1,8-Cineol Attenuates LPS-Induced Acute Pulmonary Inflammation in Mice

SARS-CoV-2 S1 protein induces IgG-mediated platelet activation and is prevented by 1.8-cineole

COVID-19 patients face an increased risk of thromboembolic complications, yet the exact pathophysiological role of platelets in the disease remains unclear. Considering the multifaceted nature of COVID-19 symptoms, including platelet hyperactivation and inflammation, the development of compounds that simultaneously target both represents a promising therapeutic strategy. The monoterpene 1.8-cineole (CNL-1976) is known for its anti-inflammatory and anti-aggregatory effects. Thus, understanding the mechanism behind platelet hyperactivation and the effect of 1.8-cineole during COVID-19 is crucial when aiming for a reduction of disease severity. In this study, we investigated the mechanism of platelet activation triggered by the SARS-CoV-2 S1 spike protein (S1). Utilizing S1-coupled beads, we discovered that platelet activation and aggregation were dependent on plasma components, particularly S1-specific IgG antibodies. The formation of immune complexes through IgG binding to S1 facilitated the crosslinking of the platelet expressed FcγRIIa receptor, initiating platelet activation and aggregation, as well as formation of platelet-leukocyte aggregates (PLAs). Importantly, treatment with 1.8-cineole significantly inhibited S1-bead-induced platelet activity and PLA formation. These findings strongly suggest that antibody-mediated platelet activation via FcγRIIa directly contributes to the well-recognized prothrombotic environment during COVID-19. Moreover, our data indicate that 1.8-cineole can serve as a potential therapeutic compound, alleviating platelet-driven thromboinflammatory complications associated with COVID-19 and post-acute sequelae of SARS-CoV-2 (PASC).

The protection of bisphenol A-modulated miRNAs and targets by natural products

Bisphenol A (BPA) is a ubiquitous environmental pollutant with endocrine-disrupting functions. Identifying protective drugs and exploring the mechanisms against BPA are crucial in healthcare. Natural products exhibiting antioxidant properties are considered to be able to protect against BPA toxicity. Although BPA-modulated targets and miRNAs have been individually reported, their connections to natural products were rarely organized. With the help of a protein-protein interaction database (STRING), the relationship between individual BPA-modulated targets was interconnected to provide a systemic view. In this review, BPA-downregulated and -upregulated targets are classified, and their interactive network was innovatively analyzed using the bioinformatic database (STRING). BPA-modulated miRNAs were also retrieved and ingeniously connected to BPA-modulated targets. Moreover, a novel connection between BPA-countering natural products was integrated into BPA-modulated miRNAs and targets. All these targets-associated natural products and/or miRNAs were incorporated into the STRING network, providing systemic relationships. Overall, the BPA-modulated target-miRNA-protecting natural product axis was innovatively constructed, providing a straightforward direction for exploring the integrated BPA-countering effects and mechanisms of natural products.

Therapeutic applications of eucalyptus essential oils

Eucalyptus essential oils (EEOs) have gained significant attention recently anticipated to their broad range of prospective benefits in various biological applications. They have been proven to have strong antibacterial properties against a variety of bacteria, fungi, and viruses. This makes them valuable in combating infections and supporting overall hygiene. The active compounds present in these oils can help alleviate inflammation, making them valuable in addressing inflammatory conditions such as arthritis, respiratory ailments, and skin disorders. Respiratory health benefits are another prominent aspect of EEOs. Inhalation of these oils can help promote clear airways, relieve congestion, and ease symptoms of respiratory conditions like coughs, colds, and sinusitis. They are often utilized in inhalation therapies and chest rubs. They can be used topically or in massage oils to alleviate muscle and joint pain. Furthermore, these oils have shown potential in supporting wound healing. Their antimicrobial activity helps prevent infection, while their anti-inflammatory and analgesic properties contribute to reducing inflammation and pain associated with wounds. In aromatherapy, EEOs are renowned for their invigorating and uplifting qualities, promoting mental clarity, relaxation, and stress relief. Overall, EEOs hold great promise in biological applications, offering a natural and versatile approach to promote health and well-being. Continued research and exploration of their therapeutic potential will further unveil their benefits and broaden their applications in various fields.

Essential oil from Chimonanthus nitens Oliv. Leaves ameliorate inflammation and oxidative stress in LPS-induced ALI through NF-κB and Nrf2 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Initial investigative research indicated that the essential oil from Chimonanthus nitens Oliv. Leaves (CLO) significantly reduces lung tissues inflammation and effectively repairs Acute lung injury (ALI) mice model. However, the mechanism underlying is not clear, and the impacts of CLO on oxidative stress require further investigation.

AIM OF THE STUDY

The purpose of the experiment was to validate the influence of CLO in ALI model mice, as well as its potential mechanisms.

MATERIALS AND METHODS

Lipopolysaccharide-induced establishment of the A549 cell inflammation model, and ALI mice model was established by intrathecal administration of LPS.

RESULTS

CLO significantly reduced the release of inflammatory cytokines in A549 cells, lowered MDA and ROS levels, and enhanced SOD activity. Animal experiment results showed that CLO dramatically decreased white blood cell count, the expression of inflammatory cytokines, and the destruction of alveolar structures. CLO enhances the activity of antioxidant enzymes. Western Blot and q-PCR analyses have revealed that the mechanism of CLO is correlation with the NF-κB and Nrf2 signaling pathways in cellular and animal models. Pathway inhibitor experiments indicated that there might be functional crosstalk between these two pathways.

CONCLUSIONS

CLO may regulate inflammation and oxidative stress in LPS-induced ALI through NF-κB and Nrf2 signaling pathways. This finding could be novel in the pharmacological treatment of ALI.

Upregulation of key factors of viral entry of corona- and influenza viruses upon TLR3-signaling in cells from the respiratory tract and clinical treatment options by 1,8-Cineol

At the end of the 2019 coronavirus pandemic (COVID-19), highly contagious variants of coronaviruses had emerged. Together with influenza viruses, different variants of the coronavirus currently cause most colds and require appropriate drug treatment. We have investigated the expression of important factors for the replication of these viruses, namely transmembrane protease serine subtype 2 (TMPRSS2), neuropilin1 (NRP1), and angiotensin converting enzyme 2 (ACE2) or tumor necrosis factor-α (TNF-α) after toll like receptor-3 (TLR-3) stimulation using RT-qPCR and flow cytometry (FC) analysis. As model served primary fibroblasts derived from the lung and nasal cavity, as well as epidermal stem cells and fully matured respiratory epithelium. The stimulated cell cultures were treated with pharmaceuticals (Dexamethasone and Enzalutamide) and the outcome was compared with the phytomedicine 1,8-Cineol. The stimulation of TLR3 is sufficient to induce the expression of exactly those targets that were highly expressed in the corresponding culture type, specifically ACE2 and TMPRSS2 in respiratory epithelial stem cells and NRP1 in fibroblast cells. It seems this self-perpetuating cycle of infection-driven upregulation of key viral replication factors by the innate immune system represents an evolutionary advantage for viruses using these transcripts as viral replication factors. Likewise, to the standard pharmaceuticals with proven clinical efficiency, 1,8-Cineol was able to disrupt this self-perpetuating cycle. Considering the minor side effects and negligible pharmacological interactions with other drugs, it is conceivable that an adjuvant or combinatorial therapy with 1,8-Cineol for respiratory diseases caused by corona- or influenza viruses would be beneficial.

Yinqin Qingfei granules alleviate Mycoplasma pneumoniae pneumonia via inhibiting NLRP3 inflammasome-mediated macrophage pyroptosis

BACKGROUND

Mycoplasma pneumoniae pneumonia (MPP) is a prevalent respiratory infectious disease in children. Given the increasing resistance of M. pneumoniae (MP) to macrolide antibiotics, the identification of new therapeutic agents is critical. Yinqin Qingfei granules (YQQFG), a Chinese patent medicine formulated specifically for pediatric MPP, lacks a clear explanation of its mechanism.

METHODS

The primary components of YQQFG were identified using LC-MS/MS. In vitro, RAW264.7 cells infected with MP underwent morphological examination via scanning electron microscopy. Drug-containing serum was prepared, and its intervention concentration was determined using the CCK-8 assay. The active components of YQQFG were molecularly docked with NLRP3 protein using Autodock Vina software. A RAW264.7 cell line overexpressing NLRP3 was created using lentivirus to pinpoint the target of YQQFG. In vivo, MPP model mice were established via nasal instillation of MP. Lung damage was assessed by lung index and H&E staining. Pyroptosis-associated protein levels in cells and lung tissue were measured by western blot, while interleukin (IL)-1β and IL-18 levels in cell supernatants and mouse serum were quantified using ELISA. Immunofluorescence double staining of lung tissue sections was conducted to assess the correlation between NLRP3 protein expression and macrophages. The expression of the community-acquired respiratory distress syndrome toxin (CARDS TX) was evaluated by qPCR.

RESULTS

25 effective components with favorable oral bioavailability were identified in YQQFG. Both in vitro and in vivo studies demonstrated that YQQFG substantially reduced the expression of the NLRP3/Caspase-1/GSDMD pathway, decreasing the release of IL-1β and IL-18, and inhibited MP exotoxin. Molecular docking indicated strong affinity between most YQQFG components and NLRP3 protein. Lentivirus transfection and immunofluorescence double staining confirmed that YQQFG significantly suppressed NLRP3 expression in macrophages, outperforming azithromycin (AZM). The combination of YQQFG and AZM yielded the optimal therapeutic effect for MPP.

