Effect of Evolvulus alsinoides Linn. on learning behavior and memory enhancement activity in rodents

In the Ayurvedic system of medicine, the whole herb of ‘Shankhpushpi’ has been employed clinically for centuries for its memory potentiating, anxiolytic and tranquilizing properties. The present study was undertaken to investigate the effects of Evolvulus alsinoides (EA), considered as Shankhpushpi on learning and memory in rodents. Nootropic activity using Cook and Weidley's pole climbing apparatus, passive avoidance paradigms and active avoidance tests were used to test learning and memory. The ethanol extract of EA and its ethyl acetate and aqueous fractions were evaluated for their memory enhancing properties. Two doses (100 and 200 mg/kg p.o.) of the ethanol extract and ethyl acetate and aqueous fractions were administered in separate groups of animals. Both doses of all the extracts of EA significantly improved learning and memory in rats. Furthermore, these doses significantly reversed the amnesia induced by scopolamine (0.3 mg/kg i.p.). Nootropic activity was compared using piracetam as the standard. EA also exhibited potent memory enhancing effects in the step‐down and shuttle‐box avoidance paradigms. Copyright © 2009 John Wiley & Sons, Ltd.     

Procyanidins extracted from the lotus seedpod ameliorate scopolamine‐induced memory impairment in mice

The major purpose of this study was to determine the effect of procyanidins extracted from the lotus seedpod (LSPC) on the learning and memory impairments induced by scopolamine (1 mg/kg, i.p.) in mice. The capacities of memory and learning were evaluated by the Morris water maze and the step‐down avoidance test. LSPC (50, 100, 150 mg/kg BW, p.o.) significantly reversed scopolamine‐induced learning and memory impairments in the Morris water maze test, as evaluated by shortened escape latency and swimming distance. In the step‐down avoidance test, LSPC (50, 100, 150 mg/kg BW, p.o.) treatment significantly reduced the number of errors and shortened latency compared with that of scopolamine. In addition, LSPC was also found to inhibit acetyl cholinesterase (AChE) activity. These results of this study suggest that LSPC may play a useful role in the treatment of cognitive impairment caused by AD and aging. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of Kamikihi-To,a traditional Chinese Medicine,on learning and memory performance in mice

The effects of Kamikihi-To (KMK), a traditional Chinese medicine (Chinese name Jia-Wei-Gui-Pi-Tang), on learning and memory performance abilities in normal or memory-impaired mice were studied using step through and step down type passive avoidance tests. The effects were also studied using shuttle box and lever press type conditioned avoidance tests in normal mice. KMK (0.5 and 1.0 g/kg p.o.) showed no influence on the learning abilities in passive and conditioned avoidance tests in normal mice. In contrast, KMK (1.0 g/kg p.o.) exerted ameliorating effects on memory registration impairment induced by ethanol in step through and step down tests. KMK at this dose also significantly improved memory retrieval disability induced by electroconvulsive shock (ECS) in step through test. Moreover, KMK (0.5 g/kg p.o.) ameliorated memory consolidation impairment induced by ECS in step down test. These results suggest that KMK ameliorates the impaired learning performance through its influence on memory registration, consolidation and retrieval.     

Protective effect of Morinda citrifolia fruits on β‐amyloid (25–35) induced cognitive dysfunction in mice: An experimental and biochemical study

The neuroprotective effect of an ethyl acetate extract of Morinda citrifolia (Rubiaceae) Linn. fruits (EMC, ethyl acetate extract of Morinda citrifolia) at doses of 200 and 400 mg/kg, p.o. was studied on β‐amyloid (25–35) peptide induced cognitive dysfunction in mice. In the step‐down inhibitory avoidance, EMC exhibited a significant increase in short‐term memory and long‐term memory (p < 0.05). A significant decrease (p < 0.01) in escape latency was noticed in the animals in the water maze. A significant increase (p < 0.01) in alteration of behavior was exhibited upon administration of EMC 200 and 400 mg/kg on the Y maze. Exploratory parameters such as line crossings, head dipping and rearing were increased significantly in EMC treated groups in a dose‐dependent manner (p < 0.05 and p < 0.01). A significant reduction (p < 0.05) in acetyl cholinesterase activity was noticed in the EMC 200 and 400 mg/kg treated groups. The level of monoamine oxidase‐A was decreased by the administration of EMC 200 and 400 mg/kg (p < 0.05 and p < 0.01, respectively). EMC at a dose of 400 mg/kg exhibited a significant increase (p < 0.01) in the levels of serotonin and dopamine. Antioxidant enzymes such as superoxide dismutase, glutathione reductase, glutathione peroxidase and ascorbic acid were decreased significantly in the b‐amyloid peptide injected group, whose levels were restored significantly (p < 0.01) by the administration of EMC (400 mg/kg). Copyright © 2009 John Wiley & Sons, Ltd.     

