Eugenol as an anti-stress agent: modulation of hypothalamic-pituitary-adrenal axis and brain monoaminergic systems in a rat model of stress

Chemical Composition, In Vivo, and In Silico Molecular Docking Studies of the Effect of Syzygium aromaticum (Clove) Essential Oil on Ochratoxin A-Induced Acute Neurotoxicity

The aim of our research was to understand the impact of ochratoxin A (OTA) exposure on various physiological and behavioral aspects in adult Wistar rats, and to evaluate the efficacy of a Syzygium aromaticum essential oil (EOC) treatment in restoring the damage caused by this toxin. The essential oils were extracted by hydrodistillation, a yield of 12.70% was obtained for EOC, and the GC-MS characterization of this essential oil revealed that its principal major components are eugenol (80.95%), eugenyl acetate (10.48%), β-caryophyllene (7.21%), and α-humulene (0.87%). Acute OTA intoxication was induced by an intraperitoneal (IP) injection of 289 µg/kg/b.w. every 48 h for 12 doses, resulting in significant reductions in the body and brain weights of exposed rats when compared with controls. The neurobehavioral analysis using several behavioral testing techniques, such as the forced swimming, the dark/light test, the Morris water maze, and the open field test, clearly revealed that OTA exposure causes neurobehavioral disorders, including decreased locomotor activity, a reduced willingness to explore the environment, reflecting a state of stress, anxiety and depression, as well as impaired memory and learning. In addition, OTA intoxication has been associated with metabolic disturbances such as hyperglycemia and hypercortisolemia. However, treatment with EOC mitigated these adverse effects by improving body and brain weights and restoring neurobehavioral function. The in silico analysis revealed significant affinities between clove oils and two tested esterase enzymes (ACh and BuChE) that were more than or similar to the four neurotransmitters "dopamine, serotonin, norepinephrine, and glutamic acid" and the co-crystallized ligands NAG, MES, and GZ5. These results highlight the therapeutic potential of EOC in combating the toxic effects of OTA and pave the way for future research into the mechanisms of action and therapeutic applications of natural compounds in the prevention and treatment of poison-induced diseases.

Anti-Aging Effect of Traditional Plant-Based Food: An Overview

Aging is a complex process that involves many physiological mechanisms that gradually impair normal cellular and tissue function and make us more susceptible to diseases and death. It is influenced by intrinsic factors like cellular function and extrinsic factors like pollution and UV radiation. Recent scientific studies show that traditional plant-based foods and supplements can help mitigate the effects of aging. Nutraceuticals, which are dietary supplements with medicinal properties, have gained attention for their ability to prevent chronic and age-related diseases. Antioxidants like flavonoids, carotenoids, ascorbic acid, terpenes, tannins, saponins, alkaloids, minerals, etc. found in plants are key to managing oxidative stress, which is a major cause of aging. Well-known plant-based supplements from Bacopa monnieri, Curcuma longa, Emblica officinalis, Ginkgo biloba, Glycyrrhiza glabra, and Panax ginseng have been found to possess medicinal properties. These supplements have been shown to improve cognitive function, reduce oxidative stress, improve overall health, and potentially extend life and enhance the excellence of life. The obtained benefits from these plant species are due to the presence of their bioactive secondary metabolites, such as bacosides in Bacopa monnieri, curcumin in Curcuma longa, ginsenosides in Panax ginseng, and many more. These compounds not only protect against free radical damage but also modulate key biological pathways of aging. Also, traditional fermented foods (tempeh and kimchi), which are rich in probiotics and bioactive compounds, support gut health, boost immune function, and have anti-aging properties. The molecular mechanisms behind these benefits are the activation of nutrient-sensing pathways like AMPK, SIRT/NAD+, and mTOR, which are important for cellular homeostasis and longevity. This review shows the potential of traditional plant-based foods and dietary supplements for healthy aging, and more studies are needed to prove their efficacy and safety in humans. Incorporating these natural products into our diet may be a practical and effective way to counteract the effects of aging and overall well-being. The foremost goal of this review is to emphasize the importance of supporting the body's antioxidant system by consuming the right balance of natural ingredients in the diet.

Eugenol relieves the pathological manifestations of Alzheimer's disease in 5×FAD mice

BACKGROUND

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by the accumulation of amyloid-β (Aβ) and excessive neuroinflammation, resulting in neuronal cell death and cognitive impairments. Eugenol, a phenylpropene, is the main component of Syzygium aromaticum L. (Myrtaceae) and has multiple therapeutic effects, including neuroprotective and anti-inflammatory effects, through multimodal mechanisms.

PURPOSE

We aimed to investigate the effect of eugenol on AD pathologies using a 5× familiar AD (5×FAD) mouse model.

METHODS

Eight-month-old 5×FAD and wild-type mice were administered with eugenol (10 or 30 mg/kg/day, p.o) for 2 months. Y-maze and Morris water maze tests were performed to assess the cognitive function of mice. After the behavioral test, molecular analysis was conducted to investigate the therapeutic mechanism of eugenol.

RESULTS

Our findings indicate that eugenol treatment effectively mitigated cognitive impairments in 5×FAD mice. This beneficial effect was associated with a decrease in AD pathologies, including neuronal cell loss and Aβ deposition. Specifically, eugenol inhibited necroptosis activation and increased microglial phagocytosis, which were the underlying mechanisms for the observed reductions in neuronal cell loss and Aβ deposition, respectively.

CONCLUSION

Overall, our data suggest that eugenol would be a potential therapeutic candidate for AD.

Rosinidin inhibits NF-κB/ Nrf2/caspase-3 expression and restores neurotransmitter levels in rotenone-activated Parkinson's disease

Objectives

The examination was sighted to study the preventive effects of rosinidin against rotenone-activated Parkinson's disease in rats.

Methods

Animals were randamoized into five groups: I-saline, II-rotenone (0.5 mg/kg/b.wt.), III- IV-10 and 20 mg/kg rosinidin after rotenone and V-20 mg/kg rosinidin per se for 28 days and were assigned for behavioral analysis., Biochemical parameters i.e. lipid peroxidation, endogenous antioxidants, nitrite level, neurotransmitter levels, proinflammatory biomarkers such as interleukin- 6 (IL-6), tumor necrosis factor-α, IL-1β, nuclear factor kappa B, nuclear factor erythroid 2-related factor 2, and caspase-3 were assessed on the 29th day of the research.

Results

Rosinidin augmented the effectiveness of rotenone on akinesia, catalepsy, forced-swim test, rotarod, and open-field test. Biochemical findings indicated that treatment of rosinidin showed restoring neuroinflammatory cytokines, antioxidants, and neurotransmitter levels in rotenone-injected rats.

Conclusion

As a result of rosinidin treatment, the brain was protected from oxidative stress-induced neuronal damage and inhibited neuroinflammatory cytokines.