CONCLUSION

YQQFG mitigates inflammatory responses by suppressing NLRP3 inflammasome-mediated macrophage pyroptosis, thereby ameliorating MP-induced acute lung injury. YQQFG serves as an effective adjunct and alternative medication for pediatric MPP treatment.

1.8-cineole prevents platelet activation and aggregation by activating the cAMP pathway via the adenosine A2A receptor

AIMS

Dysregulated platelet aggregation is a fatal condition in many bacterial- and virus-induced diseases. However, classical antithrombotics cannot completely prevent immunothrombosis, due to the unaddressed mechanisms towards inflammation. Thus, targeting platelet hyperactivation together with inflammation might provide new treatment options in diseases, characterized by immunothrombosis, such as COVID-19 and sepsis. The aim of this study was to investigate the antiaggregatory effect and mode of action of 1.8-cineole, a monoterpene derived from the essential oil of eucalyptus leaves, known for its anti-inflammatory proprieties.

MAIN METHODS

Platelet activity was monitored by measuring the expression and release of platelet activation markers, i.e., P-selectin, CD63 and CCL5, as well as platelet aggregation, upon treatment with 1.8-cineole and stimulation with several classical stimuli and bacteria. A kinase activity assay was used to elucidate the mode of action, followed by a detailed analysis of the involvement of the adenylyl-cyclase (AC)-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway by Western blot and ELISA.

KEY FINDINGS

1.8-cineole prevented the expression and release of platelet activation markers, as well as platelet aggregation, upon induction of aggregation with classical stimuli and immunological agonists. Mechanistically, 1.8- cineole influences the activation of the AC-cAMP-PKA pathway, leading to higher cAMP levels and vasodilator-stimulated phosphoprotein (VASP) phosphorylation. Finally, blocking the adenosine A2A receptor reversed the antithrombotic effect of 1.8-cineole.

SIGNIFICANCE

Given the recognized anti-inflammatory attributes of 1.8-cineole, coupled with our findings, 1.8-cineole might emerge as a promising candidate for treating conditions marked by platelet activation and abnormal inflammation.

Cang-ai volatile oil ameliorates imiquimod-induced psoriatic skin lesions by suppressing the ILC3s

ETHNOPHARMACOLOGICAL RELEVANCE

Cang-ai volatile oil (CAVO) is an aromatic Chinese medicine with potent antibacterial and immune regulatory properties. While CAVO has been used to treat upper respiratory tract infections, depression, otomycosis, and bacterial infections in the skin, its effect on psoriasis is unknown.

AIM OF THE STUDY

This study explores the effect and mechanism of CAVO in psoriasis intervention.

MATERIAL AND METHODS

The effect of CAVO on the expression of IL-6 and IL-1β was assessed in TNF-α-induced HaCaT cells using enzyme-linked immunosorbent assay (ELISA). Mice were given imiquimod (IMQ) and administered orally with different CAVO doses (0.03 and 0.06 g/kg) for 5 days. The levels of inflammatory cytokines related to group-3 innate lymphoid cells (ILC3s) in the skin were assessed using hematoxylin and eosin (H&E) staining, ELISA, and western blotting (WB). The frequency of ILC3s in mice splenocytes and skin cells was evaluated using flow cytometry.

RESULTS

The results demonstrated that CAVO decreased the expression of IL-6 and IL-1β in TNF-α- induced HaCaT cells. CAVO significantly reduced the severity of psoriatic symptoms in IMQ-induced mice. The expression of inflammatory cytokines in the skin, such as IL-1β, IL-6, IL-8, IL-22, IL-23, and IL-17 A were decreased, whereas IL-10 levels were increased. The mRNA expressions of TNF-α, IL-23 A, IL-23 R, IL-22, IL-17 A, and RORγt were down-regulated in skin tissues. CAVO also decreased the levels of NF-κB, STAT3, and JAK2 proteins.

CONCLUSIONS

CAVO potentially inhibits ILC3s activation to relieve IMQ-induced psoriasis in mice. These effects might be attributed to inhibiting the activation of NF-κB, STAT3, and JAK2 signaling pathways.

Eucalyptol ameliorates chlorpyrifos-induced necroptosis in grass carp liver cells by down-regulating ROS/NF-κB pathway

Chlorpyrifos (Diethoxy-sulfanylidene-(3,5,6-trichloropyridin-2-yl) oxy-λ5-phosphane, CPF) was extensively used organophosphorus pesticide, extensively deteriorating public problem with the enrichment in the water bodies. Eucalyptol (1,3,3-Trimethyl-2-oxabicyclo[2.2.2] octane, EUC), a colorless cyclic monoterpene oxide, has shown anti-inflammatory and anti-oxidation properties. To explore the effect of EUC on CPF-induced necroptosis in the grass carp liver cells (L8824 cells), we treated L8824 cells with 60 mM CPF and 5 μM EUC for 24 h. The results showed that CPF exposed lead to excessive accumulation of reactive oxygen species (ROS) and oxidative stress, activating the NF-κB and RIPK1 pathway, increasing the level of cell necroptosis. However, EUC treatment attenuated the toxic effects of CPF treatment on L8824 cells. In summary, the study demonstrated that CPF induced necroptosis and inflammation, and EUC treatment could decrease CPF-caused cell injury.

Volatile profiling coupled with multivariate analysis, antiproliferative and anti-inflammatory activities of rhizome essential oil of four Hedychium species from India

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Hedychium of family Zingiberaceae comprises several perennial rhizomatous species widely used in perfumery and traditional folk medicine to treat diseases related to asthma, diarrhoea, nausea, stomach disorders, inflammation and tumours. Several species of Hedychium have remained under-explored with respect to their chemical composition and biological activities.

AIM OF THE STUDY

The current research aimed to explore the chemical composition and evaluate the antiproliferative and anti-inflammatory activities of rhizome essential oil from four Hedychium species (H. coccineum, H. gardnerianum, H. greenii and H. griffithianum).

MATERIALS AND METHODS

Compound identification was accomplished using a Clarus 580 gas chromatography system in conjunction with mass spectrometry (GC-MS). The multivariate data statistics using chemometrics (PCA, PLS-DA, sPLS-DA) and cluster analysis (Dendrogram, Heat maps, K-means) were used to compare the similarity and relationship among Hedychium metabolomes. MTT assay was employed to visualize the antiproliferative property against MCF7, HepG2 and PC3 cancerous cell lines. The toxicity of essential oils was determined using 3T3-L1 non-tumorigenic/normal cells. Lipopolysaccharide (LPS)-induced RAW 264.7 cells were used to investigate the anti-inflammatory properties of Hedychium essential oils by measuring the production of nitric oxide (NO) using the Griess reagent method. Furthermore, the levels of prostaglandin (PGE2) and pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) was assessed using the ELISA technique.

RESULTS

In total, 82 compounds were identified in four targeted species of Hedychium from which 1,8-cineole (52.71%), β-pinene (32.83%), α-pinene (19.62%), humulene epoxide II (19.86%) and humulene epoxide I (19.10%) were the major constituents. Monoterpenes (8.5-59.9%) and sesquiterpenes (2.87-54.11%) were the two class of compounds, found as the most prevalent in the extracted essential oils. The multivariate analysis classified the four Hedychium species into three different clusters. Hedychium essential oils exhibited potent antiproliferative activity against MCF7, HepG2 and PC3 cancer cell lines with IC50 values less than 150 μg/mL where H. gardnerianum exhibited the highest selective cytotoxicity against human breast and prostate adenocarcinoma cells with an IC50 value of 44.04 ± 1.07 μg/mL and 56.11 ± 1.44 μg/mL, respectively. The essential oils on normal (3T3-L1) cells displayed no toxicity with higher IC50 values thereby concluding as safe to use for normal human health without causing any side effects. Besides, the essential oils at 100 μg/mL concentration revealed remarkable anti-inflammatory activity in LPS-activated RAW 264.7 murine macrophages by inhibiting the production of inflammatory mediators, with H. greenii exhibiting the maximum anti-inflammation response by significantly suppressing the levels of NO (84%), PGE2 (87%), TNF-α (94.3%), IL-6 (95%) and IL-1β (85%) as compared to LPS treated group.

CONCLUSION

The present findings revealed that the Hedychium species traditionally used in therapeutics could be a potential source of active compounds with antiproliferative and anti-inflammatory properties.

Suberosin Alleviates Sepsis-Induced Lung Injury in A Rat Model of Cecal Ligation and Puncture

BACKGROUND/AIMS

Sepsis is one of the major problems encountered in intensive care units, causing organ damage and increasing mortality. Suberosin (SBR) is a type of coumarin with antioxidant and anti-inflammatory activities. The goal of this study is to explore the protective effects of SBR on the lungs in a rat model of sepsis.

METHODS

Male Wistar rats were utilized in this study. A cecal ligation and puncture (CLP) model was applied to induce sepsis. Rats were separated into six groups with nine animals in each group, including healthy control, SBR, CLP, and CLP + SBR (5, 10, and 20 mg/kg) groups. Superoxide dismutase (SOD), glutathione (GSH) enzyme activities, and malondialdehyde (MDA) level were measured via enzyme-linked immunosorbent assay (ELISA). The messenger RNA (mRNA) expressions of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) were evaluated by real-time polymerase chain reaction (RT-PCR). Histopathological changes in the lungs were investigated with hematoxylin and eosin (H&E).