Beneficial effects of Centella asiatica aqueous extract against arsenic-induced oxidative stress and essential metal status in rats

The efficacy of an aqueous extract of Centella asiatica (100, 200 and 500 mg/kg for 5 consecutive days) was studied in the depletion of arsenic and in the recovery of a few altered biochemical variables in arsenic pre-exposed rats (20 ppm in drinking water for 5 weeks). Exposure to arsenic significantly depleted delta-aminolevulinic acid dehydratase (ALAD) activity, reduced glutathione (GSH) level, superoxide dismutase (SOD) and increased thiobarbituric acid reactive substance (TBARS) activity in red blood cells. Significant depletion of ALAD activity, GSH level, glutathione peroxidase (GPx), SOD and catalase (CAT) activities and an increase in TBARS levels in liver tissues was also noted. There was a significant depletion of SOD, CAT and GPx activities in kidneys and an increased TBARS levels in kidney and brain accompanied by increased arsenic concentration in blood and soft tissues. Treatment with aqueous extract of Centella asiatica provided significant protection against ALAD, GSH and TBARS levels, particularly at doses of 200 and 500 mg. Centella asiatica also provided significant recovery in the inhibited liver ALAD and G6PD activities. Arsenic concentration in blood and soft tissues remained uninfluenced after Centella asiatica administration. The present study thus suggests a beneficial effect of Centella asiatica against arsenic-induced oxidative stress but possesses no chelating property.     

黄连解毒汤提取物对脑缺血小鼠学习记忆的促进作用

采用避暗法和水迷宫法研究了黄连解毒汤提取物对实验性慢性脑缺血小鼠的作用。结果表明，黄连解毒汤提取物０５ｇ／ｋｇ、１０ｇ／ｋｇ能显著减少脑缺血小鼠避暗错误次数，并延长其钻洞潜伏期；提取物０５ｇ／ｋｇ、１０ｇ／ｋｇ和２０ｇ／ｋｇ均能显著增加脑缺血小鼠在水迷宫中的正确反应次数；且对脑缺血小鼠脑内丙二醛的生成有显著抑制作用。     

Antinociceptive and antiedematogenic effects of the aqueous extract of Hyptis pectinata leaves in experimental animals

The aqueous leaf extract of Hyptis pectinata (L.) Poit (Lamiaceae), popularly known in Brazil as "sambaicatá" or "canudinho", was tested for its antinociceptive effects using the abdominal writhing, hot plate and formalin test models, and for its aniedematogenic effects using the carrageenin and arachidonic acid-induced rat paw edema. The aqueous extract of Hyptis pectinata administered orally at doses of 100, 200 and 400 mg/kg had a significant antinociceptive effect in the test of acetic acid-induced abdominal writhing, with 43, 51 and 54% reduction of writhes, respectively, compared to the control. An increase in hot-plate latency of 47 and 37.5% was also observed in animals receiving doses of 200 and 400 mg/kg, p.o. when placed on a hot plate. In the formalin test, doses of 200 and 400 mg/kg, p.o. had no significant effect during the first phase of the test (0-5 min), while the dose of 200 mg/kg, p.o. reduced the nociceptive effect by 70% during the second phase (20-25 min). At the dose of 600 mg/kg, p.o., the aqueous extract inhibited carrageenin-induced rat paw edema by 34.1%, and the dose of 300 mg/kg administered intraperitoneally inhibited the rat paw edema induced by subplantar injection of arachidonic acid by 32.8%. These results suggest that the aqueous extract from the Hyptis pectinata leaves produces antiedematogenic and antinociceptive effects. The antinocipetion observed with the hot-plate test probably involves the participation of the opioid system.     

