α-Terpineol, a monoterpene alcohol, complexed with β-cyclodextrin exerts antihyperalgesic effect in animal model for fibromyalgia aided with docking study

Analysis strategy of contamination source using chemical fingerprint information based on GC-HRMS: A case study of landfill leachate

With the increasing prevalence of emerging contaminants (ECs) in the environment, gaining a deeper understanding of the chemical information pertaining to the contamination source is a crucial step toward effective prevention and control of these ECs. This study presents a novel strategy for analyzing the chemical information of contamination sources using gas chromatography-high resolution mass spectrometry (GC-HRMS) and demonstrates it on landfill leachate, a common and representative environmental contamination source. Initially, a non-targeted screening approach using HRMS was used to characterize a total of 5344 organic compounds with identification confidence levels 1 and 2 in 14 landfill leachate samples. Leveraging this as a base data set, the similarity analysis was first performed, and the classification fingerprints exhibited a pronounced level of similarity. Second, 169 characteristic marker contaminants with important and significant differences were identified in the 3 groups of landfill leachate with different solid waste compositions (mostly kitchen waste, mostly plastic & daily chemical product waste, and proportion average) by difference analysis. Finally, 101 hazardous chemicals (HCs) were screened in the data set. The results demonstrated that a class of contamination source exhibited certain common characteristics, while different groups of samples had their own distinct contamination signatures. This work offers a unique perspective on the interpretation of chemical information from contamination sources, aiming to provide a valuable reference for environmental pollution management.

Toxicogenetic profile of the monoterpene alpha-terpineol on normal and tumor eukaryotic cells

Alpha-terpineol is a monoterpene alcohol found in essential oils from medicinal plants with some well-known pharmacological activities and widely used in cosmetics. However, the toxicological effects and additional pharmacological activities need to be clarified. Thus, the study evaluated the toxic, cytotoxic, genotoxic, hemolytic, and oxidative potential of alpha-terpineol in non-clinical bioassays. Different concentrations of alpha-terpineol were used in bioassays, including MTT (50, 100, 200, and 400 μg/mL), Artemia salina (6.25-400 μg/mL), Allium cepa (10, 50, and 100 μg/mL), comet assay (100, 200, and 500 μg/mL), cytokinesis-block micronucleus (100, 250, and 500 μg/mL), confocal microscopy for apoptosis quantification (100 and 500 μg/mL), hemolysis and Saccharomyces cerevisiae central disk test (10, 35, and 75 μg/mL). For the MTT test, alpha-terpineol was more cytotoxic on melanoma murine B16-F10 cells rather than macrophages. For A. salina test, alpha-terpineol showed LC50 of 68.29 and 76.36 μg/mL for 24 h and 48 h of exposure time, respectively. Meanwhile, alpha-terpineol was also cytotoxic to meristematic cells, which revealed inhibition of cellular division and mutagenic action by formation of bridges and delayed anaphases. The compound increased damage index and frequency of damage corroborated by the presence of micronuclei, bridges and nuclear buds at 500 μg/mL, but it caused neither hemolysis, oxidative damage on the S. cerevisiae nor cell death in normal fibroblasts. The findings indicate alpha-terpineol has cytotoxic potential by cytogenetic and molecular mechanisms associated with apoptosis and probable target effects against melanoma cells.

Advancements in application of chitosan and cyclodextrins in biomedicine and pharmaceutics: recent progress and future trends

The global community is faced with numerous health concerns such as cancer, cardiovascular and neurological diseases, diabetes, joint pain, osteoporosis, among others. With the advancement of research in the fields of materials chemistry and medicine, pharmaceutical technology and biomedical analysis have entered a new stage of development. The utilization of natural oligosaccharides and polysaccharides in pharmaceutical/biomedical studies has gained significant attention. Over the past decade, several studies have shown that chitosan and cyclodextrin have promising biomedical implications in background analysis, ongoing development, and critical applications in biomedical and pharmaceutical research fields. This review introduces different types of saccharides/natural biopolymers such as chitosan and cyclodextrin and discusses their wide-ranging applications in the biomedical/pharmaceutical research area. Recent research advances in pharmaceutics and drug delivery based on cyclodextrin, and their response to smart stimuli, as well as the biological functions of cyclodextrin and chitosan, such as the immunomodulatory effects, antioxidant, and antibacterial properties, have also been discussed, along with their applications in tissue engineering, wound dressing, and drug delivery systems. Finally, the innovative applications of chitosan and cyclodextrin in the pharmaceutical/biomedicine were reviewed, and current challenges, research/technological gaps, and future development opportunities were surveyed.

Lipid raft disruption as an opportunity for peripheral analgesia

Chronic pain conditions are unmet medical needs, since the available drugs, opioids, non-steroidal anti-inflammatory/analgesic drugs and adjuvant analgesics do not provide satisfactory therapeutic effect in a great proportion of patients. Therefore, there is an urgent need to find novel targets and novel therapeutic approaches that differ from classical pharmacological receptor antagonism. Most ion channels and receptors involved in pain sensation and processing such as Transient Receptor Potential ion channels, opioid receptors, P2X purinoreceptors and neurokinin 1 receptor are located in the lipid raft regions of the plasma membrane. Targeting the membrane lipid composition and structure by sphingolipid or cholesterol depletion might open future perspectives for the therapy of chronic inflammatory, neuropathic or cancer pain, most importantly acting at the periphery.

Assessment of the therapeutic potential of lutein and beta-carotene nanodispersions in a rat model of fibromyalgia

Fibromyalgia (FM) is a chronic disorder characterized by widespread musculoskeletal pain, fatigue, and cognitive impairment. Despite the availability of various treatment options, FM remains a challenging condition to manage. In the present study, we investigated the efficacy of formulated nanodispersions of lutein and beta-carotene in treating FM-related symptoms induced by reserpine in female Wistar rats. Several techniques have been implemented to assess this efficacy at various levels, including biochemical, bioelectrical, and behavioral. Namely, oxidative stress markers, monoamine levels, electrocorticography, pain threshold test, and open field test were conducted on control, FM-induced, and FM-treated groups of animals. Our results provided compelling evidence for the efficacy of carotenoid nanodispersions in treating FM-related symptoms. Specifically, we found that the dual action of the nanodispersion, as both antioxidant and antidepressant, accounted for their beneficial effects in treating FM. With further investigation, nano-carotenoids and particularly nano-lutein could potentially become an effective alternative treatment for patients with FM who do not respond to current treatment options.