RESULTS

MDA levels and GSH and SOD enzyme activities were negatively affected in the CLP group, but SBR treatment ameliorated these oxidative stress parameters in the SBR1-3 groups (p< 0.05). The mRNA expressions of TNF-α and IL-1β were increased in the CLP group, and SBR treatment decreased those expression levels in a dose-dependent manner (p < 0.05). Organ damage and necrosis were seen in the CLP group and were alleviated in the SBR3 group. Immunohistochemical (IHC) analysis of lung tissues demonstrated decreased TNF-α and IL-1β immunopositivity in the SBR1-3 groups (p< 0.05).

CONCLUSIONS

SBR ameliorated sepsis-related lung injury in a dose-dependent manner. This compound has significant potential as a future agent in the treatment of sepsis.

1,8-cineole (eucalyptol): A versatile phytochemical with therapeutic applications across multiple diseases

1,8-cineole (Eucalyptol), a naturally occurring compound derived from botanical sources such as eucalyptus, rosemary, and camphor laurel, has a long history of use in traditional medicine and exhibits an array of biological properties, including anti-inflammatory, antioxidant, antimicrobial, bronchodilatory, analgesic, and pro-apoptotic effects. Recent evidence has also indicated its potential role in managing conditions such as Alzheimer's disease, neuropathic pain, and cancer. This review spotlights the health advantages of 1,8-cineole, as demonstrated in clinical trials involving patients with respiratory disorders, including chronic obstructive pulmonary disease, asthma, bronchitis, and rhinosinusitis. In addition, we shed light on potential therapeutic applications of 1,8-cineole in various conditions, such as depression, epilepsy, peptic ulcer disease, diarrhea, cardiac-related heart diseases, and diabetes mellitus. A comprehensive understanding of 1,8-cineole's pharmacodynamics and safety aspects as well as developing effective formulations, might help to leverage its therapeutic value. This thorough review sets the stage for future research on diverse health benefits and potential uses of 1,8-cineole in tackling complex medical conditions.

Proposed mechanisms of action of herbal drugs and their biologically active constituents in the treatment of coughs: an overview

Various medicinal plants find their use in cough treatment, based on traditions and long-term experience. Pharmacological principles of their action, however, are much less known. Herbal drugs usually contain a mixture of potentially active compounds, which can manifest diverse effects. Expectorant or antitussive effects, which can be accompanied by others, such as anti-inflammatory or antibacterial, are probably the most important in the treatment of coughs. The aim of this review is to summarize the current state of knowledge of the effects of medicinal plants or their constituents on cough, based on reliable pharmacological studies. First, a comprehensive description of each effect is provided in order to explain the possible mechanism of action in detail. Next, the results related to individual plants and substances are summarized and critically discussed based on pharmacological in vivo and in vitro investigation.

Immunomodulatory effects and mechanisms of the extracts and secondary compounds of Zingiber and Alpinia species: a review

Zingiber and Alpinia species (family: Zingiberaceae) are popularly used in food as spices and flavoring agents and in ethnomedicine to heal numerous diseases, including immune-related disorders. However, their ethnomedicinal uses have not been sufficiently supported by scientific investigations. Numerous studies on the modulating effects of plants and their bioactive compounds on the different steps of the immune system have been documented. This review aimed to highlight up-to-date research findings and critically analyze the modulatory effects and mechanisms of the extracts and secondary compounds of several Zingiber and Alpinia species, namely, Zingiber officinale Roscoe, Z. cassumunar Roxb., Z. zerumbet (L.) Roscoe ex Sm., Alpinia galanga Linn., A. conchigera Griff, A. katsumadai Hayata, A. oxyphylla Miq., A. officinarum Hance, A. zerumbet (Pers.) Burtt. et Smith, and A. purpurata (Viell.) K. Schum. on the immune system, particularly via the inflammation-related signaling pathways. The immunomodulating activities of the crude extracts of the plants have been reported, but the constituents contributing to the activities have mostly not been identified. Among the extracts, Z. officinale extracts were the most investigated for their in vitro, in vivo, and clinical effects on the immune system. Among the bioactive metabolites, 6-, 8-, and 10-gingerols, 6-shogaol, and zerumbone from Zingiber species and cardamomin, 1'-acetoxychavicol acetate, yakuchinone, rutin, 1,8-cineole, and lectin from Alpinia species have demonstrated strong immunomodulating effects. More experimental studies using cell and animal models of immune-related disorders are necessary to further understand the underlying mechanisms, together with elaborate preclinical pharmacokinetics, pharmacodynamics, bioavailability, and toxicity studies. Many of these extracts and secondary metabolites are potential candidates for clinical development in immunomodulating agents or functional foods to prevent and treat chronic inflammatory disorders.

Effects of centipedic acid on acute lung injury: A dose-response study in a murine model

Centipedic Acid (CPA), a natural diterpene from Egletes viscosa, an endemic species of the Caatinga biome, has shown antioxidant and anti-inflammatory properties. However, no report on the CPA on respiratory system mechanics has been so far advanced. We aimed to investigate the dose-response behavior of CPA on E. coli lipopolysaccharide (LPS)-triggered acute lung injury (ALI). Forty-eight C57BL/6 mice were randomly divided into six groups: control (SS), induced to ALI (LPS), 4 groups induced to ALI pre-treated with 12.5, 25, 50 and 100 mg/kg of CPA (CPA12.5, CPA25, CPA50 and CPA100 groups). CPA 100 mg/kg could prevent inflammatory cell infiltration, alveolar collapse, changes in tissue micromechanics and lung function (airway resistance, tissue elastance, tissue resistance and Static compliance). These results indicate preventive potential of this compound in the installation of ALI.

Pharmacologic effects approach of essential oils and their components on respiratory diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Essential oils (EOs) are concentrated hydrophobic liquids with volatility and a unique aroma. Formed by aromatic plants as secondary metabolites, EOs have been used as traditional medicines to treat various health problems worldwide. Historical records show that herbs rich in EOs have been widely used to treat respiratory diseases in China, Europe, and many other regions.

AIM OF THE REVIEW

This review summarizes the traditional applications and modern pharmacological mechanisms of EOs derived from aromatic herbs and their active ingredients in respiratory diseases in preclinical and clinical trials through multitarget synergy.

MATERIALS AND METHODS

Information about EOs and respiratory diseases was collected from electronic databases, such as ScienceDirect, Web of Science, PubMed, Google Scholar, Baidu Scholar, and the China National Knowledge Infrastructure (CNKI).

RESULTS

This review presents the preventive and therapeutic effects of EOs on respiratory diseases, including chronic obstructive pulmonary disease, bronchial asthma, acute lung injury, pulmonary infection, and pulmonary fibrosis. The molecular mechanisms of EOs in treating different lung diseases are summarized, including anti-inflammation, anti-oxidation, mucolytic, and immune regulatory mechanisms.

CONCLUSIONS

EOs show potential as supplements or substitutes for treating lung diseases.

Molecular Docking Identifies 1,8-Cineole (Eucalyptol) as A Novel PPARγ Agonist That Alleviates Colon Inflammation

Inflammatory bowel disease, comprising Crohn's disease (CD) and ulcerative colitis (UC), is often debilitating. The disease etiology is multifactorial, involving genetic susceptibility, microbial dysregulation, abnormal immune activation, and environmental factors. Currently, available drug therapies are associated with adverse effects when used long-term. Therefore, the search for new drug candidates to treat IBD is imperative. The peroxisome proliferator-activated receptor-γ (PPARγ) is highly expressed in the colon. PPARγ plays a vital role in regulating colonic inflammation. 1,8-cineole, also known as eucalyptol, is a monoterpene oxide present in various aromatic plants which possess potent anti-inflammatory activity. Molecular docking and dynamics studies revealed that 1,8-cineole binds to PPARγ and if it were an agonist, that would explain the anti-inflammatory effects of 1,8-cineole. Therefore, we investigated the role of 1,8-cineole in colonic inflammation, using both in vivo and in vitro experimental approaches. Dextran sodium sulfate (DSS)-induced colitis was used as the in vivo model, and tumor necrosis factor-α (TNFα)-stimulated HT-29 cells as the in vitro model. 1,8-cineole treatment significantly decreased the inflammatory response in DSS-induced colitis mice. 1,8-cineole treatment also increased nuclear factor erythroid 2-related factor 2 (Nrf2) translocation into the nucleus to induce potent antioxidant effects. 1,8-cineole also increased colonic PPARγ protein expression. Similarly, 1,8-cineole decreased proinflammatory chemokine production and increased PPARγ protein expression in TNFα-stimulated HT-29 cells. 1,8-cineole also increased PPARγ promoter activity time-dependently. Because of its potent anti-inflammatory effects, 1,8-cineole may be valuable in treating IBD.

