Anti-inflammatory activity of 1.8-cineol (eucalyptol) in bronchial asthma: a double-blind placebo-controlled trial

1, 8-Cineol Protect Against Influenza-Virus-Induced Pneumonia in Mice

1,8-Cineol is a major monoterpene principally from eucalyptus essential oils and has been shown to exert anti-inflammatory, antiviral, and inhibitory of nuclear factor (NF)-kB effect. In the present study, we evaluated the effect of 1,8-cineol on mice infected with influenza A virus. We found that 1,8-cineol protects against influenza viral infection in mice. Moreover, 1,8-cineol efficiently decreased the level of IL-4, IL-5, IL-10, and MCP-1 in nasal lavage fluids and the level of IL-1β, IL-6, TNF-α, and IFN-γ in lung tissues of mice infected with influenza virus. The results also showed that 1,8-cineol reduced the expression of NF-kB p65, intercellular adhesion molecule (ICAM)-1, and vascular cell adhesion molecule (VCAM)-1 in lung tissues. Thus, 1,8-cineol appears to be able to augment protection against IFV infection in mice via attenuation of pulmonary inflammatory responses.

Chitin-Induced Airway Epithelial Cell Innate Immune Responses Are Inhibited by Carvacrol/Thymol

Chitin is produced in large amounts by fungi, insects, and other organisms and has been implicated in the pathogenesis of asthma. Airway epithelial cells are in direct contact with environmental particles and serve as the first line of defense against inhaled allergens and pathogens. The potential contributions of airway epithelial cells to chitin-induced asthma remain poorly understood. We hypothesized that chitin directly stimulates airway epithelial cells to release cytokines that promote type 2 immune responses and to induce expression of molecules which are important in innate immune responses. We found that chitin exposure rapidly induced the expression of three key type 2-promoting cytokines, IL-25, IL-33 and TSLP, in BEAS-2B transformed human bronchial epithelial cells and in A549 and H292 lung carcinoma cells. Chitin also induced the expression of the key pattern recognition receptors TLR2 and TLR4. Chitin induced the expression of miR-155, miR-146a and miR-21, each of which is known to up-regulate the expression of pro-inflammatory cytokines. Also the expression of SOCS1 and SHIP1 which are known targets of miR-155 was repressed by chitin treatment. The monoterpene phenol carvacrol (Car) and its isomer thymol (Thy) are found in herbal essential oils and have been shown to inhibit allergic inflammation in asthma models. We found that Car/Thy inhibited the effects of chitin on type 2-promoting cytokine release and on the expression of TLRs, SOCS1, SHIP1, and miRNAs. Car/Thy could also efficiently reduce the protein levels of TLR4, inhibit the increase in TLR2 protein levels in chitin plus Car/Thy-treated cells and increase the protein levels of SHIP1 and SOCS1, which are negative regulators of TLR-mediated inflammatory responses. We conclude that direct effects of chitin on airway epithelial cells are likely to contribute to allergic airway diseases like asthma, and that Car/Thy directly inhibits epithelial cell pro-inflammatory responses to chitin.

Anti-neuroinflammatory and neuroprotective effects of the Lindera neesiana fruit in vitro

BACKGROUND

Lindera neesiana Kurz (Lauraceae), popularly known as Siltimur in Nepal, is an aromatic and spicy plant with edible fruits. It is a traditional herbal medicine widely used for the treatment of diarrhea, tooth pain, headache, and gastric disorders and is also used as a stimulant.

PURPOSE

The aim of the present study was to examine in vitro cytoprotective, anti-neuroinflammatory and neuroprotective potential of an aqueous extract of L. neesiana (LNE) fruit using different central nervous system (CNS) cell lines.

METHODS

In order to study the neuroprotective potential of LNE, we used three different types of CNS cell lines: murine microglia (BV2), rat glioma (C6), and mouse neuroblastoma (N2a). Cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reagent, and prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and nerve growth factor (NGF) release in the culture media was determined using enzyme linked immunosorbent assay (ELISA) kits. Western blot analysis was performed to determine the protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX2), mitogen activated protein kinase (MAPK) family proteins, Bax, B cell lymphoma (BCL)-2, and cleaved caspase 3. Neurite outgrowth was determined using the IncuCyte imaging system.

RESULTS

LNE treatment not only reduced nitric oxide (NO) production in a dose-dependent manner, but also significantly reduced proinflammatory cytokines, iNOS and COX-2 production by lipopolysaccharide (LPS) stimulated BV-2 cells. LNE increased the expression of phosphorylated (p)-extracellular signal-regulated kinase (ERK), whereas p-p38 and p- janus kinase (JNK) expression was significantly decreased in activated microglia. Furthermore, LNE increased cell viability of N2a cells, which was accompanied by decreased caspase-3 expression and the ratio of Bax/Bcl2 protein expression as well as increased NGF and neurite outgrowth, suggesting its neuroprotective potential against LPS-induced effects. Additionally, LNE substantially increased nuclear factor erythroid 2-related factor 2 (Nrf2) secretion in N2a cells and inhibited lipid dehydrogenase (LDH) release in H2O2-stimulated BV2 cells demonstrating the strong anti-inflammatory and antioxidant effects of LNE in CNS cell lines.

CONCLUSION

Here we found that water the soluble extract of LNE has promising anti-neuroinflammation and anti-apoptotic properties and identify LNE as a potential natural candidate for neuroprotection.