Nutraceuticals for Fibromyalgia and Neuropathic Pain

Both neuropathic pain and fibromyalgia are horrific painful conditions arising due to impairment in the somatosensory nervous system and the musculoskeletal system, respectively. They share some common symptoms like hyperalgesia, allodynia, insomnia, cognitive deficits, and mood disturbances. It is believed that fibromyalgia is the consequence of dysfunction of the central nervous system, autonomic nervous system, imbalance in neurotransmitters, and psychological and emotional stress. Henceforth, these pain syndromes have become a major challenge for healthcare professionals due to their complex etiology and poor availability and effectiveness of the drugs. Notably, the available synthetic drugs possess serious side effects including physical dependence and tolerance. Therefore, researchers are now seeking natural-based therapy for modulating chronic pain conditions. This chapter has been written with the intention of exploring the beneficial effects of various nutraceuticals including herbal dietary supplements in neuropathic pain and fibromyalgia.

Evaluation of the terpenes β-caryophyllene, α-terpineol, and γ-terpinene in the mouse chronic constriction injury model of neuropathic pain: possible cannabinoid receptor involvement

Pain is one of the most common reasons to seek medical attention, and chronic pain is a worldwide epidemic. Anecdotal reports suggest cannabis may be an effective analgesic. As cannabis contains the terpenes α-terpineol, β-caryophyllene, and γ-terpinene, we hypothesized these terpenes would produce analgesia in a mouse model of neuropathic pain. We used the chronic constriction injury of the sciatic nerve mouse model, which produces mechanical allodynia, assessed via the von Frey assay, as well as thermal hyperalgesia assessed via the hotplate assay. Compounds were further assessed in tests of locomotor activity, hypothermia, and acute antinociception. Each terpene produced dose-related reversal of mechanical allodynia and thermal hyperalgesia. Thermal hyperalgesia displayed higher sensitivity to the effects of each terpene than mechanical allodynia, and the rank order potency of the terpenes was α-terpineol > β-caryophyllene > γ-terpinene. To examine the involvement of cannabinoid receptors, further tests were conducted in mice lacking either functional cannabinoid type 1 receptors (CB₁R (-/-)) or cannabinoid type 2 receptors (CB₂R (-/-)). Compared to wild type mice, CB₁R (-/-) mice treated with α-terpineol displayed a 2.91-fold decrease in potency to reverse mechanical allodynia; in CB₂R (-/-) mice, the potency of α-terpineol was decreased 11.73-fold. The potency of β-caryophyllene to reverse mechanical allodynia decreased 1.80-fold in CB₂R (-/-) mice. Each terpene produced a subset of effects in tests of locomotor activity, hypothermia, and acute antinociception. These findings suggest α-terpineol, β-caryophyllene, and γ-terpinene may have differential cannabinoid receptor activity and a pharmacological profile that may yield new efficacious analgesics.

Carvone and its pharmacological activities: A systematic review

Natural products from plants have gained prominence in the search for therapeutic alternatives. Monoterpenes, such as carvone, are suggested as candidates for the treatment of several diseases. Therefore, the objective of this study is to review the pharmacological activities of carvone in experimental models in vitro and in vivo. For this, the searches were carried out in May 2020 (upgraded in July 2021) in the databases of PubMed, Web of Science and Scopus and gathered studies on the pharmacological activities of carvone. Two independent reviewers performed the selection of articles using the Rayyan application, extracted the relevant data and assessed the methodological quality of the selected studies using Syrcle's risk of bias tool. Ninety-one articles were selected that described 10 pharmacological activities of carvone, such as antimicrobial, antispasmodic, anti-inflammatory, antioxidant, antinociceptive, anticonvulsant, among others. The evaluation of the methodological quality presented an uncertain risk of bias for most studies. In light of that, carvone stands out as a viable and promising alternative in the treatment of several pathological conditions. However, carrying out studies to evaluate possible mechanisms of action and the safety of this monoterpene is recommended.

Effect of α-Terpineol on Chicken Meat Quality during Refrigerated Conditions

The present study was designed to evaluate the in vitro antimicrobial properties of nine bioactive compounds (BACs). Applying the disc paper and minimum inhibitory concentration (MIC) assays, we found that the BACs with the widest spectrum of in vitro antibacterial activity against the studied bacteria were carvacrol and α-terpineol (αTPN). Subsequently, αTPN was selected and applied at different concentrations into the fresh minced chicken meat. The meat was then vacuum packaged and stored for 14 days at 4 °C. Physicochemical properties, lipid oxidation (thiobarbituric acid reactive substances, TBARS), electronic-nose-based smell detection, and microbiological characteristics were monitored. At day 14, meat treated with higher concentrations of αTPN (MIC-2 and MIC-4) exhibited a significantly increased pH and lightness (L*), increased yellowness (b*), decreased redness (a*), caused a significant decrease in water holding capacity (WHC), and decreased lipid oxidation by keeping TBARS scores lower than the control. Although αTPN showed perceptibly of overlapped aroma profiles, the E-nose was able to distinguish the odor accumulation of αTPN between the different meat groups. During the 2-week storage period, αTPN, particularly MIC-4, showed 5.3 log CFU/g reduction in aerobic mesophilic counts, causing total inhibition to the Pseudomonas lundessis, Listeria monocytogenes, and Salmonella Typhimurium. These promising results highlight that αTPN is exploitable to improve the shelf life and enhance the safety of meat and meat products.