Identification of bioactive compounds and cytogenotoxicity of the essential oil from the leaves of Croton heliotropiifolius Kunth

Croton heliotropiifolius Kunth, popularly known as "quince" and "velame," contains a high concentration of volatile oils in the leaves, and widely used in folk medicine as an antiseptic, analgesic, sedative, anti-inflammatory, spasmolytic and local anesthetic. The objectives of this investigation were to (1) identify the phytochemical compounds and (2) assess the cytogenotoxicity of the essential oil extracted from the leaves of C. heliotropiifolius Kunth. The oil was extracted utilizing hydrodistillation and phytochemical profile determined using gas chromatography and mass spectrometry (GCMS). In the toxicogenetics analysis, Allium cepa roots were exposed to 1% dimethylsulfoxide or methylmethanesulfonate (MMS, 10 µg/ml) negative and positive controls, respectively, and to C. heliotropiifolius oil at 6 concentrations (0.32; 1.6; 8; 40; 200 or 1000 µg/ml). The phytochemical profile exhibited 40 chromatographic bands, and 33 compounds identified. α-pinene (16.7%) and 1,8-cineole (13.81%) were identified as the major compounds. Some of these identified secondary metabolites displayed biological and pharmacological activities previously reported including antiseptic, analgesic, sedative, anti-inflammatory as well insecticidal, antiviral, anti-fungal actions. In the A. cepa test, C. heliotropiifolius leaves oil induced cytotoxicity at concentrations of 0.32, 1.6 or 200 µg/ml and genotoxicity at 200 or 1000 µg/ml as evidenced by increased presence of micronuclei and significant chromosomal losses. Based upon our observations data demonstrated that the essential oil of C. heliotropiifolius leaves contain monoterpene hydrocarbons, and oxygenated monoterpenes, sesquiterpenes, and oxygenated sesquiterpenes which are associated with cytotoxic and genotoxic responses noted in on A. cepa cells.

The Essential Oil of Hyptis crenata Inhibits the Increase in Secretion of Inflammatory Mediators

Background: Hyptis crenata is a plant of great ethnopharmacological importance widely distributed in South American countries. In Northeast Brazil, teas or infusions of its aerial parts are used in folk medicine to treat several acute and chronic inflammatory diseases. In a previous work we have demonstrated that the essential oil of H. crenata (EOHc) has an antiedematogenic effect. The aim of this work was to evaluate the effect of EOHc on cytokines secretion and cellular infiltration. Methods: Peritonitis and paw edema models induced by carrageenan were used to determine leucocyte count, myeloperoxidase (MPO) activity, nitrite, and cytokines secretion. Results: EOHc (10−300 mg/kg) significantly inhibited leucocyte migration and reduced the neutrophil count (control: 1.46 × 103 ± 0.031 × 103/mL) of the total leucocytes population in extracellular exudate (control: 2.14 × 103 ± 0.149 × 103/mL) by 15.00%, 43.29%, 65.52%, and 72.83% for the doses of 10, 30, 100, and 300 mg/kg EOHc, respectively (EC50: 24.15 mg/kg). EOHc (100 mg/kg) inhibited the increase in myeloperoxidase activity and completely blocked the increase in nitrite concentration induced by carrageenan. EOHc markedly reduced the pro-inflammatory cytokines (IL-6, MCP-1, IFN-γ, TNF-α, and IL-12p70) and increased IL-10, an anti-inflammatory cytokine (compared to control group, p < 0.05). Conclusions: This study demonstrates that EOHc has a long-lasting anti-inflammatory effect mediated through interference on MPO activity, and nitrite, and cytokines secretion. This effect, coupled with low EOHc toxicity, as far as results obtained in mice could be translated to humans, suggests that EOHc has great potentiality as a therapeutic agent.

Tanshinone IIA loaded bioactive nanoemulsion for alleviation of lipopolysaccharide induced acute lung injury via inhibition of endothelial glycocalyx shedding

Acute lung injury (ALI) and its more serious form; acute respiratory distress syndrome are major causes of COVID-19 related mortality. Finding new therapeutic targets for ALI is thus of great interest. This work aimed to prepare a biocompatible nanoformulation for effective pulmonary delivery of the herbal drug; tanshinone-IIA (TSIIA) for ALI management. A nanoemulsion (NE) formulation based on bioactive natural ingredients; rhamnolipid biosurfactant and tea-tree oil, was developed using a simple ultrasonication technique, optimized by varying oil concentration and surfactant:oil ratio. The selected TSIIA-NE formulation showed 105.7 nm diameter and a PDI ∼ 0.3. EE exceeded 98 % with biphasic sustained drug release and good stability over 3-months. In-vivo efficacy was evaluated in lipopolysaccharide (LPS)-induced ALI model. TSIIA-NE (30 µg/kg) was administered once intratracheally 2 h after LPS instillation. Evaluation was performed 7days post-treatment. Pulmonary function assessment, inflammatory, oxidative stress and glycocalyx shedding markers analysis in addition to histopathological examination of lung tissue were performed. When compared to untreated rats, in-vivo efficacy study demonstrated 1.4 and 1.9-fold increases in tidal volume and minute respiratory volume, respectively, with 32 % drop in wet/dry lung weight ratio and improved levels of arterial blood gases. Lung histopathology and biochemical analysis of different biomarkers in tissue homogenate and bronchoalveolar lavage fluid indicated that treatment may ameliorate LPS-induced ALI symptoms thorough anti-oxidative, anti-inflammatory effects and inhibition of glycocalyx degradation. TSIIA-NE efficacy was superior to free medication and blank-NE. The enhanced efficacy of TSIIA bioactive nanoemulsion significantly suggests the pharmacotherapeutic potential of bioactive TSIIA-NE as a promising nanoplatform for ALI.

The Amomum tsao-ko Essential Oils Inhibited Inflammation and Apoptosis through p38/JNK MAPK Signaling Pathway and Alleviated Gentamicin-Induced Acute Kidney Injury

The clinical application of gentamicin may lead to acute kidney injury (AKI), and the nephrotoxicity of gentamicin is related to the pathological mechanism of several oxidative and inflammatory cytokines. Plant-derived essential oils have good anti-inflammatory and antioxidant properties. This study aimed to clarify the protective effect of Amomum tsao-ko essential oils (AOs) on gentamicin-induced AKI in rats and its possible mechanism. The rat AKI model was induced by intraperitoneal injection of gentamicin. After 14 days of oral AO treatment, the renal function and pathological changes of the kidney tissues were evaluated, and the level of kidney tissue oxidative stress was detected. The content of inflammatory cytokines was measured by ELISA. The expression of ERK1/2, JNK1/2, p38, NF-κB, caspase-3, and Bax/Bcl-2 proteins were estimated by Western blot analysis. The results showed that taking AO reduced the contents of serum urea and creatinine in AKI rats and improve the pathological changes and oxidative stress of the kidney tissue in rats. At the same time, AO reduced inflammation and apoptosis during AKI by regulating the MAPK pathway. The data show that AO has a protective effect on the kidneys and may be a potential drug for treating kidney injury.

Prophylactic management of radiation-induced mucositis using herbal mouthwash in patients with head and neck cancer: an assessor-blinded randomized controlled trial

OBJECTIVES

Radiation-induced mucositis (RIOM) is one of the most common side effects from head and neck radiotherapy. Several reagents have been introduced to manage the symptom; however, there is still a limited number of effective reagents. Herbal mouthwashes with payayor (Clinacanthus nutans Lindau) and fingerroot (Boesenbergia rotunda) were tested their efficacies in preventing and reducing severity of RIOM in comparison with normal saline with sodium bicarbonate.

METHODS

One hundred twenty patients with head and neck cancer undergoing radiotherapy participated in the study and were randomly assigned into three treatment groups using block randomization method. The participants were assigned one of the three mouthwashes for use throughout their radiotherapy course and were assessed for their mucositis scores from week one to six into their radiotherapy course as well as at one-month follow-up. Body mass index was also measured for comparison of nutritional status.

RESULTS

The two mouthwashes were similarly effective in prophylaxis of RIOM in term of severity. The averaged mucositis scores were less than two for all groups. For the onset of RIOM, both herbal mouthwashes could slightly delay the symptom but not statistically significant. Patients' body mass index across the three treatment groups was also comparable. The patients were largely satisfied with all the mouthwashes with no clear preference on any of them.

CONCLUSIONS

Prophylactic treatment of RIOM using herbal mouthwashes could substitute the current standard of normal saline with bicarbonate. A different formulation of the two herbs could potentially improve the prophylactic outcome.

TRIAL REGISTRATION NO

NCT03359187.

Unravelling the Immune Modulatory Effect of Indian Spices to Impede the Transmission of COVID-19: A Promising Approach

Months after WHO declared COVID-19 as a Global Public Health Emergency of International Concern, it does not seem to be flattening the curve as we are still devoid of an effective treatment modality and vaccination is in the first phase in many countries. Amid such uncertainty, being immune is the best strategy to defend against corona attacks. As the whole world is referring back to immune-boosting traditional remedies, interest is rekindled in the Indian system of Medicine, which is gifted with an abundance of herbal medicines as well as remedies. Among them, spices (root, rhizome, seed, fruit, leaf, bud, and flower of various plants used to add taste and flavors to food) are bestowed with immense medicinal potential. A plethora of clinical as well as preclinical studies reported the effectiveness of various spices for various ailments. The potential immune-boosting properties together with their excellent safety profiles are making spices the current choice of phytoresearch as well as the immune-boosting home remedies during these sceptical times. The present review critically evaluates the immune impact of various Indian spices and their potential to tackle the novel coronavirus, with comments on the safety and toxicity aspects of spices.

Eucalyptol ameliorates early brain injury after subarachnoid haemorrhage via antioxidant and anti-inflammatory effects in a rat model

CONTEXT

As the terpenoid oxide extracted from Eucalyptus L. Herit (Myrtaceae), eucalyptol (EUC) has anti-inflammatory and antioxidant effects.

