The anti-allergic activity of Cymbopogon citratus is mediated via inhibition of nuclear factor kappa B (Nf-Κb) activation

Therapeutic potential of a novel hybrid protein: Mitigating allergy and airway remodeling in chronic asthma models induced by Dermatophagoides pteronyssinus

BACKGROUND

The house-dust mite Dermatophagoides pteronyssinus is a key trigger of allergic asthma. Therefore, it is essential to develop new vaccines that can alter inflammatory processes and airway remodeling. The goal of this study was to test the hypoallergenic and immunogenic characteristics of the hypoallergen rDer p 2231 in a murine model of chronic asthma induced by D. pteronyssinus.

METHODS

For this, we measured the levels of IgE, IgG1, IgG2a, and cytokines produced by mice receiving the rDer p 2231 protein. Histopathological parameters of the chronic inflammatory response were also investigated by assessing inflammation and airway remodeling.

RESULTS

rDer p 2231 given as a therapeutic vaccine, led to a reduction in the production of IgE, eosinophils, and neutrophils, a lower activity of eosinophilic peroxidase in the airways, and an increase in the production of IgG1 and IgG2a antibodies. IgG antibodies blocked IgE binding to parental allergens in sera from atopic patients. Splenocytes, BALF, and lung from mice treated with rDer p 2231 secreted higher levels of Th1 and regulatory cytokines, as well as reduced levels of Th2 cytokines. Histopathological investigation of the lower airways demonstrated reductions in the thickness of the bronchiolar smooth muscle layer, in the subepithelial fibrosis, and in the goblet cells hyperplasia.

CONCLUSIONS

Our preclinical studies suggest that rDer p 2231 is a promising candidate for the treatment of D. pteronyssinus allergy, as the hypoallergen has demonstrated the ability to reduce IgE production, induce specific blocking antibodies, restore and balance Th1/Th2 immune responses, and significantly reduce airway remodeling factors. However, additional clinical studies are needed to more accurately assess the efficacy and safety of rDer p 2231 as a vaccine against D. pteronyssinus-induced allergy.

Ethnopharmacology, chemical composition and functions of Cymbopogon citratus

Cymbopogon citratus in the gramineous family, also known as lemongrass (LG), is a perennial herb. LG, a drug and food homologous medicine, has a widely recorded medicinal value and food applications. To date, 158 LG compounds have been reported, including terpenoids, flavonoids, phenolic acids. Pharmacological and clinical studies have indicated that LG has antibacterial, neuroprotective, hypoglycemic, hypotensive, anti-inflammatory, and anti-tumor effects. This article reviews LG in ethnopharmacology, chemical composition, pharmacology, food, medicine, and daily chemical applications to provide a basis for the subsequent development of food and medicine.

The hybrid protein BTH2 suppresses allergic airway inflammation in a murine model of HDM-specific immunotherapy

BACKGROUND

Allergen-specific immunotherapy (AIT) is the only disease-modifying treatment approach to change disease-causing allergens. Hypoallergenic derivatives show promise as potential therapeutics, amongst which BTH2 was designed to induce tolerance against Blomia tropicalis allergy. Our aim was to investigate the hypoallergenicity and immunoregulatory activity of BTH2 in vitro and its therapeutic potential in a mouse model of AIT.

METHODS

Recombinant Blo t 5 and Blo t 21 allergens and their hybrid derivatives (BTH1 and BTH2) were expressed and purified. IgE binding capacity was tested by ELISA using sera from Brazilian, Colombian, and Ecuadorian subjects. Secretion of cytokines in supernatants from human cell cultures was measured following stimulation with the four recombinants and controls. The capacity of BTH2 to ameliorate allergic airway inflammation induced by B. tropicalis extract was evaluated in a murine model of AIT.

RESULTS

rBlo t 5 and rBlo t 21 were identified as major allergens in Latin American patients, and BTH2 had the lowest IgE binding. In vitro stimulation of human cells induced greater levels of IL-10 and IFN-γ and reduced the secretion of Th2 cytokines. BTH2 ameliorated allergic airway inflammation in B. tropicalis-challenged A/J mice, as evidenced by the histopathological and humoral biomarkers: decreased Th2 cytokines and cellular infiltration (especially eosinophils), lower activity of eosinophil peroxidase, an increase in IgG blocking antibodies and strong reduction of mucus production by goblet cells.