Effects of standardized ginseng extract on learning, memory and physical capabilities

Standardized ginseng extract (G115, Pharmaton, Lugano) was administered orally at doses of 3, 10, 30, 100 and 300 mg/kg for 10 days as ten rats were used with each dose. With the "shuttle-box" method for active avoidance most pronounced effect on learning and memory was obtained by the dose of 10 mg/kg. With the "step-down" method for passive avoidance the dose of 30 mg/kg significantly improved retention. In the staircase maze training with positive (alimentary) reinforcement only the dose of 10 mg/kg significantly improved learning and memory. The dose of 100 mg/kg greatly increased the locomotor activity of mice. The results show that ginseng at appropriate doses improves learning, memory and physical capabilities. Bell-shaped dose-effect curves, reported with other nootropic drugs, were obtained.     

党参复方对化学药物所致小鼠记忆损伤的改善作用

本文采用跳台法、避暗法和Y型水迷路法,观察了党参复方对小鼠学习记忆的改善作用,发现该方对多种小鼠学习记忆障碍模型均有不同程度的保护作用。并初步分析此种作用可能与其增强Ach的M—效应和改变脑中5-HT含量有关。     

Effects of saffron (Crocus sativus L.) and its active constituent, crocin, on recognition and spatial memory after chronic cerebral hypoperfusion in rats

Cerebral ischemia produces brain damage and related behavioral deficits such as memory. In this study, a rat model of chronic cerebral hypoperfusion was used to determine whether saffron extract and crocin, which are potent antioxidants and free radical scavengers, can reduce vascular cognitive impairment. Male adult Wistar rats were administered different doses of an aqueous solution of crocin or hydroalcohol extract of saffron intraperitoneally (i.p.) 5 days after permanent occlusion of the common carotid arteries. Spatial learning and memory were assessed in training trials, 7–11 days after common carotid artery ligation using the Morris water maze. The results showed that the escape latency time was significantly reduced from 24.64 s in the control group to 8.77 and 10.47 s by crocin (25 mg/kg) and saffron extract (250 mg/kg). The traveled distance to find the platform was also changed from 772 cm in the control group to 251 and 294 cm in the crocin (25 mg/kg) and saffron extract (250 mg/kg) groups. The percentages of time spent in the target quadrant, in comparison with the control group (24.16%), increased to 34.25% in the crocin (25 mg/kg) and 34.85% in the saffron extract (250 mg/kg) group. This study suggests that saffron extract and crocin improve spatial cognitive abilities following chronic cerebral hypoperfusion and that these effects may be related to the antioxidant effects of these compounds. Copyright © 2011 John Wiley & Sons, Ltd.     

Biphasic effects of Morus alba leaves green tea extract on mice in chronic forced swimming model

In this study, the effects of an aqueous extract of Morus alba leaves green tea (ME) on mouse behaviors (depression, anxiety, climbing activity and thermal response), muscle coordination and muscle strength were studied. Male IRC mice received a single intraperitoneal injection of either the ME, desipramine or diazepam. Thirty minutes after injection, the mice were tested in all experimental models. A significant antidepressant-like effect could be detected in the animals receiving either 100 or 200 mg/kg ME. The effect of 200 mg/kg ME in decreasing the immobility time was comparable to 10 mg/kg desipramine. With higher dose (1000 mg/kg), a significant increase in immobility time could be observed. In the elevated plus maze, no increase in time in the open arm could be observed in mice treated with ME at either 100 or 200 mg/kg. However, high doses of ME (500 or 1000 mg/kg) decreased both time in the open arm and the number of entries in the maze. No change in thermal response could be seen in mice treated with ME at doses up to 500 mg/kg, however, at 1000 mg/kg, the response time to heat was increased significantly. The ME at either 500 or 1000 mg/kg also decreased muscle coordination, strength and climbing activity significantly when compared with the control. This study suggests that ME possesses an antidepressant- without an anxiolytic-like effect, however, at high doses, the extract might show the sedative effect and alter other functions such as muscle strength, animal activity in the maze and pain response.     

