Cineole inhibits the biosynthesis of leukotrienes and prostaglandins to alleviate allergic rhinitis: Insights from metabolomics.

Allergic rhinitis (AR) is a common allergic disease characterized by nasal congestion, rhinorrhoea, and sneezing. Cineole, a monoterpenoid compound widely present in various volatile oils, has a wide range of pharmacological activities and is of interest in allergic airway diseases for its anti-inflammatory and anti-mucus production abilities. However, the protective effects of cineole in mice with allergic rhinitis and its mechanisms have not been well investigated. In this study, the protective effect of cineole against ovalbumin-induced (OVA-induced) allergic rhinitis and its molecular mechanism is investigated by metabolomic analysis based on ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). OVA combined with aluminum hydroxide adjuvant is used to sensitize and establish the allergic rhinitis (AR) mouse model. The mice are randomly divided into groups of control, AR, cineole (30 mg/kg), and budesonide (38.83 µg/kg). The pharmacodynamic results show that cineole significantly reduces the levels of Th2-type cytokines and OVA-specific IgE (OVA-sIgE) in AR mice, improves nasal mucosal tissue damage and alleviates nasal symptoms compared to the untreated AR group. Metabolomic results show that arachidonic acid (AA) metabolism and tryptophan (Trp) metabolism are reprogrammed on the basis of 27 significantly altered metabolites. Further studies show that cineole inhibits the biosynthesis of pro-inflammatory lipid mediators leukotrienes (LTs) and prostaglandins (PGs) in mice by inhibiting the activity of 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) in the arachidonic acid metabolic (AA metabolic) pathway. It also inhibits the production of Th2 cytokines and inflammatory cell infiltration, thereby alleviating symptoms such as nasal congestion and nasal leakage. These results reveal the action and molecular mechanism of cineole in alleviating AR and provide a theoretical basis for the clinical application of cineole in treating AR.

Anti-inflammatory mechanisms of eucalyptol rich Eucalyptus globulus essential oil alone and in combination with flurbiprofen.

Inflammation is the core contributor in the pathogenesis of various acute and chronic illness including appendicitis, bronchitis, arthritis, cancer and neurological diseases. NSAIDs, commonly used medications for inflammatory diseases, on prolonged use cause GI bleeding, ulcers and many more issues. Plant-based therapeutic agents including essential oils in combination with low-dose synthetic drugs have been shown to produce synergistic effects and reduce complications of synthetic drugs. This study was designed to evaluate the anti-inflammatory, analgesic and anti-pyretic properties of Eucalyptus globulus essential oil alone and in combination with flurbiprofen. GC-MS analysis was performed to screen chemical composition of oil. In vitro anti-inflammatory assay (membrane stabilization assay) and in vivo inflammatory acute (carrageenan and histamine-induced paw oedema) and chronic (cotton pellet-induced granuloma and Complete Freund's adjuvant-induced arthritis) models were performed to check anti-inflammatory properties. Acetic acid-induced algesia and yeast-induced pyrexia models were performed to check analgesic and anti-pyretic properties. qRT-PCR was performed to study the effect of treatments on the expression of inflammatory biomarkers. GC-MS analysis of E. globulus essential oil showed the presence of eucalyptol along with other active biomolecules. 500 + 10 mg/kg of oil-drug combination showed significantly (p < 0.05) better in vitro membrane stabilization effects as compared with groups treated with 500 mg/kg of E. globulus oil and 10 mg/kg of Flurbiprofen alone. 500 + 10 mg/kg of oil-drug combination showed significantly (p < 0.05) better anti-inflammatory, analgesic and antipyretic effects as compared to 500 mg/kg of E. globulus oil alone in all in vivo models. When comparison was done between 500 + 10 mg/kg of oil-drug combination-treated and 10 mg/kg Flurbiprofen-treated group, the former group showed significantly (p < 0.05) better anti-inflammatory and anti-pyretic effects, but there were non-significant differences in the analgesic model. Animal group treated with 10 mg/kg of Flurbiprofen showed significantly (p < 0.05) better anti-inflammatory and analgesic effects than group treated with 500 mg/kg of oil alone while, there were non-significant differences in anti-pyretic effects. qRT-PCR analysis showed significant (p < 0.05) down-regulation in the expression of IL-4 and TNF-α in serum samples of animals treated with 500 + 10 mg/kg of oil-drug combination as compared to the diseased control (arthritic) group. Overall, the current research demonstrates that Eucalyptus globulus essential oil in combination with flurbiprofen showed better anti-inflammatory, analgesic and anti-pyretic effects than oil and flurbiprofen alone which is attributed to the down-regulation of pro-inflammatory biomarkers (IL-4 and TNF-α). Further studies are required to formulate a stable dosage form and to check the anti-inflammatory efficacy in different inflammatory disorders.

