molecular breeding, which is of significance for the generation of beneficial secondary metabolites and the improvement of plant varieties.

Screening for α-glucosidase inhibitors from Selaginella uncinata based on the ligand fishing combined with ultra-high-performance liquid chromatography-quadrupole time-of-flight-tandem mass spectrometry

Biflavonoids are naturally occurring compounds consisting of two flavonoid moieties that have received substantial attention from researchers. Although many kinds of biflavonoids are typically distributed in Selaginella uncinata with hypoglycemic effect, their anti-α-glucosidase activities are not yet clear. In this study, a ligand fishing strategy for fast screening of α-glucosidase inhibitors from S. uncinata was proposed. α-Glucosidase was first immobilized on Fe₃ O₄ magnetic nanoparticles (MNPs) and then the α-glucosidase-functionalized MNPs were incubated with crude extracts of S. uncinata to fish out the ligands. Furthermore, considering the similarity and easy confusion of the structures of biflavonoids, the fragmentation patterns of different types of biflavonoids were studied. Based on this, 11 biflavonoids ligands with α-glucosidase inhibitory activities were accurately and quickly identified from S. uncinata with ultra-high-performance liquid chromatography-quadrupole time-of-flight-tandem mass spectrometry. Furthermore, these ligands were confirmed to be potential inhibitors through the in vitro inhibitory assay and molecular docking.

Protective Effects of Herba Houttuyniae Aqueous Extract against OVA-Induced Airway Hyperresponsiveness and Inflammation in Asthmatic Mice

Herba Houttuyniae is the well-knownfood-medicine herb with the special taste and smell. It is also widely used in south China for prevention of various chronic pulmonary inflammatory diseases including asthma. However, the active ingredients and therapeutic mechanism of this herb remain obscure. In this study, network pharmacology technology was employed to investigate the effects of Herba Houttuyniae aqueous extract (HHAE) on OVA-induced airway hyperresponsiveness and inflammation. The results showed that six compounds (isoramanone, kaempferol, 1-methyl-2-nonacosyl-4-quinolone, C09747, spinasterol, and quercetin) were found to be mainly responsible for the therapeutic effects of the herb, which totally regulated the expressions of 168 asthma-related proteins. All those targets involved in the signal transduction of the prolactin signaling pathway, central carbon metabolism in cancer, EGFR tyrosine kinase inhibitor resistance, endocrine resistance, and VEGF signaling pathway. The in vivo experiment also revealed that orally administrated with HHAE alleviated airway hyperresponsiveness and inflammation in OVA-induced asthmatic mice. It significantly decreased the counts of neutrophils, eosinophils, and lymphocytes as well as the levels of IL-1β, IL-4, IL-6, and IL-13 in BALF of asthmatic mice. Mechanically, HHAE downregulated both the mRNA and protein expressions of p38 MAPK, PI3K, AKT, and VEGF in the lung tissues of asthmatic mice. Therefore, HHAE improved OVA-induced airway hyperresponsiveness and inflammation in mice and could be a potential supplement for asthma treatment.

Natural compounds targeting glycolysis as promising therapeutics for gastric cancer: A review

Gastric cancer, a common malignant disease, seriously endangers human health and life. The high mortality rate due to gastric cancer can be attributed to a lack of effective therapeutic drugs. Cancer cells utilize the glycolytic pathway to produce energy even under aerobic conditions, commonly referred to as the Warburg effect, which is a characteristic of gastric cancer. The identification of new targets based on the glycolytic pathway for the treatment of gastric cancer is a viable option, and accumulating evidence has shown that phytochemicals have extensive anti-glycolytic properties. We reviewed the effects and mechanisms of action of phytochemicals on aerobic glycolysis in gastric cancer cells. Phytochemicals can effectively inhibit aerobic glycolysis in gastric cancer cells, suppress cell proliferation and migration, and promote apoptosis, via the PI3K/Akt, c-Myc, p53, and other signaling pathways. These pathways affect the expressions of HIF-1α, HK2, LDH, and other glycolysis-related proteins. This review further assesses the potential of using plant-derived compounds for the treatment of gastric cancer and sheds insight into the development of new drugs.