1,8-Cineole potentiates IRF3-mediated antiviral response in human stem cells and in an ex vivo model of rhinosinusitis

The common cold is one of the most frequent human inflammatory diseases caused by viruses and can facilitate bacterial superinfections, resulting in sinusitis or pneumonia. The active ingredient of the drug Soledum, 1,8-cineole, is commonly applied for treating inflammatory diseases of the respiratory tract. However, the potential for 1,8-cineole to treat primary viral infections of the respiratory tract remains unclear. In the present study, we demonstrate for the first time that 1,8-cineole potentiates poly(I:C)-induced activity of the antiviral transcription factor interferon regulatory factor 3 (IRF3), while simultaneously reducing proinflammatory nuclear factor (NF)-κB activity in human cell lines, inferior turbinate stem cells (ITSCs) and in ex vivo cultivated human nasal mucosa. Co-treatment of cell lines with poly(I:C) and 1,8-cineole resulted in significantly increased IRF3 reporter gene activity compared with poly(I:C) alone, whereas NF-κB activity was reduced. Accordingly, 1,8-cineole- and poly(I:C) treatment led to increased nuclear translocation of IRF3 in ITSCs and a human ex vivo model of rhinosinusitis compared with the poly(I:C) treatment approach. Nuclear translocation of IRF3 was significantly increased in ITSCs and slice cultures treated with lipopolysaccharide (LPS) and 1,8-cineole compared with the LPS-treated cells mimicking bacterial infection. Our findings strongly suggest that 1,8-cineole potentiates the antiviral activity of IRF3 in addition to its inhibitory effect on proinflammatory NF-κB signalling, and may thus broaden its field of application.

Effect of Inhalation of Aromatherapy Oil on Patients with Perennial Allergic Rhinitis: A Randomized Controlled Trial

This study aimed to investigate the effects of aromatherapy oil inhalation on symptoms, quality of life, sleep quality, and fatigue level among adults with perennial allergic rhinitis (PAR). Fifty-four men and women aged between 20 and 60 were randomized to inhale aromatherapy oil containing essential oil from sandalwood, geranium, and Ravensara or almond oil (the placebo) for 5 minutes twice daily for 7 days. PAR symptoms determined by Total Nasal Symptom Score (TNSS), the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), sleep quality by Verran Synder-Halpern (VSH) scale, and fatigue level by Chalder Fatigue Scale (CFS) were assessed before and after intervention period. Compared with the placebo, the experimental group showed significant improvement in TNSS, especially in nasal obstruction. The aromatherapy group also showed significantly higher improvements in total score of RQLQ and CFS. These findings indicate that inhalation of certain aromatherapy oil helps relieve PAR symptoms, improve rhinitis-specific quality of life, and reduce fatigue in patients with PAR. In conclusion, inhalation of aromatherapy essential oil may have potential as an effective intervention to alleviate PAR.

Volatile oils: Potential agents for the treatment of respiratory infections

Due to presence of secondary bioactive metabolites, natural compounds are considered a major source of new active molecules that can be developed as new drugs. Infectious diseases, and mainly the common respiratory infections, are major challenges to the current chemotherapy systems and, therefore, there is a requirement to find new compounds with therapeutic potential. The volatile natural compounds and essential oils are the main treasure agents in the natural compounds with antibiotic potential. The present chapter reviews natural traditional remedies used in the treatment of respiratory infections with the emphasis on antibacterial, antiviral, and antiinflammation activities of the volatile natural compounds (essential oils, etc.), and provides a brief view in some of structural activity relationships between antibacterial potencies and chemical structures of the essential oil’s constituents.

Eucalyptol and Its Role in Chronic Diseases

Patients with chronic diseases such as cardiovascular diseases, chronic respiratory diseases, and neurological diseases have been shown to benefit from treatments such as aromatherapy in addition to medication. Most chronic diseases are caused by chronic inflammation and oxidative stress as well as harmful factors. Eucalyptol (1,8-cineole), a terpenoid oxide isolated from Eucalyptus species, is a promising compound for treating such conditions as it has been shown to have anti-inflammatory and antioxidant effects in various diseases, including respiratory disease, pancreatitis, colon damage, and cardiovascular and neurodegenerative diseases. Eucalyptol suppresses lipopolysaccharide (LPS)-induced proinflammatory cytokine production through the action of NF-κB, TNF-α, IL-1β, and IL-6 and the extracellular signal-regulated kinase (ERK) pathway, and reduces oxidative stress through the regulation of signaling pathways and radical scavenging. The effects of eucalyptol have been studied in several cell and animal models as well as in patients with chronic diseases. Furthermore, eucalyptol can pass the blood-brain barrier and hence can be used as a carrier to deliver drugs to the brain via a microemulsion system. In summary, the various biological activities of eucalyptol such as its anti-inflammatory and antioxidant properties, as well as its physicochemical characteristics, make this compound a potentially important drug for the treatment of chronic diseases.

Evaluation of chemical composition and antiedematogenic activity of the essential oil of Hyptis martiusii Benth

Evaluations of the therapeutic potential of medicinal plants and their components have been the subject of many studies. Furthermore, the biological activities of various plant species have been reported in various pieces of literature. Hyptis martiusii Benth (Lamiaceae), popularly known as "mad balm" is commonly found in the North, Southeast, and Northeast of Brazil. Its leaves are used ethnobiologically as antiulcerogenic, antimicrobial, antitumor and as insecticide. This study aimed to analyze the chemical composition of the essential oil of H. martiusii Benth (OEHM) by GC/MS as well as its possible topical activity as an antiedematogenic. This is verified by the models of ear edema induced by single (acute edema) and multiple (chronic edema) applications of croton oil topically, and systemically verified through the model of paw edema induced by carrageenan 1%. Doses of 50, 75 and 100 mg/kg OEHM were used in all tests. Chemical analysis of the oil revealed the 1,8-cineole (34.58%) and δ-carene (21:58%) as major components present in the essential oil. On the model of ear edema, acute and chronic OEHM in all the tested doses showed no significant antiedematogenic activity (p < 0.05). The systemic model of paw edema induced by carrageenin showed that a dose of 100 mg/kg effectively reduced swelling by 55.37% in the second hour evaluation when compared to the saline group. The anti-inflammatory systemic effect can give greater bioavailability of the components present in the essential oil and your interference in cytokines and leukotriene, thromboxane and prostaglandin biosynthesis. It is therefore concluded that OEHM presents systemic antiedematogenic activity but not topical activity at these doses.