CONCLUSIONS

Our study shows that BTH2 represents a promising candidate for the treatment of B. tropicalis allergy with hypoallergenic, immune regulatory and therapeutic properties. Further pre-clinical studies are required in murine models of chronic asthma to further address the efficacy and safety of BTH2 as a vaccine against B. tropicalis-induced allergy.

Recombinant T-cell epitope conjugation: A new approach for Dermatophagoides hypoallergen design

BACKGROUND

Allergen-specific immunotherapy (AIT) is the only clinical approach that can potentially cure some allergic diseases by inducing immunological tolerance. Dermatophagoides pteronyssinus is considered as the most important source of mite allergens worldwide, with high sensitization rates for the major allergens Der p 1, Der p 2 and Der p 23. The aim of this work is to generate a hypoallergenic hybrid molecule containing T-cell epitopes from these three major allergens.

METHODS

The hybrid protein termed Der p 2231 containing T-cell epitopes was purified by affinity chromatography. The human IgE reactivity was verified by comparing those with the parental allergens. The hybrid was also characterized immunologically through an in vivo mice model.

RESULTS

The hybrid rDer p 2231 stimulated in peripheral blood mononuclear cells (PBMCs) isolated from allergic patients with higher levels of IL- 2, IL-10, IL-15 and IFN-γ, as well as lower levels of IL-4, IL-5, IL-13, TNF-α and GM-CSF. The use of hybrid molecules as a therapeutic model in D. pteronyssinus allergic mice led to the reduction of IgE production and lower eosinophilic peroxidase activity in the airways. We found increased levels of IgG antibodies that blocked the IgE binding to the parental allergens in the serum of allergic patients. Furthermore, the stimulation of splenocytes from mice treated with rDer p 2231 induced higher levels of IL-10 and IFN-γ and decreased the secretion of IL-4 and IL-5, when compared with parental allergens and D. pteronyssinus extract.

CONCLUSIONS

rDer p 2231 has the potential to be used in AIT in patients co-sensitized with D. pteronyssinus major allergens, once it was able to reduce IgE production, inducing allergen-specific blocking antibodies, restoring and balancing Th1/Th2 immune responses, and inducing regulatory T-cells.

Sinapic acid ameliorates airway inflammation in murine ovalbumin-induced allergic asthma by reducing Th2 cytokine production

OBJECTIVE

Asthma is a chronic inflammatory airway disease associated with the airway narrowing and obstruction. Sinapic acid (SA), a hydroxycinnamic acid, possesses various pharmacological properties including antioxidant and anti-inflammatory activity. This research evaluated effects of different doses of SA on murine model of ovalbumin (OVA)-induced allergic asthma.

MATERIALS AND METHODS

Allergic asthma induced by sensitizing mice on days 1 and 14 by intraperitoneal injection of OVA. After initial sensitization, between days 21 and 23, mice were challenged for 30 min with an aerosol of 1 % (wt/vol) OVA. Treatment with dexamethasone (3 mg/kg) or SA (25, 50 or 100 mg/kg) were done by oral gavage on days 15-23. Inflammatory cells infiltration and interferon-γ (IFN-γ), interlukin-4 (IL-4), IL-5 and IL-13 levels were evaluated in the bronchoalveolar lavage fluid (BALF). Serum total and OVA-specific immunoglobulin E (IgE) and lung tissue nitric oxide (NO) levels were measured. Histological changes in lung tissue were examined by staining with hematoxylin and eosin (H&E) for cell infiltration, periodic acid-Schiff (PAS) for mucus production and Masson's trichrome for collagen deposition.

RESULTS

Treatment with SA significantly inhibited inflammatory cell infiltration, enhanced IFN-γ level and decreased IL-4, IL-5 and IL-13 levels in BALF. Serum total and OVA-specific IgE levels and NO level in lung tissue were significantly reduced by SA. Histological examination demonstrated that SA significantly attenuated inflammatory cell infiltration and mucus-producing cells in the lung.

CONCLUSION

These data suggest that SA may be a new therapeutic potential to treat allergic asthma through suppressing T-helper 2 immune responses.

Review of Antimicrobial and Other Health Effects in 5 Essential Oil Producing Grass Species

The warm season essential oil producing grass species including lemongrass (Cymbopogon citratus), palmarosa grass (C. martini), geranium grass (C. schoenanthus), vetiver grass (Chrysopogon zizanioides), and scented top grass (Capillipedium parviflorum) are used worldwide for their cosmetic and health properties. A discussion providing evidence from literature reviews about the potential uses of these grass species for antimicrobial and other health uses are presented. These species could be used as new therapies for treating microbial infections. The purpose of this study is to discuss in detail, evidence from literature reviews supporting potential health uses and to provide some discussion regarding some agronomic traits for these essential oil producing species.