The Role of Respiratory Flora in the Pathogenesis of Chronic Respiratory Diseases

Large quantities of bacteria, including Firmicutes, Actinobacteria, and Bacteroidetes, colonize the surface of the respiratory mucosa of healthy people. They interact and coexist with the local mucosal immune system of the human airway, maintaining the immune stability and balance of the respiratory system. While suffering from chronic respiratory diseases, the microbial population in the airway changes and the proportion of Proteobacteria is increased in patients with asthma. The abundance of the microbial population in patients with chronic obstructive pulmonary disease (COPD) is decreased, and conversely, the proportion of Firmicutes and Proteobacteria increased. The diversity of airway microorganisms in cystic fibrosis (CF) patients is decreased, while pathogenic bacteria and conditional pathogenic bacteria are proliferated in large numbers. The proportion of Firmicutes and Proteobacteria is increased in patients with upper airway cough syndrome (UACS), which replaces the dominance of Streptococcus and Neisseria in the pharynx of a normal population. Therefore, a clear understanding of the immune process of the airway flora and the immune dysfunction of the flora on the pathogenesis of chronic respiratory diseases can provide new ideas for the prevention and treatment of human respiratory diseases.

Traditional Medicinal Plants Conferring Protection Against Ovalbumin-Induced Asthma in Experimental Animals: A Review

Asthma is a chronic inflammatory disease of the respiratory tract in which the numerous immune cells, including eosinophils, neutrophils, macrophages, T-lymphocytes, mast cells and epithelial lining play key roles. The numerous anti-asthmatic drugs are available in modern medicine to treat asthma, but they have several disadvantages, including side effects and the cost variations, which compromise treatment compliance. The literature review reveals that traditional herbal medicines have good potential as alternative treatment and management for asthma. However, communities hesitated to use the traditional herbal medicines due to lack of established mechanism of action about their anti-asthmatic potential. The present review aimed to summarise the information stated in the literature about the potential effect of traditional medicinal plants (TMPs) conferring protection against ovalbumin (OVA)-induced asthma model. The literature search was conducted in database like PubMed, Scopus, Google Scholar and ScienceDirect. After screening through the literature from 2011 to date, a total of 27 medicinal plants and two polyherbal extracts have been reported to be used as traditional herbal medicines and also utilised to be tested against OVA-induced asthma, were included. We found them to be an important alternative source of treatment for asthma, since some have comparable efficacies with drugs commonly used in the modern system against asthma. All the reported medicinal plants confirmed their traditional use against asthma or its related inflammation. The present review provides faith in traditional information and also offers new insight into the potential of natural products against asthma.

Comparison of Chemical Composition and Biological Activities of Eight Selaginella Species

Selaginella P. Beauv. is a group of vascular plants in the family Selaginellaceae Willk., found worldwide and numbering more than 700 species, with some used as foods and medicines. The aim of this paper was to compare methanolic (MeOH) and dichloromethane (DCM) extracts of eight Selaginella species on the basis of their composition and biological activities. Six of these Selaginella species are underinvestigated. Using ultra-high performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) analysis, we identified a total of 193 compounds among the tested Selaginella species, with flavonoids predominating. MeOH extracts recovered more constituents that were detected, including selaginellins, the occurrence of which is only typical for this plant genus. Of all the tested species, Selaginella apoda contained the highest number of identified selaginellins. The majority of the compounds were identified in S. apoda, the fewest compounds in Selaginella cupressina. All the tested species demonstrated antioxidant activity using oxygen radical absorption capacity (ORAC) assay, which showed that MeOH extracts had higher antioxidant capacity, with the half maximal effective concentration (EC₅₀) ranging from 12 ± 1 (Selaginella myosuroides) to 124 ± 2 (Selaginella cupressina) mg/L. The antioxidant capacity was presumed to be correlated with the content of flavonoids, (neo)lignans, and selaginellins. Inhibition of acetylcholinesterase (AChE) was mostly discerned in DCM extracts and was only exhibited in S. myosuroides, S. cupressina, Selaginella biformis, and S. apoda extracts with the half maximal inhibitory concentration (IC₅₀) in the range of 19 ± 3 to 62 ± 1 mg/L. Substantial cytotoxicity against cancer cell lines was demonstrated by the MeOH extract of S. apoda, where the ratio of the IC₅₀ HEK (human embryonic kidney) to IC₅₀ HepG2 (hepatocellular carcinoma) was 7.9 ± 0.2. MeOH extracts inhibited the production of nitrate oxide and cytokines in a dose-dependent manner. Notably, S. biformis halved the production of NO, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 at the following concentrations: 105 ± 9, 11 ± 1, and 10 ± 1 mg/L, respectively. Our data confirmed that extracts from Selaginella species exhibited cytotoxicity against cancer cell lines and AChE inhibition. The activity observed in S. apoda was the most promising and is worth further exploration.