OBJECTIVE

To evaluate the neuroprotective role of EUC in subarachnoid haemorrhage (SAH).

MATERIALS AND METHODS

Sprague-Dawley rats were divided into 4 groups: sham group, SAH group, SAH + vehicle group, and SAH + EUC group. SAH was induced by endovascular perforation. In SAH + EUC group, 100 mg/kg EUC was administrated intraperitoneally at 1 h before SAH and 30 min after SAH, respectively. Neurological deficits were examined by modified Neurological Severity Scores (mNSS). The brain edoema was evaluated by wet-dry method. Neuronal apoptosis was detected by Nissl staining. The expression of Bcl-2, cleaved caspase-3, phospho-NF-κB p65, ionised calcium-binding adapter molecule-1 (Iba-1), nuclear factor erythroid-2 (Nrf-2), and haem oxygenase 1 (HO-1) were measured by Western blot. Expression of pro-inflammatory cytokines was detected by qRT-PCR. Oxidative stress markers were also measured.

RESULTS

EUC markedly relieved brain edoema (from 81.22% to 78.33%) and neurological deficits [from 16.28 to 9.28 (24 h); from 12.50 to 7.58 (48 h)]. EUC reduced neuronal apoptosis, microglial activation, and oxidative stress. EUC increased the expression of HO-1 (1.15-fold), Nrf2 (1.34-fold) and Bcl-2 (1.17-fold) in the rats' brain tissue, and down-regulated the expressions of cleaved caspase-3 (41.09%), phospho-NF-κB p65 (14.38%) and pro-inflammatory cytokines [TNF-α (34.33%), IL-1β (50.40%) and IL-6 (59.13%)].

DISCUSSION AND CONCLUSION

For the first time, this study confirms that EUC has neuroprotective effects against early brain injury after experimental SAH in rats.

From longevity grass to contemporary soft gold: Explore the chemical constituents, pharmacology, and toxicology of Artemisia argyi H.Lév. & vaniot essential oil

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia argyi H.Lév. & Vaniot is known as the longevity grass in eastern countries for its warm effect to cure many cold diseases. It has been widely used in medicine, food, bathing, moxibustion, and fumigation for more than two thousand years. Nowadays it even becomes the cultural symbol of the Dragon Boat Festival. In traditional application, A. argyi is considered to be an important hemostatic drug and a common drug for gynecological diseases. In modern application, the Artemisia argyi H.Lév. & Vaniot essential oil (AAEO) is regarded as the important medicinal substance of A. argyi, and has been made into many health products, forming a large-scale A. argyi industry.

AIM OF THE REVIEW

This review aims to summarize the research status of AAEO and evaluate its application value. The manuscript focuses on the reported extraction methods, chemical components and influencing factors, pharmacological action, and toxicity.

MATERIALS AND METHODS

In the literature search, several databases, such as Google Scholar, Science Direct, PubMed, Elsevier, CNKI, and Wanfang, were searched for key words, including "Artemisia argyi H.Lév. & Vaniot essential oil," "Artemisia argyi H.Lév. & Vaniot," "cineole," "caryophyllene," "cyclamen," "borneol," and "camphor."

RESULTS

At present, more than 200 kinds of chemical components have been detected in AAEO, including terpenes, ketones (aldehydes), alcohols (phenols), acids (esters), alkanes (olefins) hydrocarbons, and so on. It has great anti-disease-resistant microorganism, anti-inflammatory, analgesic, and anti-cancer effects in clinical treatment and has good development potential and application prospects.

CONCLUSION

Present review provides an insight into chemical composition, extraction method, quality influencing factors, pharmacological action and toxicological action of AAEO. As an important traditional medicine herb, remarkable efficacy has been demonstrated in comprehensive literature reports, which has shown the great medicinal potential of this plant. However, the toxicity of AAEO cannot be ignored, the exact mechanism of action remains to be elucidated.

1,8-Cineole: a review of source, biological activities, and application

1,8-Cineole (also known as eucalyptol) is mostly extracted from the essential oils of plants, which showed extensively pharmacological properties including anti-inflammatory and antioxidant mainly via the regulation on NF-κB and Nrf2, and was used for the treatment of respiratory diseases and cardiovascular, etc. Although various administration routes have been used in the application of 1.8-cineole, few formulations have been developed to improve its stability and bioavailability. This review retrospects the researches on the source, biological activities, mechanisms, and application of 1,8-cineole since 2000, which provides a view for the further studies on the application and formulations of 1,8-cineole.

Usage of Natural Volatile Organic Compounds as Biological Modulators of Disease

Plants produce a wide variety of natural volatile organic compounds (NVOCs), many of which are unique to each species. These compounds serve many purposes, such as fending off herbivores and adapting to changes in temperature and water supply. Interestingly, although NVOCs are synthesized to deter herbivores, many of these compounds have been found to possess several therapeutic qualities, such as promoting nerve stability, enhancing sleep, and suppressing hyperresponsiveness, in addition to acting as antioxidants and anti-inflammatory agents. Therefore, many NVOCs are promising drug candidates for disease treatment and prevention. Given their volatile nature, these compounds can be administered to patients through inhalation, which is often more comfortable and convenient than other administration routes. However, the development of NVOC-based drug candidates requires a careful evaluation of the molecular mechanisms that drive their therapeutic properties to avoid potential adverse effects. Furthermore, even compounds that appear generally safe might have toxic effects depending on their dose, and therefore their toxicological assessment is also critical. In order to enhance the usage of NVOCs this short review focuses not only on the biological activities and therapeutic mode of action of representative NVOCs but also their toxic effects.

Monoterpenes: current knowledge on food source, metabolism, and health effects

Monoterpenes, volatile metabolites produced by plants, are involved in the taste and aroma perception of fruits and vegetables and have been used for centuries in gastronomy, as food preservatives and for therapeutic purposes. Biological activities such as antimicrobial, analgesic and anti-inflammatory are well-established for some of these molecules. More recently, the ability of monoterpenes to regulate energy metabolism, and exert antidiabetic, anti-obesity and gut microbiota modulation activities have been described. Despite their promising health effects, the lack of reliable quantification of monoterpenes in food, hindered the investigation of their role as dietary bioactive compounds in epidemiological studies. Moreover, only few studies have documented the biotransformation of these compounds and identified the monoterpene metabolites with biological activity. This review presents up-to-date knowledge about the occurrence of monoterpenes in food, their bioavailability and potential role in the modulation of intermediate metabolism and inflammation, focusing on novel findings of molecular mechanisms, underlining research gaps and new avenues to be explored.

Natural product derived phytochemicals in managing acute lung injury by multiple mechanisms

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.

DEHP-induce damage in grass carp hepatocytes and the remedy of Eucalyptol

The wide application of plastic products led to the wide exposure of plasticizer in environment. As a new environmental pollutant, plasticizers' toxicity researches were far from enough in fish. In order to further explore these mechanisms, we used Diethylhexyl phthalate (DEHP), a common plasticizer, treated the grass carp hepatocytes, and selected Eucalyptol (EUC) to study its antagonistic effect on DEHP. The results showed that after DEHP exposure, oxidative stress level and inflammation in grass carp hepatocytes were increased, and then mRNA and protein expression of apoptosis related markers were increased significantly, leading to hepatocytes apoptosis. Moreover, AO/EB staining and Hoethst staining also showed that the number of apoptotic cells increased after DEHP exposure. It should be noted that both EUC pretreatment and EUC simultaneous treatment could alleviate the oxidative stress, levels of inflammatory factors and apoptosis induced by DEHP. In comparison, the effect of EUC simultaneous treatment was better. Our results showed that DEHP induced apoptosis in grass carp hepatocytes through oxidative stress and inflammation, while EUC could alleviate apoptosis by reducing oxidative stress and inflammation caused by DEHP. The innovation of this study was to explore the interaction between DEHP and EUC for the first time. This study found that DEHP could cause apoptosis in grass carp hepatocytes through oxidative stress and inflammation; EUC had a good antagonistic effect on a series of damage in grass carp hepatocytes caused by DEHP, and EUC pretreatment and simultaneous treatment had a certain effect, among which, simultaneous treatment had a better effect. This study enriched the theoretical mechanism of DEHP toxicity in fish hepatocytes, and put forward the methods to solve the toxicity of DEHP.

Eucalyptus oil reduces allergic reactions and suppresses mast cell degranulation by downregulating IgE-FcεRI signalling

Eucalyptus oil has been used since ancient times for its bactericidal, anti-inflammatory, analgesic and sedative effects. In recent years, the action of Eucalyptus oil has been scientifically proven, and there have been reports that Eucalyptus oil suppresses the production of chemokines, cytokines and lipid mediators in basophils, alveolar macrophages and monocytes. Based on this information, we aimed to verify whether Eucalyptus oil can be used for allergic dermatitis, the incidence of which has been increasing among human skin diseases. This effect was verified using a mouse IgE-mediated local allergic model. In conclusion, topical application of Eucalyptus oil suppressed oedema and vascular permeability enhancement due to IgE-mediated allergic on the skin. In addition, we also verified the degranuration of mast cells, which is a part of its action, and examined whether 1,8-cineole, which is the main component of Eucalyptus oil, suppresses the phosphorylation of PLCγ and p38 directly or indirectly. 1,8-cineole was found to suppress degranulation of mast cells.

