Regulation of monocyte redox balance by 1,8-cineole (eucalyptol) controls oxidative stress and pro-inflammatory responses in vitro: A new option to increase the antioxidant effects of combined respiratory therapy with budesonide and formoterol?

Identification of CD8 T-cell dysfunction associated with symptoms in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID and treatment with a nebulized antioxidant/anti-pathogen agent in a retrospective case series

Background

Patients with post-acute sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection (PASC, i.e., Long COVID) have a symptom complex highly analogous to many features of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), suggesting they may share some aspects of pathogenesis in these similar disorders. ME/CFS is a complex disease affecting numerous organ systems and biological processes and is often preceded by an infection-like episode. It is postulated that the chronic manifestations of illness may result from an altered host response to infection or inability to resolve inflammation, as is being reported in Long COVID. The immunopathogenesis of both disorders is still poorly understood. Here, we show data that suggest Long COVID and ME/CFS may be due to an aberrant response to an immunological trigger-like infection, resulting in a dysregulated immune system with CD8 T-cell dysfunction reminiscent of some aspects of T-cell clonal exhaustion, a phenomenon associated with oxidative stress. As there is an urgent need for diagnostic tools and treatment strategies for these two related disabling disorders, here, in a retrospective case series, we have also identified a potential nebulized antioxidant/anti-pathogen treatment that has evidence of a good safety profile. This nebulized agent is comprised of five ingredients previously reported individually to relieve oxidative stress, attenuate NF-κB signaling, and/or to act directly to inhibit pathogens, including viruses. Administration of this treatment by nebulizer results in rapid access of small doses of well-studied antioxidants and agents with anti-pathogen potential to the lungs; components of this nebulized agent are also likely to be distributed systemically, with potential to enter the central nervous system.

Methods

and Findings: We conducted an analysis of CD8 T-cell function and severity of symptoms by self-report questionnaires in ME/CFS, Long COVID and healthy controls. We developed a CD8 T-cell functional assay, assessing CD8 T-cell dysfunction by intracellular cytokine staining (ICS) in a group of ME/CFS (n = 12) and Long COVID patients (n = 8), comparing to healthy controls (HC) with similar age and sex (n = 10). Magnet-enriched fresh CD8 T-cells in both patient groups had a significantly diminished capacity to produce both cytokines, IFNγ or TNFα, after PMA stimulation when compared to HC. The symptom severity questionnaire showed similar symptom profiles for the two disorders. Fortuitously, through a retrospective case series, we were able to examine the ICS and questionnaire data of 4 ME/CFS and 4 Long COVID patients in conjunction with their treatment (3-15 months). In parallel with the treatment pursued electively by participants in this retrospective case series, there was an increase in CD8 T-cell IFNγ and TNFα production and a decrease in overall self-reported symptom severity score by 54%. No serious treatment-associated side effects or laboratory anomalies were noted in these patients.

Conclusions

Here, in this small study, we present two observations that appear potentially fundamental to the pathogenesis and treatment of Long COVID and ME/CFS. The first is that both disorders appear to be characterized by dysfunctional CD8 T-cells with severe deficiencies in their abilities to produce IFNγ and TNFα. The second is that in a small retrospective Long COVID and ME/CFS case series, this immune dysfunction and patient health improved in parallel with treatment with an immunomodulatory, antioxidant pharmacological treatment with anticipated anti-pathogen activity. This work provides evidence of the potential utility of a biomarker, CD8 T-cell dysfunction, and suggests the potential for benefit from a new nebulized antioxidant/anti-pathogen treatment. These immune biomarker data may help build capacity for improved diagnosis and tracking of treatment outcomes during clinical trials for both Long COVID and ME/CFS while providing clues to new treatment avenues that suggest potential efficacy for both conditions.

The impact of cineole treatment timing on common cold duration and symptoms: Non-randomized exploratory clinical trial

INTRODUCTION

Common cold (CC) symptoms arise from an inflammatory response treatable with cineole and generally peak within two days, which complicates research implementation. We therefore explored the benefits of early cineole administration with enrolment of participants prior to CC onset.

METHODS

Out of 522 adults enrolled in our phase IV, open-label, non-randomized, exploratory clinical trial (EudraCT No. 2020-000860-51), 329 developed a CC and used 200 mg cineole (Soledum®, CNL-1976) t.i.d. for max. 15 (± 2) days. Primary endpoint was burden of disease based on the Wisconsin Upper Respiratory Symptom Survey (WURSS-11).

