Anticonvulsant, sedative, anxiolytic and antidepressant activities of the essential oil of Annona vepretorum in mice: Involvement of GABAergic and serotonergic systems

Cannabinoid treatments in epilepsy and seizure disorders

Cannabis has been used to treat convulsions and other disorders since ancient times. In the last few decades, preclinical animal studies and clinical investigations have established the role of cannabidiol (CBD) in treating epilepsy and seizures and support potential therapeutic benefits for cannabinoids in other neurological and psychiatric disorders. Here, we comprehensively review the role of cannabinoids in epilepsy. We briefly review the diverse physiological processes mediating the central nervous system response to cannabinoids, including Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol, and terpenes. Next, we characterize the anti- and proconvulsive effects of cannabinoids from animal studies of acute seizures and chronic epileptogenesis. We then review the clinical literature on using cannabinoids to treat epilepsy, including anecdotal evidence and case studies as well as the more recent randomized controlled clinical trials that led to US Food and Drug Administration approval of CBD for some types of epilepsy. Overall, we seek to evaluate our current understanding of cannabinoids in epilepsy and focus future research on unanswered questions.

An insight review on the neuropharmacological effects, mechanisms of action, pharmacokinetics and toxicity of mitragynine

Mitragynine is one of the main psychoactive alkaloids in Mitragyna speciosa Korth. (kratom). It has opium-like effects by acting on μ-, δ-, and κ-opioid receptors in the brain. The compound also interacts with other receptors, such as adrenergic and serotonergic receptors and neuronal Ca2+ channels in the central nervous system to have its neuropharmacological effects. Mitragynine has the potential to treat diseases related to neurodegeneration such as Alzheimer's disease and Parkinson's disease, as its modulation on the opioid receptors has been reported extensively. This review aimed to provide an up-to-date and critical overview on the neuropharmacological effects, mechanisms of action, pharmacokinetics and safety of mitragynine as a prospective psychotropic agent. Its multiple neuropharmacological effects on the brain include antinociceptive, anti-inflammatory, antidepressant, sedative, stimulant, cognitive, and anxiolytic activities. The potential of mitragynine to manage opioid withdrawal symptoms related to opioid dependence, its pharmacokinetics and toxic effects were also discussed. The interaction of mitragynine with various receptors in the brain produce diverse neuropharmacological effects, which have beneficial properties in neurological disorders. However, further studies need to be carried out on mitragynine to uncover its complex mechanisms of action, pharmacokinetics, pharmacodynamic profiles, addictive potential, and safe dosage to prevent harmful side effects.

Sclareol exerts synergistic antidepressant effects with quercetin and caffeine, possibly suppressing GABAergic transmission in chicks

This study evaluated the effects of sclareol (SCL) with or without caffeine (CAF) and quercetin (QUR) using in-vivo and in-silico studies. For this, 5-day-old chicks weighing between 45 and 48 g were randomly divided into five groups and treated accordingly. The chicks were monitored to compare the occurrence, latency, and duration of sleep as well as the loss and gain of righting reflex in response to SCL-10 mg/kg, CAF-10 mg/kg, and QUR-50 mg/kg using a thiopental sodium (TS)-induced sleeping model. Data were analyzed by one-way ANOVA followed by t-Student-Newman-Keuls' as a posthoc test at 95% confidence intervals with multiple comparisons. An in-silico study was also performed to investigate the possible antidepressant mechanisms of the test and/or standard drugs with different subunits of GABAA receptors. In comparison to the SCL, CAF, and QUR individual groups, SCL+CAF+QUR significantly increased the latency while decreasing the length of sleep. The incidence of loss and gain of the righting reflex was also modulated in the combination group. SCL showed better interaction with GABAA (α2 and α5) subunits than QUR with α2, α3, and α5. All these compounds showed stronger interactions with the GABAA receptor subunits than the standard CAF. Taken together, SCL, CAF, and QUR reduced the TS-induced righting reflex and sleeping time in the combination group more than in the individual treatments. SCL may show its antidepressant effects, possibly through interactions with GABAA receptor subunits.