Fibromyalgia: Pathogenesis, Mechanisms, Diagnosis and Treatment Options Update

Fibromyalgia is a syndrome characterized by chronic and widespread musculoskeletal pain, often accompanied by other symptoms, such as fatigue, intestinal disorders and alterations in sleep and mood. It is estimated that two to eight percent of the world population is affected by fibromyalgia. From a medical point of view, this pathology still presents inexplicable aspects. It is known that fibromyalgia is caused by a central sensitization phenomenon characterized by the dysfunction of neuro-circuits, which involves the perception, transmission and processing of afferent nociceptive stimuli, with the prevalent manifestation of pain at the level of the locomotor system. In recent years, the pathogenesis of fibromyalgia has also been linked to other factors, such as inflammatory, immune, endocrine, genetic and psychosocial factors. A rheumatologist typically makes a diagnosis of fibromyalgia when the patient describes a history of pain spreading in all quadrants of the body for at least three months and when pain is caused by digital pressure in at least 11 out of 18 allogenic points, called tender points. Fibromyalgia does not involve organic damage, and several diagnostic approaches have been developed in recent years, including the analysis of genetic, epigenetic and serological biomarkers. Symptoms often begin after physical or emotional trauma, but in many cases, there appears to be no obvious trigger. Women are more prone to developing the disease than men. Unfortunately, the conventional medical therapies that target this pathology produce limited benefits. They remain largely pharmacological in nature and tend to treat the symptomatic aspects of various disorders reported by the patient. The statistics, however, highlight the fact that 90% of people with fibromyalgia also turn to complementary medicine to manage their symptoms.

Anti-Tumor Efficiency of Perillylalcohol/β-Cyclodextrin Inclusion Complexes in a Sarcoma S180-Induced Mice Model

The low solubility and high volatility of perillyl alcohol (POH) compromise its bioavailability and potential use as chemotherapeutic drug. In this work, we have evaluated the anticancer activity of POH complexed with β-cyclodextrin (β-CD) using three complexation approaches. Molecular docking suggests the hydrogen-bond between POH and β-cyclodextrin in molar proportion was 1:1. Thermal analysis and Fourier-transform infrared spectroscopy (FTIR) confirmed that the POH was enclosed in the β-CD cavity. Also, there was a significant reduction of particle size thereof, indicating a modification of the β-cyclodextrin crystals. The complexes were tested against human L929 fibroblasts after 24 h of incubation showing no signs of cytotoxicity. Concerning the histopathological results, the treatment with POH/β-CD at a dose of 50 mg/kg promoted approximately 60% inhibition of tumor growth in a sarcoma S180-induced mice model and the reduction of nuclear immunoexpression of the Ki67 antigen compared to the control group. Obtained data suggest a significant reduction of cycling cells and tumor proliferation. Our results confirm that complexation of POH/β-CD not only solves the problem related to the volatility of the monoterpene but also increases its efficiency as an antitumor agent.

Monoterpenes as a perspective for the treatment of seizures: A Systematic Review

BACKGROUND

Epilepsy affects more than 65 million people worldwide. Treatment for epileptic seizures is ineffective and has many adverse effects. For this reason, the search for new therapeutic options capable of filling these limitations is necessary.

HYPOTHESIS/PURPOSE

In this sense, natural products, such as monoterpenes, have been indicated as a new option to control neurological disorders such as epilepsy.

STUDY DESIGN

Therefore, the objective of this study was to review the monoterpenes that have anticonvulsive activity in animal models.

METHODS

The searches were performed in the PubMed, Web of Science and Scopus databases in September, 2020 and compiled studies using monoterpenes as an alternative to seizure. Two independent reviewers performed the study selection, data extraction and methodological quality assessment using the Syrcle tool.

RESULTS

51 articles that described the anticonvulsant activity of 35 monoterpenes were selected with action on the main pharmacological target, including GABAA receptors, glutamate, calcium channels, sodium and potassium. In addition, these compounds are capable of reducing neuronal inflammation and oxidative stress caused by seizure.

CONCLUSION

These compounds stand out as a promising alternative for acting through different pharmacological mechanisms, which may not only reduce seizure, but also promote neuroprotective effect by reducing toxicity in brain regions. However, further studies are needed to determine the mechanism of action and safety assessment of these compounds.

Inclusion complex with β-cyclodextrin is a key determining factor for the cardioprotection induced by usnic acid

Ischemia-reperfusion (I/R) injury causes oxidative stress, leading to severe cardiac dysfunction. Thus, biologically active compounds with antioxidant properties may be viewed as a promising therapeutic strategy against oxidative-related cardiac disorders. Usnic acid (UA), a natural antioxidant, was complexed with β-cyclodextrin (βCD) to improve its bioavailability. Wistar male rats were orally treated with the free form of UA (50 mg/kg) or the inclusion complex UA/βCD (50 mg/kg) for seven consecutive days. Afterward, hearts were subjected to I/R injury, and the cardiac contractility, rhythmicity, infarct size, and antioxidant enzyme activities were evaluated. Here, we show that neither UA nor UA/βCD treatments developed signs of toxicity. After I/R injury, animals treated with UA/βCD showed improved post-ischemic cardiac functional recovery while the release of cell injury biomarkers decreased. Following reduced cardiac damage, a lower incidence of ventricular arrhythmias and smaller myocardial infarct size were associated with reduced lipid peroxidation, along with preserved activity of antioxidant enzymes compared to untreated rats. Surprisingly, uncomplexed UA did not protect hearts against IR injury. Altogether, our results indicate that the inclusion complex UA/βCD is a critical determining factor responsible for the cardioprotection action of UA, suggesting the involvement of an antioxidant-dependent mechanisms. Moreover, our findings support that UA/βCD is a structurally engineered compound with active cardioprotective properties.