Chemical composition and antinociceptive and anti-inflammatory activity of the essential oil of Hyptis crenata Pohl ex Benth. from the Brazilian Amazon.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaf tea of Hyptis crenata has its practical use in the Brazilian Amazon for treating gastrointestinal and liver disorders, sweating induction, and as an anti-inflammatory. AIM OF THE STUDY: Evaluation of the chemical composition, acute oral toxicity, and antinociceptive and anti-inflammatory activities of the H. crenata essential oil. MATERIAL AND METHODS: The essential oil was hydrodistilled and analyzed by GC and GC-MS. The antinociceptive action in mice was evaluated for the peripheral and central analgesic activity (abdominal contortion and hot plate tests), and the xylene-induced ear swelling was carried out for the nociception test. RESULTS: Oxygenated monoterpenes (53.0%) and monoterpene hydrocarbons (38.9%) predominated in the H. crenata oil, being 1,8-cineo1e (35.9%), α-pinene (20.8%), camphor (10.0%), and ß-pinene (7.3%) their primary constituents. The oral oil administration in the mice did not display changes in behavior patterns or animal mortality at 300 and 2000 mg/kg doses. The control group's biochemical parameters (ALP, AST, ALT) displayed a statistical difference from the treated group, unlike the renal parameters, which showed no variation between the groups. Oil reduced the abdominal contortions at doses of 100 (79.5%) and 300 mg/kg (44.4%), while with endodontacin, the dose was 5 mg/kg (75.2%). In addition, the oil could not decrease the paw licking/biting time at doses of 30, 100, and 300 mg/kg. However, it showed a significant antinociceptive effect on the second phase in the formalin test inhibiting licking time, with a reduction of 50.8% (30 mg/kg), 63.4% (100 mg/kg), 58.0% (300 mg/kg), and morphine (4 mg/kg, 78.3%). The oil administration produced significant inhibition of ear edema at all tested doses, with a better effect produced at 30 mg/kg (64.0% inhibition). CONCLUSION: The oil of Hyptis crenata, rich in 1,8-cineole, camphor, α-pinene, and ß-pinene, totaling 74%, displayed low acute toxicity and significant anti-inflammatory activity, with peripheral and no central antinociceptive action. Thus, these results show an actual perspective on using H. crenata oil in developing a phytotherapeutic product.

Topical Eucalyptol Ointment Accelerates Wound Healing and Exerts Antioxidant and Anti-Inflammatory Effects in Rats' Skin Burn Model.

Eucalyptol is a major volatile constituent among well-known wound healing medicinal plants. The current study evaluated eucalyptol wound healing activity in the rat's third-degree skin-burn model. The parameters, i.e., skin-healing, oxidative/antioxidant markers, pro-/anti-inflammatory markers, were evaluated after 1- and 2-weeks of treatment regimens with 5% eucalyptol ointment. Eucalyptol-loaded ointment base of 5% w/w strength was formulated using fusion method and physically evaluated for consistency, stability, and homogeneity. A 25-rats were divided randomly into intact, negative control (untreated), silver sulfadiazine (SS, positive control), 1-week, and 2-weeks treated eucalyptol groups. Using an aluminum cylinder (120℃, 10 second duration), 3rd-degree skin burns were created on the rat's dorsum. Skin biopsies were collected at the end of the experiment for biochemical and histological investigations. Compared to the negative group; time-dependent wound size reduction and decreased edema were observed in eucalyptol-treated animals. Histopathological examinations demonstrated epidermis integrity, decreased neutrophil, and increased capillaries number in the 2-weeks and SS groups, compared to the negative and 1-week treated eucalyptol groups. Compared to the untreated animals, the 1- and 2-weeks eucalyptol treated groups' demonstrated significantly increased antioxidant superoxide dismutase (SOD, p=0.002 and p=0.003, respectively) and reduced lipid peroxide (LP, p=0.005 and p=0.0006, respectively). However, a significant increment of catalase (CAT, p=0.0009) was found only in the 2-weeks of eucalyptol group at a level of 2.42 ± 0.39 ng/g compared to 1.14 ± 0.04 ng/g in the untreated animals. Also, significant reductions in the cytokines, IL-1b, IL-6, and TNF-α (p < 0.05); and increase in the pro-angiogenic marker, IL-10, were detected in the 2-weeks (p=0.001) and SS (p=0.002) treated animals compared to the negative and 1-week eucalyptol treated groups. The study concluded that eucalyptol induced significant duration-based wound healing properties attributed to its antioxidant and anti-inflammatory effects.