Essential oils in the treatment of respiratory tract diseases highlighting their role in bacterial infections and their anti-inflammatory action: a review

The appearance of multidrug resistant bacteria and growing antibiotic resistance is leading to a continuous need for discovering new drugs and alternative treatments against infections. The investigation of the antibacterial effect of essential oils (EOs), which are commonly used nowadays in cosmetics, health care, traditional medicine and food industry, could be one of the promising solutions for this worldwide problem. EOs have a complex mode of action due to their multiple composition. Respiratory tract diseases (RTDs) associated with bacterial infection and inflammation affect a large number of people from every age group worldwide. Because of volatility, EOs can easily reach the upper and lower parts of the respiratory tract via inhalation. Moreover, due to their antimicrobial and anti-inflammatory potency, they offer an effective treatment in respiratory tract infections (RTIs). The purpose of this review is to describe the most frequently developing infections of the upper and lower respiratory tract and to show methods used for the determination of the antibacterial activity of EOs by gaseous contact. The mode of action of EOs on bacterial cells and their anti-inflammatory action are also discussed. Results coming from recently performed in vivo animal studies as well as human trials are also reported. Patents deal with the role of EOs and their volatile constituents in the treatment of RTIs are also introduced. On the whole, this review aimed at showing EOs as potential antimicrobials and as anti-inflammatory agents to alleviate symptoms and signs of RTDs including RTIs. Copyright © 2015 John Wiley & Sons, Ltd.

Chemical Composition and In Vitro Cytotoxicity of Essential Oils from Leaves and Flowers of Callistemon citrinus from Western Himalayas

Background

Plant-based traditional system of medicine continues to play an important role in healthcare. In order to find new potent source of bioactive molecules, we studied the cytotoxic activity of the essential oils from the flowers and leaves of Callistemon citrinus. This is the first report on anticancer potential of essential oils of C. citrinus.

Methods

Cytotoxicity of essential oil was evaluated using sulfo-rhodamine B (SRB) assay against human lung carcinoma (A549), rat glioma (C-6), human colon cancer (Colo-205) and human cervical cancer (SiHa) cells. Apoptosis induction was evaluated by caspase-3/7 activity which was further confirmed by western blotting. Percentage cell apoptosis was determined by Annexin V based dead cell assay followed by DNA content as cell cycle analysis against A549 and C-6 cells. While 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to check the toxicity against normal human peripheral blood mononuclear cells (PBMCs), the immunomodulatory activity on mouse splenocytes was evaluated using SRB assay.

Results

The GC and GC-MS analysis of these essential oils revealed high content of α-pinene (32.3%), limonene (13.1%) and α-terpineol (14.6%) in leaf sample, whereas the flower oil was dominated by 1,8-cineole (36.6%) followed by α-pinene (29.7%). The leaf oil contained higher amount of monoterpene hydrocarbons (52.1%) and sesquiterpenoids (14%) as compared to flower oil (44.6% and 1.2%, respectively). However, the flower oil was predominant in oxygenated monoterpenes (43.5%). Although both leaf and flower oils showed highest cytotoxicity on A549 cells (61.4%±5.0 and 66.7%±2.2, respectively), only 100 μg/mL flower oil was significantly active against C-6 cells (69.1%±3.1). Interestingly, no toxicity was recorded on normal cells.

Conclusion

Higher concentration of 1,8-cineole and/or synergistic effect of the overall composition were probably responsible for the efficacy of flower and leaf oils against the tested cells. These oils may form potential source of natural anti-cancer compounds and play important role in human health.

In vitro acaricidal activity of 1,8-cineole against Sarcoptes scabiei var. cuniculi and regulating effects on enzyme activity

1,8-Cineole found in many essential oils is a monoterpene and acts as a repellent against Sarcoptes scabiei var. cuniculi. In the present study, the acaricidal activity of 1,8-cineole against S. scabiei var. cuniculi was evaluated and the acaricidal mechanism was also investigated by assaying enzyme activities. The results showed that the lethal concentration of 50% (LC50) value (95% confidence limit (CL)) and the lethal time of 50% (LT50) value (95% CL) of 1,8-cineole were 2.77 mg/mL and 3.606 h, respectively. The pathological changes under transmission electron microscopy showed that the morphology of the mitochondria was abnormal, the cell nuclear membrane was damaged, and the nuclear chromatin was dissoluted. The activities of superoxide dismutase (SOD), glutathione-s-transferases (GSTs), monoamine oxidase (MAO), nitric oxide synthase (NOS), and acetylcholinesterase (AChE) were significantly changed after treatment with 1,8-cineole for 4, 8, 12, and 24 h. SOD and GSTs are associated with the protection mechanism of scabies mites. And, the activities of SOD and GSTs were increased as compared with the control group. MAO, AChE, and NOS are associated with the nervous system of scabies mites. The activity of MAO was increased whereas the AChE was suppressed. The activity of NOS was suppressed in the high-dose group whereas increased in the middle-dose group and low-dose group. These results indicated that the mechanism of 1,8-cineole mainly attributed to the changes of these enzyme activities related to the nervous system of scabies mites.

1,8-Cineol Reduces Mucus-Production in a Novel Human Ex Vivo Model of Late Rhinosinusitis