Biochemical Research of the Effects of Essential Oil Obtained from the Fruit of Myrtus communis L. on Cell Damage Associated with Lipopolysaccharide-Induced Endotoxemia in a Human Umbilical Cord Vein Endothelial Cells

The aim of this study to investigate the potential effects of essential oils and compounds obtained from MC fruit on sepsis induced endothelial cell damage in human umbilical cord vein endothelial cells (HUVECs) at molecular and cellular levels on in vitro sepsis model. A sepsis model was induced by the application of LPS. The HUVEC treatment groups were as follows: control, LPS, MC, MC plus LPS, 1.8 cineole, 1.8 cineole plus LPS, α-pinene, α-pinene plus LPS, α-terpineol, and α-terpineol plus LPS. Following the treatments, cell proliferation was analyzed using the xCELLigence® system. The mRNA expression of various cytokines [tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), and IL-6] and endothelial nitric oxide (eNOS) were determined by quantitative polymerase chain reaction (qPCR) analysis. The 1.8 cineole and α-pinene treatments at specific doses showed toxic effects on α-terpineine, although it did not result in a change in the cellular index as compared with that of the control group. The application of LPS to HUVECs led to a significant decrease in the cellular index, depending on the treatment time. It did not correct the decreased cell index of MC plus LPS and α-terpineol plus LPS groups as compared with that of the LPS-only group. The 1.8 cineole plus LPS treatment and α-pinene plus LPS treatment significantly increased the cell index as compared with that of the LPS-only treatment, and the cell index in these groups was closer to that of the control. According to the results of the qPCR analysis, neither the MC-only treatment nor the α-terpineol-only treatment significantly reduced cellular damage caused by LPS-induced increases in TNF-α, IL-1β, IL-6, and eNOS mRNA expression. However, both the 1.8 cineole treatment and α-pinene treatments significantly decreased TNF-α, IL-1β, IL-6, and eNOS mRNA expression induced by LPS. Volatile oil obtained from MC fruit and the MC compound α-terpineol had no effect on the decreased cell index and increased cytokine response due to LPS-induced endothelial cell damage. However, 1.8 cineole and α-pinene, other major components of MC fruit, ameliorated LPS-induced damage in HUVECs at cellular and biomolecular levels (TNF-α, IL-1β, IL-6, and eNOS).

The Important Role of Volatile Components From a Traditional Chinese Medicine Dayuan-Yin Against the COVID-19 Pandemic

Aromatic Chinese herbs have been used to prevent plagues since ancient times. Traditional Chinese medicine has unique advantages in the prevention and treatment of epidemic diseases. According to the traditional Chinese medicine treatment plan in the National COVID-19 Diagnosis and Treatment Plan (Trial Seventh Edition) of the National Health Commission, Chinese patent medicines or prescriptions rich in aromatic Chinese herbs are selected for prevention and treatment during the period of medical observation, clinical treatment, and recovery of confirmed COVID-19 patients. Some local health committees or traditional Chinese medicine administrations recommend a variety of other ways of using traditional aromatic Chinese herbs to prevent and cure COVID-19. These involve external fumigation, use of moxibustion, and wearing of sachet. The efficacy of aromatic Chinese herbs plays a decisive role in the prevention and treatment of COVID-19. The unique properties, chemical composition, and mechanism of action of aromatic Chinese herbs are worthy of extensive and in-depth experimental and clinical research. The findings are expected to provide a reference for follow-up treatment of novel coronavirus and the development of corresponding drugs. In 2003, Dayuan-Yin produced excellent results in the treatment of the SARS virus. Individually, 112 confirmed cases were administered this drug between January and April 2003, and more than 93.7% of the patients showed noticeable mitigation of the symptoms, as well as recovery. Dayuan-Yin also was selected as one of the nationally recommended prescriptions for the COVID-19. Based on the national recommendation of Dayuan-Yin prescription, this review discusses the role of volatile components in the prevention and treatment of COVID-19, and speculates the possible mechanism of action, so as to provide a basis for the prevention and treatment of COVID-19.

Forest Volatile Organic Compounds and Their Effects on Human Health: A State-of-the-Art Review

The aim of this research work is to analyze the chemistry and diversity of forest VOCs (volatile organic compounds) and to outline their evidence-based effects on health. This research work was designed as a narrative overview of the scientific literature. Inhaling forest VOCs like limonene and pinene can result in useful antioxidant and anti-inflammatory effects on the airways, and the pharmacological activity of some terpenes absorbed through inhalation may be also beneficial to promote brain functions by decreasing mental fatigue, inducing relaxation, and improving cognitive performance and mood. The tree composition can markedly influence the concentration of specific VOCs in the forest air, which also exhibits cyclic diurnal variations. Moreover, beneficial psychological and physiological effects of visiting a forest cannot be solely attributed to VOC inhalation but are due to a global and integrated stimulation of the five senses, induced by all specific characteristics of the natural environment, with the visual component probably playing a fundamental role in the overall effect. Globally, these findings can have useful implications for individual wellbeing, public health, and landscape design. Further clinical and environmental studies are advised, since the majority of the existing evidence is derived from laboratory findings.

New Perspectives for Mucolytic, Anti-inflammatory and Adjunctive Therapy with 1,8-Cineole in COPD and Asthma: Review on the New Therapeutic Approach

The mucolytic monoterpene 1,8-cineole (eucalyptol), the major constituent of eucalyptus species, is well known for its anti-inflammatory, antioxidant, bronchodilatory, antiviral and antimicrobial effects. The main protective antiviral, anti-inflammatory and mucolytic mechanisms of 1,8-cineole are the induction of interferon regulatory factor 3 (IRF3), the control of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) along with decreasing mucin genes (MUC2, MUC19). In normal human monocytes direct inhibition was shown of reactive oxygen species (ROS)-mediated mucus hypersecretion and of steroid resistence inducing superoxides (O2·-) and pro-inflammatory hydrogen peroxides (H2O2) with partial control of superoxide dismutase (SOD), which enzymatically metabolizes O2·- into H2O2. By inhibition of NF-κB, 1,8-cineole, at relevant plasma concentrations (1.5 µg/ml), strongly and significantly inhibited in normal human monocyte lipopolysaccharide (LPS)-stimulated cytokines relevant for exacerbation (tumour necrosis factor alpha (TNFα), interleukin (IL)-1β and systemic inflammation (IL-6, IL-8). Infectious agents and environmental noxa have access via TNFα and IL-1β to the immune system with induction of bronchitis complaints and exacerbations of chronic obstructive pulmonary disease (COPD), asthma and asthma-COPD overlap. In lymphocytes from healthy human donors 1,8-cineole inhibited TNFα, IL-1β, IL-4 and IL-5 and demonstrated for the first time control of Th1/2-type inflammation. 1,8-Cineole at relevant plasma levels increased additively in vitro the efficacy of inhaled guideline medications of budesonide (BUD) and budesonide + formoterol ,and preliminary data also showed increased efficacy of long-acting muscarinic receptor antagonist (LAMA)-mediated cytokine inhibition in vitro. On the basis of the preclinical data, earlier randomised controlled studies with adjunctive therapy of 1,8-cineole (3 × 200 mg/day) for 6 months showed improvement of uncontrolled asthma by significant improvement of lung function, nocturnal asthma and quality of life scores and in COPD decrease of exacerbations (- 38.5%) (during wintertime). This review reports an update with reference to the literature of 1,8-cineole, also as adjunctive therapy, as a therapeutic agent for the protection and control of inflammatory airway diseases.

Therapeutic Potential of Volatile Terpenes and Terpenoids from Forests for Inflammatory Diseases

Forest trees are a major source of biogenic volatile organic compounds (BVOCs). Terpenes and terpenoids are known as the main BVOCs of forest aerosols. These compounds have been shown to display a broad range of biological activities in various human disease models, thus implying that forest aerosols containing these compounds may be related to beneficial effects of forest bathing. In this review, we surveyed studies analyzing BVOCs and selected the most abundant 23 terpenes and terpenoids emitted in forested areas of the Northern Hemisphere, which were reported to display anti-inflammatory activities. We categorized anti-inflammatory processes related to the functions of these compounds into six groups and summarized their molecular mechanisms of action. Finally, among the major 23 compounds, we examined the therapeutic potentials of 12 compounds known to be effective against respiratory inflammation, atopic dermatitis, arthritis, and neuroinflammation among various inflammatory diseases. In conclusion, the updated studies support the beneficial effects of forest aerosols and propose their potential use as chemopreventive and therapeutic agents for treating various inflammatory diseases.

Eucalyptol reduces airway hyperresponsiveness in rats following cigarette smoke-exposed

BACKGROUND

Cigarette smoke is the major cause of airway inflammatory disease, including airway hyperresponsiveness. Eucalyptol (EUC), also named 1.8-cineole, is a monoterpenoid found in essential oil of medicinal plants, showing several biological effects.

HYPOTHESIS/PURPOSE

Based in the eucalyptol protective activity in respiratory diseases as asthma, our hypothesis is that eucalyptol is able to reduce the airway hyperresponsiveness and the respiratory mechanic parameters in rats exposed to cigarette smoke.