Chemical Profiles and Pharmacological Properties with in Silico Studies on Elatostema papillosum Wedd

The current study attempted, for the first time, to qualitatively and quantitatively determine the phytochemical components of Elatostema papillosum methanol extract and their biological activities. The present study represents an effort to correlate our previously reported biological activities with a computational study, including molecular docking, and ADME/T (absorption, distribution, metabolism, and excretion/toxicity) analyses, to identify the phytochemicals that are potentially responsible for the antioxidant, antidepressant, anxiolytic, analgesic, and anti-inflammatory activities of this plant. In the gas chromatography-mass spectroscopy analysis, a total of 24 compounds were identified, seven of which were documented as being bioactive based on their binding affinities. These seven were subjected to molecular docking studies that were correlated with the pharmacological outcomes. Additionally, the ADME/T properties of these compounds were evaluated to determine their drug-like properties and toxicity levels. The seven selected, isolated compounds displayed favorable binding affinities to potassium channels, human serotonin receptor, cyclooxygenase-1 (COX-1), COX-2, nuclear factor (NF)-κB, and human peroxiredoxin 5 receptor proteins. Phytol acetate, and terpene compounds identified in E. papillosum displayed strong predictive binding affinities towards the human serotonin receptor. Furthermore, 3-trifluoroacetoxypentadecane showed a significant binding affinity for the KcsA potassium channel. Eicosanal showed the highest predicted binding affinity towards the human peroxiredoxin 5 receptor. All of these findings support the observed in vivo antidepressant and anxiolytic effects and the in vitro antioxidant effects observed for this extract. The identified compounds from E. papillosum showed the lowest binding affinities towards COX-1, COX-2, and NF-κB receptors, which indicated the inconsequential impacts of this extract against the activities of these three proteins. Overall, E. papillosum appears to be bioactive and could represent a potential source for the development of alternative medicines; however, further analytical experiments remain necessary.

COVID-19: Is There Evidence for the Use of Herbal Medicines as Adjuvant Symptomatic Therapy?

BACKGROUND

Current recommendations for the self-management of SARS-Cov-2 disease (COVID-19) include self-isolation, rest, hydration, and the use of NSAID in case of high fever only. It is expected that many patients will add other symptomatic/adjuvant treatments, such as herbal medicines.

AIMS

To provide a benefits/risks assessment of selected herbal medicines traditionally indicated for "respiratory diseases" within the current frame of the COVID-19 pandemic as an adjuvant treatment.

METHOD

The plant selection was primarily based on species listed by the WHO and EMA, but some other herbal remedies were considered due to their widespread use in respiratory conditions. Preclinical and clinical data on their efficacy and safety were collected from authoritative sources. The target population were adults with early and mild flu symptoms without underlying conditions. These were evaluated according to a modified PrOACT-URL method with paracetamol, ibuprofen, and codeine as reference drugs. The benefits/risks balance of the treatments was classified as positive, promising, negative, and unknown.

RESULTS

A total of 39 herbal medicines were identified as very likely to appeal to the COVID-19 patient. According to our method, the benefits/risks assessment of the herbal medicines was found to be positive in 5 cases (Althaea officinalis, Commiphora molmol, Glycyrrhiza glabra, Hedera helix, and Sambucus nigra), promising in 12 cases (Allium sativum, Andrographis paniculata, Echinacea angustifolia, Echinacea purpurea, Eucalyptus globulus essential oil, Justicia pectoralis, Magnolia officinalis, Mikania glomerata, Pelargonium sidoides, Pimpinella anisum, Salix sp, Zingiber officinale), and unknown for the rest. On the same grounds, only ibuprofen resulted promising, but we could not find compelling evidence to endorse the use of paracetamol and/or codeine.

CONCLUSIONS

Our work suggests that several herbal medicines have safety margins superior to those of reference drugs and enough levels of evidence to start a clinical discussion about their potential use as adjuvants in the treatment of early/mild common flu in otherwise healthy adults within the context of COVID-19. While these herbal medicines will not cure or prevent the flu, they may both improve general patient well-being and offer them an opportunity to personalize the therapeutic approaches.