Inflammatory diseases of the respiratory system such as rhinosinusitis, chronic obstructive pulmonary disease, or bronchial asthma are strongly associated with overproduction and hypersecretion of mucus lining the epithelial airway surface. 1,8-cineol, the active ingredient of the pharmaceutical drug Soledum, is commonly applied for treating such inflammatory airway diseases. However, its potential effects on mucus overproduction still remain unclear.In the present study, we successfully established ex vivo cultures of human nasal turbinate slices to investigate the effects of 1,8-cineol on mucus hypersecretion in experimentally induced rhinosinusitis. The presence of acetyl-α-tubulin-positive cilia confirmed the integrity of the ex vivo cultured epithelium. Mucin-filled goblet cells were also detectable in nasal slice cultures, as revealed by Alcian Blue and Periodic acid-Schiff stainings. Treatment of nasal slice cultures with lipopolysaccharides mimicking bacterial infection as observed during late rhinosinusitis led to a significantly increased number of mucin-filled goblet cells. Notably, the number of mucin-filled goblet cells was found to be significantly decreased after co-treatment with 1,8-cineol. On a molecular level, real time PCR-analysis further showed 1,8-cineol to significantly reduce the expression levels of the mucin genes MUC2 and MUC19 in close association with significantly attenuated NF-κB-activity. In conclusion, we demonstrate for the first time a 1,8-cineol-dependent reduction of mucin-filled goblet cells and MUC2-gene expression associated with an attenuated NF-κB-activity in human nasal slice cultures. Our findings suggest that these effects partially account for the clinical benefits of 1,8-cineol-based therapy during rhinosinusitis. Therefore, topical application of 1,8-cineol may offer a novel therapeutic approach to reduce bacteria-induced mucus hypersecretion.

Natural Products Useful in Respiratory Disorders: Focus on Side-Effect Neutralizing Combinations

This review summarizes literature related to medicinal plants reputed in traditional medical systems for treatment of asthma and coughs. The plants that are pharmacologically investigated for their effectiveness in such conditions, along with respective experimental protocol details, are also discussed. Some of plant origin compounds, which are considered useful as antitussive and antiasthmatic agents, are described as well. Chrysoeriol, a constituent of Aspalathus linearis (Fabaceae) was observed to be selective for relaxant effect in airways (through K⁺ channel activation), compared with other smooth muscles. We reported that Hypericum perforatum (Hyperieaceae), Andropogon muricatus (Poaceae), Juniper excelsa (Coniferae) and Nepeta cataria (Lamiaceae) exhibit bronchodilatory action, mediated through combination of Ca⁺⁺ antagonist and phospohodiesrase inhibitory mechanisms, which scientifically explains their medicinal use in asthma. Hyocyamus niger (Solanaceae), Artemisia vulgaris (Compositae), Fumaria parviflora (Fumariaceae) and Terminalia bellerica (Combretaceae) caused bronchodilation via dual blockade of muscarinic receptors and Ca⁺⁺ influx. Acorus calamus (Araceae), Carum roxburghianum (Apiaceae), Lens culinaris (Fabaceae) and Lepidium sativum (Cruciferae) mediate bronchodilatation through multiple pathways: anticholinergic and inhibition of Ca⁺⁺ channels and PDE enzyme(s). In conclusion, this review presents an analysis of different novel combinations of pharmacological activities in medicinal plants with side effect-neutralizing/synergistic potential, setting new trends in the therapeutic options for hyperactive respiratory disorders such as asthma and cough. Copyright © 2015 John Wiley & Sons, Ltd.

Participation of the TRP channel in the cardiovascular effects induced by carvacrol in normotensive rat

Carvacrol has been described as an agonist/antagonist of different transient receptor potential (TRP) channels and voltage-dependent calcium channels (Cavs). The aim of this study was to evaluate the role of Cav and TRP channels following carvacrol stimulation. Initially, in mesenteric artery rings carvacrol relaxed phenylephrine-induced contractions. Furthermore, carvacrol inhibited contraction elicited by CaCl2 in depolarizing nominally without Ca2+ medium and antagonized the contractions induced by S(-)-Bay K 8644 and inhibited Ca2+ currents indicating the inhibition of Ca2+ influx through L-type Cav. Additionally, carvacrol antagonized the contractions induced by CaCl2 in the presence of nifedipine/Cyclopiazonic acid/phenylephrine or nifedipine/Cyclopiazonic acid/KCl 60, suggesting a possible inhibition of calcium influx by store operated channels (SOCs), receptor operated channels (ROCs) and/or TRP channels. Interestingly, among the TRP channel blockers used, the effect induced by carvacrol was attenuated by Mg2+ and potentiated by La3+ and Gd3+, suggesting that TRP channels are involved in relaxation induced by carvacrol. Monoterpene also induced hypotension and bradycardia in non-anesthetized normotensive rats and negative inotropic and chronotropic effects. In conclusion, these results suggest that the hypotensive effect of carvacrol is probably due to bradycardia and a peripheral vasodilatation that involves, at least, the inhibition of the Ca2+ influx through Cav and TRP channels.

Plant terpenes: defense responses, phylogenetic analysis, regulation and clinical applications

The terpenoids constitute the largest class of natural products and many interesting products are extensively applied in the industrial sector as flavors, fragrances, spices and are also used in perfumery and cosmetics. Many terpenoids have biological activities and also used for medical purposes. In higher plants, the conventional acetate-mevalonic acid pathway operates mainly in the cytosol and mitochondria and synthesizes sterols, sesquiterpenes and ubiquinones mainly. In the plastid, the non-mevalonic acid pathway takes place and synthesizes hemi-, mono-, sesqui-, and diterpenes along with carotenoids and phytol tail of chlorophyll. In this review paper, recent developments in the biosynthesis of terpenoids, indepth description of terpene synthases and their phylogenetic analysis, regulation of terpene biosynthesis as well as updates of terpenes which have entered in the clinical studies are reviewed thoroughly.

Identifying effective medicinal plants for cold in Lorestan province, West of Iran

Cold is a kind of mild and self-limiting viral illness that is considered as a prevalent disease with global occurrence and is caused by more than 200 types of viruses. Ethnobotanical studies and the use traditional experiences have increased the probability of detecting effective medicinal substances for cold by 40%. This study aimed to identify effective medicinal plants for cold in Lorestan province. Traditional medical information of this work was obtained from information from indigenous people in 8 cities of Lorestan province. A previously prepared questionnaire was given to trained health liaisons to record the people's beliefs about the plants. The results showed that 23 medicinal plants were used in Lorestan province for treating cold and its symptoms (cough, sore throat, sneezing, runny nose, etc). Plants studied in this article contained bioactive substances that are recommended as the most popular traditional treatments. More research studies should be done on the efficacy and the potential harms of medicinal plants used by people, and in the case of their positive pharmacological impacts, they can be used to produce natural and effective drugs for cold.