Effects of raw garlic on physical performance and learning behaviour in rats

The effects of garlic (Allium sativum Linn.) on physical performance and learning behaviour were evaluated in male rats (7-8 months old, weighing 250-400 g) by comparison with the effects of pentoxifylline, a haemorheological agent with antiplatelet activity. The tests were designated as experiment A and experiment B, both conducted in two consecutive 4-week sessions. In experiment A, the rats performed in a learning maze model during the first 4 weeks then followed by moving along the rope model for another 4 weeks. In experiment B, the rats were first tested in a rotarod treadmill for 4 weeks and then a step down test model for another 4 weeks. Each experiment consisted of four groups with 6-8 rats per group. Aqueous garlic homogenate at doses of 1 and 2 g (of raw garlic)/kg/day were given orally to group 1 and group 2, respectively, while pentoxifylline dispersion at a dose of 200 mg/kg/day was given to group 3. Group 4 served as the control group and was given water. All tests (maze model, rope model, rotarod model and step down model) were performed three times a week. The number of successful tasks and the acquisition time in 1 week intervals were used for the statistical analysis. The present results demonstrated that neither aqueous garlic homogenate at both doses nor pentoxifylline exhibited any benefit in the maze model or the rotarod model. Garlic only at the lower dose and pentoxifylline however, showed benefit in the rope model and step down model. These findings may provide some evidence to support the beneficial effect of long-term garlic consumption on physical performance and learning behaviour in normal subjects.     

Age- and individual-related specificities in the effects of standardized ginseng extract on learning and memory (experiments on rats)

Using a two-way active avoidance with punishment (electric shock) reinforcement (shuttle box) we investigated the effects of Panax ginseng extract, standardized according to the content of ginsenosides on learning and memory in 2-, 10-, and 22-month old Wistar rats and in rats of the same age (5-month old) which, after a preliminary training with the same method, had been classified as ‘good’, ‘poor’ and ‘satisfactory’ learners. In experiments on rats of different ages G115 was administered orally daily for 10 consecutive days before training at increasing doses of 3, 10, 30 and 100 mg/kg body weight. The animals were trained for 5 days and the retention test was given 14 days after the last administration of G115 (10 days after the last training session). In experiments on rats with different learning capabilities G115 was administered orally at a dose of 10 mg/kg for 10 days after shuttle box training. The retention test was performed on the day following the last treatment with G115. It was found that G115 exerted the most favourable effects on learning and memory when these processes were decayed as a result either of senescence or of individual specificities.     

Memory enhancing activity of Glycyrrhiza glabra in mice

In the traditional system of medicine, the roots and rhizomes of Glycyrrhiza glabra (family: Leguminosae) have been employed clinically for centuries for their anti-inflammatory, antiulcer, expectorant, antimicrobial and anxiolytic activities. The present study was undertaken to investigate the effects of Glycyrrhiza glabra (popularly known as liquorice) on learning and memory in mice. Elevated plus-maze and passive avoidance paradigm were employed to test learning and memory. Three doses (75, 150 and 300 mg/kg p.o.) of aqueous extract of Glycyrrhiza glabra were administered for 7 successive days in separate groups of animals. The dose of 150 mg/kg of the aqueous extract of liquorice significantly improved learning and memory of mice. Furthermore, this dose significantly reversed the amnesia induced by diazepam (1 mg/kg i.p.) and scopolamine (0.4 mg/kg i.p.). Anti-inflammatory and antioxidant properties of liquorice may be contributing favorably to the memory enhancement effect. Since scopolamine-induced amnesia was reversed by liquorice, it is possible that the beneficial effect on learning and memory was due to facilitation of cholinergic-transmission in mouse brain. However, further studies are necessitated to identify the exact mechanism of action. In the present investigation, Glycyrrhiza glabra has shown promise as a memory enhancing agent in all the laboratory models employed.     

Protection of Effective Component Group from Xiaoshuan Tongluo on Brain Injury after Chronic Hypoperfusion in Rats

Objective To investigate the protective effects of purified effective component group in extract from Xiaoshuan Tongluo(CGXT) formula on chronic brain ischemia in rats.Methods CGXT 75,150,and 300 mg/kg or vehicle were ig administered daily for four weeks to rats with bilateral common carotid arteries ligation(BCCAL) .From the day 24 to 28 after BCCAL,Morris water maze was performed to assess the learning and memory impairment of rats.Four weeks after BCCAL,brain gray and white matter damage were assessed.Results In Morris test,the mean escape latency of rats in the CGXT(150 and 300 mg/kg) groups was significantly shorter than that in the vehicle group.CGXT also attenuated the neuronal damage in hippocampus and cortex and reduced the pathological damage in the optic tract and corpus callosum.Conclusion CGXT could improve learning and memory impairment resulted from BCCAL in rats.These results provide the experimental basis for the clinical use of CGXT in stroke treatment and may help in investigation of multimodal therapy strategies in ischemic cerebrovascular diseases including stroke.     