Evaluation of 28-day repeated doses oral toxicity of essential oil from Psidium glaziovianum Kiaersk leaves on various biological parameters in Swiss mice

Only a small number of the many medicinally important species in the genus Psidium L. have had their safety assessed. Psidium glaziovianum, a plant native to Brazil, is reported to exert antinociceptive and anti-inflammatory effects; however, there are no apparent reports of long-term safety following administering of repeated doses. The aim of this study was to examine the effects of 28-day oral of treatment at 250, 500 or 1,000 mg/kg Psidium glaziovianum essential oil (PgEO) on behavioral and physiological parameters in male and female Swiss mice. First, PgEO was chemically characterized by gas chromatography mass spectrometry (GC-MS). The following parameters were examined: motor activity, body temperature, blood glucose, urine, hematology, biochemistry, histology, and oxidative stress. Characterization of PgEO revealed 48 components which were dominated by sesquiterpenes 1,8-cineol (24.29%), α-pinene (19.73%) and β-pinene (17.31%). Data showed that PgEO treatment in mice increased activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) without markedly affecting body weight, hematological or biochemical parameters, as well as water or food consumption. Administration of PgEO in repeated daily dosages over 28 days did not significantly alter exploratory or locomotor activities. Based upon our findings, PgEO administration daily for 28 days, exhibited low toxicity and absence of effects on the nervous system. Data demonstrated that PgEO produced hypoglycemic and antioxidant actions which need to be considered in safety assessment.

Nose-to-brain delivery of perampanel formulated in a self-microemulsifying drug delivery system improves anticonvulsant and anxiolytic activity in mice

Perampanel (PER) is a potent third-generation antiepileptic drug only available for oral administration. Additionally, PER has shown potential in managing epilepsy comorbidities such as anxiety. Previously, we demonstrated that the intranasal (IN) administration of PER, loaded in a self-microemulsifying drug delivery system (SMEDDS), improved brain-targeting and exposure in mice. Herein, we investigated PER brain biodistribution, its anticonvulsant and anxiolytic effects, and its potential olfactory and neuromotor toxicity after IN administration to mice (1 mg/kg). PER showed a rostral-caudal brain biodistribution pattern when administered intranasally. At short times post-nasal dosing, high PER concentrations were found in olfactory bulbs (olfactory bulbs/plasma ratios of 1.266 ± 0.183 and 0.181 ± 0.027 after IN and intravenous administrations, respectively), suggesting that a fraction of the drug directly reaches brain through the olfactory pathway. In maximal electroshock seizure test, IN PER protected 60% of mice against seizure development, a substantially higher value than the 20% protected after receiving oral PER. . PER also demonstrated anxiolytic effects in open field and elevated plus maze tests. Buried food-seeking test showed no signs of olfactory toxicity. Neuromotor impairment was found in rotarod and open field tests at the times of PER maximum concentrations after IN and oral administrations. Nevertheless, neuromotor performance was improved after repeated administrations. Compared with IN vehicle, PER IN administration decreased brain levels of L-glutamate (0.91 ± 0.13 mg/mL vs 0.64 ± 0.12 mg/mL) and nitric oxide (100 ± 15.62% vs 56.62 ± 4.95%), without interfering in GABA levels. Altogether, these results suggest that the IN PER delivery through the developed SMEDDS can be a safe and promising alternative to oral treatment, which support the design of clinical studies to evaluate the IN PER delivery to treat epilepsy and neurological-related conditions as anxiety.

In silico molecular modeling, neuro-behavioral profile, and toxicity assessment of the essential oil of Ferula gummosa Boiss. as an anti-seizure agent

ETHNOPHARMACOLOGICAL RELEVANCE

Ferula gummosa Boiss., known in Persian as "Baridje," belongs to the Apiaceae family. All parts of this plant, especially the root, contain galbanum. Galbanum, the oleo-gum resin of F. gummosa, is one of the essential traditional herbal medicines in Iran, which is used as a tonic for epilepsy and chorea, memory enhancement, gastrointestinal diseases, and wound healing.

AIM OF THE STUDY

We investigated the toxicity, anticonvulsant effects, and molecular modeling of the essential oil (EO) distilled from the oleo-gum resin of F. gummosa.

MATERIALS AND METHODS

Gas chromatography-mass spectrometry was used to identify the EO components. The cytotoxicity of EO on HepG2 cell lines was assessed by the MTT method. Male mice were arranged as follows: negative control groups (sunflower oil (10 ml/kg, i.p.) or saline (10 ml/kg, p.o.)), EO groups (0.5, 1, 1.5, and 2.5 ml/kg, p.o.), and positive control groups (ethosuximide (150 mg/kg, p.o.) or diazepam (1.0 or 2 mg/kg, i.p.)). The motor coordination and neurotoxicity of EO were studied using the rota-rod test. Open-field, novel object recognition, and passive avoidance learning tests were used to investigate the effect of EO on locomotor activity and memory function. An acute pentylenetetrazole-induced seizure model was utilized to evaluate the anticonvulsant properties of the EO. The interaction of the EO main components with the GABA_A receptor was investigated by coarse-grained molecular dynamics simulations.