STUDY DESIGN

Wistar rats were divided into control and cigarettes smoke (CS) groups. CS group was daily subjected to cigarette smoke and treated by inhalation for 15 min/day with EUC (1 mg/mL) or vehicle during 30 days. After treatment, bronchoalveolar lavage (BAL) was collected to analyze the inflammatory profile, and tracheal rings were isolated for evaluation of the airway smooth muscle hyperresponsiveness. Lung function was analyzed in vivo.

METHODS

The inflammatory profile was evaluated by optical microscopy performing total (Neubauer chamber) and differential leukocyte count (smear slides stained in H&E). The hyperresponsiveness was evaluated in tracheal rings contracted with potassium chloride (KCl) carbamoylcholine (CCh), or Barium chloride (BaCl₂) in presence or absence of nifedipine. The lung function (Newtonian resistance-R_N) was evaluated by bronco stimulation with methacholine (MCh).

RESULTS

BAL from CS group increased the influx of leukocyte, mainly neutrophils and macrophages compared to control group. EUC reduced by 71% this influx. The tracheal contractions induced by KCl, CCh or BaCl₂ were reduced by EUC in 59%, 42% and 26%, respectively. The last one was not different of nifedipine activity. Newtonian resistance (R_N) was also reduced in 37% by EUC compared to CS group. 
 CONCLUSION: EUC reduces the hyperresponsiveness and the airway inflammatory profile, recovering the lung function.

Suppression of Propionibacterium acnes-Induced Skin Inflammation by Laurus nobilis Extract and Its Major Constituent Eucalyptol

Acne is an inflammatory skin disorder in puberty with symptoms including papules, folliculitis, and nodules. Propionibacterium acnes (P. acnes) is the main anaerobic bacteria that cause acne. It is known to proliferate within sebum-blocked skin hair follicles. P. acnes activates monocytic cell immune responses to induce the expression of proinflammatory cytokines. Although the anti-inflammatory function of the Laurus nobilis (L. nobilis) extract (LNE) on several immunological disorders have been reported, the effect of LNE in P. acnes-mediated skin inflammation has not yet been explored. In the present study, we examined the ability of the LNE to modulate the P. acnes-induced inflammatory signaling pathway, and evaluated its mechanism. LNE significantly suppressed the expression of P. acnes-mediated proinflammatory cytokines, such as IL-1β, IL-6, and NLRP3. We also found that LNE inhibited the inflammatory transcription factor NF-κB in response to P. acnes. In addition, eucalyptol, which is the main constituent of LNE, consistently inhibited P. acnes-induced inflammatory signaling pathways. Moreover, LNE significantly ameliorated P. acnes-induced inflammation in a mouse model of acne. We suggest for the first time that LNE hold therapeutic value for the improvement of P. acnes-induced skin inflammation.

1,8-Cineole Ameliorates LPS-Induced Vascular Endothelium Dysfunction in Mice via PPAR-γ Dependent Regulation of NF-κB

1,8-Cineole (eucalyptol), a monoterpene, has been widely reported for the anti-inflammatory effects. Our previous data confirmed that 1,8-cineole ameliorated the inflammatory phenotype of human umbilical vein endothelial cells (HUVECs) by mediating NF-κB expression in vitro. At present, we investigated the protection effects of 1,8-cineole on vascular endothelium in lipopolysaccharide (LPS)-induced acute inflammatory injury mice and the potential mechanisms involved in the protection in HUVECs. Results from enzyme linked immunosorbent assays revealed that 1,8-cineole suppressed the secretion of interleukin (IL)-6 and IL-8 and increased the expression of IL-10 in the serum of LPS-induced mice. 1,8-Cineole reduced the inflammatory infiltration and the expression of vascular cell adhesion molecular 1 (VCAM-1) in the sections of thoracic aorta in LPS-induced acute inflammatory mice. Western blotting indicated that 1,8-cineole significantly decreased the phosphorylation of NF-κB p65 and increased the expression of PPAR-γ in the thoracic aorta tissue. 1,8-Cineole increased the expression of PPAR-γ in LPS-induced HUVECs. 1,8-Cineole and rosiglitazone reduced the protein and mRNA levels of VCAM-1, E-selectin, IL-6, and IL-8 in LPS-induced HUVECs, which could be reversed by the action of GW9662 (inhibitor of PPAR-γ). 1,8-Cineole and rosiglitazone blocked the LPS-induced IκBα degradation and NF-κB p65 nucleus translocation, which could be reversed by the pretreatment of GW9662 or silence of PPAR-γ gene. In conclusion, 1,8-cineole attenuated LPS-induced vascular endothelial cells injury via PPAR-γ dependent modulation of NF-κB.

Eucalyptol promotes lung repair in mice following cigarette smoke-induced emphysema

BACKGROUND

Eucalyptol is a monoterpenoid oil present in many plants, principally the Eucalyptus species, and has been reported to have anti-inflammatory and antioxidative effects.

HYPOTHESIS/PURPOSE

Since the potential effect of eucalyptol on mouse lung repair has not yet been studied, and considering that chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide, the aim of this study was to investigate eucalyptol treatment in emphysematous mice.

STUDY DESIGN

Male mice (C57BL/6) were divided into the following groups: control (sham-exposed), cigarette smoke (CS) (mice exposed to 12 cigarettes a day for 60 days), CS + 1 mg/ml (CS mice treated with 1 mg/ml eucalyptol for 60 days), and CS + 10 mg/ml (CS mice treated with 10 mg/ml eucalyptol for 60 days). Mice in the CS and control groups received vehicle for 60 days. Eucalyptol (or the vehicle) was administered via inhalation (15 min/daily). Mice were sacrificed 24 h after the completion of the 120-day experimental procedure.

METHODS

Histology and additional lung morphometric analyses, including analysis of mean linear intercept (Lm) and volume density of alveolar septa (Vv[alveolar septa]) were performed. Biochemical analyses were also performed using colorimetric assays for myeloperoxidase (MPO), malondialdehyde (MDA), and superoxide dismutase (SOD) activity, in addition to using ELISA kits for the determination of inflammatory marker levels (tumor necrosis factor alpha [TNF-α], interleukin-1 beta [IL-1β], interleukin 6 [IL-6], keratinocyte chemoattractant [KC], and tumor growth factor beta 1 [TGF-β1]). Finally, we investigated protein levels by western blotting (nuclear factor (erythroid-derived 2)-like 2 [Nrf2], nuclear factor kappa B [NF-κB], matrix metalloproteinase 12 [MMP-12], tissue inhibitor of matrix metalloproteinase 1 [TIMP-1], neutrophil elastase [NE], and elastin).

RESULTS

Eucalyptol promoted lung repair at the higher dose (10 mg/ml), with de novo formation of alveoli, when compared to the CS group. This result was confirmed with Lm and Vv[alveolar septa] morphometric analyses. Moreover, collagen deposit around the peribronchiolar area was reduced with eucalyptol treatment when compared to the CS group. Eucalyptol also reduced all inflammatory (MPO, TNF-α, IL-1β, IL-6, KC, and TGF-β1) and redox marker levels (MDA) when compared to the CS group (at least p < 0.05). In general, 10 mg/ml eucalyptol was more effective than 1 mg/ml and, at both doses, we observed an upregulation of SOD activity when compared to the CS group (p < 0.001). Eucalyptol upregulated elastin and TIMP-1 levels, and reduced neutrophil elastase (NE) levels, when compared to the CS group.

CONCLUSION

In summary, eucalyptol promoted lung repair in emphysematous mice and represents a potential therapeutic phytomedicine in the treatment of COPD.

Rosmarinus officinalis essential oil: A review of its phytochemistry, anti-inflammatory activity, and mechanisms of action involved

ETHNOPHARMACOLOGICAL RELEVANCE

Plant species Rosmarinus officinalis L. (Lamiaceae; Synonyms: Salvia rosmarinus Schleid. and Rosmarinus angustifolius Mill.) is a herb widely used worldwide. In local and traditional medicine, its used for inflammation-related diseases. Currently, studies report anti-inflammatory activity in its essential oil (EORO). However, to better understand EORO's anti-inflammatory activity its necessary to understand its phytochemistry and the signaling pathways affected by it. Hence, this review aimed to describe EORO phytochemical profile, ethnopharmacological uses, some biological activities of EORO will be described but emphasizing its anti-inflammatory potential and possible mechanisms of action involved.

MATERIALS AND METHODS

The research was performed using the databases Medline, Embase, BVS Regional Portal, Science Direct, CAPES Journals, and Scopus; using the keywords "Rosmarinus officinalis", "anti-inflammatory" and "essential oil". Additional information was gathered from related textbooks, reviews, and documents.

RESULTS AND DISCUSSION

Until now about 150 chemical compounds were identified in EORO samples, more frequently reported molecules were 1,8-cineole, α-pinene, and camphor. Studies suggest that the anti-inflammatory activity of EORO occur mainly through inhibition of NF-κB transcription and suppression of arachidonic acid cascade. Its antioxidant activity also aids by preventing injury caused by the reactive species of inflammation; its smooth muscle relaxant activity contributes to ameliorating airway inflammatory diseases. Lastly, toxicity assessments indicate low toxicity to EORO.

CONCLUSIONS

Current evidence indicates anti-inflammatory activity in EORO, supporting its ethnopharmacological uses in inflammatory-related diseases, and potential future applications. However, although considerable acute inflammatory models were tested, more chronic inflammatory models are needed; clinical studies are still absent, this may be due to the high doses needed for essential oils to exert pharmacological effects, but recent studies show this issue can be bypassed using the oil formulated as nanoemulsions to improve its bioavailability.