1,8-Cineole ameliorates oxygen-glucose deprivation/reoxygenation-induced ischaemic injury by reducing oxidative stress in rat cortical neuron/glia

Objectives

1,8-Cineole, the main monoterpene in many essential oils, has been used as an ingredient in flavourings and medicine. 1,8-Cineole has been shown to possess pharmacological properties, including anti-oxidative, anti-inflammatory and anti-nociceptive actions. However, to date, no studies have examined the potential of 1,8-cineole to protect against cerebral ischaemic injury.

Methods

In this study, we investigated the neuroprotective effects of 1,8-cineole against cortical neuronal/glial cell injury caused by oxygen-glucose deprivation/reoxygenation (OGD/R) in an in-vitro model of ischaemia.

Key findings

1,8-Cineole significantly attenuated OGD/R-induced cortical cell injury, as well as reduced n-methyl-d-aspartate (NMDA)-induced cell injury. However, it did not inhibit NMDA-induced cytosolic calcium overload. Nevertheless, 1,8-cineole significantly reduced the OGD/R- and NMDA-induced overproduction of reactive oxygen species (ROS). These results indicate that 1,8-cineole exerts neuroprotection through its anti-oxidative rather than its anti-excitotoxic, properties. The decrease in OGD/R-induced intracellular superoxide in 1,8-cineole-treated cortical cells was associated with the upregulation of superoxide dismutase activity. Moreover, 1,8-cineole showed direct ROS scavenging activity in an assay of oxygen radical absorbance capacity.

Conclusion

Collectively, these results suggest 1,8-cineole as a potentially effective neuroprotective and anti-oxidative candidate for the treatment of patients with ischaemic stroke.

The eucalyptus oil ingredient 1,8-cineol induces oxidative DNA damage

The natural compound 1,8-cineol, also known as eucalyptol, is a major constituent of eucalyptus oil. This epoxy-monoterpene is used as flavor and fragrance in consumer goods as well as medical therapies. Due to its anti-inflammatory properties, 1,8-cineol is also applied to treat upper and lower airway diseases. Despite its widespread use, only little is known about the genotoxicity of 1,8-cineol in mammalian cells. This study investigates the genotoxicity and cytotoxicity of 1,8-cineol in human and hamster cells. First, we observed a significant and concentration-dependent increase in oxidative DNA damage in human colon cancer cells, as detected by the Formamidopyrimidine-DNA glycosylase (Fpg)-modified alkaline comet assay. Pre-treatment of cells with the antioxidant N-acetylcysteine prevented the formation of Fpg-sensitive sites after 1,8-cineol treatment, supporting the notion that 1,8-cineol induces oxidative DNA damage. In the dose range of DNA damage induction, 1,8-cineol did neither reduce the viability of colon cancer cells nor affected their cell cycle distribution, suggesting that cells tolerate 1,8-cineol-induced oxidative DNA damage by engaging DNA repair. To test this hypothesis, hamster cell lines with defects in BRCA2 and Rad51, which are essentials players of homologous recombination (HR)-mediated repair, were treated with 1,8-cineol. The monoterpene induced oxidative DNA damage and subsequent DNA double-strand breaks in the hamster cell lines tested. Intriguingly, we detected a significant concentration-dependent decrease in viability of the HR-defective cells, whereas the corresponding wild-type cell lines with functional HR were not affected. Based on these findings, we conclude that 1,8-cineol is weakly genotoxic, inducing primarily oxidative DNA damage, which is most likely tolerated in DNA repair proficient cells without resulting in cell cycle arrest and cell death. However, cells with deficiency in HR were compromised after 1,8-cineol treatment, suggesting a protective role of HR in response to high doses of 1,8-cineol.

Seasonal Influence on the Essential Oil of Eucalyptus microcorys

The chemical composition of the essential oil, phenolic contents, and foliar nutrients of Eucalyptus microcorys leaves, cultivated in Brazil, was analysed on a monthly basis for one year. Canonical redundancy analysis correlated results with climate conditions (rainfall, humidity, and mean temperature), allowing three groups to be distinguished as regards temperature, flavonoids, and the content of some metals. Strong correlations between Mn, Cu, Zn, Ca, P, and K with some monoterpenes and phenolic compounds were observed. Oxygenated monoterpenes were predominant in all sampling months. Oil chemovariation may be influenced by climatic factors as well as by foliar nutrient variation.

TRP modulation by natural compounds

The use of medicinal plants or other naturally derived products to relieve illness can be traced back over several millennia, and these natural products are still extensively used nowadays. Studies on natural products have, over the years, enormously contributed to the development of therapeutic drugs used in modern medicine. By means of the use of these substances as selective agonists, antagonists, enzyme inhibitors or activators, it has been possible to understand the complex function of many relevant targets. For instance, in an attempt to understand how pepper species evoke hot and painful actions, the pungent and active constituent capsaicin (from Capsicum sp.) was isolated in 1846 and the receptor for the biological actions of capsaicin was cloned in 1997, which is now known as TRPV1 (transient receptor potential vanilloid 1). Thus, TRPV1 agonists and antagonists have currently been tested in order to find new drug classes to treat different disorders. Indeed, the transient receptor potential (TRP) proteins are targets for several natural compounds, and antagonists of TRPs have been synthesised based on the knowledge of naturally derived products. In this context, this chapter focuses on naturally derived compounds (from plants and animals) that are reported to be able to modulate TRP channels. To clarify and make the understanding of the modulatory effects of natural compounds on TRPs easier, this chapter is divided into groups according to TRP subfamilies: TRPV (TRP vanilloid), TRPA (TRP ankyrin), TRPM (TRP melastatin), TRPC (TRP canonical) and TRPP (TRP polycystin). A general overview on the naturally derived compounds that modulate TRPs is depicted in Table 1.

