Anxiolytic Effect of Satureja montana Dry Extract and its Active Compounds Rosmarinic Acid and Carvacrol in Acute Stress Experimental Model.

BACKGROUND: Anxiety disorders are an important not only medical, but also social problem, affecting approx. 300 million people worldwide in 2019. Medications used in the treatment of anxiety are associated with many adverse reactions, which explains the increased use of herbal products as anxiolytics. METHODS: An anxiolytic activity of Satureja montana, rosmarinic acid and carvacrol after 14-day long administration on an animal model of acute stress was studied. For measurement of anxiolytic effect elevated plus maze, social interaction and Vogel tests were provided as well as examination of locomotor activity. RESULTS: The dry extract of Satureja montana at both tested doses significantly increased locomotor activity as well as the time spent in the social recognition, compared to the control groups. The extract reduced the time in the closed arms and the proportion of entries into open arms to total entries and increased the time in the open arms of elevated plus maze compared to the positive control group. Likewise, rosmarinic acid and carvacrol increased significantly the time spent with a new congener in the social interaction test. Both compounds reduced the ratio of entries into open arms to total entries similarly to the dry extract of Satureja montana. Only rosmarinic acid increased the time in the open arms and reduced the time in the closed arms. CONCLUSIONS: Satureja montana at both experimental doses exerted a significant anxiolytic activity in almost all the tests employed for evaluating anxious behavior. Carvacrol and rosmarinic acid showed a moderate anxiolytic effect.

Biological Screening of Novel Structural Analog of Celecoxib as Potential Anti-Inflammatory and Analgesic Agent.

Background and objectives: The clinical use of non-steroidal anti-inflammatory drugs is limited due to high incidence of adverse drug reactions. The pyrrole heterocycle is included in the chemical structure of a number of drugs with various activities and shows relatively good tolerability and safety. The objectives of our study were to evaluate the analgesic and anti-inflammatory activity, as well as possible organ toxicity, of 2-[3-acetyl-5-(4-chloro-phenyl)-2-methyl-pyrrol-1-yl]-3-(1H-indol-3-yl)-propionic acid (compound 3g), a novel N-pyrrolylcarboxylic acid structurally similar to celecoxib. Materials and methods: All experiments were performed on 6-week-old male Wistar rats divided into parallel groups (n = 8). Antinociception was assessed using animal pain models with thermal and chemical stimuli (paw withdrawal, tail-flick, and formalin tests). Criteria for the analgesic effect were increased latency in the paw withdrawal and tail-flick tests and decreased paw licking time in the formalin test compared to animals treated with saline (control). Anti-inflammatory activity was measured using a carrageenan-induced paw edema model; the criterion for anti-inflammatory effect was decreased edema compared to control. Blood samples were obtained after animals were sacrificed to assess possible organ toxicity. Statistical analysis was performed with IBM SPSS 20.0. Results: 2-[3-Acetyl-5-(4-chloro-phenyl)-2-methyl-pyrrol-1-yl]-3-(1H-indol-3-yl)-propionic acid had analgesic action against chemical stimulus after single and multiple administration and against thermal stimulus after single administration. Compound 3g significantly suppressed carrageenan-induced paw edema after both single and continuous administration. After continuous administration, hematological tests showed that compound 3g decreased leukocyte and platelet levels and elevated serum creatinine levels. Conclusions: Antinociception with the tested compound is most likely mediated by spinal, peripheral, and anti-inflammatory mechanisms. Possible tolerance of the analgesic action at the spinal level develops after continuous administration. Anti-inflammatory activity is significant and probably the leading cause of antinociception. After multiple administration, compound 3g showed signs of potential nephrotoxicity and antiplatelet activity, as well as suppression of leukocyte levels.

In Vivo Evaluation of Anti-inflammatory Activity of 2-[3-Acetyl- 5-(4-chloro-phenyl)-2-methyl-pyrrol-1-yl]-4-methylsulfanylbutyric Acid.