Preparation and protective effects of 1,8-cineole-loaded self-microemulsifying drug delivery system on lipopolysaccharide-induced endothelial injury in mice

An optimised 1,8-cineole-loaded self-microemulsifying drug delivery system (CIN-SMEDDS) with a mean droplet size, polydispersity index, mean zeta potential and encapsulation efficiency of 38.14 ± 1.47 nm, 0.208 ± 0.036, -9.312 ± 1.764 mV and 95.35% ± 1.13%, respectively, successfully ameliorated the lipopolysaccharide (LPS)-induced endothelial injury in mice. Acute toxicity assay in mice through the oral administration of CIN-SMEDDS showed that the median lethal dose of CIN-SMEDDS was 2998.9 mg/kg. The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated that the cytotoxicity of CIN-SMEDDS to Caco-2 cells may be ascribed to the surfactant/co-surfactant mixture. In particular, CIN-SMEDDS remarkably inhibited inflammatory cytokines IL-1β, IL-6 and IL-8 with a simultaneous increase in IL-10 in LPS-treated mice. Haematoxylin-eosin staining results showed that CIN-SMEDDS attenuated LPS-induced vascular endothelial injury. Western blot results showed that the vascular protective effects of CIN-SMEDDS were associated with the NF-κB and peroxisome proliferator-activated receptor γ signalling pathways. These findings indicated that CIN-SMEDDS can attenuate LPS-induced endothelial injury and thus was proposed as a promising agent for the treatment of inflammatory cardiovascular disease.

Monoterpenes modulating cytokines - A review

Inflammatory response can be driven by cytokine production and is a pivotal target in the management of inflammatory diseases. Monoterpenes have shown that promising profile as agents which reduce the inflammatory process and also modulate the key chemical mediators of inflammation, such as pro and anti-inflammatory cytokines. The main interest focused on monoterpenes were to develop the analgesic and anti-inflammatory drugs. In this review, we summarized current knowledge on monoterpenes that produce anti-inflammatory effects by modulating the release of cytokines, as well as suggesting that which monoterpenoid molecules may be most effective in the treatment of inflammatory disease. Several different inflammatory markers were evaluated as a target of monoterpenes. The proinflammatory and anti-inflammatory cytokines were found TNF-α, IL-1β, IL-2, IL-5, IL-4, IL-6, IL-8, IL-10, IL-12 IL-13, IL-17A, IFNγ, TGF-β1 and IFN-γ. Our review found evidence that NF-κB and MAPK signaling are important pathways for the anti-inflammatory action of monoterpenes. We found 24 monoterpenes that modulate the production of cytokines, which appears to be the major pharmacological mechanism these compounds possess in relation to the attenuation of inflammatory response. Despite the compelling evidence supporting the anti-inflammatory effect of monoterpenes, further studies are necessary to fully explore their potential as anti-inflammatory compounds.

A Comparative Evaluation of the Cytotoxic and Antioxidant Activity of Mentha crispa Essential Oil, Its Major Constituent Rotundifolone, and Analogues on Human Glioblastoma

Cancer is a major public health problem around the globe. This disorder is affected by alterations in multiple physiological processes, and oxidative stress has been etiologically implicated in its pathogenesis. Glioblastoma (GBM) is considered the most common and aggressive brain tumor with poor prognosis despite recent improvements in surgical, radiation, and chemotherapy-based treatment approaches. The purpose of this study was to evaluate antitumor activity from Mentha crispa essential oil (MCEO), its major constituent rotundifolone (ROT), and a series of six analogues on the human U87MG glioblastoma cell line. Cytotoxic effects of the compounds on the human U87MG-GBM cell line were assessed using in vitro cell viability and oxidative and molecular genetic assays. In addition, biosafety assessment tests were performed on cultured human blood cells. Our findings revealed that MCEO, 1,2-perillaldehyde epoxide (EPER1), and perillaldehyde (PALD) were the most cytotoxic compounds against U87MG cells, with IC50 values of 16.263, 15.087, and 14.888 μg/mL, respectively. Further, these compounds increased the expressions of BRAF, EGFR, KRAS, NFκB1, NFκB1A, NFκB2, PIK3CA, PIK3R, PTEN, and TP53 genes at different degrees and decreased the expression of some genes such as AKT1, AKT2, FOS, and RAF1. Finally, treatment with MCEO, EPER1, and PALD did not lead to genotoxic damage in blood cells. Taken together, our findings reveal antiproliferative potential of MCEO, its major component ROT, and its tested analogues. Some of these chemical analogues may be useful as prototypes for the development of novel chemotherapeutic agents for treating human brain cancer and/or other cancers due to their promising activities as well as nonmutagenic property and safety.

Knockdown of TNF‑α alleviates acute lung injury in rats with intestinal ischemia and reperfusion injury by upregulating IL‑10 expression

Intestinal ischemia and reperfusion (II/R) injury often triggers severe injury in remote organs, with the lungs being considered the main target. Excessive elevation of proinflammatory cytokines is a major contributor in the occurrence and development of II/R-induced acute lung injury (ALI). Therefore, the present study aimed to investigate whether blocking tumor necrosis factor-α (TNF-α) expression could protect the lungs from injury following II/R, and to explore the possible underlying mechanism involving interleukin-10 (IL-10). Briefly, II/R was induced in rats by 40 min occlusion of the superior mesenteric artery and celiac artery, followed by 8, 16 or 24 h of reperfusion. Subsequently, lentiviral vectors containing TNF-α short hairpin (sh)RNA were injected into the right lung tissues, in order to induce TNF-α knockdown. The severity of ALI was determined according to lung injury scores and lung edema (lung wet/dry weight ratio). The expression levels of TNF-α were analyzed by quantitative polymerase chain reaction (qPCR), western blotting and immunofluorescence (IF) staining. IL-10 expression, in response to TNF-α knockdown, was detected in lung tissues by qPCR and IF. The results detected marked inflammatory responses, and increased levels of lung wet/dry weight ratio and TNF-α expression, in the lungs of II/R rats. Conversely, treatment with TNF-α shRNA significantly alleviated the severity of ALI and upregulated the expression levels of IL-10 in lung tissues. These findings suggested that TNF-α RNA interference may exert a protective effect on II/R-induced ALI via the upregulation of IL-10. Therefore, TNF-α knockdown may be considered a potential strategy for the prevention or treatment of ALI induced by II/R in future clinical trials.

Effect of Lavender (Lavandula angustifolia) Essential Oil on Acute Inflammatory Response

Lavandula angustifolia is a plant of Lamiaceae family, with many therapeutic properties and biological activities, such as anticonvulsant, anxiolytic, antioxidant, anti-inflammatory, and antimicrobial activities. The aim of this study was to evaluate the effect of Lavandula angustifolia Mill. essential oil (LEO) on acute inflammatory response. LEO was analyzed using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR) methods and showed predominance of 1,8-cineole (39.83%), borneol (22.63%), and camphor (22.12%). LEO at concentrations of 0.5, 1, 3, and 10 μg/ml did not present in vitro cytotoxicity. Additionally, LEO did not stimulate the leukocyte chemotaxis in vitro. The LEO topical application at concentrations of 0.25, 0.5, and 1 mg/ear reduced edema formation, myeloperoxidase (MPO) activity, and nitric oxide (NO) production in croton oil-induced ear edema model. In carrageenan-induced paw edema model, LEO treatment at doses of 75, 100, and 250 mg/kg reduced edema formation, MPO activity, and NO production. In dextran-induced paw edema model, LEO at doses of 75 and 100 mg/kg reduced paw edema and MPO activity. In conclusion, LEO presented anti-inflammatory activity, and the mechanism proposed of LEO seems to be, at least in part, involving the participation of prostanoids, NO, proinflammatory cytokines, and histamine.

Endothelial Cdc42 deficiency impairs endothelial regeneration and vascular repair after inflammatory vascular injury

Background

Endothelial cell (EC) regeneration is essential for inflammation resolution and vascular integrity recovery after inflammatory vascular injury. Cdc42 is a central regulator of cell survival and vessel formation in EC development. However, it is unknown that whether Cdc42 could be a regulating role of EC repair following the inflammatory injury in the lung. The study sought to test the hypothesis that Cdc42 is required for endothelial regeneration and vascular integrity recovery after LPS-induced inflammatory injury.

Methods and results

The role of Cdc42 for the regulation of pulmonary vascular endothelial repair was tested in vitro and in vivo. In LPS-induced acute lung injury (ALI) mouse models, knockout of the Cdc42 gene in ECs increased inflammatory cell infiltration and pulmonary vascular leakage and inhibited vascular EC proliferation, which eventually resulted in more severe inflammatory lung injury. In addition, siRNA-mediated knockdown of Cdc42 protein on ECs disrupted cell proliferation and migration and tube formation, which are necessary processes for recovery after inflammatory vascular injury, resulting in inflammatory vascular injury recovery defects.

Conclusion

We found that Cdc42 deficiency impairs EC function and regeneration, which are crucial in the post-inflammatory vascular injury repair process. These findings indicate that Cdc42 is a potential target for novel treatments designed to facilitate endothelial regeneration and vascular repair in inflammatory pulmonary vascular diseases, such as ALI/ARDS.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0729-8) contains supplementary material, which is available to authorized users.