Suppression of Chronic Unpredictable Stress-Persuaded Increased Monoamine Oxidase Activity by Taurine Promotes Significant Neuroprotection in Zebrafish Brain

Neuropsychiatric upshots following chronic exposure to unpredictable adverse stressors have been well documented in the literature. Considering the significant impact of chronic unpredictable stress (CUS), the literature is elusive regarding the neuroprotective efficacy of taurine against CUS-induced oxidative stress and chromatin condensation in the zebrafish brain. In this study, to ameliorate CUS-persuaded neurological outcomes, waterborne treatment of taurine as a prophylactic intervention was undertaken. Further, our approach also focused on the gross neurobehavioral response of zebrafish, oxidative stress indices and neuromorphology of the zebrafish brain following CUS exposure with taurine treatment. Because taurine provides significant neuroprotection against oxidative insult, the cytosolic level of monoamine oxidase (MAO) in the zebrafish brain following CUS exposure is worth investigating. Further, as heightened MAO activity is associated with augmented oxidative and chromatin condensation, the focus of this study was on whether taurine provides neuroprotection by downregulating MAO levels in the brain. Our findings show that CUS-persuaded altered neurobehavioral response was significantly rescued by taurine. Moreover, our findings firmly support the hypothesis that taurine acts as a radical neuroprotector by restoring glutathione biosynthesis in the zebrafish brain subsequent to CUS exposure. Additionally, the rising level of brain MAO following chronic exposure to CUS is ameliorated by taurine treatment. These findings strongly advocate the role of taurine as a natural MAO inhibitor through the neuroprotection it provides against CUS-instigated oxidative stress in zebrafish. However, the fundamental neuroprotective mechanism of such natural compounds needs to be elucidated to determine their neuroprotective efficacy against stress regimens.

Antidepressive-Like Effect of Aegle marmelos Leaf Extract in Chronic Unpredictable Mild Stress-Induced Depression-Like Behaviour in Rats

Background

Depression is a psychiatric disorder leading to anhedonia and lack of interest and motivation. Depressive symptoms are triggered by stressful life events, and patients with major depression are at significantly increased risk of attempting suicide. The crucial concern in depression treatment with antidepressant medications is that few weeks are required to show the therapeutic effect along with moderate side effects. The use of herbal medications is a new strategy for the treatment of depression which is often based on medicinal plants.Aegle marmelos (L.) Corr. (family: Rutaceae) is reported to have several actions on the central nervous system producing beneficial effects in anxiety, Alzheimer's disease, Parkinson's disease, epilepsy, and convulsion. Thus, the current investigation designed to assess the antidepressant activity of the standardized hydroethanolic extract of Aegle marmelos (EAM) leaves in male rats exposed to the chronic unpredictable mild stress (CUMS) paradigm.

Methods

Rats were divided in 5 groups. The control group was not subjected to experimental CUMS paradigm, while 4 other groups were subjected to CUMS paradigm to induce depression-like behaviour from day 1 to day 28. Following the CUMS paradigm, 4 groups were divided as CUMS disease control, CUMS+EAM (150 mg/kg, p.o.), CUMS+EAM (300 mg/kg, p.o.), and CUMS+imipramine (15 mg/kg, p.o.), and treatment was given for seven consecutive days to the respective groups (day 29 to day 35). Behavioural parameters such as open field test, forced swim test, sucrose feeding test, and tail suspension test on day 1, day 28, and day 35 were measured, and biochemical parameters such as plasma corticosterone level, serotonergic system (5-HT, 5-HIAA, and 5-HT/5-HIAA), mitochondrial function, and proinflammatory mediators (TNF-α, IL-1β, and IL-6) were estimated in hippocampus (HIP) and prefrontal cortex (PFC) regions of the brain on day 35, after the behavioural observations. On the other hand, phytochemical profile of Aegle marmelos was done.

Results

On day 35, EAM (300 mg/kg) significantly reduced the immobility time during the tail suspension test from 208.66 ± 4.72 s to 108.83 ± 4.81 s and forced swim test from 200.16 ± 4.12 s to 148.5 ± 4.58 s. It also enhanced the behavioural parameters in the open field test such as ambulation from 26.5 ± 2.14 to 56.5 ± 1.80, rearing from 8.33 ± 0.71 to 19 ± 0.57, time spent in centre from 9.16 ± 0.9 to 17.16 ± 0.79 s, total distance travelled from 2.36 ± 0.12 to 4.68 ± 0.10 m, and anhedonia in the sucrose feeding test from 109.33 ± 1.08 to 135.83 ± 3.91 mL. The stimulation of the HPA axis resulting elevated corticosterone level caused by CUMS was reduced by EAM (300 mg/kg) from 80.12 ± 2.020 to 48.25 ± 2.407 μg/dL. Furthermore, EAM (300 mg/kg) increase CUMS-induced changes in serotonin (5-HT) level in HIP and PFC from 3.132 ± 0.09586 to 4.518 ± 0.1812 and 4.308 ± 0.1593 to 5.262 ± 0.1014 ng/mg protein, respectively. EAM (300 mg/kg) significantly attenuated the CUMS-induced changes in proinflammatory cytokine production and mitochondrial function in HIP and PFC. One group used to determine the acute toxicity as per OECD-23 standard protocol which resulted that 300 mg/kg EAM has no significant acute toxicity. Total phenolic content and total flavonoid content of standardized hydroalcoholic extract of AM was found 95.024 ± 2.431 and 36.820 ± 3.41, respectively, and additional identification tests showed the presence of alkaloids, tannins, saponins, cardiac glycosides, flavonoids, and terpenoids.

Conclusion

On the basis of findings, EAM can be inferred as a potential antidepressant-like effect of this plan in preclinical research.

Mechanistic insights into the protective role of eugenol against stress-induced reproductive dysfunction in female rat model

The challenging and highly demanding life rhythm nowadays subjects people to unavoidable chronic stress. Chronic stress is associated with a wide array of serious health complications including neuroendocrine dysregulations. Women are more prone to chronic stress-related hormonal disturbances and their physical and psychological consequences, especially reproductive impairment. Eugenol is a natural phenolic anti-oxidant that has several beneficial biological activities. The current study intended to scrutinize the potential protective effect of eugenol in female Wistar rats exposed to chronic unpredictable mild stress (CUMS). Rats were randomly allocated into 4 groups; group 1 received olive oil, group 2 received eugenol in olive oil, groups 3 and 4 were subjected to CUMS protocol for 8 weeks, with pre- and concomitant treatment with eugenol (50 mg/kg/day; p.o.) in group 4. The results showed that CUMS exposure led to weight loss and depressive-like behaviours. CUMS induced hypothalamic-pituitary-adrenal axis activation with subsequent elevation of serum corticosterone level which, in turn, caused decline in ovarian release of estradiol and antimullerian hormones together with an increased production of follicle-stimulating and luteinizing hormones by the anterior pituitary, leading to reproductive disturbances. In ovaries, CUMS imposed oxidative stress, insulin resistance and molecular damage. Intriguingly, all these adverse effects were significantly mitigated by the administration of eugenol that improved animals' behaviours, corrected corticosterone upsurge, tempered hormonal disturbances, and amended ovarian damage. All biochemical results were further confirmed by hippocampal and ovarian histopathological examinations. In conclusion, the current study highlights the prophylactic role of eugenol against reproductive disturbances induced by chronic stress in female rats.

Comparison of intranasal and intraperitoneal administration of Eugenia caryophyllata (clove) essential oil on spatial memory, anxiety-like behavior and locomotor activity in a pilocarpine-induced status epilepticus rat model

Background

Epilepsy induces behavioral effects and histological changes in the hippocampus. Eugenol, the main component of clove essential oil, has modulatory effects on seizure. We aimed to investigate the effect of intraperitoneal (IP) and intranasal (IN) clove essential oil on cognitive and histological changes during the chronic phase of temporal lope epilepsy.

Methods

Male Wistar rats were divided into eight groups of seven including control, pilocarpine (PLC), clove oil (IP and IN), sesame oil (IP and IN), phenobarbital (positive control) and saline. Rats were injected with 350 mg/kg PLC to induce status epilepticus (SE). We evaluated the effects of 14 days IP (0.1 ml/kg) and IN (0.02 ml/kg) administration of clove essential oil on locomotor/explorative activity, anxiety-like behavior, spatial recognition memory, and hyperexcitability, as well as hippocampal cell survival in PLC-treated rats.