BACKGROUND: Persisting inflammatory stimuli cause chronic inflammation recognized as the major factor contributing to the development of a number of diseases. One group of drugs used in the treatment of chronic inflammation is the group of non-steroidal anti-inflammatory drugs and, more specifically, the selective COX-2 inhibitors (coxibs). However, most of the coxibs were withdrawn from the market in view of their safety profile. In the present study, 2-[3-Acetyl-5-(4-chlorophenyl)- 2-methyl-pyrrol-1-yl]-4-methylsulfanyl-butyric acid (compound 3e), an Npyrrolylcarboxylic acid derivative structurally related to celecoxib, is evaluated for anti-inflammatory activity after single and multiple (14 days) administration using an animal inflammation model. AIM: To evaluate the anti-inflammatory properties of 2-[3-Acetyl-5-(4-chlorophenyl)-2-methyl-pyrrol-1-yl]-4-methylsulfanyl-butyric acid (compound 3e) after single and multiple (14 days) administration using an animal inflammation model. MATERIALS AND METHODS: Forty Wistar rats were allocated into 5 groups (n=8) treated with saline (controls), diclofenac (25 mg/kg b.w.), compound 3e (10, 20 and 40 mg/kg b.w.) intraperitoneally. The volume of the right hind paw of the animals of all groups is measured prior to treatment and two, three and four hours after administration of carrageenan using a plethysmometer (Ugo Basile, Italy). The percentage of paw edema is calculated using the Trinus formula. RESULTS: In a single administration, compound 3e in doses of 10 and 20 mg/kg b.w. did not inhibit paw edema, while a dose of 40 mg/kg b.w. significantly inhibited carrageenan-induced paw edema at 2 hours in comparison with the control group. After continuous administration, compound 3e in doses of 10, 20 and 40 mg/kg b.w. significantly reduced paw edema at 2, 3, and 4 hours compared to animals treated with saline. CONCLUSIONS: Compound 3e shows anti-inflammatory properties similar to those of diclofenac after continuous administration.

Experimental Study of the Analgesic Effect of the Antidepressant Escitalopram.

BACKGROUND: Antidepressants have been found to possess antinociceptive and analgesic properties and are prescribed in the treatment of chronic pain. AIM: To evaluate the antinociceptive properties of escitalopram after a single administration. MATERIALS AND METHODS: Forty Wistar rats were used in the study. They were divided into 5 groups (n=8) treated with saline solution (control group), metamizole (150 mg/kg b.w.), escitalopram (5, 10 and 20 mg/kg b.w.) intraperitoneally. The nociceptive tests we used employed thermal (hot plate and plantar test), mechanical (analgesimeter) and chemical (formalin test) stimuli. Criteria for analgesic effect were increased latency in hot plate, plantar test, analgesimeter and decreased paw licking time in formalin test. RESULTS: The reference analgesic metamizole showed significant analgesic effect in all tests excluding the first phase with formalin. Escitalopram in doses of 5 and 20 mg/kg b.w. increased paw withdrawal latency in analgesimeter at 2 hours compared to control. Escitalopram in a dose of 5 mg/kg b.w. increased the duration of the stay on the hot plate at 1 hour, while doses of 10 and 20 mg/kg b.w. significantly increased this indicator at 1 and 3 hours in comparison to the saline treated group. In the plantar test, escitalopram in all used doses significantly increased the nociceptive response latency compared to control. A dose of 5 mg/kg b.w. decreased hind paw licking time during phase 1 of the formalin test, whereas doses of 10 and 20 mg/kg b.w. decreased phase 2 licking time compared to the control group. CONCLUSION: The antidepressant escitalopram has analgesic properties but they are not dose- or time-dependent.

Experimental study on the role of 5-HT2 serotonin receptors in the mechanism of anti-inflammatory and antihyperalgesic action of antidepressant fluoxetine.