RESULTS

Comparing three strata based on time to treatment (≤ 12 h, > 12 to ≤ 24 h and > 24 h), earliest treatment resulted in lowest AUC-WURSS (Spearman correlation coefficient of 0.36) and reduced the overall burden of disease by 38% (p < 0.0001). Earlier and lower symptom severity peak resulted, with shorter time to remission (average 8.9 vs. 10.7 days with latest treatment initiation, p < 0.05), and higher and faster recovering quality of life (p < 0.05). Tolerability was mostly rated as "very good", with adverse events of suspected causal relationship reported in 4.3% of participants.

CONCLUSIONS

Early intervention shows clinical benefits relevant for the effective treatment of CC with cineole.

The Fate of 1,8-cineole as a Chemical Penetrant: A Review

The stratum corneum continues to pose the biggest obstacle to transdermal drug delivery. Chemical penetrant, the first generation of transdermal drug delivery system, offers a lot of potential. In order to fully examine the permeation mechanism of 1,8-cineole, a natural monoterpene, this review summarizes the effects of permeation-enhancing medications on drugs that are lipophilic and hydrophilic as well as the toxicity of this substance on the skin and other tissues. For lower lipophilic drugs, 1,8-cineole appears to have a stronger osmotic-enhancing impact. An efficient and secure tactic would be to combine enhancers and dose forms. 1,8-cineole is anticipated to be further developed in the transdermal drug delivery system and even become a candidate drug for brain transport due to its permeability and low toxicity.

Effect of adding lavender oil to laying quail diets on performance, egg quality, oxidative status, and fatty acid profile

This study aims to investigate the effects of lavender essential oil on performance, egg quality parameters in quails, malondialdehyde (MDA) in fresh and stored (28 days at ₊4°C) eggs, and individual and total fatty acids. To this end, 100 female quails (Coturnix coturnix Japonica) which were 5 weeks old with an average weight of 224 g were used. The study lasted 45 days, including 10 days of introduction and 35 days of study. Quails were fed ad libitum with four different treatments. Four groups were formed as control groups (0g lavender essential oil/kg feed), Lav125 (125mg lavender essential oil/kg feed), Lav250 (250mg lavender essential oil/kg feed), and Lav500 (500mg lavender essential oil/kg feed). There were five subgroups under each group and five quails in each subgroup. Feed consumption and egg weight parameters increased in Lav500 group compared to the control group (p<0.05). The highest egg yield compared to the control group was determined in Lav500 group (p>0.05), and the highest egg mass compared to the control group was determined in Lav125 group. The highest feed conversion ratio compared to the control group was in Lav250 group (p>0.05). In addition, egg white height and Haugh Unit (HU) compared to the control group were the highest in Lav500 group (p<0.05). The MDA concentration decreased in Lav125 and Lav250 group in fresh and in Lav500 group in stored eggs (at +4C for 28 days) compared to the control group (p<0.05). Omega 3 fatty acids in fresh and stored eggs were higher in lavender groups compared to the control group (p<0.05). However, the concentration of omega 9 (oleic acid) fatty acid decreased in the lavender groups compared to the control group (p<0.05). As a result, it was found that adding lavender essential oil to the diet leads to an increase in body weight, egg yield, egg mass, egg weight, egg white height, HU, omega 3 fatty acids, and a decrease in MDA concentration.

Essential Oil Composition, Antioxidant Activity and Leaf Micromorphology of Five Tunisian Eucalyptus Species

Eucalyptus species have been widely employed in the projects of reforestation in Tunisia. Although their ecological functions are controversial, these plants are indeed important to counteract soil erosion, and represent a fast-growing source of fuelwood and charcoal wood. In the present study, we considered five Eucalyptus species, namely Eucalyptus alba, E. eugenioides, E. fasciculosa, E. robusta, and E. stoatei cultivated in the Tunisian Arboreta. The aim was to carry out the micromorphological and anatomical characterization of the leaves, the extraction and phytochemical profile of the essential oils (EOs), and the evaluation of their biological properties. Four of the EOs showed the prevalence of eucalyptol (1,8-cineole) varying from 64.4 to 95.9%, whereas a-pinene predominated in E. alba EO (54.1%). These EOs showed in vitro antioxidant activity, and reduced the oxidative cellular stress as shown by their activity on reactive oxygen species (ROS) production, and modulation of the expression of antioxidant enzymes, such as glutamate-cysteine ligase (GCL) and heme oxygenase-1 (Hmox-1). Moreover, the EOs inhibited the production of nitric oxide (NO), showing anti-inflammatory activity. The data collected suggest that these EOs may be considered a promising therapeutic strategy for inflammation-based diseases and may represent an additional value for the economy of Tunisia.