Results

Our findings indicated that clove oil could effectively ameliorate PLC-induced behavioral deficits, and also alleviate neuronal death in the cornu ammonis 1 (CA1) region of the hippocampus. Behavioral results as in the Y-maze, Open field and elevated plus maze featured significant differences between control and treated groups. Post-seizure behavioral battery (PBSS) results explicated that behavioral hyperexcitability were less in clove oil groups (both IN and IP) compared to PLC-treated rats. Moreover, results of this study demonstrated that IN administration of clove oil was more potent in alleviating behavioral impairment at a lower dosage than by IP route. The results of this study, also demonstrated that intranasal administration of clove oil could reduce duration of recurrent seizures.

Conclusion

In summary, clove oil treatment ameliorated histopathological and behavioral consequences of PLC-induced SE.

Effects of eugenol on the behavioral and pathological progression in the MPTP-induced Parkinson's disease mouse model

Parkinson's disease (PD) is the world's second most common neurological disorder. Oxidative stress and neuroinflammation play a crucial role in the pathogenesis of PD. Eugenol is a phytochemical with potent antioxidant and anti-inflammatory activity. The present investigation is aimed to study the effect of eugenol in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced mouse model of PD and its relationship to antioxidant effect. The effects of seven days of oral pre-treatment and post-treatment with three doses of eugenol (25, 50 and 100 mg/kg/day) were investigated against the MPTP-induced PD mouse model. In addition to the assessment of behavioural parameters using various tests (actophotometer, beam walking test, catalepsy, rearing, rotarod), biochemical parameters including lipid peroxidation and reduced glutathione levels in brain tissues, were also estimated in this study. The binding mode of eugenol in the human myeloid differentiation factor-2 (hMD-2) was also studied. Results showed that MPTP administration in mice resulted in the development of motor dysfunction (impaired motor coordination and hypo locomotion) similar to that of PD in different behavioural studies. Pre-treatment with eugenol reversed motor dysfunction caused by MPTP administration while post-treatment with eugenol at a high dose aggravated the symptoms of akinesia associated with MPTP administration. MPTP resulted in increased lipid peroxidation while decreased reduced glutathione levels in the brains of mice. MPTP-induced increased lipid peroxidation and attenuated levels of reduced glutathione were found to be alleviated with eugenol pre-treatment while augmented with eugenol post-treatment. Eugenol showed a binding affinity of -6.897 kcal/mol against the MD2 coreceptor of toll-like receptor-4 (TLR4). Biochemical, as well as neurobehavioral studies, showed that eugenol is having a protective effect, but does not have a curative effect on PD.

Eugenol reduces serum testosterone levels and sperm viability in adult Wistar rats

Eugenol is the main constituent of clove extract. It is a remarkably versatile molecule incorporated as a functional ingredient in several food products and widely applied in the pharmaceutical industry. Men consume natural products enriched with eugenol for treating sexual disorders and using as aphrodisiacs. Nevertheless, there is no information about the impact of eugenol intake on the reproductive parameters of healthy males. Therefore, we provided 10, 20, and 40 mg kg^-1 pure eugenol to adult Wistar rats for 60 days. Testis, epididymis, and spermatozoa were analyzed under microscopic, biochemical, and functional approaches. This phenolic compound did not alter testicular and epididymal biometry and microscopy. However, 20 and 40 mg kg^-1 eugenol reduced serum testosterone levels. The highest dose altered lactate and glucose concentrations in the epididymis. All the eugenol concentrations diminished CAT activity and MDA levels in the testis and increased FRAP and CAT activity in the epididymis. Epididymal sperm from rats receiving 10, 20, and 40 mg kg^-1 eugenol presented high Ca²⁺ ATPase activity and low motility. In conclusion, eugenol at low and high doses negatively impacted the competence of epididymal sperm and modified oxidative parameters in male organs, with no influence on their microscopy.

Lateral Hypothalamus Corticotropin-releasing Hormone Receptor-1 Inhibition and Modulating Stress-induced Anxiety Behavior

INTRODUCTION

Stress is a reaction to unwanted events disturbing body homeostasis and its pathways and target areas. Stress affects the brain through the lateral hypothalamic area (LHA), the orexinergic system that mediates the effect of corticotropin-releasing hormone (CRH) through CRH Receptor Type 1 (CRHr1). Therefore, this study explores the outcome of stress exposure on anxiety development and the involvement of the LHA through LHA-CRHr1.

METHODS

Male Wistar rats (220-250 g) implanted with a cannula on either side of the LHA received acute or chronic stress. Subsequently, exploratory behavior was examined using the Open Field (OF), and anxiety was tested by Elevated Plus Maze (EPM). Before sacrifice, the cerebrospinal fluid (CSF) and the blood were sampled. Nissl stain was performed on fixed brain tissues.

RESULTS

Acute stress reduced exploration in of and increased anxiety in EPM. LHA-CRHr1 inhibition reversed the variables to increase the exploration and decrease anxiety. In contrast, chronic stress did not show any effect on anxiety-related behaviors. Chronic stress decreased the cell population in the LHA, which was prevented by the CRHr1 inhibition. However, the CRHr1 inhibition could not reverse the chronic stress-induced increase in the CSF orexin level. Furthermore, plasma corticosterone levels increased through acute or chronic stress, impeded by the inhibition of CRHr1.

CONCLUSION

Our results recognize LHA-CRHr1 as a capable candidate that modulates acute stress-induced anxiety development and chronic stress-induced changes in the cellular population of the region.

HIGHLIGHTS

Acute stress, increased immobility of the rat in open field and elevated plus maze.Chronic stress, increased orexin production while decreasing neuronal survival.The anxiety and immobility were not developed in presence of CRHr1.CRHr1 blocking reversed the chronic stress changes in corticosterone and orexin.

PLAIN LANGUAGE SUMMARY

Lateral Hypothalamus (LH) is a region involved in sleep and appetite regulation and recently known to play role in stress pathophysiology. The stress mediating function of the LH is performed through Corticotropin Releasing Hormone Receptor type-1 (CRHr1). This study explored the role of LH- CRHr1 in anxiety development and orexin production. Acute and chronic stress affected the behavior and molecular changes, differently. The acute stress increased the anxiety condition, while the chronic stress could only change the molecular criteria. Although we assumed that the inability of the chronic stress to develop anxiety may be attributable to habituation, the chronic stress could increase the plasma corticosterone and orexin level. All of the stress mal-changes in behavior and molecular level prevented by antagonising CRHr1 in the LH, indicating a gating function of LH-CRHr1 for stress development.

Dual pH and Temperature-Sensitive Nanogels Loaded with Eugenol for Regulating Central Nervous System

Fragrances have many biological activities such as anti-anxiety, anti-depression, and improving cognitive memory. However, most fragrances are so volatile that the useful lifespan of the fragrances is very short and excessive fragrance concentration makes us uncomfortable. In this study, dual pH and temperature-sensitive nanogels named EG@CPMONGs were prepared to encapsulate eugenol. This nano-fragrance was then applied to silk. In the following, the effects of EG@CPMO-NGs on the regulation of central nervous systems were evaluated. Open-field tests showed that EG@CPMONGs had an obvious effect on stress relief. Elevated plus-maze tests proved the significant effect of EG@CPMO-NGs on anti-anxiety. Morris water maze tests demonstrated the positive impact of nano-fragrance on spatial learning and memory. Therefore, these dual pH and temperature-sensitive nanogels loaded with eugenol had significant and positive effects on the central nervous system.