β-Cyclodextrin/Isopentyl Caffeate Inclusion Complex: Synthesis, Characterization and Antileishmanial Activity

Isopentyl caffeate (ICaf) is a bioactive ester widely distributed in nature. Our patented work has shown promising results of this molecule against Leishmania. However, ICaf shows poor solubility, which limits its usage in clinical settings. In this work, we have proposed the development of an inclusion complex of ICaf in β-cyclodextrin (β-CD), with the aim to improve the drug solubility, and thus, its bioavailability. The inclusion complex (ICaf:β-CD) was developed applying three distinct methods, i.e., physical mixture (PM), kneading (KN) or co-evaporation (CO) in different molar proportions (0.25:1, 1:1 and 2:1). Characterization of the complexes was carried out by thermal analysis, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and molecular docking. The ICaf:β-CD complex in a molar ratio of 1:1 obtained by CO showed the best complexation and, therefore, was selected for further analysis. Solubility assay showed a marked improvement in the ICaf:β-CD (CO, 1:1) solubility profile when compared to the pure ICaf compound. Cell proliferation assay using ICaf:β-CD complex showed an IC50 of 3.8 and 2.7 µg/mL against L. amazonesis and L. chagasi promastigotes, respectively. These results demonstrate the great potential of the inclusion complex to improve the treatment options for visceral and cutaneous leishmaniases.

(-)-linalool-Loaded Polymeric Nanocapsules Are a Potential Candidate to Fibromyalgia Treatment

Fibromyalgia (FM) is a chronic disease that has as main characteristic generalized musculoskeletal pain, which can cause physical and emotional problems to patients. However, pharmacological therapies show side effects that hamper the adhesion to treatment. Given this, (-)-linalool (LIN), a monoterpene with several therapeutic properties already reported in scientific literature as anti-depressive, antinociceptive, anti-inflammatory, and antihyperalgesic also demonstrated therapeutic potential in the treatment of FM. Nevertheless, physicochemical limitations as high volatilization and poor water-solubility make its use difficult. In this perspective, this present research had performed the incorporation of LIN into polymeric nanocapsules (LIN-NC). Size, morphology, encapsulation efficiency, cytotoxicity, and drug release were performed. The antihyperalgesic effect of LIN-NC was evaluated by a chronic non-inflammatory muscle pain model. The results demonstrated that the polymeric nanocapsules showed particle size of 199.1 ± 0.7 nm with a PDI measurement of 0.13 ± 0.01. The drug content and encapsulation efficiency were 13.78 ± 0.05 mg/mL and 80.98 ± 0.003%, respectively. The formulation did not show cytotoxicity on J774 macrophages. The oral treatment with LIN-NC and free-LIN increased the mechanical withdrawal threshold on all days of treatment in comparison with the control group. In conclusion, LIN-NC is a promising proposal in the development of phytotherapy-based nanoformulations for future clinical applications.

Alpha-terpineol complexed with beta-cyclodextrin reduces damages caused by periodontitis in rats

BACKGROUND AND OBJECTIVE

This study aimed to assess the effectiveness of the treatment with alpha-terpineol (αTPN) complexed with beta-cyclodextrin (βCD) on oral, blood, and hepatic parameters in ligature-induced periodontitis.

MATERIAL AND METHODS

Forty female rats were distributed among the following groups: control (vehicle solution), periodontitis (ligature + vehicle solution), 5 mg/kg of αTPN-βCD (ligature), and 25 mg/kg of αTPN-βCD (ligature). Compounds were administered daily via intraperitoneal injection over a 20-day period. Periodontitis was induced with the bilateral insertion of ligatures around the first lower molars of each rat. Oral parameters, as well as blood biomarkers, were measured: histopathological assessment of the hepatic tissue was carried out using light and transmission electron microscopy.

RESULTS

The treatment with αTPN-βCD significantly improved several oral parameters and blood biomarkers in comparison with rats with periodontitis. In addition, the treatment with αTPN-βCD significantly ameliorated the steatosis score and reduced the number of lipid droplets and the amount of foamy cytoplasm in the hepatocytes of rats with periodontitis.

CONCLUSION

The results obtained suggest that the treatment with αTPN-βCD improves several oral and blood parameters in rats with experimental periodontitis. In addition, hepatic alterations caused by periodontitis were ameliorated in the rats treated with αTPN-βCD.

Antinociceptive Activity of Chemical Components of Essential Oils That Involves Docking Studies: A Review

INTRODUCTION

Pain is considered an unpleasant sensory and emotional experience, being considered as one of the most important causes of human suffering. Computational chemistry associated with bioinformatics has stood out in the process of developing new drugs, through natural products, to manage this condition.

OBJECTIVE

To analyze, through literature data, recent molecular coupling studies on the antinociceptive activity of essential oils and monoterpenes.

DATA SOURCE

Systematic search of the literature considering the years of publications between 2005 and December 2019, in the electronic databases PubMed and Science Direct.

ELIGIBILITY CRITERIA

Were considered as criteria of 1) Biological activity: non-clinical effects of an OE and/or monoterpenes on antinociceptive activity based on animal models and in silico analysis, 2) studies with plant material: chemically characterized essential oils and/or their constituents isolated, 3) clinical and non-clinical studies with in silico analysis to assess antinociceptive activity, 4) articles published in English. Exclusion criteria were literature review, report or case series, meta-analysis, theses, dissertations, and book chapter.

RESULTS

Of 16,006 articles, 16 articles fulfilled all the criteria. All selected studies were non-clinical. The most prominent plant families used were Asteraceae, Euphorbiaceae, Verbenaceae, Lamiaceae, and Lauraceae. Among the phytochemicals studied were α-Terpineol, 3-(5-substituted-1,3,4-oxadiazol-2-yl)-N'-[2-oxo-1,2-dihydro-3H-indol-3-ylidene] propane hydrazide, β-cyclodextrin complexed with citronellal, (-)-α-bisabolol, β-cyclodextrin complexed with farnesol, and p-Cymene. The softwares used for docking studies were Molegro Virtual Docker, Sybyl®X, Vlife MDS, AutoDock Vina, Hex Protein Docking, and AutoDock 4.2 in PyRx 0.9. The molecular targets/complexes used were Nitric Oxide Synthase, COX-2, GluR2-S1S2, TRPV1, β-CD complex, CaV1, CaV2.1, CaV2.2, and CaV2.3, 5-HT receptor, delta receptor, kappa receptor, and MU (μ) receptor, alpha adrenergic, opioid, and serotonergic receptors, muscarinic receptors and GABAA opioid and serotonin receptors, 5-HT3 and M2 receptors. Many of the covered studies used molecular coupling to investigate the mechanism of action of various compounds, as well as molecular dynamics to investigate the stability of protein-ligand complexes.