RESULTS

β-pinene, sabinene, α-pinene, and ρ-cymene were the main components of EO. The IC₅₀ of the EO at 24, 48, and 72 h was found to be 59.90, 12.96, and 3.93 μl/ml, respectively. No adverse effects were observed in memory, motor coordination, and locomotor activity in mice treated with EO. Administration of EO (1, 1.5, and 2.5 ml/kg) improved survival rates in mice receiving pentylenetetrazole (PTZ; to induce an epileptic seizure). Sabinene was able to bind to the binding site of benzodiazepines at the GABA_A receptor.

CONCLUSIONS

Acute treatment with the EO of F. gummosa caused antiepileptic effects and could effectively increase the survival rate in PTZ-treated mice with no significant toxicity.

Antidepressant Effects of Essential Oils: A Review of the Past Decade (2012-2022) and Molecular Docking Study of Their Major Chemical Components

Depression is a mental disorder that affects more than 300 million people worldwide. The medications available for treatment take a long time to exhibit therapeutic results and present several side effects. Furthermore, there is a decrease in the quality of life of people suffering from this affliction. Essential oils are traditionally used to relieve the symptoms of depression due to the properties of the constituents of these oils to cross the blood-brain barrier acting on depression-related biological receptors associated with reduced toxicity and side effects. In addition, compared to traditional drugs, they have several administration forms. This review provides a comprehensive assessment of studies on plants whose essential oil has exhibit antidepressant activity in the past decade and the mechanism of action of the major components and models tested. An additional in silico study was conducted with the frequent compounds in the composition of these essential oils, providing a molecular approach to the mechanism of action that has been reported in the past decade. This review is valuable for the development of potential antidepressant medications in addition to providing a molecular approach to the antidepressant mechanism of action of the major volatile compounds that have been reported in the past decade.

Anxiolytic-like effects of citral in the mouse elevated plus maze: involvement of GABAergic and serotonergic transmissions

Citral, a monoterpene which is a part of the essential oil of several medicinal plants, is generally regarded as safe for human and animal consumption. Studies have introduced citral as a functional component of some essential oils in anxiolytic and antidepressant therapies; however, the neuropharmacological characteristics of citral have not yet been reported. In the present study, we evaluated the anxiolytic activities of citral in comparison to two standard anxiolytics, diazepam and buspirone, in Swiss albino mice by intraperitoneal administration of 1, 2, 5, 10, and 20 mg/kg using elevated plus maze (EPM) and open-field test (OFT). Moreover, we also examined whether the GABA_A-benzodiazepine and 5-HT_1A receptor are involved in the anxiolytic-like effects of citral by pretreatment with flumazenil and WAY-100635, respectively. Citral dose-dependently decreased the number of border crossings and time spent in borders, and also the number of grooming and rearing in OFT without altering the exploratory behavior of mice. In the EPM, this monoterpene led to a significant increase in number of entries in open arms and time spent in open arms, as well as a decrease in time spent in closed arms. Pretreatment with flumazenil and WAY-100635 both could reverse the anxiolytic effects of the citral in the EPM. These results suggest that anxiolytic activity of citral occurs via the GABA_A and 5-HT_1A receptor modulation.

Neuroprotective Natural Products’ Regulatory Effects on Depression via Gut–Brain Axis Targeting Tryptophan

L-tryptophan (Trp) contributes to regulating bilateral communication of the gut–brain axis. It undergoes three major metabolic pathways, which lead to formation of kynurenine, serotonin (5-HT), and indole derivatives (under the control of the microbiota). Metabolites from the principal Trp pathway, kynurenic acid and quinolinic acid, exhibit neuroprotective activity, while picolinic acid exhibits antioxidant activity, and 5-HT modulates appetite, sleep cycle, and pain. Abnormality in Trp plays crucial roles in diseases, including depression, colitis, ulcer, and gut microbiota-related dysfunctions. To address these diseases, the use of natural products could be a favorable alternative because they are a rich source of compounds that can modulate the activity of Trp and combat various diseases through modulating different signaling pathways, including the gut microbiota, kynurenine pathway, and serotonin pathway. Alterations in the signaling cascade pathways via different phytochemicals may help us explore the deep relationships of the gut–brain axis to study neuroprotection. This review highlights the roles of natural products and their metabolites targeting Trp in different diseases. Additionally, the role of Trp metabolites in the regulation of neuroprotective and gastroprotective activities is discussed. This study compiles the literature on novel, potent neuroprotective agents and their action mechanisms in the gut–brain axis and proposes prospective future studies to identify more pharmaceuticals based on signaling pathways targeting Trp.