Modulation of cigarette smoke extract-induced human bronchial epithelial damage by eucalyptol and curcumin.

Smoking is one of the most important leading death cause worldwide. From a toxicological perspective, cigarette smoke serves hazards especially for the human being exposed to passive smoke. Over the last decades, the effects of natural compounds on smoking-mediated respiratory diseases such as COPD, asthma, and lung cancer have been under investigation, as well as the mechanistic aspects of disease progression. In the present study, the protective mechanism of eucalyptol (EUC), curcumin (CUR), and their combination on BEAS-2B cells were investigated in vitro to understand their impact on cell death, oxidative cell injury, and inflammatory response induced by 3R4F reference cigarette extract (CSE). According to the present findings, EUC, CUR, and their combination improved cell viability, attenuated CSE-induced apoptosis, and LC3B expression. Further, CSE-induced oxidative damage and inflammatory response in human bronchial epithelial cells were remarkably reduced by the combination treatment through modification of enzymatic antioxidant activity, GSH, MDA, and intracellular ROS levels as well as nitrite and IL-6 levels. In addition, nuclear translocation of Nrf2, a regulatory protein involved in the indirect antioxidant response, was remarkably up-regulated with the combination pre-treatment. In conclusion, EUC and CUR in combination might be a potential therapeutic against smoking-induced lung diseases through antioxidant and inflammatory pathways and results represent valuable background for future in vivo pulmonary toxicity studies.

Eucalyptal A inhibits glioma by rectifying oncogenic splicing of MYO1B mRNA via suppressing SRSF1 expression.

Glioma is the most common primary intracranial tumor, in which glioblastoma (GBM) is the most malignant and lethal. However, the current chemotherapy drugs are still unsatisfactory for GBM therapy. As the natural products mainly extracted from Eucalyptus species, phloroglucinol-terpene adducts have the potential to be anti-cancer lead compounds that attracted increasing attention. In order to discover the new lead compounds with the anti-GBM ability, we isolated Eucalyptal A with a phloroglucinol-terpene skeleton from the fruit of E. globulus and investigated its anti-GBM activity in vitro and in vivo. Functionally, we verified that Eucalyptal A could inhibit the proliferation, growth and invasiveness of GBM cells in vitro. Moreover, Eucalyptal A had the same anti-GBM activity in tumor-bearing mice as in vitro and prolonged the overall survival time by maintaining mice body weight. Further mechanism research revealed that Eucalyptal A downregulated SRSF1 expression and rectified SRSF1-guided abnormal alternative splicing of MYO1B mRNA, which led to anti-GBM activity through the PDK1/AKT/c-Myc and PAK/Cofilin axes. Taken together, we identified Eucalyptal A as an important anti-GBM lead compound, which represents a novel direction for glioma therapy.

The Effect of Eucalyptol on Nursing Home Residents.

Eucalyptol is one of the most popular volatile components. It is used in many essential oils for relieving sinus and lung congestion caused by a variety of conditions. This pilot study sought to analyze clinical evidence for the effect of the scent of eucalyptol on the cognitive function of elderly people. Seventy nursing-home residents with cognitive impairment were recruited. Three one-week experiments were performed: eucalyptol scent was diffused in bedrooms with a diffuser only at wake-up time in the first experiment, and at wake-up time and bedtime in the second and third experiments. Results showed that although an improvement was not seen when using Mini Mental State Examination (MMSE) and Cohen-Mansfild Agitation Inventory (CMAI) measures, Dementia Behavior Disturbance Scale (DBD) scores improved significantly, even though no subject reported perceiving the scent. The significant improvements of the behaviour were found not only among the subjects whose room had a diffuser but also among the subjects who were exposed to an unperceivable level of eucalyptol drifted in the living room.