INTRODUCTION: Fluoxetine is an antidepressant that has anti-inflammatory and antihyperalgesic effects in experimental models of pain and inflammation. The AIM of the present study was to determine the role of 5-HT2 receptors in the mechanism of anti-inflammatory and antihyperalgesic action of fluoxetine after single and repeated administration of the drug. MATERIALS AND METHODS: 40 male Wistar rats were randomly divided in five groups (n = 8) treated for 14 days with saline (control), diclofenac (positive control), fluoxetine, cyproheptadine (5-HT2 antagonist), and fluoxetine + cyproheptadine, respectively. We used the experimental model of inflammation induced by intraplantar injection of carrageenan and nociceptive test with mechanical pressure on the inflamed hind paw. RESULTS: Single and repeated administration of fluoxetine showed that it had significant anti-inflammatory and antihyperalgesic effects when compared with the control (p < 0.05). Cyproheptadine did not change significantly the anti-inflammatory effect of fluoxetine in the first 4 hours, after a single administration. At 24 hours the combination did not differ statistically when compared with the control. Cyproheptadin did not change significantly the anti-inflammatory effect of fluoxetine after repeated administration. After prolonged treatment the group that received fluoxetine + cyproheptadine showed a statistically significant increase in paw pressure to withdraw the hind paw compared with that treated with fluoxetine alone (p < 0.05). CONCLUSIONS: Fluoxetine has anti-inflammatory and antihyperalgesic effects in the carrageenan model of inflammation. 5-HT2 receptor mediated its anti-inflammatory effect in single dose treated animals. Spinal 5-HT2 receptors are involved in the antihyperalgesic effect of fluoxetine after repeated administration.

Study on anti-inflammatory and immunomodulatory effects of clomipramine in carrageenan- and lipopolysaccharide-induced rat models of inflammation.

The aim of the present study was to evaluate the anti-inflammatory effect of clomipramine in carrageenan- and lipopolysaccharide-induced (LPS-induced) models of inflammation by investigating the changes in serum levels of the pro-inflammatory cytokine TNF-α and the anti-inflammatory cytokines IL-10 and TGF-ß after single and repeated administration of the drug. In order to study the effect of single and repeated doses of clomipramine on carrageenan-induced paw oedema, male Wistar rats were divided in five groups (n = 8): control, positive control group and three experimental groups treated with 5, 10 and 20 mg/kg bw clomipramine, respectively. The effect of single and repeated doses of clomipramine on serum cytokine levels was studied as animals were divided in four groups: two control groups treated with saline and two experimental groups treated with clomipramine 20 mg/kg bw. Carrageenan and LPS were injected immediately after clomipramine or saline injection. Serum cytokine concentrations were tested by enzyme immunoassay. Following acute administration only the highest dose that was used inhibited the carrageenan-induced inflammation. Oedema inhibition was observed with 5, 10 and 20 mg/kg bw clomipramine after repeated administration. Single and repeated administration of clomipramine at a dose of 20 mg/kg bw did not significantly change the serum levels of TGF-1ß, IL-10 and TNF-α when compared to the controls in carrageenan-induced inflammation. Following LPS-induced inflammation clomipramine significantly increased the serum levels of TGF-1ß after repeated administration and decreased TNF-α in rats after single-dose and repeated pretreatment with 20 mg/kg bw clomipramine. A significant increase in the levels of IL-10 in relation to this inflammatory model was observed only in single dose treated animals. Clomipramine possesses an anti-inflammatory effect in the carrageenan-induced model of exudative inflammation. In LPS-induced inflammation, clomipramine showed an immunomodulatory effect, decreasing TNF-α and increasing TGF-1ß after repeated administration, and increasing IL-10 after a single dose.

Effect of testosterone propionate on erythropoiesis after experimental orchiectomy.