Anxiolytic and antidepressant-like effects of monoterpene tetrahydrolinalool and in silico approach of new potential targets

INTRODUCTION- The drugs currently available for treatment of anxiety and depression act through modulation of the neurotransmission systems involved in the neurobiology of the disorder, yet they of-ten present side effects, which can impair patient adherence to treatment. METHOD- This, has driven the search for new molecules with anxiolytic and antidepressant potential. Aromatic plants are rich in essential oils, and their chemical constituents, such as monoterpenes, are be-ing studied for these disorders. This study aims to evaluate the anxiolytic and antidepressant-like poten-tial of the monoterpene tetrahydrolinalool in in vivo animal models, and review pharmacological targets with validation through molecular docking. Male Swiss mice (Mus musculus) were treated with THL (37.5-600 mg kg-1 p.o.) and submitted to the elevated plus maze, open field, rota rod, and forced swim tests. In the elevated plus-maze, THL at doses of 37.5 and 75 mg kg-1 induced a significant increase in the percentage of entries (72.7 and 64.3% respectively), and lengths of stay (80.3 and 76.8% respective-ly) in the open arms tests. RESULT- These doses did not compromise locomotor activity or motor coordination in the animals. In the open field, rota rod tests, and the forced swimming model, treatment with THL significantly reduced immobility times at doses of 150, 300, and 600 mg kg-1, and by respective percentages of 69.3, 60.9 and 68.7%. CONCLUSION- In molecular docking assay, which investigated potential targets, THL presented sat-isfactory energy values for: nNOs, SGC, IL-6, 5-HT1A, NMDAr, and D1. These demonstrate the po-tential of THL (a derivative of natural origin) in in vivo and in silico models, making it a drug candidate.

Behavioral Pharmacology of Five Uncommon Passiflora Species Indicates Sedative and Anxiolytic-like Potential

BACKGROUND

There are over 500 species in the Passiflora genus, and while some of them are very well known in folk medicine for their anxiolytic effects, very little is known for the other genus representants, which could also present medicinal effects.

OBJECTIVE

In this study, we performed an interspecific pharmacological comparison of five little investigated Passiflora species, all native to Brazil: P. bahiensis, P. coccinea, P. quadrangularis, P. sidaefolia, and P. vitifolia.

METHOD

Extracts were administered to mice before behavioral testing, which included a general pharmacological screening and anxiolytic-like effect investigation.

RESULTS

Three of the species [P. coccinea, P. quadrangularis, and P. sidaefolia] induced a decrease in locomotor activity of mice; P. coccinea also reduced the latency to sleep. Importantly, none of the species interfered with motor coordination. Oral administration evoked no severe signs of toxicity even at higher doses. Regarding the anxiolytic-like profile, P. sidaefolia reduced the anxious-like behavior in the Holeboard test in a similar way to the positive control, Passiflora incarnata, while not affecting total motricity.

CONCLUSION

These results indicate that P. coccinea, P. quadrangularis, and P. sidaefolia reduced the general activity of mice and confer a calmative/sedative potential to these three species, which must be further elucidated by future investigations.

Antinociceptive and anti-inflammatory effects of hydrazone derivatives and their possible mechanism of action in mice

Pain and inflammation are unpleasant experiences that usually occur as a result of tissue damage. Despite the number of existing analgesic drugs, side effects limit their use, stimulating the search for new therapeutic agents. In this sense, five hydrazone derivatives (H1, H2, H3, H4, and H5), with general structure R1R2C = NNR3R4, were synthesized with molecular modification strategies. In this paper, we describe the ability of hydrazone derivatives to attenuate nociceptive behavior and the inflammatory response in mice. Antinociceptive activity was evaluated through acetic acid-induced writhing and formalin-induced nociception tests. In both experimental models, the hydrazone with the greatest potency (H5) significantly (p < 0.05) reduced nociceptive behavior. Additionally, methods of acute and chronic inflammation induced by different chemicals (carrageenan and histamine) were performed to evaluate the anti-inflammatory effect of H5. Moreover, molecular docking analysis revealed that H5 can block the COX-2 enzyme, reducing arachidonic acid metabolism and consequently decreasing the production of prostaglandins, which are important inflammatory mediators. H5 also changes locomotor activity. In summary, H5 exhibited relevant antinociceptive and anti-inflammatory potential and acted on several targets, making it a candidate for a new multi-target oral anti-inflammatory drug.