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)-1ß and systemic inflammation (IL-6, IL-8). Infectious agents and environmental noxa have access via TNFα and IL-1ß 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-1ß, 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.

Is 1,8-Cineole-Rich Extract of Small Cardamom Seeds More Effective in Preventing Alzheimer's Disease than 1,8-Cineole Alone?

The present study demonstrates the efficacies of synthetic 1,8-cineole and an 1,8-cineole-rich supercritical carbon dioxide (SC-CO2) extract of small cardamom seeds in preventing oligomerization of amyloid beta peptide (Aß42) and inhibiting iron-dependent oxyradical production in vitro. The oligomerization of Aß42 was monitored by thioflavin T assay and MALDI-TOF analysis of the oligomers. The iron-dependent production of oxygen free radicals was detected by fluorometric benzoate hydroxylation assay. We observed that both pure 1,8-cineole and 1,8-cineole-rich extract of small cardamom seeds at concentrations of 50 µM and 100 µM prevented the production of reactive hydroxyl radicals from a mixture of Fe2+ and ascorbate. However, the 1,8-cineole-rich extract of small cardamom seeds prevented in vitro Aß42 oligomerization more effectively vis-à-vis the synthetic (99% pure) 1,8-cineole. Additional study on SHSY5Y cells indicated that both pure 1,8-cineole and 1,8-cineole-rich SC-CO2 extract of small cardamom seeds prevented iron-dependent cell death. Since oxidative damage, Aß42 aggregation and loss of cell viability (iron-induced) are characteristics of onset of Alzheimer's disease pathology, our results suggest a putative therapeutic role of 1,8-cineole-rich extract of small cardamom seeds over pure 1,8-cineole in preventing this neurodegenerative disease.

Acaricidal activity of plant-derived essential oil components against Psoroptes ovis in vitro and in vivo.

BACKGROUND: Treatment of Psoroptes ovis in cattle is limited to topical acaricides or systemic treatment with macrocyclic lactones. Treatment failure of macrocyclic lactones has been reported. The aim of this study was to evaluate a potential alternative treatment against P. ovis. METHODS: The acaricidal activity against P. ovis of four plant-derived essential oil components, i.e. geraniol, eugenol, 1,8-cineol and carvacrol, was assessed in vitro and in vivo. In vitro contact, fumigation and residual bioassays were performed. In addition, 12 Belgium Blue cattle were artificially infested and treated topically once a week for three successive weeks with carvacrol in Tween-80 (treatment group) or with Tween-80 alone (control). The efficacy of carvacrol was determined by the reduction in lesion size and mite counts. Six additional animals were topically treated with carvacrol to assess local adverse reactions. RESULTS: Three components showed a concentration-dependent acaricidal activity in a contact assay, with LC50 of 0.56, 0.38 and 0.26% at 24 h for geraniol, eugenol, and carvacrol, respectively. However, 1,8-cineol showed no activity at any of the tested concentrations in a contact bioassay. In a fumigation bioassay, carvacrol killed all mites within 50 min after treatment, whereas geraniol, eugenol and 1,8-cineol needed 90 to 150 min. Following a 72 h incubation period in a residual bioassay, carvacrol killed all mites after 4 h of exposure to LC90, while geraniol and eugenol killed all mites only after 8 h exposure. Based on these results, carvacrol was further assessed in vivo. Mite counts in the treatment group were reduced by 98.5 ± 2.4% at 6 weeks post-treatment, while in the control group the mite population had increased. Topical application of carvacrol only caused mild and transient erythema 20 min after treatment. No other side effects were observed. CONCLUSIONS: Considering the strong acaricidal activity of carvacrol in vitro and in vivo and the mild and transient local side effects, carvacrol shows potential as an acaricidal agent in the treatment of P. ovis in cattle.