Integrative medicine in allergy and immunology

Integrative medicine is a relatively new discipline which attempts to combine allopathic medicine with alternative or complementary medicine, to reap the benefits of both forms of medicine in optimizing the care of patients. Integrative medicine concentrates on treating the patient as a whole, both in body and mind. While the scientific method and "evidence-based" clinical research drives the management and treatment of diseases in conventional Western medicine, alternative or complementary medicine is based on unproven yet potentially beneficial techniques that have been developed throughout history, dating back to the ancient cultures in the Middle East, Africa, and China. In spite of the lack of evidence of most alternative medicine techniques, these methodologies have been practiced for centuries with great acceptance in many countries. It is in the Western world, where "modern" medicine is dictated by the scientific method, that the most controversy in the use of these alternative modes of therapy exists. Since the science behind alternative medicine is incomplete or non-existent, it is difficult for those trained in Western medicine to accept or adopt this approach. But perhaps it is the failure of Western medicine to adequately guarantee our well being and good health that have led to the ongoing debate between the medical profession and the general public as to the benefits of these alternative treatments. In one sense, integrative medicine may be a futile attempt to coin a new term in the hope of legitimizing alternative medicine. On the other hand, there is a wealth of historical experience in the use of the techniques. Studies to evaluate the scientific basis behind ancient medical techniques are ongoing, and it is to be expected that the results will neither be uniformly positive nor negative. Of particular interest is the effect of traditional medicine, herbal formulations, and manipulative techniques on the immune system, and its application in the treatment of autoimmune and allergic diseases. Studies are being designed or conducted to investigate immune effects of herbal formulations or their components. Herbal plants or medicines may lead to skewing of the Th1/Th2 balance in either direction, thus may offer potential application in the treatment of allergic or autoimmune diseases.

Efficacy and safety of topical Trikatu preparation in, relieving mosquito bite reactions: a randomized controlled trial

INTRODUCTION

Trikatu is composed of dried fruits of Piper nigrum L and Piper retrofractum Vahl, and dried rhizomes of Zingiber officinale R. Although this preparation has been used to relieve pruritis, pain, and inflammation for a long time, there is no clinical evidence to confirm its efficacy and safety. Therefore, we performed a double-blind, within person-randomized controlled study of 30 healthy volunteers to determine efficacy and safety of topical Trikatu on mosquito bite reactions.

METHODS

All subjects were bitten by Aedes aegypti laboratory mosquitoes on their forearms and they were randomly assigned arms to apply either Trikatu or reference product on the mosquito bite papule. The main outcome was the difference of papule size reduction at 30 min, measured by a caliper, between the Trikatu and reference arms. Pruritis, redness, pain, and patient satisfaction were assessed at 15, 30, 60, 180, and 360 min as secondary outcomes.

RESULTS

There were no significant differences between treatment and reference arms on any outcome at any time of measurement.

CONCLUSION

Trikatu did not show additional effects for relieving mosquito bite reaction as compared with the reference product containing camphor, menthol, and eucalyptus. For further study, it is very important to consider a proper selection of subjects, comparator product, and concentration of extract when Trikatu preparation is investigated.

Anti-inflammatory Activity of Ocimum americanum L. Essential Oil in Experimental Model of Zymosan-Induced Arthritis

Essential oils are potential sources of novel components for medicinal use. The present study was performed to investigate the composition and anti-inflammatory activity of Ocimum americanum L. essential oil (OEO) and its components in an experimental model of zymosan-induced arthritis and paw edema. The essential oil was obtained by hydro-distillation and analyzed by gas chromatography-mass spectrometry. Twenty-six components, representing 98.9% of the total oil, were characterized, with linalool (19.63%) and 1,8-cineole (17.27%) as the main components. The OEO and its two constituents inhibited leukocyte influx into the synovial space and reduced paw edema induced by zymosan. The OEO also inhibited interferon-γ levels but did not reduce transforming growth factor-β levels. Additionally, the OEO protected against leukocyte influx into the synovial membrane and cartilage destruction in knee joints in arthritic mice. These findings indicate that the essential oil of Ocimum americanum L. exerted significant anti-inflammatory effects, likely related to its main compounds.

1,8-Cineol inhibits nuclear translocation of NF-κB p65 and NF-κB-dependent transcriptional activity

Natural plant-derived products are commonly applied to treat a broad range of human diseases, including cancer as well as chronic and acute airway inflammation. In this regard, the monoterpene oxide 1,8-cineol, the active ingredient of the clinically approved drug Soledum®, is well-established for the therapy of airway diseases, such as chronic sinusitis and bronchitis, chronic obstructive pulmonary disease and bronchial asthma. Although clinical trials underline the beneficial effects of 1,8-cineol in treating inflammatory diseases, the molecular mode of action still remains unclear. Here, we demonstrate for the first time a 1,8-cineol-depending reduction of NF-κB-activity in human cell lines U373 and HeLa upon stimulation using lipopolysaccharides (LPS). Immunocytochemistry further revealed a reduced nuclear translocation of NF-κB p65, while qPCR and western blot analyses showed strongly attenuated expression of NF-κB target genes. Treatment with 1,8-cineol further led to increased protein levels of IκBα in an IKK-independent matter, while FRET-analyses showed restoring of LPS-associated loss of interaction between NF-κB p65 and IκBα. We likewise observed reduced amounts of phosphorylated c-Jun N-terminal kinase 1/2 protein in U373 cells after exposure to 1,8-cineol. In addition, 1,8-cineol led to decreased amount of nuclear NF-κB p65 and reduction of its target gene IκBα at protein level in human peripheral blood mononuclear cells. Our findings suggest a novel mode of action of 1,8-cineol through inhibition of nuclear NF-κB p65 translocation via IκBα resulting in decreased levels of proinflammatory NF-κB target genes and may therefore broaden the field of clinical application of this natural drug for treating inflammatory diseases.