CONCLUSIONS

The studies revealed that through the advancement of more robust computational techniques that complement the experimental studies, they may allow some notes on the identification of a new candidate molecule for therapeutic use.

Antidepressant-Like Effect of Terpineol in an Inflammatory Model of Depression: Involvement of the Cannabinoid System and D2 Dopamine Receptor

Depression has a multifactorial etiology that arises from environmental, psychological, genetic, and biological factors. Environmental stress and genetic factors acting through immunological and endocrine responses generate structural and functional changes in the brain, inducing neurogenesis and neurotransmission dysfunction. Terpineol, monoterpenoid alcohol, has shown immunomodulatory and neuroprotective effects, but there is no report about its antidepressant potential. Herein, we used a single lipopolysaccharide (LPS) injection to induce a depressive-like effect in the tail suspension test (TST) and the splash test (ST) for a preventive and therapeutic experimental schedule. Furthermore, we investigated the antidepressant-like mechanism of action of terpineol while using molecular and pharmacological approaches. Terpineol showed a coherent predicted binding mode mainly against CB1 and CB2 receptors and also against the D2 receptor during docking modeling analyses. The acute administration of terpineol produced the antidepressant-like effect, since it significantly reduced the immobility time in TST (100-200 mg/kg, p.o.) as compared to the control group. Moreover, terpineol showed an antidepressant-like effect in the preventive treatment that was blocked by a nonselective dopaminergic receptor antagonist (haloperidol), a selective dopamine D2 receptor antagonist (sulpiride), a selective CB1 cannabinoid receptor antagonist/inverse agonist (AM281), and a potent and selective CB2 cannabinoid receptor inverse agonist (AM630), but it was not blocked by a nonselective adenosine receptor antagonist (caffeine) or a β-adrenoceptor antagonist (propranolol). In summary, molecular docking suggests that CB1 and CB2 receptors are the most promising targets of terpineol action. Our data showed terpineol antidepressant-like modulation by CB1 and CB2 cannabinoid receptors and D2-dopaminergic receptors to further corroborate our molecular evidence.

Antiedematogenic and Anti-Inflammatory Activity of the Monoterpene Isopulegol and Its β-Cyclodextrin (β-CD) Inclusion Complex in Animal Inflammation Models

Isopulegol (ISO) is an alcoholic monoterpene widely found in different plant species, such as Melissa officinalis, and has already been reported to have a number of pharmacological properties. Like other terpenes, ISO is a highly volatile compound that is slightly soluble in water, so its inclusion into cyclodextrins (CDs) is an interesting approach to increase its solubility and bioavailability. Thus, our aim was to evaluate the antiedematogenic and anti-inflammatory activity of isopulegol and a β-cyclodextrin-isopulegol inclusion complex (ISO/β-CD) in rodent models. For the anti-inflammatory activity evaluation, antiedematogenic plethysmometry and acute (peritonitis and pleurisy), as well as chronic (cotton pellet-induced granuloma) anti-inflammatory models, were used. The docking procedure is used to evaluate, analyze, and predict their binding mode of interaction with H1 and Cox-2 receptors. The animals (n = 6) were divided into groups: ISO and ISO/β-CD, negative control (saline), and positive control (indomethacin and promethazine). ISO and ISO/β-CD were able to reduce acute inflammatory activity by decreasing albumin extravasation, leukocyte migration, and MPO concentration, and reducing exudate levels of IL-1β and TNF-α. ISO and ISO/β-CD significantly inhibited edematogenic activity in carrageenan- and dextran-induced paw edema. Moreover, both significantly reduced chronic inflammatory processes, given the lower weight and protein concentration of granulomas in the foreign body granulomatous inflammation model. The results suggest that the inclusion of ISO in β-cyclodextrins improves its pharmacological properties, with the histamine and prostaglandin pathways as probable mechanisms of inhibition, and also reinforces the anti-inflammatory profile of this terpene.

Phytol, a Chlorophyll Component, Produces Antihyperalgesic, Anti-inflammatory, and Antiarthritic Effects: Possible NFκB Pathway Involvement and Reduced Levels of the Proinflammatory Cytokines TNF-α and IL-6

Phytol is a diterpene constituent of chlorophyll and has been shown to have several pharmacological properties, particularly in relation to the management of painful inflammatory diseases. Arthritis is one of the most common of these inflammatory diseases, mainly affecting the synovial membrane, cartilage, and bone in joints. Proinflammatory cytokines, such as TNF-α and IL-6, and the NFκB signaling pathway play a pivotal role in arthritis. However, as the mechanisms of action of phytol and its ability to reduce the levels of these cytokines are poorly understood, we decided to investigate its pharmacological effects using a mouse model of complete Freund's adjuvant (CFA)-induced arthritis. Our results showed that phytol was able to inhibit joint swelling and hyperalgesia throughout the whole treatment period. Moreover, phytol reduced myeloperoxidase (MPO) activity and proinflammatory cytokine release in synovial fluid and decreased IL-6 production as well as the COX-2 immunocontent in the spinal cord. It also downregulated the p38MAPK and NFκB signaling pathways. Therefore, our findings demonstrated that phytol can be an innovative antiarthritic agent due to its capacity to attenuate inflammatory reactions in joints and the spinal cord, mainly through the modulation of mediators that are key to the establishment of arthritic pain.