A systematic review on COVID-19 pandemic with special emphasis on curative potentials of Nigeria based medicinal plants

Despite the frightening mortality rate associated with COVID-19, there is no known approved drug to effectively combat the pandemic. COVID-19 clinical manifestations include fever, fatigue, cough, shortness of breath, and other complications. At present, there is no known effective treatment or vaccine that can mitigate/inhibit SARS-CoV-2. Available clinical intervention for COVID-19 is only palliative and limited to support. Thus, there is an exigent need for effective and non-invasive treatment. This article evaluates the possible mechanism of actions of SARS-CoV-2 and present Nigeria based medicinal plants which have pharmacological and biological activities that can mitigate the hallmarks of the pathogenesis of COVID-19. SARS-CoV-2 mode of actions includes hyper-inflammation characterized by a severe and fatal hyper-cytokinaemia with multi-organ failure; immunosuppression; reduction of angiotensin-converting enzyme 2 (ACE2) to enhance pulmonary vascular permeability causing damage to the alveoli; and further activated by open reading frame (ORF)3a, ORF3b, and ORF7a via c-Jun N- terminal kinase (JNK) pathway which induces lung damage. These mechanisms of action of SARS-CoV-2 can be mitigated by a combination therapy of medicinal herbs based on their pharmacological activities. Since the clinical manifestations of COVID-19 are multifactorial with co-morbidities, we strongly recommend the use of combined therapy such that two or more herbs with specific therapeutic actions are administered to combat the mediators of the disease.

Lemon Grass Essential Oil Does not Modulate Cancer Cells Multidrug Resistance by Citral-Its Dominant and Strongly Antimicrobial Compound

With strong antimicrobial properties, citral has been repeatedly reported to be the dominant component of lemongrass essential oil. Here, we report on a comparison of the antimicrobial and anticancer activity of citral and lemongrass essential oil. The lemongrass essential oil was prepared by the vacuum distillation of fresh Cymbopogon leaves, with a yield of 0.5% (w/w). Citral content was measured by gas chromatography/high-resolution mass spectrometry (GC-HRMS) and determined to be 63%. Antimicrobial activity was tested by the broth dilution method, showing strong activity against all tested bacteria and fungi. Citral was up to 100 times more active than the lemongrass essential oil. Similarly, both citral and essential oils inhibited bacterial communication and adhesion during P. aeruginosa and S. aureus biofilm formation; however, the biofilm prevention activity of citral was significantly higher. Both the essential oil and citral disrupted the maturated P. aeruginosa biofilm with the IC₅₀ 7.3 ± 0.4 and 0.1 ± 0.01 mL/L, respectively. Although it may seem that the citral is the main biologically active compound of lemongrass essential oil and the accompanying components have instead antagonistic effects, we determined that the lemongrass essential oil-sensitized methicillin-resistant S. aureus (MRSA) and doxorubicin-resistant ovarian carcinoma cells and that this activity was not caused by citral. A 1 mL/L dose of oil-sensitized MRSA to methicillin up to 9.6 times and a dose of 10 µL/L-sensitized ovarian carcinoma to doxorubicin up to 1.8 times. The mode of multidrug resistance modulation could be due to P-glycoprotein efflux pump inhibition. Therefore, the natural mixture of compounds present in the lemongrass essential oil provides beneficial effects and its direct use may be preferred to its use as a template for citral isolation.

Effect of Astragalus membranaceus in Ovalbumin-Induced Allergic Rhinitis Mouse Model

Background

Astragalus membranaceus (AM), a traditional Chinese medicine, has been used to treat allergic diseases, but the mechanism for treating allergic rhinitis (AR) remains unclear.

Objective

The purpose of this study was to look at the anti-inflammatory effect of AM on AR and the mechanism of anti-allergy.

Methods

The mouse model of AR was induced by ovalbumin. Allergic symptoms, number of eosinophils in nasal mucosa, and levels of inflammatory cells in nasal lavage fluid were analyzed. We explored the serum immunoglobulin E (IgE), interleukin-4 (IL-4), IL-5, IL-13, interferon-γ (IFN-γ), and IL-10. Besides, the relative mRNA of IL-4, IL-5, and IL-13 was also detected in nasal mucosa tissue. The proportion of CD4+ CD25+ Foxp3+ T cells in the spleen and nasal lymphoid tissue were analyzed. The mRNA levels of nuclear factor-kappa B p65 (NF-κB p65) and inhibitory kappa B alpha (IκBα), as well as NF-κB p65 DNA binding activity, were tested. We also measured the protein levels of NF-κB p65 and p-NF-κB p65 in nasal mucosa.