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.

Exogenous Paclobutrazol Reinforces the Antioxidant and Antimicrobial Properties of Lavender (Lavandula officinalis L.) Oil through Modulating Its Composition of Oxygenated Terpenes

Plant growth regulators can affect the primary and secondary metabolites of various plant species. However, the effect of paclobutrazol (PBZ) on the composition of lavender oil, especially related to the terpenoid pathway, is still unclear in literatures. In this study, the effect of PBZ as a foliar spray (0.200, 400 and 600 ppm) on the vegetative growth, phytochemical content, and both antioxidant and antimicrobial properties of lavender oil were investigated. The results indicated that all examined PBZ treatments led to a significant (p ≤ 0.05) decrease in growth parameters compared to the untreated plants. Meanwhile, the yield of essential oil was significantly decreased by the treatment of PBZ at 200 ppm compared to the control. In contrast, applied-PBZ significantly enhanced the chlorophyll content and displayed a marked change in the composition of the essential oil. This change included an obvious and significant increase in 3-carene, eucalyptol, γ-terpinene, α-pinocarvone, caryophyllene, β-vetivenene, β-santalol, ledol, geranyl isovalerate, farnesol, caryophyllene oxide, and phytol percentage. Generally, the highest significant values were achieved by the treatment of 400 ppm compared to the other treatments. Furthermore, this treatment showed the highest free radical scavenging activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) by 13% over the control. Additionally, to determine the antimicrobial activities of the extracted oil, each treatment was examined against two strains of Gram positive bacteria (S. aureus and B. cereus), two strains of Gram negative bacteria (S. enteritidis and E. coli), and two fungal species (C. albicans and A. niger) represent the yeast modal and filamentous fungus, respectively. The findings demonstrated that all examined species were more sensitive to the oil that was extracted from lavender plants, treated with 400 ppm PBZ, compared to the other concentrations.

Currently Applied Extraction Processes for Secondary Metabolites from Lippia turbinata and Turnera diffusa and Future Perspectives

The poleo (Lippia turbinata Griseb.) and damiana (Turnera diffusa Wild) are two of the most valued species in the Mexican semidesert due to their medicinal uses. The conventional essential oil extraction process is hydrodistillation, and for the extraction of antioxidants, the use of organic solvents. However, these techniques are time-consuming and degrade thermolabile molecules, and the efficiency of the process is dependent on the affinity of the solvent for bioactive compounds. Likewise, they generate solvent residues such as methanol, hexane, petroleum ether, toluene, chloroform, etc. Therefore, in recent years, ecofriendly alternatives such as ohmic heating, microwaves, ultrasound, and supercritical fluids have been studied. These methodologies allow reducing the environmental impact and processing times, in addition to increasing yields at a lower cost. Currently, there is no up-to-date information that provides a description of the ecofriendly trends for the recovery process of essential oils and antioxidants from Lippia turbinata and Turnera diffusa. This review includes relevant information on the most recent advancements in these processes, including conditions and methodological foundation.

Anti-inflammatory and analgesic properties of Moroccan medicinal plants: Phytochemistry, in vitro and in vivo investigations, mechanism insights, clinical evidences and perspectives

Moroccan medicinal plants exhibit several pharmacological properties such as antimicrobial, anticancer, antidiabetic, analgesic, and anti-inflammatory effects, which are related to the presence of numerous bioactive compounds, including phenolic acids, flavonoids, and terpenoids. In the present review, we systematically evaluate previously published reports on the anti-inflammatory and analgesic effects of Moroccan medicinal plants. The in vitro investigations revealed that Moroccan medicinal plants inhibit several enzymes related to inflammatory processes, whereas in vivo studies noted significant anti-inflammatory and analgesic effects as demonstrated using different experimental models. Various bioactive compounds exhibiting in vitro and in vivo anti-inflammatory and analgesic effects, with diverse mechanisms of action, have been identified. Some plants and their bioactive compounds reveal specific secondary metabolites that possess important anti-inflammatory effects in clinical investigations. Our review proposes the potential applications of Moroccan medicinal plants as sources of anti-inflammatory and analgesic agents.

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Anti-inflammatory and analgesic effects of Moroccan medicinal plants were highlighted.

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Chemical nature of Moroccan medicinal plants with anti-inflammatory and analgesic effects was reported.