Terpenoids, Cannabimimetic Ligands, beyond the Cannabis Plant

Medicinal use of Cannabis sativa L. has an extensive history and it was essential in the discovery of phytocannabinoids, including the Cannabis major psychoactive compound-Δ9-tetrahydrocannabinol (Δ9-THC)-as well as the G-protein-coupled cannabinoid receptors (CBR), named cannabinoid receptor type-1 (CB1R) and cannabinoid receptor type-2 (CB2R), both part of the now known endocannabinoid system (ECS). Cannabinoids is a vast term that defines several compounds that have been characterized in three categories: (i) endogenous, (ii) synthetic, and (iii) phytocannabinoids, and are able to modulate the CBR and ECS. Particularly, phytocannabinoids are natural terpenoids or phenolic compounds derived from Cannabis sativa. However, these terpenoids and phenolic compounds can also be derived from other plants (non-cannabinoids) and still induce cannabinoid-like properties. Cannabimimetic ligands, beyond the Cannabis plant, can act as CBR agonists or antagonists, or ECS enzyme inhibitors, besides being able of playing a role in immune-mediated inflammatory and infectious diseases, neuroinflammatory, neurological, and neurodegenerative diseases, as well as in cancer, and autoimmunity by itself. In this review, we summarize and critically highlight past, present, and future progress on the understanding of the role of cannabinoid-like molecules, mainly terpenes, as prospective therapeutics for different pathological conditions.

Biotransformation of α-terpineol by Alternaria alternata

α-Terpineol (1), the main volatile constituent in some traditional Chinese medicines, has been reported to be metabolized to 4R-oleuropeic acid by the larvae of common cutworms. The present study verified that α-terpineol could be converted to 4R-oleuropeic acid (2) and (1S,2R,4R)-p-menthane-1,2,8-triol (3) by Alternaria alternata fermentation. Using shortened fermentation times, 7-hydroxy-α-terpineol (2a) was identified as an oxidative intermediate, which was consistent with the hypothesis put forward by previous studies. Cytochrome P450 enzymes were also confirmed to catalyze this biotransformation. This is the first study on the biotransformation of α-terpineol by microbial fermentation.

Endogenous opiates and behavior: 2017

This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Antinociceptive activity of the Psidium brownianum Mart ex DC. leaf essential oil in mice

Chronic pain management has several adverse effects and research looking for new and effective pain management drugs posing lower undesirable effects is necessary. Given the above, the pharmacological investigation of medicinal plants significantly contributes to the dissemination of plant-derived therapeutics. The aim of this study was to evaluate the antinociceptive activity of the Psidium brownianum Mart ex DC. leaf essential oil (PBEO) and the participation of the opioid pathway in this effect in mice. Swiss Mus musculus male mice were tested using acute nociception models (acetic acid induced abdominal contortions, formalin, capsaicin and hot plate tests). The possible myorelaxant action of the PBEO was tested using the rotarod test. The essential oil reduced animal nociception in chemical and heat models, with this action being devoid of a myorelaxant effect. Naloxone (2 mg/kg, intraperitoneally - i.p.) partially antagonized the PBEO activity, possibly acting via opioid receptors. The results obtained provide evidence that the traditional Psidium brownianum use may be effective for pain treatment.

Eplingiella fruticosa (Lamiaceae) essential oil complexed with β-cyclodextrin improves its anti-hyperalgesic effect in a chronic widespread non-inflammatory muscle pain animal model

Eplingiella fruticosa (Lamiaceae), formally known as Hyptis fruticosa, is an important aromatic medicinal herb used in folk medicine in northeastern Brazil. We aimed to evaluate the anti-hyperalgesic effect of essential oil obtained from E. fruticosa (HypEO) complexed with βCD (HypEO-βCD) in a chronic widespread non-inflammatory muscle pain animal model (a mice fibromyalgia-like model, FM). The HypEO was extracted by hydro distillation and its chemical composition was determined by GC-MS/FID. Moreover, Fos protein expression in the spinal cord was assessed by immunofluorescence. (E)-caryophyllene, bicyclogermacrene, 1,8-cineole, α-pinene, β-pinene and 21 other compounds were identified in the HypEO. The treatment with HypEO-βCD produced a longer-lasting anti-hyperalgesic effect compared to HypEO, without alterations in motor coordination or myorelaxant effects. Moreover, HypEO and HypEO-βCD produced a significant anti-hyperalgesic effect over 7 consecutive treatment days. Immunofluorescence assay demonstrated a decrease in Fos protein expression in the spinal cord (p < 0.001). We demonstrated that the anti-hyperalgesic effect produced by HypEO was improved after complexation with β-CD and this seems to be related to the central pain-inhibitory pathway, suggesting the possible use of E. fruticosa for chronic pain management.

Essential oil extracted from erythrina corallodendron L. leaves inhibits the proliferation, migration, and invasion of breast cancer cells

Erythrina corallodendron L., a kind of landscape tree, has long been used as a traditional medicine. In this study, the composition of essential oil extracted from the leaves was analysed by GC-MS (gas chromatograph-mass spectrometer), with linalool identified as the main compound. Its cytotoxicity against MDA-MB-231, MCF-7 and HMLE cells was examined by MTT and cloning assays. Transwell and wound-healing assays were used to examine the inhibition of migration and invasion. Western blot, qRT-PCR and immunofluorescence staining were used to measure the mRNA and protein expression of factors related to EMT (snail, slug, E-cadherin, N-cadherin and vimentin). The essential oil of Erythrina corallodendron leaves was found to inhibit the proliferation, migration and invasion of breast cancer cells in a dose-dependent manner. The findings of this study suggest that the essential oil of E. corallodendron leaves may merit further investigation as a potential clinical or adjuvant drug for treating breast cancer migration and invasion.