Essential Oils from Annonaceae Species from Brazil: A Systematic Review of Their Phytochemistry, and Biological Activities

The present work involves a systematic review of the chemical composition and biological effects of essential oils from the Annonaceae species collected in Brazil from 2011 to 2021. Annonaceae is one of the most important botanical families in Brazil, as some species have economic value in the market as local and international fruit. In addition, the species have useful applications in several areas-for instance, as raw materials for use in cosmetics and perfumery and as medicinal plants. In folk medicine, species such as Annona glabra L. and Xylopia sericea A. St.-Hil. are used to treat diseases such as rheumatism and malaria. The species of Annonaceae are an important source of essential oils and are rich in compounds belonging to the classes of mono and sesquiterpenes; of these compounds, α-pinene, β-pinene, limonene, (E)-caryophyllene, bicyclogermacrene, caryophyllene oxide, germacrene D, spathulenol, and β-elemene are the most abundant. The antimicrobial, anti-inflammatory, antileishmania, antioxidant, antiproliferative, cytotoxic, larvicidal, trypanocidal, and antimalarial activities of essential oils from the Annonaceae species in Brazil have been described in previous research, with the most studies on this topic being related to their antiproliferative or cytotoxic activities. In some studies, it was observed that the biological activity reported for these essential oils was superior to that of drugs available on the market, as is the case of the essential oil of the species Guatteria punctata (Aubl.) R. A. Howard., which showed a trypanocidal effect that was 34 times stronger than that of the reference drug benznidazol.

Medicinal Plants in the Treatment of Depression: Evidence from Preclinical Studies

Medicinal plants and their extracts are natural remedies with enormous potential for treating various diseases, including depression and anxiety. In the case of depression, hundreds of plants have traditionally been used in folk medicine for generations. Different plant extracts and natural products have been analyzed as potential antidepressant agents with validated models to test for antidepressant-like effects in animals, although other complementary studies have also been employed. Most of these studies focus on the possible mediators implicated in these potential effects, with dopamine, serotonin, and noradrenaline being the principal neurotransmitters implicated, both through interference with receptors and with their metabolism by monoamino oxidases, as well as through neuro-endocrine and neuroprotective effects. There are approximately 650 reports of antidepressant-like medicinal plants in PubMed; 155 of them have been compiled in this review, with a relevant group yielding positive results. Saffron and turmeric are the most relevant species studied in both preclinical and clinical studies; St. John's wort or kava have also been tested extensively. To the best of our knowledge, no review to date has provided a comprehensive understanding of the biomolecular mechanisms of action of these herbs or of whether their potential effects could have real benefits. The purpose of this narrative review is to provide an update regarding medicinal plants from the year 2000 to the present to examine the therapeutic potential of these antidepressant-like plants in order to contribute to the development of new therapeutic methods to alleviate the tremendous burden that depression causes worldwide.

Anxiolytic and antidepressant-like effects of essential oil from the fruits of Piper nigrum Linn. (Black pepper) in mice: involvement of serotonergic but not GABAergic transmission system

In this study, the anxiolytic activity of Piper nigrum essential oil (PNEO) was evaluated in the elevated plus maze (EPM) and the antidepressant-like effect was evaluated through tail suspension test (TST) in mice. Flumazenil, a competitive inhibitor of GABA_A receptor in the benzodiazepine site and WAY-100635 maleate salt, a 5-HT_1A receptor antagonist were used to find out the possible mechanism(s) of action of PNEO. To exclude the false-positive results due to the enhancement of the locomotor activity, the animals were submitted to open field test (OFT). We also measured monoamines levels of the mice brain after acute PNEO treatment. The data obtained from the study suggest that the anxiolytics and antidepressant-like effect of PNEO have observed in EPM and TST respectively in a dose-dependent manner after oral acute and repetitive treatment. WAY-100635, but not flumazenil was able to reverse the effect of PNEO in EPM and TST both, indicating the possible involvement of 5-HT_1A receptor. The neurochemical analysis showed no alteration in monoamine levels in mice brains. Furthermore, no locomotor impairment or sign of toxicity or changes in body weight or abnormalities in the biochemical parameters, except for a significant decrease in total cholesterol level was observed after treatment with PNEO. The findings suggest that Piper nigrum EO possesses a dual anxiolytic and antidepressant-like effect through the possible involvement of serotonergic transmission.