Pharmacological Properties and Health Benefits of Eugenol: A Comprehensive Review

The biologically active phytochemicals are sourced from edible and medicinally important plants and are important molecules being used for the formulation of thousands of drugs. These phytochemicals have great benefits against many ailments particularly the inflammatory diseases or oxidative stress-mediated chronic diseases. Eugenol (EUG) is a versatile naturally occurring molecule as phenolic monoterpenoid and frequently found in essential oils in a wide range of plant species. EUG bears huge industrial applications particularly in pharmaceutics, dentistry, flavoring of foods, agriculture, and cosmeceutics. It is being focused recently due to its great potential in preventing several chronic conditions. The World Health Organization (WHO) has declared EUG as a nonmutant and generally recognized as safe (GRAS) molecule. The available literature about pharmacological activities of EUG shows remarkable anti-inflammatory, antioxidant, analgesic, and antimicrobial properties and has a significant effect on human health. The current manuscript summarizes the pharmacological characteristics of EUG and its potential health benefits.

Edible and highly biocompatible nanodots from natural plants for the treatment of stress gastric ulcers

The incidence rate of stress ulcers has increased in recent years, with an increase in life pressure, unavoidable trauma and other factors. The therapy of acute stress ulcers has always been an important challenge. Carbon dots (CDs) have been reported to show excellent biological activities, but research on the stress ulcer curative effect of CDs is unprecedented. Here, we prepared a series of semi-carbonized nanodots (SCNDs) from natural plants or herbs as precursors and the as prepared SCNDs were later proved to be effective in the treatment and inhibition of stress gastric ulcers in a rat model. One kind of SCND from edible and medicinal plants, charred Atractylodes macrocephala (SCNDs-1), is demonstrated in detail for its strong anti-stress gastric ulcer effect with inhibition up to 90% and shows extremely high biocompatibility and ultra-low toxicity. These SCNDs lead to the reduction of inflammatory factors and oxidative stress, and the protection of the gastric mucosa. The SCNDs also reduce the excessive neuroendocrine response caused by stress, regulate the energy metabolism and the structure of intestinal flora, improve the damage to the body caused by the stress state, thus alleviating the occurrence of stress-induced gastric ulcers. This work provides new insights into the preparation of carbon nanomaterials from natural plants through a semi-carbonization process and opens new ways to apply bio-active and bio-safe SCNDs in the modern pharmaceutical field.

Therapeutic effects of eugenol in a rat model of traumatic brain injury: A behavioral, biochemical, and histological study

Background and aim

Traumatic brain injury (TBI) results in death or long term functional disabilities. Eugenol is demonstrated to be beneficial in a range of experimental models of neurological disorders via its anti-inflammatory and antioxidant properties. Thus, the present study was designed to investigate the neuroprotective effects of eugenol in a weight-drop induced rat model of TBI.

Experimental procedure

Rats were assigned into five groups; control and TBI groups pretreated with vehicle, and three TBI groups pretreated with different doses of eugenol (25, 50, and 100 mg/kg/day, p.o., seven consecutive days). Except for the control, all other groups were subjected to TBI using Marmarou’s weight-drop method. 24 h after TBI, locomotor functions and short term memory were evaluated. Lastly animals were scarified and the estimation of lipid peroxidation in brain tissue, blood-brain barrier (BBB) integrity, brain water content (brain edema) and histopathology of the brain tissue were performed.

Results

Weight-drop induced TBI caused functional disabilities in the rats as indicated by impairment in locomotor activities and short term memory. The TBI also resulted in augmented neuronal cell death designated by chromatolysis. The results also showed disruption in the BBB integrity, increased edema, and lipid peroxidation in the brain of the rats exposed to trauma. Pretreatment with eugenol (100 mg/kg) ameliorated histopathological, neurochemical, and behavioral consequences of trauma.

Conclusion

For the first time this study revealed that eugenol can be considered as a potential candidate for managing the functional disabilities associated with TBI because of its antioxidant activities.

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Eugenol pretreatment ameliorated the TBI induced disruption in the BBB integrity and increased brain edema in the rats.

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Eugenol pretreatment in rats mitigated the TBI induced increase in lipid peroxidation and chromatolysis.

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Eugenol pretreatment in rats reduced the TBI induced impairment in memory, locomotor activity, and motor coordination.

Uncaria rhynchophylla ameliorates unpredictable chronic mild stress-induced depression in mice via activating 5-HT1A receptor: Insights from transcriptomics

BACKGROUND

Depression is a pervasive or persistent mental disorder that causes mood, cognitive and memory deficits. Uncaria rhynchophylla has been widely used to treat central nervous system diseases for a long history, although its efficacy and potential mechanism are still uncertain.

PURPOSE

The present study aimed to investigate anti-depression effect and potential mechanism of U. rhynchophylla extract (URE).

STUDY DESIGN AND METHODS

A mouse depression model was established using unpredictable chronic mild stress (UCMS). Effects of URE on depression-like behaviours, neurotransmitters, and neuroendocrine hormones were investigated in UCMS-induced mice. The potential target of URE was analyzed by transcriptomics and bioinformatics methods and validated by RT-PCR and Western blot. The agonistic effect on 5-HT1A receptor was assayed by dual-luciferase reporter system.

RESULTS

URE ameliorated depression-like behaviours, and modulated levels of neurotransmitters and neuroendocrine hormones, including 5-hydroxytryptamine (5-HT), 5-hydroxyindole acetic acid (5-HIAA), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), corticosterone (CORT), corticotropin-releasing hormone (CRH), and adrenocorticotropic hormone (ACTH), in UCMS-induced mice. Transcriptomics and bioinformatics results indicated that URE could regulate glutamatergic, cholinergic, serotonergic, and GABAergic systems, especially neuroactive ligand-receptor and cAMP signaling pathways, revealing that Htr1a encoding 5-HT1A receptor was a potential target of URE. The expression levels of downstream proteins of 5-HT1A signaling pathway 5-HT1A, CREB, BDNF, and PKA were increased in UCMS-induced mice after URE administration, and URE also displayed an agonistic effect against 5-HT1A receptor with an EC50 value of 17.42 μg/ml.

CONCLUSION

U. rhynchophylla ameliorated depression-like behaviours in UCMS-induced mice through activating 5-HT1A receptor.

Mustard Leaf Extract Suppresses Psychological Stress in Chronic Restraint Stress-Subjected Mice by Regulation of Stress Hormone, Neurotransmitters, and Apoptosis

Mustard leaf (Brassica juncea var. crispifolia L. H. Bailey) has been reported to have psychological properties such as anti-depressant activities. However, studies on chronic stress and depression caused by restraint have not been conducted. Therefore, this study aimed to evaluate the effects of a mustard leaf (ML) extract on chronic restraint stress (CRS) in mice. Male mice were subjected to a CRS protocol for a period of four weeks to induce stress. The results showed that the ML extract (100 and 500 mg/kg/perorally administered for four weeks) significantly decreased corticosterone levels and increased neurotransmitters levels in stressed mice. Apoptosis by CRS exposure was induced by Bcl-2 and Bax expression regulation and was suppressed by reducing caspase-3 and poly (ADP-ribose) polymerase expression after treatment with the ML extract. Our results confirmed that apoptosis was regulated by increased expression of brain-derived neurotrophic factor (BDNF). Additionally, cytokine levels were regulated by the ML extract. In conclusion, our results showed that the ML extract relieved stress effects by regulating hormones and neurotransmitters in CRS mice, BDNF expression, and apoptosis in the brain. Thus, it can be suggested that the studied ML extract is an agonist that can help relieve stress and depression.