INTRODUCTION: Androgen deficiency anemia occurs most frequently in pharmacogenic suppression of androgen synthesis or with advancing age in men. Bilateral orchiectomy is a surgical modality used in the treatment of metastatic prostate carcinoma. It is accompanied by marked decrease in circulating serum levels of androgens. AIM: The aim of the experimental study was to determine the effect of substitution therapy with testosterone propionate (TP) on some haematological parameters of erythropoiesis in male rats after orchiectomy. MATERIAL AND METHODS: Eighty Wistar male rats with mean weight of 252.3 g were used in the study. The animals were allocated into 2 control orchidectomized groups, 2 sham-operated groups and 4 experimental orchidectomized groups. Testosterone propionate was administered intramuscularly, once a week at a dose of 4 mg and 8 mg per kilogram of body weight for 15 days and for 15 weeks. Erythrocyte count was performed and hemoglobin and hematocrit levels were measured. RESULTS: In the chronic experiment there was a significant decrease in red blood cells and hemoglobin, and a tendency of decrease in hematocrit after orchiectomy. The effect of TP on erythropoiesis in orchiectomised rats is dose-dependent. CONCLUSION: TP replacement therapy in doses of 4 mg/kg and 8 mg/kg has a stimulating effect on erythropoiesis only in chronic administration.

Cannabidiol improves memory and decreases IL-1ß serum levels in rats with lipopolysaccharide-induced inflammation.

AIM: Memory improving and anti-inflammatory properties of cannabidiol (CBD) were investigated in an experimental model of lipopolysaccharide (LPS)-induced inflammation.

Antinociceptive effect of clomipramine through interaction with serotonin 5-HT2 and 5-HT3 receptor subtypes.

INTRODUCTION: Tricyclic antidepressants are used in the treatment of various pain syndromes. The antidepressant clomipramine inhibits predominantly the reuptake of serotonin in the central nervous system. The mechanism of its analgesic effect is not fully understood. The AIM of the present study was to find experimentally any dose-effect dependence in the analgesic effect of clomipramine and the involvement of the 5-HT2 and 5-HT3 receptors in the mechanism of this effect. MATERIAL AND METHODS: Fifty male Wistar rats were used in the study allocated to five groups (10 animals each): a saline treated control group, one positive control group treated with metamizole and three experimental groups treated with intraperitoneally administered clomipramine in doses of 5, 10 and 20 mg/kg bw, respectively. To study the role of 5-HT2 and 5-HT3 receptors in this effect we used another five groups (10 animals each): control, positive control and three experimental groups treated with clomipramine only, clomipramine and granisetrone and clomipramine and cyproheptadine, respectively. Three nociceptive tests were used: the hot plate test, analgesimeter and the acetic acid-induced writhing test. To gauge the antinociceptive action we used the increased latency in the hot plate test expressed as maximum possible effect % (%MPE), the increase in paw pressure to withdraw the hind paw in analgesimeter and decrease in the number of spinal cord writhes in the acetic acid test. RESULTS: Clomipramine in a dose of 20 mg/kg bw significantly increased the %MPE in hot plate test and the pressure to withdraw the hind paw in the analgesimeter when compared with the control. In the acetic acid test clomipramine decreased non-significantly the number of writhes compared with the controls. Granisetrone reduced non-significantly the antinociceptive effect of clomipramine in all tests. Cyproheptadine potentiated the analgesic effect of clomipramine in acetic acid test and decreased it significantly in the hot plate test. In analgesimeter cyproheptadine decreased significantly the paw pressure to withdraw the tested hind paw at 1 hour and non-significantly at 2 hours. CONCLUSION: Clomipramine in the dose of 20 mg/kg bw has a pronounced antinociceptive affect towards thermal and mechanical pain stimulation. The 5-HT2 and 5-HT3 receptor subtypes are very likely involved in the mechanism of this effect.

Vitamin D3 exerts immunomodulatory and memory improving properties in rats with lipopolysaccharide-induced inflammation.