Results

AM could reduce the number of eosinophils in the nasal mucosa and decrease the levels of inflammatory cells in nasal lavage fluid. The serum IgE, IL-4, IL-5, and IL-13 were also decreased, while levels of IFN-γ and IL-10 were increased. The relative mRNA of IL-4, IL-5, and IL-13 was decreased by AM. AM increased the proportion of CD4+ CD25+ Foxp3+ T cells in the spleen and nasal lymphoid tissue. In addition, AM could reduce the activity of NF-kB by inhibiting the mRNA expression and DNA binding activity of NF-κB p65. However, AM had no significant effect on mRNA of IκBα. Above all, AM could reduce the p-NF-κB p65 protein expression of nasal mucosa.

Conclusions

AM could reduce the secretion of inflammatory cytokines by increasing the level of CD4+ CD25+ Foxp3+ T cells and inhibiting the activation of the NF-κB.

[Blomia tropicalis: A house dust mite in the tropics]

INTRODUCTION

Blomia tropicalis is a mite that belongs to the superfamily of Glycyphagidae. Initially described as a storage mite, it is now considered as a house dust mite of tropical and sub-tropical areas.

STATE OF THE ART

Sensitization to this mite is very common in South America and Southeast Asia. Epidemiological studies have also found sensitization to this mite in Africa and Central America. Blo t 5 is the major allergen of B. tropicalis. Co-sensitization to other house dust mites such as Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f) is very common. Cross-reactivity has been described but recombinant allergens revealed by molecular biology techniques do not explain this cross-reactivity. Sensitization to B. tropicalis seems to begin at the age of 36 months, the incidence increases until adulthood, and decreases from the age of 50. The involvement of B. tropicalis in allergic rhinitis and asthma is well described. It is also implicated in other allergic diseases. Few studies have assessed the therapeutic strategies available against this mite but immunotherapy is widely used.

PERSPECTIVES

Studies are needed to better understand the role of B. tropicalis in human diseases and to develop specific treatments.

EFFECTS OF COMBRETUM HEREROENSE AND CANTHIUMMUNDIANUM water EXTRACTS ON PRODUCTION AND EXPRESSION OF INTERLEUKIN-4

BACKGROUND

Combretum hereroense and Canthium mundianum are two plants commonly used by traditional healers in the Northern region of Limpopo, South Africa for the treatment of diarrhea and inflammation. In the present study, the effects of their water extracts on the production and expression of interleukin-4 by peripheral blood mononuclear cells (PBMC'S) from HIV positive and negative individuals was evaluated.

MATERIALS AND METHODS

Blood samples were collected from both HIV positive and HIV negative volunteers and were used for the purification of Peripheral blood mononuclear cells (PBMC). The PBMCs were cultured together with the water extracts after activation with phytohemagglutinin (PHA) for three days. Solid-phase sandwich ELISA (MABTECH) kit was used to detect IL-4 on un-stimulated and stimulated PBMC'S with phytohemaglutinin (PHA) and plant extracts, followed by the isolation of RNA using RNAesy Qiagen mini kit from the cells. Reverse transcriptase real time PCR was used to evaluate IL-4 gene expression by the cells.

RESULTS

Combretum hereroense showed higher production of IL-4 at three different concentrations and a significant expression of mRNA with 4-fold amplification increase at 300μg/ml and 2-fold amplification increase at 20μg/ml. Canthium mundianum also showed increased production of IL-4 at 300μg/ml, but inhibited its production at 20μg/ml. Both extracts showed no expression at 50μg/ml. The response of the PBMCs from HIV negative individuals was more pronounced than that of HIV positive individuals who mostly increased production of IL4 at smaller concentrations unlike their HIV negative counterparts. Although in vitro studies do not necessarily predict in vivo outcomes, the plant extracts modulated the immune system by enhancing the production and expression of IL-4 in both HIV- and HIV+ individuals at different concentrations.

CONCLUSIONS

For the first time we have shown that the immunomodulatory effect of medicinal plants may depend on the clinical status of the individual. The present study revealed that the effect of the water extracts from the two plants on IL-4 expression and production is dependent on the microbiological state of the individual and is dose dependent. Further studies are needed to identify the active components in the extracts and also characterize the patients further for a better understanding of the mechanisms of action of these extracts.