Was Hawan Designed to Fight Anxiety-Scientific Evidences?

Anxiety is a psychiatric disorder with unknown neurobiology; however, neurotransmitters like gamma-amino butyric acid, norepinephrine and serotonin (5-HT) play crucial roles in mediating anxiety. Present drug modules pose dependence risk to the patient; hence, there is a great need to develop complementary therapies to fight this disorder. Aromatherapy has also been employed in ancient times for a number of mental disorders. Mahamrituanjay Mantra, Om triambkum yajamahe, sughandhim puushtivardhanam, urvarukmev vandhanaat, mrityu mokshay mamritaat!!!!, the part of veda enlightens that aroma gives rise to good health (sughandhim puushtivardhanam). Hawan is a religious practice recommended for mental peace. Hawan is a process in which special herbs are offered in the fire of medicinal woods ignited in a specially designed fire pit. Analysis of literature demonstrates that the components of Hawan are having a number of volatile oils that are specifically useful for prevention and treatment of anxiety through some mechanism of action. Due to high temperature of fire, the vapors of these oils from herbs enter into the central nervous system through nasal route. As per modern science and ancient texts on medicine, nasal drug delivery systems are the best for the diseases related to brain and head. The routine of performing Hawan might keep the threshold value of the therapeutic components in the body and help in preventing anxiety. In the present manuscript, authors highlight and integrate the modern and ancient concepts for treatment and prevention of anxiety through scientific evidences.

Naringin Exhibits Neuroprotection Against Rotenone-Induced Neurotoxicity in Experimental Rodents

Parkinson's disease (PD) is a neurodegenerative disease that is accompanied with the loss of dopaminergic neurons in the substantia nigra pars compacta which subsequently leads to a reduction in the dopamine level in the striatum. The flavonoids are gaining critical attention in the management of PD due to the toxic effects of the synthetic drugs. Naringin, a potent flavonoid, exerts neuroprotective activity against experimental animal models of PD. It also exhibits protective activity against rotenone-induced neurotoxicity in cell line studies. Therefore, the present study was designed to evaluate the therapeutic potential of naringin against rotenone-induced animal model of PD. The rotenone was injected through intracerebroventricular route into substantia nigra pars compacta (SNpc) to induce PD-like manifestations in the male rats. The behavioral deficits of the animals due to dopaminergic toxicity were evaluated in actophotometer, OFT, bar catalepsy, narrow beam walk, rota-rod, grip strength and foot print analysis. Naringin-attenuated rotenone-induced behavioral abnormalities in the experimental rats. Further, naringin reduced the rotenone-induced dopaminergic toxicity in striatum and SNpc the animals. At the sub-cellular level, naringin attenuated the rotenone-induced decrease in the mitochondrial function, integrity and bioenergetics in the SNpc of the animals. Furthermore, naringin reduced the rotenone-induced mitochondria-dependent apoptosis in the rat SNpc. However, Trigonelline significantly abolished the therapeutic effects of naringin on behavioral, biochemical and molecular observations in rotenone-induced PD-like animals. These observations indicate that naringin may exert neuroprotective activity against rotenone-induced toxicity in the animals possibly through Nrf2-mediated pathway. Thus, it can be presumed that naringin could be an alternative option in the management of PD.

Celecoxib potentiates the antianxiety and anticompulsive-like activity of fluoxetine against chronic unpredictable mild stress in experimental animals

Obsessive-compulsive disorder (OCD) is considered a heterogeneous anxiety disorder that includes compulsions. Celecoxib is considered an adjuvant to fluoxetine in the management of OCD in a clinical study. However, the experimental evidence is yet to be established. Therefore, the antianxiety and anticompulsive-like activity of celecoxib (20 mg/kg, orally) was evaluated in the presence or absence of fluoxetine (20 mg/kg, orally) in mice who were exposed to chronic unpredictable mild stress (CUMS) for 14 consecutive days. Seven-day treatment of celecoxib significantly attenuated the CUMS-induced anxiety in open-field, hole-board, elevated plus maze tests, and compulsion in the marble-burying test. Celecoxib significantly reversed the CUMS-induced decrease and increase in the levels of serotonin (5-HT) and its metabolite (5-hydroxyindole acetic acid) in the prefrontal cortex, and attenuated the CUMS-induced increase in the levels of inflammatory markers such as interleukin-6 and tumor necrosis factor-α, and apoptosis marker caspase-3 in the prefrontal cortex. Celecoxib also potentiated the anxiolytic, anticompulsive, serotonergic, anti-inflammatory, and antiapoptotic activity of 7-day treatment with fluoxetine in CUMS-challenged animals compared with their monotherapy. Thus, it can be speculated that the combination of an anti-inflammatory agent with selective serotonin reuptake inhibitor could be a better therapeutic option in the management of stress-related disorders including selective serotonin reuptake inhibitor-resistant OCD.

Calotropis procera attenuates chronic unpredictable mild stress-induced depression in experimental animals

Calotropis procera (CP; Apocynaceae) is reported to have several neuroprotective activities however it's anti-depressant activity yet to be established. Therefore, the present study was proposed to evaluate the anti-depressant activity of the standardized ethanolic extract of CP (ECP) in chronic unpredictable mild stress (CUMS) paradigm exposed male rats. Animals were exposed to CUMS from day-1 (D-1) to D-28 except control group animals of the experimental schedule. ECP (50, 100 and 200 mg/kg, p.o.) and Imipramin (15.0 mg/kg, p.o.) were administered for seven consecutive days after CUMS paradigm. On D-35, ECP (200 mg/kg) significantly attenuated immobility period of the animals in both forced-swim and tail suspension and improved behavioural parameters in open-field and anhedonia in sucrose feeding tests. ECP (200 mg/kg) attenuated CUMS-induced hyperactivity of HPA-axis function. Further, ECP (200 mg/kg) mitigated CUMS-induced decrease in serotonin (5-HT), increase in 5-hydroxy indole acetic acid (5-HIAA) and increase in the ratio of 5-HIAA/5-HT in hippocampus and pre-frontal cortex. The CUMS-induced decrease in the level of expression of BDNF was significantly reversed with ECP (200 mg/kg) treatment. Moreover, ECP (200 mg/kg) significantly reduced the CUMS-induced decrease in the mitochondrial function and integrity in terms of level of formazan formed and intensity of tetramethyl rhodamine methylester dye in both the brain regions respectively. Therefore, ECP (200 mg/kg) mitigates CUMS-induced alterations in the behaviours, HPA-axis function, serotonergic activity, neurogenesis and mitochondrial function in the rodents. Thus, it can be assumed that ECP could be a potential alternative candidate in the management of depression.