INTRODUCTION: Vitamin D is a fat-soluble secosteroid, its primary function being regulation of calcium-phosphate homeostasis and maintenance of bone integrity and mineralization. Recently, pleotropic effects of this vitamin have been recognized, including an immunomodulatory role and involvement in normal brain development and functioning.

Pramipexole and tolcapone alleviate thermal and mechanical nociception in naive rats.

INTRODUCTION: Parkinson's disease (PD) is а neurodegenerative disorder characterized mainly by its motor symptoms. The non-motor symptoms including pain are increasingly recognized in the last few decades. Existing evidence suggests that the dopaminergic neurotransmission has an essential role in pain control. AIM: The aim of the present study was to investigate the antinociceptive effect of dopaminergic drugs pramipexole and tolcapone against chemical and thermal stimuli in naive rats. MATERIALS AND METHODS: Male Wistar rats divided into 8 groups (n=8): saline; diclofenac 25 mg/kg body weight (bw) (positive control); pramipexole 0.5; 1 and 3 mg/kg bw; tolacapone 5; 15 and 30 mg/kg bw. Paw pressure and plantar tests were performed. Paw withdrawal pressure and latent time were measured. Statistical analysis was done by SPSS 19. RESULTS: In the paw pressure test, pramipexole, in a dose of 1 and 3 mg/kg bw and tolcapone in a dose of 30 mg/kg bw, increased significantly the latency at 1, 2, and 3 hours compared to saline (p<0.05). In the plantar test, only the highest dose of pramipexole reached significance at 3 hours compared to the control rats (p<0.05). In contrast to pramipexole the three experimental groups with tolcapone markedly increased the latent time at 1 and 3 hours compared to saline (p<0.05). CONCLUSIONS: Pramipexole and tolcapone reduce mechanical and thermal nociception in naïve rats by enhancing dopaminergic neurotransmission at both spinal and supraspinal levels. In addition, tolcapone stimulates noradrenergic mediation which may contribute to its antinociceptive effect.

An experimental study on phytochemical composition and memory enhancing effect of Ginkgo biloba seed extract.

INTRODUCTION: The Ginkgo biloba L. tree is considered as one of the oldest species on Earth. It is known as a "living fossil" dating back approximately 200 million years. Both the leaves and seeds of this tree have been used for millennia in traditional Chinese medicine. AIM: To study the phytochemical profile of Gingko biloba seed extract (GBSE) and its memory enhancing effects. MATERIALS AND METHODS: Liquid chromatography with mass detection (LC-MS) was performed for phytochemical analyses of the extracts. For the in vivo experiments, male Wistar rats were divided randomly into 5 groups (n=8): saline; piracetam;  GBSE 50; 100, and 200 mg/kg b.w. Y-maze, T-maze, step-down passive avoidance and novel object recognition test (NORT) were performed. The observed parameters were: percentage of spontaneous alternations (% SA), working memory index, latency of reaction and recognition index, respectively. Statistical analysis was done using SPSS 19. RESULTS: LC-MS analysis showed the presence of the flavonoids quercetin, kaempferol and isorhamnetin (as aglycones), the ginkgolides A, B, C, J, and bilobalide. In Y-maze task, the groups treated with 50 and 100 mg/kg of GBSE significantly increased the % SA during the memory test compared to saline (p<0.05). In T-maze test, the three experimental groups with GBSE significantly increased the working memory index in comparison with that of the control group (p<0.05). In step-down test, the animals receiving 100 mg/kg b.w. GBSE, notably increased the latency during both retention tests (p<0.05 and p<0.01, respectively). In NORT, only the animals with the middle dose of GBSE ameliorated the recognition index when compared to saline (p<0.05). CONCLUSIONS: GBSE enhances spatial working memory, recognition memory, and short- and long-term recall in naïve rats due to the synergic effects of detected flavonoids and terpene lactones on brain functions. The brain structures involved are probably the hippocampus and prefrontal cortex.

Dopaminergic agonist pramipexole improves memory and increases IL-10 production in LPS-challenged rats.