Herbal Medicine in the Treatment of Epilepsy

Epilepsy is one of the most common disorders of the central nervous system. Although epilepsy is common worldwide, approximately 80% of epileptic patients live in the developing countries or those with low-middle income. Up until the second decade of the 20th century, epilepsy was treated mostly by traditional remedies. Today, antiepileptic drugs are used as a general treatment instead to prevent and control epileptic seizures. However, patient access to these drugs is hindered due to the healthcare systems of their countries and a number of other reasons, such as cultural, socio-demographic, and financial poverty. In addition, approximately 30-40%of epileptic patients suffer from refractory epilepsy, additionally, AEDs have adverse side-effects that can lead to treatment failure or reduce the patient's quality of life. Despite recent advances in the treatment of epilepsy, there is still a need for improving medical treatment with a particular focus on efficacy, safety, and accessibility. Since herbal medicines have been used for many centuries around the world for treating epilepsy, it is, therefore, plausible that a rigorous study on herbal medicine and phytochemical components within plants of various species and origin may lead to the discovery of novel AEDs. Nowadays, many medicinal plants used in different cultures and regions of the world have been identified. Most phytochemical components of these plants have been identified and, in some cases, their targets located. Therefore, it is possible that new, effective, and accessible anticonvulsants drugs can be obtained from a medicinal plant.

Modulation of the Serotonergic Receptosome in the Treatment of Anxiety and Depression: A Narrative Review of the Experimental Evidence

Serotonin (5-HT) receptors are found throughout central and peripheral nervous systems, mainly in brain regions involved in the neurobiology of anxiety and depression. 5-HT receptors are currently promising targets for discovering new drugs for treating disorders ranging from migraine to neuropsychiatric upsets, such as anxiety and depression. It is well described in the current literature that the brain expresses seven types of 5-HT receptors comprising eighteen distinct subtypes. In this article, we comprehensively reviewed 5-HT1-7 receptors. Of the eighteen 5-HT receptors known today, thirteen are G protein-coupled receptors (GPCRs) and represent targets for approximately 40% of drugs used in humans. Signaling pathways related to these receptors play a crucial role in neurodevelopment and can be modulated to develop effective therapies to treat anxiety and depression. This review presents the experimental evidence of the modulation of the “serotonergic receptosome” in the treatment of anxiety and depression, as well as demonstrating state-of-the-art research related to phytochemicals and these disorders. In addition, detailed aspects of the pharmacological mechanism of action of all currently known 5-HT receptor families were reviewed. From this review, it will be possible to direct the rational design of drugs towards new therapies that involve signaling via 5-HT receptors.

Identification of VOCs in essential oils extracted using ultrasound- and microwave-assisted methods from sweet cherry flower

The floral fragrance of plants is an important indicator in their evaluation. The aroma of sweet cherry flowers is mainly derived from their essential oil. In this study, based on the results of a single-factor experiment, a Box-Behnken design was adopted for ultrasound- and microwave-assisted extraction of essential oil from sweet cherry flowers of the Brooks cultivar. With the objective of extracting the maximum essential oil yield (w/w), the optimal extraction process conditions were a liquid-solid ratio of 52 mL g^-1, an extraction time of 27 min, and a microwave power of 435 W. The essential oil yield was 1.23%, which was close to the theoretical prediction. The volatile organic compounds (VOCs) of the sweet cherry flowers of four cultivars (Brooks, Black Pearl, Tieton and Summit) were identified via headspace solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). The results showed that a total of 155 VOCs were identified and classified in the essential oil from sweet cherry flowers of four cultivars, 65 of which were shared among the cultivars. The highest contents of VOCs were aldehydes, alcohols, ketones and esters. Ethanol, linalool, lilac alcohol, acetaldehyde, (E)-2-hexenal, benzaldehyde and dimethyl sulfide were the major volatiles, which were mainly responsible for the characteristic aroma of sweet cherry flowers. It was concluded that the VOCs of sweet cherry flowers were qualitatively similar; however, relative content differences were observed in the four cultivars. This study provides a theoretical basis for the metabolism and regulation of the VOCs of sweet cherry flowers.