Restraint Stress Induced Hyperpermeability and Damage of the Blood-Brain Barrier in the Amygdala of Adult Rats

Intense or prolonged exposure to stress can damage various brain structures, including the amygdala and hippocampus, which are associated with emotional-cognitive functions. Furthermore, this deterioration has been linked to a myriad of neurodegenerative and psychiatric disorders, in particular through disruption of the blood-brain barrier (BBB). However, insights remain scarce concerning the effects and mechanisms associated with stress on the BBB in the amygdala. This study explored the effects of restraint stress on the permeability and integrity of the BBB in the amygdala of male adult SD rats. Serum levels of corticosterone (CORT) and S100B were determined through ELISA. The permeability of the BBB was assessed by measuring Evans Blue (EB) leakage in tissue samples from the rats’ amygdala. These samples were immunostained for markers of tight junctions (Claudin-5, Occludin, ZO-1) and adherens junctions (VE-cadherin), as well as GLUT-1 and AQP-4. Staining was evaluated through confocal microscopy, and the level of expression of these proteins was quantified using the Western Blot (WB) technique. The ultrastructure of brain microvascular endothelial cells was assessed with transmission electron microscopy. Moreover, interleukin-1 beta (IL-1β) content in serum and amygdalar tissues were determined by employing ELISA. Exposure to restraint stress was associated with higher serum levels of S100B and EB leakage in amygdala tissues, especially in days 14 and 21 of the experiment, indicating increased permeability of the BBB. After restraint stress, significant decreases in protein expression were detected for tight junctions, adherens junctions and GLUT-1, while a significant increase was observed for AQP-4. The variation trends of fluorescence intensity generally paralleled these results. Following restraint stress, transmission electron microscopy ascertained enlarged gaps in tight junctions and thickened basal membranes in amygdalar capillaries. In addition, increased IL-1β contents in serum and amygdalar tissues were observed in the restraint-stressed groups. These findings suggest that restraint stress mediates time-dependent alterations in the permeability of the BBB, with modifications in the expression of proteins from tight junctions and adherens junctions, as well as ultrastructural changes in brain microvascular endothelial cells. And it was associated with the inflammation. These alterations may be associated with behavioral and cognitive dysfunctions and neurodegenerative disorders.

Hippocampal orexin receptor blocking prevented the stress induced social learning and memory deficits

Stress as a homeostatic challenge leads to the malfunction of learning and memory processes, namely social learning and memory. The orexin system is involved in stress responses through connections to the hypothalamic-pituitary axis (HPA). In addition, the hippocampus, a structure vulnerable to stress-induced changes, expresses orexin receptors 1 and 2 (OXr1 and OXr2) in various sub-regions. The present study is aimed at assessing the effects of hippocampal orexin receptor blockade on social learning and memory impairments and anxiety development following stress. Male Wistar rats (220-250 g) underwent cannula implantation in the hippocampus. Acute (two mild electric shocks, 5.5 mA) and chronic stresses (ten days of restraint, 6 h daily) were applied with or without injection of orexin receptor antagonists (SB-334867 or TCS OX 29). Sociability and social novelty in animals were assessed in a three-chamber social maze at the end of stress application. Anxiety and exploratory behavior of animals were then examined, with 20 min intervals, using the open field (OF) and elevated plus maze (EPM) tests, respectively. Cisterna Magna cerebro-spinal fluid (CSF) was drained, before sacrifice, for orexin (OX) assay and trunk blood was collected to measure the plasma corticosterone (CRT). Neither the acute nor the chronic stress could affect the sociability. The acute but not chronic stress prevented the animal from sniffing the familiar caged rat in the novelty session, a response which was reversed following the blockade of both OXRs. Furthermore, acute but not chronic stress, led to increased anxiety and immobility behavior which were both impeded by blocking the orexin receptor (OXR). Conversely, OX content in CSF increased due to chronic restraint stress, an effect that was reversed by orexin blockade. Finally, elevated plasma CRT was recorded in response to both acute and chronic stresses. The observed increase in plasma CRT in chronically-stressed rats was abolished following inhibition of OXRs, however a similar effect was not seen in the acute-stress group. Our results identify hippocampal OXRs as potential candidates capable of preventing acute stress-induced impairments of social novelty and anxiety behavior, and chronic stress-induced plasma CRT and CSF orexin, changes. OXR manipulation may improve adaptation to stress pathophysiology.

Recent development in antihyperalgesic effect of phytochemicals: anti-inflammatory and neuro-modulatory actions

INTRODUCTION

Pain is an unpleasant sensation triggered by noxious stimulation. It is one of the most prevalent conditions, limiting productivity and diminishing quality of life. Non steroidal anti inflammatory drugs (NSAIDs) are widely used as pain relievers in present day practice as pain is mostly initiated due to inflammation. However, due to potentially serious side effects, long term use of these antihyperalgesic drugs raises concern. Therefore there is a demand to search novel medicines with least side effects. Herbal products have been used for centuries to reduce pain and inflammation, and phytochemicals are known to cause fewer side effects. However, identification of active phytochemicals of herbal medicines and clear understanding of the molecular mechanism of their action is needed for clinical acceptance.

MATERIALS AND METHODS

In this review, we have briefly discussed the cellular and molecular changes during hyperalgesia via inflammatory mediators and neuro-modulatory action involved therein. The review includes 54 recently reported phytochemicals with antihyperalgesic action, as per the literature available with PubMed, Google Scholar and Scopus.

CONCLUSION

Compounds of high interest as potential antihyperalgesic agents are: curcumin, resveratrol, capsaicin, quercetin, eugenol, naringenin and epigallocatechin gallate (EGCG). Current knowledge about molecular targets of pain and their regulation by these phytochemicals is elaborated and the scope of further research is discussed.

Antidepressant-Like Effect of Lipid Extract of Channa striatus in Postpartum Model of Depression in Rats

Postpartum depression affects 15% of women. Channa striatus, a freshwater fish, is consumed in local Malay population as a rejuvenating diet during postpartum period. This study evaluated the antidepressant-like effect of lipid extract of C. striatus fillet and its mechanism of action in female Sprague-Dawley rats in postpartum model of depression. The rats were ovariectomized and treated with high dose of progesterone and estradiol benzoate for 23 days to have hormone-simulated pregnancy. The day 24 and afterwards were considered as the postpartum period. During the postpartum period, lipid extract was administered at 125, 250, and 500 mg/kg through intraperitoneal route for 15 days. Fluoxetine (10 mg/kg) was used as the positive control. On postpartum day 15, the animals were tested in forced swimming test (FST) and open field test (OFT) followed by biochemical analysis. Withdrawal of hormone administration during the postpartum period induced depressive-like behavior in FST. Administration of lipid extract reversed that depressive-like behavior at 125, 250, and 500 mg/kg in FST. In OFT, it decreased the exploratory activity. The mechanism of the antidepressant-like effect may be mediated through the decrease in plasma corticosterone, increase in plasma oxytocin, and decrease in nuclear factor-kappa B in prefrontal cortex of rats.