OBJECTIVES: A variety of cytokines are involved in cognitive functioning. Balance restoration between protective and degenerative neuro-inflammation is of great interest in newer therapeutic approaches. In the current study, we investigated the effect of pramipexole (PMX) on memory functions, hippocampal amyloid deposition, serum cytokines, and brain-derived neurotrophic factor (BDNF) levels in lipopolysaccharide (LPS) challenged-rats. MATERIALS AND METHODS: Male Wistar rats were divided into 5 groups (n=8): control (saline), lipoppolysacharide (LPS 250 mcg/kg bw), and experimental groups (LPS and PMX 0.5, 1, and 3 mg/kg bw). Learning and memory were assessed by the novel object recognition test (NORT), Y-maze, and step-through test. Immunological and histological assays were performed. RESULTS: In memory tasks, LPS-challenged rats showed reduction in the observed parameters. In NORT, PMX 1 mg/kg increased recognition index compared with controls, whereas the other two doses increased this index only against the LPS-control. In Y-maze, all doses of PMX significantly had increased alternation when compared with LPS. In the step-through test, only the lowest dose of PMX extended the latency compared with LPS. Histological examination revealed that PMX at doses of 0.5 and 1 mg/kg reduced amyloid deposition in the hippocampus. Interleukin (IL)-10 serum levels were elevated by 1 mg/kg PMX. Tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-ß1 serum levels remained under the detectable minimum in all experimental groups. PMX at all doses significantly decreased BDNF serum concentration. CONCLUSION: In rats with LPS-induced neuro-inflammation PMX improved hippocampal-dependent memory and exerted immuno-modulatory effects by increasing IL-10.

Physiological and clinical characteristics of andropause.

The process of aging in man involves a lot of functional and structural changes in the body organs and systems. In this review we shall characterize the physiological and clinical manifestations of andropause. We'll review the physiological basis of the ageing process, the age-related changes in the testosterone secretion regulation, and the dynamics of androgen action and active testosterone metabolism. We also investigate the multifactorial etiology of age-related physiological changes--the body undergoes changes in its structure, there is a loss of muscle strength and decline in physical functions. Sexual dysfunction, hypogonadism and psychological changes are also commonly observed symptoms in this condition. Changes of similar kind can also be seen in young males with androgen deficiency. The age-related changes in physiological functions can potentially lead to some important consequences such as reduced physical activity, higher risk of developing specific diseases (ischemic heart disease, diabetes, osteoporosis), diminished capacity to recover after acute diseases, but most often it leads to increased fracture predisposition. All these may eventually affect negatively the self-care capacity of patients making them require a long-term professional care, and lead to severe psychological and social isolation and increased mortality and change in quality of life. To limit the age-related physiological decline in serum testosterone levels, we should be able to tackle the still unresolved important clinical issue--can hormone replacement therapy administered to elderly men improve their functional status, prevent diseases from developing, improve quality of life and reduce fracture risk. The data included in the present review will contribute to determining the potential benefits and risks of testosterone replacement therapy.

Catechol-o-methyltransferase inhibitor tolcapone improves learning and memory in naïve but not in haloperidol challenged rats.

OBJECTIVES: Dopamine plays an important role in cognitive functions. Inhibition of the dopamine-degrading enzyme catechol-O-methyltransferase (COMT) may have beneficial effects. Our aim was to assess the effect of COMT inhibitor tolcapone (TCP) on learning and memory in naïve and haloperidol-challenged rats. MATERIALS AND METHODS: Male Wistar rats were divided into 9 groups (n=8): naïve-saline, tolcapone 5; 15 and 30 mg/kg BW; haloperidol (HP) challenged-saline, haloperidol, haloperidol+tolcapone 5; 15 and 30 mg/kg BW. Two-way active avoidance test (TWAA), elevated T-maze, and activity cage were performed. Observed parameters were: number of conditioned responses (CR) and unconditioned responses (UCR), working memory index, and vertical and horizontal movements. RESULTS: Naïve rats with 30 mg/kg BW TCP had a significantly increased number of CR and UCR during the long-term memory test. The animals with 5 mg/kg BW TCP significantly increased the number of UCR during the two retention tests. In haloperidol-challenged rats, the three experimental groups decreased the number of CR and UCR during the learning session and the two memory tests, compared to the saline group. There was no significant difference between the HP-challenged rats treated with TCP and the haloperidol control group. All experimental naïve groups had significantly increased working memory index whereas none of the HP-challenged groups showed significant increase in this parameter. CONCLUSION: Our results demonstrate that in naïve rats tolcapone improves memory in the hippocampal-dependent TWAA task and spatial working memory in T-maze.