Natural volatile oils derived from herbal medicines: A promising therapy way for treating depressive disorder

Depression is a common global mental disorder that seriously harms human physical and mental health. With the development of society, the increase of pressure and the role of various other factors make the incidence of depression increase year by year. However, there is a lack of drugs that have a fast onset, significant effects, and few side effects. Some volatile oils from traditional natural herbal medicines are usually used to relieve depression and calm emotions, such as Lavender essential oil and Acorus tatarinowii essential oil. It was reported that these volatile oils, are easy to enter the brain through the blood-brain barrier and have good antidepressant effects with little toxicity and side effects. In this review, we summarized the classification of depression, and listed the history of using volatile oils to fight depression in some countries. Importantly, we summarized the anti-depressant natural volatile oils and their monomers from herbal medicine, discussed the anti-depressive mechanisms of the volatile oils from natural medicine. The volatile oils of natural medicine and antidepressant drugs were compared and analyzed, and the application of volatile oils was explained from the clinical use and administration routes. This review would be helpful for the development of potential anti-depressant medicine and provide new alternative treatments for depressive disorders.

Effects of Cassava Juice (Manihot esculenta Crantz) on Renal and Hepatic Function and Motor Impairments in Male Rats

Cassava (Manihot esculenta Crantz) is a plant that contains neurotoxins such as linamarin and lotaustraline. Its long-term consumption is associated with neuronal damage and contributes to the development of motor impairment in humans and rats. We investigated the effects of the consumption of cassava juice on renal and hepatic function and motor impairments in male rats. The rats received the vehicle, non-toxic and toxic doses of cassava juice, or linamarin as a pharmacological control, over 35 consecutive days. The effects were evaluated in an open field test, rotarod, and swim test. The toxic cassava dose and linamarin resulted in motor impairments in the rotarod and swim test from day 7 of treatment. The toxic cassava dose and linamarin increased the parameters that indicate renal and hepatic damage, with the exception of total protein and albumin levels. Behavioral variables that show motor incoordination (i.e., latency to fall in the rotarod) were negatively correlated with biochemical parameters of renal and kidney damage, whereas spin behavior was positively correlated. Our data indicate that chronic oral consumption of cassava juice caused renal and hepatic damage that was correlated with motor coordination impairment in rats, similarly to their principal neurotoxic compound, linamarin.

Anxiolytic properties of Cymbopogon citratus (DC.) stapf extract, essential oil and its constituents in zebrafish (Danio rerio)

ETHNOPHARMACOLOGICAL RELEVANCE

Cymbopogon citratus (DC.) Stapf (Poaceae) leaves is often consumed as infusion in folk medicine due to its therapeutic properties. This plant is also rich in essential oil, which has several beneficial effects to the human health. It is known that medications commonly used to treat anxiety disorders cause undesirable side effects. Thus, it is important to evaluate the anxiolytic effects of natural products from plants, such as C. citratus, as an alternative therapy to treat these disorders.

OBJECTIVE

The aim of this study was to investigate the anxiolytic properties of C. citratus essential oil (EO), hydroalcoholic extract (E1), citral (CIT), geraniol (GER) and the mixture of these terpenoids, as well as its possible mechanism of action by using zebrafish as an anxiety model.

METHODS

Adult zebrafish were treated (by immersion) with C. citratus EO, E1, CIT and/or GER. The anxiolytic effects were analyzed by using the light-dark test. The mechanism involved in the anxiolytic effects was further investigated by the coadministration of flumazenil (FMZ), an antagonist of GABA_A receptors. The total polyphenols (phenolic and flavonoid compounds) content of E1 was determined by using spectrophotometric assays.

RESULTS

All analyzed samples showed a remarkable anxiolytic effect on zebrafish in the highest concentrations, as the animals showed a preference for the light side of the tank. Furthermore, the observed effect of EO, E1, CIT and GER was reversed by pre-treatment with FMZ, suggesting that GABAergic receptors were involved in the anxiolytic effect displayed by these samples. The association between CIT and GER in the lowest studied concentrations showed an interesting synergistic behavior on anxiolytic effect observed in light-dark test. Besides, it was demonstrated that E1 was constituted by phenolic and flavonoid compounds, which could be involved in the observed effect.