Neuroprotective effects of eugenol against aluminiuminduced toxicity in the rat brain

Aluminium (Al) is a neurotoxic metal that contributes to the progression of several neurodegenerative diseases. The aim of the present study was to evaluate the protective effect of dietary eugenol supplementation against aluminium (Al)- induced cerebral damage in rats. Male Wistar rats were divided into four groups: normal controls, rats fed a diet containing 6,000 μg g-1 eugenol, rats intoxicated daily with aluminium chloride (84 mg kg-1 body weight) p. o. and fed either a basal diet or a eugenol-containing diet. Daily oral administration of Al for four consecutive weeks to rats significantly reduced brain total antioxidant status (TAS) (11.42±0.31 μmol g-1 tissue, p<0.001) with a subsequent significant enhancement of lipid peroxidation (MDA) (32.55±1.68 nmol g-1 tissue, p<0.002). In addition, Al enhanced brain acetylcholinesterase activity (AChE) (46.22±4.90 U mg-1 protein, p<0.001), tumour necrosis factor alpha (TNF-α) (118.72±11.32 pg mg-1 protein, p<0.001), and caspase 3 (Casp-3) (8.77±1.26 ng mg-1 protein, p<0.001) levels, and in contrast significantly suppressed brain-derived neurotrophic factor (BDNF) (82.74±14.53 pg mg-1 protein, p<0.002) and serotonin (5-HT) (1.54±0.12 ng mg-1 tissue, p<0.01) levels. Furthermore, decreased glial fibrillary acidic protein (GFAP) immunostaining was noticed in the striatum of Al-intoxicated rats, compared with untreated controls. On the other hand, co-administration of dietary eugenol with Al intoxication restored brain BDNF (108.76±2.64 pg mg-1 protein) and 5-HT (2.13±0.27 ng mg-1 tissue) to normal levels, enhanced brain TAS (13.43±0.24 μmol g-1 tissue, p<0.05), with a concomitant significant reduction in TNF-α (69.98±4.74 pg mg-1 protein) and Casp-3 (3.80±0.37 ng mg-1 protein) levels (p<0.001), as well as AChE activity (24.50±3.25 U mg-1 protein, p<0.001), and increased striatal GFAP immunoreactivity, compared with Al-treated rats. Histological findings of brain tissues verified biochemical data. In conclusion, eugenol holds potential as a neuroprotective agent through its hydrophobic, antioxidant, and anti-apoptotic properties, as well as its neurotrophic ability against Al-induced brain toxicity in rats.

Chemical composition of Ocimum sanctum by LC-ESI-MS/MS analysis and its protective effects against smoke induced lung and neuronal tissue damage in rats

Smoke induced oxidative stress is known to cause various cancers and associated health problems including lung cancer. Herbal extracts have been reported as antioxidant supplements which attenuate free radical induced oxidative damage of tissues, among which Ocimum sanctum has been reported as the elixir of life due to its innumerable health benefits. In the present study, we investigated the protective effect of O. sanctum against cracker smoke induced lung and brain tissue damage. The results of the study demonstrate that O. sanctum regulates the hematological and serum biochemical parameters such as RBC, WBC, blood urea nitrogen and creatinine kinase. O. sanctum supplementation inhibited oxidative stress as analyzed by SOD, CAT enzyme levels and i-NOS, HSP-70 protein expression. O. sanctum administration also regulated neurotransmitter levels, such as serotonin, dopamine, and regulated acetylcholine esterase levels which play a vital role in neuronal function. Further O. sanctum treatment also preserved the morphology of lung and brain tissues of smoke stress induced rats as observed by histopathology and transmission electron microscope analysis. The biodistribution of O. sanctum was showed its accumulation in key tissues such as kidney, liver, lungs and heart. The LC-ESI-MS/MS analysis of O. sanctum showed the presence of polyphenols, flavonoids and fatty acids which might be responsible for the observed anti-stress effects.

Essential oil eugenol: sources, extraction techniques and nutraceutical perspectives

Graphical representation regarding sources, extraction techniques and nutraceutical perspectives of eugenol.

Anti-stress Activity of Ocimum sanctum: Possible Effects on Hypothalamic-Pituitary-Adrenal Axis

The present study investigated anti-stress potential of Ocimum sanctum in chronic variable stress (CVS) paradigm. Further, the possible mechanism of anti-stress was explored in vitro using cell and cell-free assays. Rats were administered O. sanctum followed by CVS regimen for a period of 16 days. On days 4, 8, 12, and 16, body weight and immobility time in forced swim test were measured. In addition, the possible inhibitory effect of O. sanctum and ursolic acid on cortisol release and CRHR1 receptor activity were studied in cell-based assays, while inhibitory effects on 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and catechol-O-methyltransferase (COMT) were studied in cell-free assays. CVS group demonstrated less body weight gain and higher immobility time than O. sanctum administered groups, while oral administration of O. sanctum significantly increased body weight gain and decreased the immobility time. Further, O. sanctum and its constituents inhibited cortisol release and exhibited a significant CRHR1 receptor antagonist activity. Also, they had specific inhibitory activity towards 11β-HSD1 and COMT activity. Thus, O. sanctum was found to be effective in the management of stress effects, and anti-stress activity could be due to inhibition of cortisol release, blocking CRHR1 receptor, and inhibiting 11β-HSD1 and COMT activities. Copyright © 2016 John Wiley & Sons, Ltd.

Protective effect of eugenol against restraint stress-induced gastrointestinal dysfunction: Potential use in irritable bowel syndrome

CONTEXT

Eugenol, an essential constituent found in plants such as Eugenia caryophyllata Thunb. (Myrtaceae) is reported to possess neuroprotective and anti-stress activities. These activities can potentially be useful in the treatment of stress-induced irritable bowel syndrome (IBS).

OBJECTIVE

The protective effect of eugenol was assessed against restraint stress (RS)-induced IBS-like gastrointestinal dysfunction in rats. Further, its centrally mediated effect was evaluated in this model.

MATERIALS AND METHODS

Eugenol (12.5, 25, and 50 mg/kg), ondansetron (4.0 mg/kg, p.o.), and vehicle were administered to rats for 7 consecutive days before exposure to 1 h RS. One control group was not exposed to RS-induction. The effect of eugenol (50 mg/kg) with and without RS exposure was evaluated for mechanism of action and per se effect, respectively. The hypothalamic-pituitary-adrenal cortex (HPA)-axis function was evaluated by estimating the plasma corticosterone level. The levels of brain monoamines, namely serotonin, norepinephrine, dopamine, and their metabolites were estimated in stress-responsive regions such as hippocampus, hypothalamus, pre-frontal cortex (PFC), and amygdala. Oxidative damage and antioxidant defenses were also assessed in brain regions.

RESULTS

Eugenol (50 mg/kg) reduced 80% of RS-induced increase in fecal pellets similar to that of ondansetron. Eugenol attenuated 80% of stress-induced increase in plasma corticosterone and modulated the serotonergic system in the PFC and amygdala. Eugenol attenuated stress-induced changes in norepinephrine and potentiated the antioxidant defense system in all brain regions.

CONCLUSION

Eugenol protected against RS-induced development of IBS-like gastrointestinal dysfunction through modulation of HPA-axis and brain monoaminergic pathways apart from its antioxidant effect.

Risperidone Attenuates Modified Stress-Re-stress Paradigm-Induced Mitochondrial Dysfunction and Apoptosis in Rats Exhibiting Post-traumatic Stress Disorder-Like Symptoms

Mitochondria play a significant role in the pathophysiology of post-traumatic stress disorder (PTSD). Risperidone and paroxetine were evaluated for their effect on mitochondrial dysfunction and mitochondria-dependent apoptosis in discrete brain regions in modified stress re-stress (SRS) animal model of PTSD. Male rats were subjected to stress protocol of 2 h restraint and 20 min forced swim followed by halothane anesthesia on day 2 (D-2). Thereafter, rats were exposed to re-stress (forced swim) on D-8 and at 6-day intervals on D-14, D-20, D-26, and D-32. The rats were treated with risperidone (0.01, 0.1, and 1.0 mg/kg p.o.) and paroxetine (10.0 mg/kg p.o.) from D-8 to D-32. Risperidone at median dose and paroxetine ameliorated modified SRS-induced depressive-like symptom (increase in immobility period) in forced swim, anxiety-like behavior (decrease in percentage of open arm entries and time spent) in elevated plus maze and cognitive deficits (loss in spatial recognition memory) in Y-maze tests on D-32. Risperidone, but not paroxetine, attenuated modified SRS-induced decreases in plasma corticosterone levels. Risperidone ameliorated increase in the activity of mitochondrial respiratory complex (I, II, IV, and V), decreases in the levels of mitochondrial membrane potential, cytochrome-C and caspase-9 in the hippocampus, hypothalamus, pre-frontal cortex, and amygdala. However, both drugs attenuated modified SRS-induced increase in the number of apoptotic cells and caspase-3 levels in all the brain regions indicating anti-apoptotic activity of these drugs. Hence, these results suggest that anti-apoptotic activity could be a common mechanism for anti-PTSD-like effect irrespective of the pathways of apoptosis in the modified SRS model.