1,8-cineole (eucalyptol) ameliorates cerulein-induced acute pancreatitis via modulation of cytokines, oxidative stress and NF-κB activity in mice

AIMS

Acute pancreatitis (AP) is an inflammatory condition wherein pro-inflammatory mediators, oxidative stress, and NF-κB signaling play a key role. Currently, no specific therapy exists and treatment is mainly supportive and targeted to prevent local pancreatic injury and systemic inflammatory complications. This study was aimed to examine whether 1,8-cineole, a plant monoterpene with antioxidant and anti-inflammatory properties could ameliorate cerulein-induced acute pancreatitis.

MAIN METHODS

AP was induced in Swiss mice by six one hourly injections of cerulein (50 μg/kg, i.p.). 1,8-cineole (100, 200 and 400mg/kg, p.o.) was administered 1h prior to first cerulein injection, keeping vehicle and thalidomide treated groups as controls. Blood samples were taken 6-h later to determine serum levels of amylase and lipase, and cytokines. The pancreas was removed for morphological examination, myeloperoxidase (MPO) and malondialdehyde (MDA) assays, reduced glutathione (GSH) levels, and for nuclear factor (NF)-κB immunostaining.

KEY FINDINGS

1,8-cineole effectively reduced the cerulein-induced histological damage, pancreatic edema and NF-κB expression, levels of MPO activity and MDA, and replenished the GSH depletion. Cerulein increased serum levels of amylase and lipase, and pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 were also decreased by 1,8-cineole pretreatment, similar to thalidomide, a TNF-α inhibitor. The anti-inflammatory IL-10 cytokine level was, however, enhanced by 1,8-cineole.

SIGNIFICANCE

These findings indicate that 1,8-cineole can attenuate cerulein-induced AP via an anti-inflammatory mechanism and by combating oxidative stress. Further studies are needed to clearly elucidate its benefits in patients on acute pancreatitis.

Identification of 1,8-cineole, borneol, camphor, and thujone as anti-inflammatory compounds in a Salvia officinalis L. infusion using human gingival fibroblasts

Drinking or gargling Salvia officinalis L. infusion (sage infusion) is thought to soothe a sore throat, tonsillitis, and inflamed, red gums, although structure-based scientific evidence for the key anti-inflammatory compounds in sage infusion is scarce. Human gingival fibroblasts (HGF-1) were treated with sage infusion (SI) or SI fractions containing either its volatile components and water (aqueous distillate, AD) or its dry matter (DM) for six hours. SI, AD, and DM reduced a mean phorbol-12-myristate-13-acetate/ionomycin (PMA/I)-stimulated release of the pro-inflammatory interleukins IL-6 and IL-8 by more than 50% (p < 0.05). Cellular uptake experiments and subsequent GC-MS analysis using stable-isotope-labeled internal standards revealed the presence of 1,8-cineole, borneol, camphor, and α-/β-thujone in SI-treated cells; LC-MS analysis demonstrated the presence of rosmarinic acid. A significant, more than 50% mean inhibition of PMA/I-induced IL-6 and IL-8 release was demonstrated for the volatile compounds 1,8-cineole, borneol, camphor, and thujone, but not for the nonvolatile rosmarinic acid when applied in concentrations representative of sage infusion. Therefore, the volatile compounds were found to be more effective than rosmarinic acid. 1,8-Cineole, borneol, camphor, and α-/β-thujone chiefly contribute to the anti-inflammatory activity of sage infusion in human gingival fibroblasts.

Patients with asthma benefit from concomitant therapy with cineole: a placebo-controlled, double-blind trial

BACKGROUND AND AIMS

Cineole is the main constituent of eucalyptus oil, and it is mainly used as a mucolytic agent in inflammatory airway diseases. With its known mucolytic, bronchodilating, and anti-inflammatory effects, cineole reduces the exacerbation rate in patients suffering from chronic obstructive pulmonary disease. Based on these pharmacodynamic effects, we arrived at the hypothesis that asthma patients would benefit from concomitant therapy with cineole.

METHODS

As part of a double-blind, placebo-controlled, multicenter study, 247 patients with confirmed asthma were randomly selected according to the guidelines for this study. All patients were administered 200 mg of cineole, or a placebo, three times per day as a concomitant therapy over a period of 6 months. The combined primary outcome measures, which were implemented as a multiple criteria testing process, were improvement of lung function, asthma symptoms, and quality of life.

RESULTS

Following the completion of the 6-month treatment period, it was noted that the patient group treated with cineole showed significantly more improvements to the multiple testing criteria than the patients in the placebo group (p = .0027). The statistical significance of the individual outcome measures could also be proven in accordance with the Wei-Lachin procedure (i.e., for Forced expiratory Volume 1 Second, p = .0398; for asthma symptoms, p = .0325; and for Asthma Quality of Life Questionnaire (AQLQ), p = .0475).

CONCLUSION

Concomitant therapy using cineole can lead to notable improvement in lung function and health condition as well as to reduce dyspnea in asthma patients.

Characterisation of the metabolites of 1,8-cineole transferred into human milk: concentrations and ratio of enantiomers

1,8-Cineole is a widely distributed odorant that also shows physiological effects, but whose human metabolism has hitherto not been extensively investigated. The aim of the present study was, thus, to characterise the metabolites of 1,8-cineole, identified previously in human milk, after the oral intake of 100 mg of this substance. Special emphasis was placed on the enantiomeric composition of the metabolites since these data may provide important insights into potential biotransformation pathways, as well as potential biological activities of these substances, for example on the breastfed child. The volatile fraction of the human milk samples was therefore isolated via Solvent Assisted Flavour Evaporation (SAFE) and subjected to gas chromatography-mass spectrometry (GC-MS). The absolute concentrations of each metabolite were determined by matrix calibration with an internal standard, and the ratios of enantiomers were analysed on chiral capillaries. The concentrations varied over a broad range, from traces in the upper ng/kg region up to 40 µg/kg milk, with the exception of the main metabolite α2-hydroxy-1,8-cineole that showed concentrations of 100-250 µg/kg. Also, large inter- and intra-individual variations were recorded for the enantiomers, with nearly enantiomerically pure α2-hydroxy- and 3-oxo-1,8-cineole, while all other metabolites showed ratios of ~30:70 to 80:20.