CONCLUSION

This work has proved that the low-cost zebrafish can be an adequate alternative as an animal model to evaluate the anxiolytic effect of C. citratus and its related compounds. Moreover, the involvement of GABA_A receptors could be responsible for the effect showed by the samples. These obtained results can potentially validate the ethnopharmacological use of C. citratus as a medicinal plant for the treatment of anxiety disorders in folk medicine.

Vitexin Possesses Anticonvulsant and Anxiolytic-Like Effects in Murine Animal Models

Different types of epilepsy and forms of pathological anxiety have been described as significant neurological disorders that may exist as comorbidities. Some of those disorders share the association of affected limbic areas/neuropathological triggers as well as the use of drugs for their clinical management. The aim of this work was to investigate the anticonvulsant and anxiolytic properties of the vitexin (apigenin-8-C-glucoside), since this compound is a flavonoid usually found as one of the major constituents in several medicinal plants claimed as anxiolytics and/or anticonvulsants. This investigation was performed by the use of a series of classical murine animal models of chemically induced-seizures and of anxiety-related tests (open-field, elevated plus-maze, and light-dark box tests). Here, we show that the systemic administration of vitexin (1.25; 2.5 and 5 mg/kg; i.p.) exhibited selective protection against chemically-induced seizures. Vitexin did not block seizures evoked by glutamate receptors agonists (NMDA and kainic acid), and it did not interfere with the latencies for these seizures. Conversely, the same treatments protected the animals in a dose-dependent manner against the seizures evoked by the Gabaergic antagonists picrotoxin and PTZ and rise the latency time for the first seizure on non-protected animals. The higher dose of vitexin protected 100% of animals against the tonic-clonic seizures triggered by GABA antagonists. The results from open-field, elevated plus-maze, and light-dark box tests indicated the anxiolytic properties of vitexin at similar range of doses described for the anticonvulsant action screening. Furthermore, these results pointed that vitexin did not cause sedation or locomotor impairment on animals. The selective action of vitexin against picrotoxin and PTZ may reinforce the hypothesis by which this compound acts mainly by the modulation of GABAergic neurotransmission and/or related pathways. This could be useful to explain the dual activity of vitexin as anticonvulsant and anxiolytic, and highlight the pharmacological interest on this promising flavonoid.

The Effects of Essential Oils and Terpenes in Relation to Their Routes of Intake and Application

Essential oils have been used in multiple ways, i.e., inhaling, topically applying on the skin, and drinking. Thus, there are three major routes of intake or application involved: the olfactory system, the skin, and the gastro-intestinal system. Understanding these routes is important for clarifying the mechanisms of action of essential oils. Here we summarize the three systems involved, and the effects of essential oils and their constituents at the cellular and systems level. Many factors affect the rate of uptake of each chemical constituent included in essential oils. It is important to determine how much of each constituent is included in an essential oil and to use single chemical compounds to precisely test their effects. Studies have shown synergistic influences of the constituents, which affect the mechanisms of action of the essential oil constituents. For the skin and digestive system, the chemical components of essential oils can directly activate gamma aminobutyric acid (GABA) receptors and transient receptor potential channels (TRP) channels, whereas in the olfactory system, chemical components activate olfactory receptors. Here, GABA receptors and TRP channels could play a role, mostly when the signals are transferred to the olfactory bulb and the brain.

Dose-Dependent, Antidepressant, and Anxiolytic Effects of a Traditional Medicinal Plant for the Management of Behavioral Dysfunctions in Animal Models

The present work was carried out to assess the Onosma bracteatum anxiolytic and antidepressant properties. Swiss albino mice (male) were fed orally with hydroalcoholic extract at different doses 50, 100, and 200 mg 1 hour prior to test with the standard diazepam and fluoxetine. Anxiolytic and antidepressant activities were evaluated by using open field, elevated plus maze, force swimming, and tail suspension test. Results of open field test showed an increase in number of line crossing as well as number of rearing in dosage-dependent design. Although results of elevated plus maze test evidently showed antianxiety effect of O bracteatum by increasing the time spent in open arms along with decreasing the time spent in closed arms in dosage-dependent way. For the evaluation of antidepressant effect, O bracteatum diminished the immobility time and expanded mobility time in forced swim model in dosage-dependent way. Likewise, O bracteatum expanded time span of mobility along with diminished immobility time in tail suspension method in dosage-dependent way. Outcome demonstrated that plant at the dose of 200 mg/kg body weight showed significant potential which was similar to that standard diazepam and fluoxetine. Hence, O bracteatum may be used as potent natural psychotherapeutic agent against the mental disorders.