Medicinal Properties of Cannabinoids, Terpenes, and Flavonoids in Cannabis, and Benefits in Migraine, Headache, and Pain: An Update on Current Evidence and Cannabis Science

BACKGROUND

Comprehensive literature reviews of historical perspectives and evidence supporting cannabis/cannabinoids in the treatment of pain, including migraine and headache, with associated neurobiological mechanisms of pain modulation have been well described. Most of the existing literature reports on the cannabinoids Δ⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD), or cannabis in general. There are many cannabis strains that vary widely in the composition of cannabinoids, terpenes, flavonoids, and other compounds. These components work synergistically to produce wide variations in benefits, side effects, and strain characteristics. Knowledge of the individual medicinal properties of the cannabinoids, terpenes, and flavonoids is necessary to cross-breed strains to obtain optimal standardized synergistic compositions. This will enable targeting individual symptoms and/or diseases, including migraine, headache, and pain.

OBJECTIVE

Review the medical literature for the use of cannabis/cannabinoids in the treatment of migraine, headache, facial pain, and other chronic pain syndromes, and for supporting evidence of a potential role in combatting the opioid epidemic. Review the medical literature involving major and minor cannabinoids, primary and secondary terpenes, and flavonoids that underlie the synergistic entourage effects of cannabis. Summarize the individual medicinal benefits of these substances, including analgesic and anti-inflammatory properties.

CONCLUSION

There is accumulating evidence for various therapeutic benefits of cannabis/cannabinoids, especially in the treatment of pain, which may also apply to the treatment of migraine and headache. There is also supporting evidence that cannabis may assist in opioid detoxification and weaning, thus making it a potential weapon in battling the opioid epidemic. Cannabis science is a rapidly evolving medical sector and industry with increasingly regulated production standards. Further research is anticipated to optimize breeding of strain-specific synergistic ratios of cannabinoids, terpenes, and other phytochemicals for predictable user effects, characteristics, and improved symptom and disease-targeted therapies.

Natural products as a perspective for cancer pain management: A systematic review

BACKGROUND

Cancer is the leading cause of death in the world and one of the main symptoms affecting these individuals is chronic pain, which must be evaluated and treated in its various components. Several drugs are currently used, but beyond the high cost, they have harmful side effects to patients or are transitorily effective. Ergo, there is a need to look for new options for cancer pain relief. Natural products (NPs) present themselves as strong candidates for the development of new drugs for the treatment of chronic pain, such as cancer pain.

PURPOSE

This systematic review aimed to summarize current knowledge about the analgesic profile of NPs in cancer pain.

METHODS

The search included PubMed, Scopus and Web of Science (from inception to June 2018) sought to summarize the articles studying new proposals with NPs for the management of oncological pain. Two independent reviewers extracted data on study characteristics, methods and outcomes.

RESULTS

After an extensive survey, 21 articles were selected, which described the analgesic potential of 15 natural compounds to relieve cancer pain. After analyzing the data, it can be suggested that these NPs, which have targets in central and peripheral mechanisms, are interesting candidates for the treatment of cancer pain for addressing different pharmacological mechanisms (even innovative), but ensuring the safety of these compounds is still a challenge. Likewise, the cannabinoids compounds leave the front as the most promising compounds for direct applicability due to the clinical studies that have already been developed and the background already established about these effects on chronic pain.

CONCLUSION

Regarding these findings, it can be concluded that the variability of possible biological sites of action is strategic for new perspectives in the development of therapeutic proposals different from those available in the current market.

Monoterpenes modulating cytokines - A review

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

Medicinal properties of terpenes found in Cannabis sativa and Humulus lupulus

Cannabaceae plants Cannabis sativa L. and Humulus lupulus L. are rich in terpenes - both are typically comprised of terpenes as up to 3-5% of the dry-mass of the female inflorescence. Terpenes of cannabis and hops are typically simple mono- and sesquiterpenes derived from two and three isoprene units, respectively. Some terpenes are relatively well known for their potential in biomedicine and have been used in traditional medicine for centuries, while others are yet to be studied in detail. The current, comprehensive review presents terpenes found in cannabis and hops. Terpenes' medicinal properties are supported by numerous in vitro, animal and clinical trials and show anti-inflammatory, antioxidant, analgesic, anticonvulsive, antidepressant, anxiolytic, anticancer, antitumor, neuroprotective, anti-mutagenic, anti-allergic, antibiotic and anti-diabetic attributes, among others. Because of the very low toxicity, these terpenes are already widely used as food additives and in cosmetic products. Thus, they have been proven safe and well-tolerated.

α-Terpineol reduces cancer pain via modulation of oxidative stress and inhibition of iNOS

α-Terpineol (TP) is present in a wide range of essential oils of the genus Eucalyptus, with recognized potential for a range of biological effects, such as analgesic. Hence, our study aimed to investigate the effect of TP on cancer pain induced by sarcoma 180 in Swiss mice. Our results showed that TP reduced significantly mechanical hyperalgesia and spontaneous and palpation-induced nociception, improved paw use without reducing tumor growth and grip strength. Importantly, no evident biochemical and hematological toxicity was oberved. Furthermore, TP increased the tissue antioxidant capacity due to ferric-reducing antioxidant power (FRAP) and glutathione (GSH). TP also reduced inducible nitric oxide synthase (iNOS) immunocontent in the tumors. Molecular docking estimated that TP binds within the same range of iNOS regions (other iNOS inhibitors), such as N-Nitroarginine methyl ester (L-NAME). These data provide strong evidence that TP may be an interesting candidate for the development of new safe analgesic drugs that are effective for cancer pain control.

Alcoholic monoterpenes found in essential oil of aromatic spices reduce allergic inflammation by the modulation of inflammatory cytokines

Allergic inflammation is a response of the body against pathogens by cytokine release and leucocyte recruitment. Recently, there was an increase in morbimortality associated with allergic inflammation, especially asthma. The treatment has many adverse effects, requiring the search for new therapies. Monoterpenes are natural products with anti-inflammatory activity demonstrated in several studies and can be an option to inflammation management. Thus, we investigated the effects of citronellol, α-terpineol and carvacrol on allergic inflammation. The model of asthma was established by OVA induction in male Swiss mice. The monoterpenes were administered (25, 50 or 100 mg/kg, i.p.) 1 h before induction. After 24hs, the animals were sacrificed to leucocytes and TNF-α quantification. Monoterpenes significantly decrease leucocyte migration and TNF-α levels, possibly by modulation of COX, PGE₂ and H1 receptor, as demonstrated by molecular docking. These findings indicate that alcoholic monoterpenes can be an alternative for treatment of allergic inflammation and asthma.