A review on anti-inflammatory activity of monoterpenes

Faced with the need to find new anti-inflammatory agents, great effort has been expended on the development of drugs for the treatment of inflammation. This disorder reduces the quality of life and overall average productivity, causing huge financial losses. In this review the anti-inflammatory activity of 32 bioactive monoterpenes found in essential oils is discussed. The data demonstrate the pharmacological potential of this group of natural chemicals to act as anti-inflammatory drugs.

Bismuth compounds in medicinal chemistry

In recent years, the chemical potential of bismuth and bismuth compounds has been actively exploited. Bismuth salts are known for their low toxicity, making them potential valuable reagents for large-scale synthesis, which becomes more obvious when dealing with products such as active pharmaceutical ingredients or synthetic intermediates. Conversely, bismuth compounds have been widely used in medicine. After extensive use in the treatments of syphilis and other bacterial infections before the advent of modern antibiotics, bismuth compounds remain important for the treatment of several gastrointestinal disorders and also exhibit antimicrobial properties and cytotoxic activity, among others. This review updates relevant advances in the past few years, concerning the application of bismuth reagents and catalysts in innovative synthetic processes for the preparation of compounds of medicinal interest, as well as the preparation, biological evaluation and potential medicinal uses of bismuth compounds.

1,8-cineole, a TRPM8 agonist, is a novel natural antagonist of human TRPA1

BACKGROUND

Essential oils are often used in alternative medicine as analgesic and anti-inflammatory remedies. However, the specific compounds that confer the effects of essential oils and the molecular mechanisms are largely unknown. TRPM8 is a thermosensitive receptor that detects cool temperatures and menthol whereas TRPA1 is a sensor of noxious cold. Ideally, an effective analgesic compound would activate TRPM8 and inhibit TRPA1.

RESULTS

We screened essential oils and fragrance chemicals showing a high ratio of human TRPM8-activating ability versus human TRPA1-activating ability using a Ca2+-imaging method, and identified 1,8-cineole in eucalyptus oil as particularly effective. Patch-clamp experiments confirmed that 1,8-cineole evoked inward currents in HEK293T cells expressing human TRPM8, but not human TRPA1. In addition, 1,8-cineole inhibited human TRPA1 currents activated by allyl isothiocyanate, menthol, fulfenamic acid or octanol in a dose-dependent manner. Furthermore, in vivo sensory irritation tests showed that 1,8-cineole conferred an analgesic effect on sensory irritation produced by TRPA1 agonists octanol and menthol. Surprisingly, 1,4-cineole, which is structurally similar and also present in eucalyptus oil, activated both human TRPM8 and human TRPA1.

CONCLUSIONS

1,8-cineole is a rare natural antagonist of human TRPA1 that has analgesic and anti-inflammatory effects possibly due to its inhibition of TRPA1.

1,8-cineole, a TRPM8 agonist, is a novel natural antagonist of human TRPA1

Background

Essential oils are often used in alternative medicine as analgesic and anti-inflammatory remedies. However, the specific compounds that confer the effects of essential oils and the molecular mechanisms are largely unknown. TRPM8 is a thermosensitive receptor that detects cool temperatures and menthol whereas TRPA1 is a sensor of noxious cold. Ideally, an effective analgesic compound would activate TRPM8 and inhibit TRPA1.

Results

We screened essential oils and fragrance chemicals showing a high ratio of human TRPM8-activating ability versus human TRPA1-activating ability using a Ca²⁺-imaging method, and identified 1,8-cineole in eucalyptus oil as particularly effective. Patch-clamp experiments confirmed that 1,8-cineole evoked inward currents in HEK293T cells expressing human TRPM8, but not human TRPA1. In addition, 1,8-cineole inhibited human TRPA1 currents activated by allyl isothiocyanate, menthol, fulfenamic acid or octanol in a dose-dependent manner. Furthermore, in vivo sensory irritation tests showed that 1,8-cineole conferred an analgesic effect on sensory irritation produced by TRPA1 agonists octanol and menthol. Surprisingly, 1,4-cineole, which is structurally similar and also present in eucalyptus oil, activated both human TRPM8 and human TRPA1.

Conclusions

1,8-cineole is a rare natural antagonist of human TRPA1 that has analgesic and anti-inflammatory effects possibly due to its inhibition of TRPA1.

Evaluation of the antinociceptive and anti-inflammatory effects of essential oil of Nepeta pogonosperma Jamzad et Assadi in rats

Background and the purpose of study

Concerning the different effects of essential oils from Nepeta genus on the central nervous system including pain killing effect, this study was designed to evaluate the antinociceptive and anti-inflammatory effects of essential oil of Nepeta pogonosperma Jamzad et Assadi (NP), a recently identified species.

Methods

Air-dried aerial parts of NP were hydrodistillated and GC-MS analysis of obtained essential oil was conducted. Total 24 male Wister rats weighing 225 ± 25 gm were studied. Essential oil of NP was administered intraperitoneally at the doses of 50 mg/kg, 100 mg/kg and 200 mg/kg for the experimental groups. Control rats received equal volume (2 ml/kg) of normal saline. Antinociception was assessed by tail flick test (after 30 minutes) and formalin test (for further 60 minutes). Then the animal was sacrificed and the paw edema was measured using a water plethysmometer.

Results

4aα,7α,7aβ-nepetalactone and 1,8-cineole were found as the main concentrated components of NP essential oil. All the doses of NP showed antinociception. NP 200 mg/kg reduced the pain sensation in tail flick (p <0.01) and formalin test (p <0.001 in both phases). In paw edema test, NP 100 and 200 mg/kg significantly reduced the inflammation (p <0.01 and p <0.05).

Conclusion

This study reveals that the essential oil of NP may minimize both the acute and chronic forms of nociception and may have potent role against inflammation, but the dose should be maintained precisely to obtain the intended effect.