Diazepam potentiates the antidiabetic, antistress and anxiolytic activities of metformin in type-2 diabetes mellitus with cooccurring stress in experimental animals

Psychological stress is considered as one of the limiting factors in the management of type-2 diabetes mellitus (T2DM). Therefore, the basic objective of the present study was to evaluate the antidiabetic effect of metformin, diazepam, and their combination in cooccurring T2DM and stress condition (DMS). T2DM was induced in the male rats by administering streptozotocin (45 mg/kg, i.p.) and nicotinamide (110 mg/kg, i.p.) with time lag of 15 min. Rats were subjected to two sessions of cold restraint stress paradigm for one hour on the sixth and seventh day after streptozotocin injection. Administration of metformin (25 mg/kg, p.o.) and diazepam (1 mg/kg, p.o.) in combination from the seventh to thirteenth day after streptozotocin injection showed better improvement in glucose tolerance and insulin sensitivity compared to monotherapy of either drug. In addition, the combination significantly attenuated DMS-induced hyperglycemia, hypertriglyceridaemia, hypercorticosteronemia, anxiety-like behavior, and insulin resistance through modulating insulin signaling pathway in the liver compared to monotherapy. Further, improvement of mitochondrial function, integrity, and oxidative stress in hippocampus, hypothalamus, prefrontal cortex, striatum, amygdala, and nucleus accumbens was observed with the combination. Therefore, metformin in combination with diazepam may be a better therapeutic option in the management of T2DM with cooccurring stress condition.

Citalopram protects against cold-restraint stress-induced activation of brain-derived neurotrophic factor and expression of nuclear factor kappa-light-chain-enhancer of activated B cells in rats

The present study evaluates the protective effect of citalopram against cold-restraint stress (CRS) paradigm. Rats were pretreated with citalopram (0.1, 1.0, and 10.0 mg/kg) acutely and repeatedly for 21 days before exposure to the CRS procedure. None of the doses of citalopram attenuated CRS-induced gastric ulcers in the acute study. In contrast, repeated pretreatment of citalopram at a dose level of 0.1 mg/kg attenuated the CRS-induced gastric ulcers. Citalopram (0.1 mg/kg) diminished CRS-induced increase in plasma corticosterone, but not plasma norepinephrine level in the chronic study indicating its effect on hypothalamic-pituitary-adrenal axis function. Repeated citalopram (0.1 mg/kg) pretreatment attenuated CRS-induced changes in serotonin turnover in the hippocampus and amygdala. Moreover, repeated pretreatment with citalopram (0.1 mg/kg) mitigated the CRS-induced increase in the expression of brain-derived neurotrophic factor (BDNF) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) in the hippocampus and amygdala. These results suggest that there is a region- and a dose-specific effect of citalopram on CRS-induced BDNF-NFκB activation. Therefore, citalopram showed antistress activity in the CRS model through changes in the stress-responsive pathways such as hypothalamic-pituitary-adrenal-axis and brain serotonergic system apart from decreasing the expression of BDNF and NFκB.

Asparagus racemosus attenuates anxiety-like behavior in experimental animal models

Asparagus racemosus Linn. (AR) is used worldwide as a medicinal plant. In the present study, the anxiolytic activity of standardized methanolic extract of root of AR (MAR) was evaluated in open-field test (OFT), hole-board, and elevated plus maze (EPM) tests. Rats received oral pretreatment of MAR in the doses of 50, 100, and 200 mg/kg daily for 7 days and then were evaluated for the anxiolytic activity in different animal models. Both MAR (100 and 200 mg/kg) and diazepam (1 mg/kg, p.o.) increased the grooming behavior, number of central squares crossed, and time spent in the central area during OFT. Further, MAR (100 and 200 mg/kg) increased the head-dip and head-dip/sniffing behavior, and decreased sniffing activity in hole-board test. Furthermore, MAR (100 and 200 mg/kg) increased the percentage entries and time spent to open arm in EPM test paradigm. The anxiolytic activity in the experimental models was similar to that of diazepam. MAR (100 and 200 mg/kg) enhanced the level of amygdalar serotonin and norepinephrine. It also increased the expression of 5-HT2A receptors in the amygdala. In another set of experiment, flumazenil attenuated the anxiolytic effect of minimum effective dose of MAR (100 mg/kg) in OFT, hole-board, and EPM tests, indicating GABAA-mediated mechanism. Moreover, the anxiolytic dose of MAR did not show sedative-like effect in OFT and EPM tests compared to diazepam (6 mg/kg, p.o.). Thus, the anxiolytic response of MAR may involve GABA and serotonergic mechanisms. These preclinical data show that AR can be a potential agent for treatment of anxiety disorders.

Composition of Essential Oil from Aerial and Underground Parts of Geum rivale and G. urbanum Growing in Poland

A study of the composition of essential oils from aerial and underground parts of Geum rivale L. and Geum urbanum L. growing in Poland led to the identification of 130 compounds. The main compound of the essential oil from underground parts of G. urbanum was eugenol (69.2%), whereas cis-myrtanal (53.3%) was the major constituent of the essential oil from roots of G. rivale. The essential oils from aerial parts of the plants contained large amounts of aliphatic compounds with ( Z)-3-hexenol (38.4%) being the dominant constituent of the essential oil from aerial parts of G. urbanum and 1-octen-3-ol (33.9%) from G. rivale.

Asparagus racemosus modulates the hypothalamic-pituitary-adrenal axis and brain monoaminergic systems in rats

OBJECTIVES

Asparagus racemosus (AR) is classified as an adaptogen, an important medicinal plant and food. Even though AR is widely used as food and nutraceutical, it has only been evaluated in the context of experimental disorders. Hence, the present study was designed to evaluate the effect of standardized methanolic extract of AR (MAR) on experimentally un-manipulated animals to observe the per se effects on stress pathways.

METHODS

MAR (50, 100, and 200 mg/kg, per oral) was administered for 7 days. Lorazepam (0.5 mg/kg, intraperitoneal) was used as a positive control. On the seventh day, plasma was collected for the estimation of corticosterone (CORT) and norepinephrine (NE), and brain was microdissected into hippocampus, hypothalamus (HYP), pre-frontal cortex, amygdala, and nucleus accumbens to estimate tissue level of monoamines (serotonin, dopamine, and NE), their metabolites, and turnover.

RESULTS

MAR dose-dependently decreased the plasma CORT and NE levels, indicating its effects on the hypothalamic-pituitary-adrenal cortex axis and the sympathetic-noradrenergic system, respectively. MAR increased the levels of all monoamines in the HYP. However, MAR showed region-specific changes in monoamines and their metabolites, and turnover in other brain regions.

DISCUSSION

MAR showed a physiological modulation of the stress pathways. Interestingly, in most brain regions the change in monoaminergic systems was limited by a ceiling effect at a dose of 100 mg/kg. These observations could explain the traditional use of AR as an adaptogen and a functional food.