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Insights into anti-inflammatory mechanisms of bioactive compounds were highlighted.

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Toxicological investigations of Moroccan medicinal plants were reviewed.

Prevalence of Diterpenes in Essential Oil of Euphorbia mauritanica L.: Detailed Chemical Profile, Antioxidant, Cytotoxic and Phytotoxic Activities

Plants belonging to Euphorbia L. genus are considered very interesting from a medicinal point of view due to their diverse metabolites and bioactivities. The essential oil (EO) of Euphorbia mauritanica L. is not studied up to date. Therefore, the present study aimed to explore the chemical profile of this EO and evaluate its antioxidant, cytotoxic, and allelopathic potentialities. The EO was extracted from the whole plant via hydrodistillation and then, analyzed by gas chromatography/mass spectrometry (GC/MS). The correlation of E. mauritanica with the other Euphorbia plants was established using chemometric analysis. The antioxidant activity was determined based on scavenging of the free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The anti-proliferation of the EO on the Hep G2 and MCF-7 cells was evaluated. Finally the allelopathic activity of the EO was assessed against the two noxious weeds, Dactyloctenium aegyptium and Urospermum picroides. Forty-one compounds were identified using GC/MS analysis, with an abundance of terpenoids (91.54 %) that were categorized into mono- (30.75 %), sesqui- (15.23 %), and diterpenes (45.56 %). Interestingly, the results revealed the preponderance of diterpenoid constituents although they are rarely found in the EOs of the plant kingdom. The major compounds were (3E)-cembrene A (18.66 %), verticiol (17.05 %), limonene (7.91 %), eucalyptol (7.26 %), α-pinene (5.61 %), neo-cembrene A (3.52 %), kaur-16-ene (3.24 %), and cembrene (3.09 %). The EO showed moderate antioxidant activity where it attained IC₅₀ values of 83.34 and 64.21 μg mL^-1 for DPPH and ABTS compared to 23.01 and 19.23 μg mL^-1 for ascorbic acid as standard, respectively. The EO exhibited very weak cytotoxic effect on MCF-7 and Hep G2 cells. The EO showed significant allelopathic activities against the weeds D. aegyptium and U. picroides in a concentration-dependent manner. EO was found more effective against U. picroides than D. aegyptium with IC₅₀ values of 0.79, 0.45, and 0.67 mg mL^-1 and 1.17, 0.55, and 1.08 mg mL^-1 for germination, root, and shoot growth, respectively. Due to the high content of diterpenes in E. mauritanica, further study is recommended for more characterization of pure forms of the identified diterpenes as well as evaluating their bioactivity either solely or synergistically.

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.

Interspecific variability of 1,8-cineole content, phenolics and bioactivity among nine Eucalyptus taxa growing under the sub-humid bioclimate stage

Background Eucalyptus essential oils and extracts are used since the ancient times in alternative medicine. The 1,8-cineole is the most significant constituent of Eucalyptus essential oil, while phenolic contents define the value of eucalyptus extracts. Based on the last considerations, interspecific variability of 1,8-cineole content, phenolics and antioxidant potentials among nine Eucalyptus taxa growing under the sub-humid bioclimate stage of Tunisia was investigated. Methods Essential oil profiling was assessed based on gas chromatography-mass spectrometry analysis. Total phenolic and flavonoid contents were assessed using Folin-Ciocalteau and aluminium chloride colorimetric methods, respectively. The antioxidant ability of Eucalyptus volatile metabolites and extracts was achieved based on two test systems namely DPPH and FRAP assays. Results Qualitative and quantitative variations in the composition of essential oils according to the studied taxon were shown. The total phenolic and flavonoid contents varied also significantly among the investigated samples. Based on the obtained results, the species Eucalyptus sideroxylon exhibits the highest 1,8-cineole content (76.24 ± 0.86), total phenolics and flavonoids contents (38.5 ± 1.4 mg GAE /g DW and 18.6 ± 0.3 mg RE /g DW, respectively). Moreover this species highlighted the highest free radical-scavenging ability and ferric reducing power for both essential oil and methanolic extracts. Chemometric multivariate analysis showed the classification of the nine studied taxa to three clusters. Conclusions The pattern of 1,8-cineole concentration, phenolic and flavonoid contents for the studied nine Eucalyptus species and hybrid showed E. sideroxylon species as the potential candidate for further improvement strategies regarding the production of eucalyptus essential oils and phenolics with high quality for pharmaceutical industry.