Robustaflavone-4'-dimethyl ether from Selaginella uncinata attenuated lipopolysaccharide-induced acute lung injury via inhibiting FLT3-mediated neutrophil activation

Neutrophils act as both messenger and effector which contributed to the pathogenesis of acute lung injury (ALI). Targeting neutrophils could be a novel strategy for prevention and treatment of ALI. Selaginella uncinata is widely used as an antitussive, antipyretic and anti-inflammatory herb to treat various pulmonary diseases, including lung cancer, asthma, pulmonary fibrosis and pneumonia. However, its effective constituents remain unknown. In the present study, the protective effects of flavonoids from S. uncinata (SUF) and its major compound robustaflavone-4'-dimethyl ether (RDE) against lipopolysaccharide (LPS)-induced ALI were investigated in mice and in neutrophils.The results showed that both SUF and RDE had the same inhibition on LPS-induced lung edema and neutrophil infiltration as well as the increased levels of IL-6, TNF-α, P-selectin and ICAM-1 in serum of LPS-challenged mice. Furthermore, RDE significantly inhibited inducible neutrophil activation in a concentration-dependent manner, and also reduced the levels of intracellular calcium as well as the expressions of CCR2. Rescue experiment showed that RDE suppressed FLT3 and its downstream p-p38 and p-AKT, which could be abolished by FLT3 agonist FLT3L but partly by MAPK agonist PDBu or AKT agonist SC79. Therefore, these results indicated that RDE as the main bioactive compound in SUF alleviated LPS-induced acute lung injury and inhibited neutrophil activation via inhibition of FLT3-mediatied AKT and MAPK pathways.

Use of Natural Products in Asthma Treatment

Asthma, a disease classified as a chronic inflammatory disorder induced by airway inflammation, is triggered by a genetic predisposition or antigen sensitization. Drugs currently used as therapies present disadvantages such as high cost and side effects, which compromise the treatment compliance. Alternatively, traditional medicine has reported the use of natural products as alternative or complementary treatment. The aim of this review was to summarize the knowledge reported in the literature about the use of natural products for asthma treatment. The search strategy included scientific studies published between January 2006 and December 2017, using the keywords "asthma," "treatment," and "natural products." The inclusion criteria were as follows: (i) studies that aimed at elucidating the antiasthmatic activity of natural-based compounds or extracts using laboratory experiments (in vitro and/or in vivo); and (ii) studies that suggested the use of natural products in asthma treatment by elucidation of its chemical composition. Studies that (i) did not report experimental data and (ii) manuscripts in languages other than English were excluded. Based on the findings from the literature search, aspects related to asthma physiopathology, epidemiology, and conventional treatment were discussed. Then, several studies reporting the effectiveness of natural products in the asthma treatment were presented, highlighting plants as the main source. Moreover, natural products from animals and microorganisms were also discussed and their high potential in the antiasthmatic therapy was emphasized. This review highlighted the importance of natural products as an alternative and/or complementary treatment source for asthma treatment, since they present reduced side effects and comparable effectiveness as the drugs currently used on treatment protocols.

Toward the Identification of Extra-Oral TAS2R Agonists as Drug Agents for Muscle Relaxation Therapies via Bioinformatics-Aided Screening of Bitter Compounds in Traditional Chinese Medicine