Role of l-arginine/SNAP/NO/cGMP/KATP channel signalling pathway in antinociceptive effect of α-terpineol in mice

OBJECTIVES

The main purpose of this study was to assess the role of l-arginine/SNAP/NO/cGMP/K_ATP channel pathway in analgesic effects of α-terpineol in mice.

METHODS

Male NMRI mice were pretreated intraperitoneally with NO precursor (l-arginine, 100 mg/kg), NO synthase inhibitor (l-NAME, 30 mg/kg), NO donor (SNAP, 1 mg/kg), guanylyl cyclase inhibitor (methylene blue, 20 mg/kg), PDE inhibitor (sildenafil, 0.5 mg/kg), K_ATP channel blocker (glibenclamide, 10 mg/kg) and naloxone (2 mg/kg) 20 min before the administration of α-terpineol. The formalin test was performed 20 min after the administration of α-terpineol, and nociceptive responses of mice were recorded during 30 min.

KEY FINDINGS

A significant and dose-dependent antinociception was produced by α-terpineol (40 and 80 mg/kg) in both the phases of formalin test. The antinociceptive effect of α-terpineol was significantly potentiated by l-arginine in the second phase while significantly antagonized by l-NAME in both phases of formalin test. Also, SNAP and sildenafil non-significantly enhanced-while methylene blue significantly diminished-the antinociceptive effect of α-terpineol in both phases of formalin test. Glibenclamide significantly reversed the α-terpineol-induced antinociception, indicating the involvement of K_ATP channels in antinociceptive effect of α-terpineol.

CONCLUSIONS

These results indicate that the antinociceptive effect of α-terpineol is mediated through l-arginine/SNAP/NO/cGMP/K_ATP channel pathway.

Monoterpenes as a renewable source of biologically active compounds

Monoterpenes and their derivatives play an important role in the creation of new biologically active compounds including drugs. The review focuses on the data on various types of biological activity exhibited by monoterpenes and their derivatives, including analgesic, anti-inflammatory, anticonvulsant, antidepressant, anti-Alzheimer, anti-Parkinsonian, antiviral, and antibacterial (anti-tuberculosis) effects. Searching for novel potential drugs among monoterpene derivatives shows great promise for treating various pathologies. Special attention is paid to the effect of absolute configuration of monoterpenes and monoterpenoids on their activity.

D-limonene exhibits superior antihyperalgesic effects in a β-cyclodextrin-complexed form in chronic musculoskeletal pain reducing Fos protein expression on spinal cord in mice

Chronic musculoskeletal pain is one of the main symptoms found in Fibromyalgia with unclear etiology and limited pharmacological treatment. The aim of this study was to complex LIM in β-cyclodextrin (LIM-βCD) and then evaluate its antihyperalgesic effect in an animal model of chronic musculoskeletal pain. Differential scanning calorimetry and scanning electron microscopy was used for the characterization of the inclusion complex. Male Swiss mice were used for experimental procedures where mechanical hyperalgesia, thermal hyperalgesia, muscular strength, Fos immunofluorescence was studied after induction of hyperalgesia. Mechanism of action was also investigated through tail flick test and capsaicin-induced nociception. Endothermic events and morphological changes showed that the slurry complex method was the best method for the complexation. After induction of hyperalgesia, the oral administration of LIM-βCD (50mg/kg) significantly increased the paw withdrawal threshold compared to uncomplexed limonene. Fos immunofluorescence showed that both compounds significantly decreased the number of Fos-positive cells in the dorsal horn. In nociceptive tests, FLU was able to reverse the antinociceptive effect of LIM-βCD. After intraplantar administration of capsaicin, LIM was able to significantly decrease time to lick. LIM-βCD has antihyperalgesic action superior to its uncomplexed form, with possible action in the dorsal horn of the spinal cord. These results suggest the possible applicability of LIM, uncomplexed or complexed with βCD, in conditions such as FM and neuropathic pain, for which there are currently only limited pharmacological options.

Anti-hyperalgesic effect of Lippia grata leaf essential oil complexed with β-cyclodextrin in a chronic musculoskeletal pain animal model: Complemented with a molecular docking and antioxidant screening

BACKGROUND

Due to its unclear pathophysiology, the pharmacological treatment of fibromyalgia is a challenge for researchers. Studies using medicinal plants, such as those from the genus Lippia, complexed with cyclodextrins (CDs) have shown innovative results.

OBJECTIVE

The present research intended to evaluate the effect of an inclusion complex containing β-cyclodextrin (βCD) inclusion complex with Lippia grata (LG) essential oil in a chronic musculoskeletal pain model, its central activity and its possible interaction with neurotransmitters involved in pain.

METHODS

After acid saline-induced chronic muscle pain, male mice were evaluated for primary and secondary hyperalgesia and muscle strength. Moreover, an antagonist assay was performed to assess the possible involvement of the opioidergic, serotonergic and noradrenergic pathways. In addition, Fos protein in the spinal cord was assessed, and a docking study and antioxidant assays were performed.

RESULTS

The treatment with LG-βCD, especially in the dose of 24mg/kg, was able to significantly decrease (p<0.05) the paw withdrawal and muscle threshold. Furthermore, LG-βCD was shown to affect the opioidergic and serotonergic pathways. There were no significant changes in muscle strength. Fos protein immunofluorescence showed a significant decrease in expression in the dorsal horn of the spinal cord. The main compounds of LG showed through the docking study interaction energies with the alpha-adrenergic and μOpioid receptors. In all antioxidant assays, LG exhibited stronger antioxidant activities than LG-βCD.

CONCLUSION

This study suggested that LG-βCD could be considered as a valuable source for designing new drugs in the treatment of chronic pain, especially musculoskeletal pain.