Effects of Pramipexole on Learning and Memory Processes in Naïve and Haloperidol-challenged Rats in Active Avoidance Test.

BACKGROUND: Parkinson's disease (PD) is the second most common neurode-generative disease, usually detected by its motor symptoms. The non-motor symptoms, including cognitive deficits, have been of great interest to researchers in the last few decades. AIM: To assess the effect of pramipexole on learning and memory in naïve and haloperidol-challenged rats. MATERIALS AND METHODS: Male Wistar rats divided into 9 groups (n=8): naïve - saline, pramipexole 0.5; 1 and 3 mg/kg bw; Haloperidol groups - saline, haloperidol, haloperidol + pramipexole 0.5; 1 and 3 mg/kg bw. Two-way active avoidance test (TWAA) and activity cage were performed. The studied parameters were: number of conditioned and unconditioned responses, vertical and horizontal movements. Statistical analysis was done using SPSS 19. RESULTS: The naïve experimental groups significantly increased the number of conditioned responses during the tests for short- and long-term memory, compared with the saline groups (p<0.05). During the short-memory test only the animals with the lowest dose of PMX significantly increased the number of unconditioned responses whereas during the long-term memory test all experimental groups increased the number of escapes in comparison with the saline groups (p<0.05). Challenge dose of haloperidol attenuates learning and memory in pramipexol treated rats. Only the highest dose of pramipexol showed significant increase in conditioned and unconditioned responses compared with the haloperidol group (p<0.05). CONCLUSION: Pramipexole improves learning and memory in naïve rats by enhancing dopaminergic neurotransmission. This is probably not the only mechanism involved. This is confirmed by the decrease in learning and memory ability in rats with haloperidol-challenge.

Antioxidant Activity of Dry Birch (Betula Pendula) Leaves Extract.

BACKGROUND: Betula pendula is widespread in Europe and Asia. It has been used in traditional medicine since ancient times. Birch leaf extracts are known to exhibit a number of pharmacological activities. Antioxidant activity has also been reported. AIM: The aim of this work was to investigate the antioxidant activity of a dry leaf extract from Betula pendula Roth. MATERIALS AND METHODS: The total flavonoid content was determined. Some of the most commonly used methods were applied to evaluate the antioxidant capacity of the extract in vitro and in vivo. The ability of the extract to scavenge DPPH free radicals was evaluated by the method described by Brand-Williams with suitable modifications. ABTS decolorization assay was also applied. The in vivo assay was performed after acute and chronic administration of the extract into white albino rats, in a dose of 100 and 500 mg/kg bw. The antioxidant potential of the plasma was determined using FRAP reagent. RESULTS: A total flavonoid content of 42.5 mg/g was found, expressed as quercetin. The antioxidant activity against ABTS was concentration and time dependent. For example the concentration of 200 µg/ml led to 70.95% - 99.46% scavenging activity. DPPH scavenging activity was found to be about 98% at a concentration of 80 µg/ml. The extract possesses antioxidant potential, comparable with that of Trolox, in acute application. In chronic application, poorer results are observed, probably due to biotransformation and elimination processes. CONCLUSION: Dried birch leaf extract has a relatively high antioxidant potential and could be used as a natural source of antioxidants.