Significant advances have been made in the past decade in mapping the distributions and the physiological functions of extra-oral bitter taste receptors (TAS2Rs) in non-gustatory tissues. In particular, it has been found that TAS2Rs are expressed in various muscle tissues and activation of TAS2Rs can lead to muscle cell relaxation, which suggests that TAS2Rs may be important new targets in muscle relaxation therapy for various muscle-related diseases. So far, however, there is a lack of potent extra-oral TAS2R agonists that can be used as novel drug agents in muscle relaxation therapies. Interestingly, traditional Chinese medicine (TCM) often characterizes a drug’s property in terms of five distinct flavors (bitter, sweet, sour, salty, and pungent) according to its taste and function, and commonly regards “bitterness” as an intrinsic property of “good medicine.” In addition, many bitter flavored TCM are known in practice to cause muscle relaxation after long term use, and in lab experiments the compounds identified from some bitter flavored TCM do activate TAS2Rs and thus relax muscle cells. Therefore, it is highly possible to discover very useful extra-oral TAS2R agonists for muscle relaxation therapies among the abundant bitter compounds used in bitter flavored TCM. With this perspective, we reviewed in literature the distribution of TAS2Rs in different muscle systems with a focus on the map of bitter flavored TCM which can regulate muscle contractility and related functional chemical components. We also reviewed the recently established databases of TCM chemical components and the bioinformatics software which can be used for high-throughput screening and data mining of the chemical components associated with bitter flavored TCM. All together, we aim to present a knowledge-based approach and technological platform for identification or discovery of extra-oral TAS2R agonists that can be used as novel drug agents for muscle relaxation therapies through screening and evaluation of chemical compounds used in bitter flavored TCM.

Anti-inflammatory effects of linalool on ovalbumin-induced pulmonary inflammation

Linalool is a natural product present in fruits and aromatic plants with biological activities. Researchers have reported that the inhalation of linalool exerts anti-inflammatory activities. In this study, we examined the therapeutic effects of linalool on airway inflammation and mucus overproduction in mice with allergic asthma. Oral administration of linalool significantly inhibited the levels of eosinophil numbers, Th2 cytokines and immunoglobulin E (IgE) caused by ovalbumin (OVA) exposure. Linalool exerted preventive effects against the influx of inflammatory cells and mucus hypersecretion in the lung tissues. Linalool also dose-dependently decreased the levels of inducible nitric oxide synthase (iNOS) expression and protein kinase B (AKT) activation in the lung tissues. Linalool effectively downregulated the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) caused by OVA exposure. Furthermore, linalool exerted inhibitory effect on OVA-induced airway hyperresponsiveness (AHR). In the in vitro study, the increased secretion of MCP-1 was attenuated with linalool treatment in lipopolysaccharide (LPS)-stimulated H292 airway epithelial cells. In conclusion, linalool effectively exerts a protective role in OVA-induced airway inflammation and mucus hypersecretion, and its protective effects are closely related to the downregulation of inflammatory mediators and MAPKs/NF-κB signaling.

Anti-cancer stemness and anti-invasive activity of bitter taste receptors, TAS2R8 and TAS2R10, in human neuroblastoma cells

Neuroblastoma (NB) originates from immature neuronal cells and currently has a poor clinical outcome. NB cells possess cancer stem cells (CSCs) characteristics that facilitate the initiation of a tumor, as well as its metastasis. Human bitter taste receptors, referred to as TAS2Rs, are one of five types of basic taste receptors and they belong to a family of G-protein coupled receptors. The recent finding that taste receptors are expressed in non-gustatory tissues suggest that they mediate additional functions distinct from taste perception. While it is generally admitted that the recognition of bitter tastes may be associated with a self-defense system to prevent the ingestion of poisonous food compounds, this recognition may also serve as a disease-related function in the human body. In particular, the anti-cancer stemness and invasion effects of TAS2Rs on NB cells remain poorly understood. In the present study, endogenous expression of TAS2R8 and TAS2R10 in SK-N-BE(2)C and SH-SY5Y cells was examined. In addition, higher levels of TAS2R8 and TAS2R10 expression were investigated in more differentiated SY5Y cells. Both TAS2Rs were up-regulated following the induction of neuronal cell differentiation by retinoic acid. In addition, ectopic transfection of the two TAS2Rs induced neurite elongation in the BE(2)C cells, and down-regulated CSCs markers (including DLK1, CD133, Notch1, and Sox2), and suppressed self-renewal characteristics. In particular, TAS2RS inhibited tumorigenicity. Furthermore, when TAS2Rs was over-expressed, cell migration, cell invasion, and matrix metalloproteinases activity were inhibited. Expression levels of hypoxia-inducible factor-1α, a well-known regulator of tumor metastasis, as well as its downstream targets, vascular endothelial growth factor and glucose transporter-1, were also suppressed by TAS2Rs. Taken together, these novel findings suggest that TAS2Rs targets CSCs by suppressing cancer stemness characteristics and NB cell invasion, thereby highlighting the chemotherapeutic potential of bitter taste receptors.