绿茶多酚对D-半乳糖与Aβ25～35诱导的AD模型小鼠学习记忆障碍的改善作用

目的:建立D-半乳糖与Aβ25~35诱导的AD模型小鼠,观察绿茶多酚对其学习记忆障碍的改善作用。方法:皮下注射D-半乳糖(120 mg/kg,连续给药12 w),并在第7 w时于侧脑室注射Aβ25~35(4 nmol/L),建立AD模型小鼠。利用跳台法、水迷宫、避暗法和开场实验评价绿茶多酚对AD模型小鼠学习记忆障碍的改善作用。结果:绿茶多酚明显延长跳台潜伏期,减少跳台错误次数;缩短游出迷宫时间和减少进入盲端的错误次数;减少避暗活动错误次数和延长进入穿梭箱潜伏期;同时,明显增加AD小鼠的探究行为。结论:绿茶多酚对D-半乳糖与Aβ25~35诱导的AD模型小鼠学习记忆障碍具有改善作用。     

The Mechanism of Memory Enhancement of Acteoside (Verbascoside) in the Senescent Mouse Model Induced by a Combination of d‐gal and AlCl3

Acteoside (verbsacoside), one of the main active phenylethanoid glycosides from Cistanche deserticola, is known to have antioxidant and neuroprotective activity, and herbs containing it are used to enhance memory. However, there is relatively little direct experimental evidence to support the use of acteoside in Alzheimer's disease (AD). The purpose of this study was to elucidate the effects of acteoside in improving learning and memory, using a mouse model of senescence induced by a combination of d ‐galactose and AlCl₃, and investigate its potential mechanisms compared with the positive controls vitamin E and piracetam. Acteoside was administered intragastrically at doses of 30, 60 and 120 mg/kg/day for 30 days after AD was induced. Memory function was evaluated using a step‐down test. The number of neuron was analysed by haematoxylin and eosin staining and the number of Nissl bodies by Nissl staining. The expression of caspase‐3 protein in hippocampus was detected by immunohistochemistry and western blot. Nitric oxide and total nitric oxide synthase level in hippocampus were also assessed. Our results showed that the latency of step down was shortened in AD model mice and the number of errors decreased after treatment with all doses of acteoside. Neurons and Nissl bodies in the hippocampus were increased significantly with higher doses (60 and 120 mg/kg/day) of acteoside. The content of nitric oxide, the activity of nitric oxide synthase and the expression of caspase‐3 protein were decreased by 120 mg/kg/day acteoside compared with that of the AD model group. Our results support the results obtained previously using the Morris maze test in the same mouse model of senescence, and the use of traditional medicinal herbs containing acteoside for neuroprotection and memory loss. Copyright © 2015 John Wiley & Sons, Ltd.     

Studies on the hypoglycaemic activity of Punica granatum seed in streptozotocin induced diabetic rats.

The hypoglycaemic activity of Punica granatum Linn. (Family Punicaceae) seed extract on rats made diabetic by streptozotocin (STZ) was investigated. The methanol extract of the seed at doses of 300 and 600 mg/kg, and chlorpropamide 200 mg/kg was administered to STZ diabetic rats. The seed extract (150, 300 and 600 mg/kg, orally) caused a significant reduction of blood glucose levels in STZ induced diabetic rats by 47% and 52%, respectively, at the end of 12 h.     

蜜蜂幼虫增强老龄大鼠记忆力实验研究

采用穿梭箱被动回避反应及组织化学、图像分析等法,研究鲜蜜蜂１０ｄ龄幼虫浆对２４月龄老年大鼠记忆保持力和大脑边缘系统海马内胆碱能神经纤维形态学影响。结果显示老龄大鼠每ｄ灌服鲜蜂幼虫浆２５０ｍｇ／ｋｇ,２１ｄ后,记忆力保持功能明显增强（Ｐ〈０．０５）,胆碱能神经纤维积分光密度明显增加（Ｐ〈０．０５）。初步推断蜜蜂幼虫浆具有增强老龄大鼠记忆力功能。     

Anxiolytic‐like effects of standardized extract of Justicia pectoralis (SEJP) in mice: Involvement of GABA/benzodiazepine in receptor

Justicia pectoralis (Acanthaceae) is used as an antiinflammatory, antimicrobial and bronchodilator, and its extract exerts an anxiolytic‐like effect profile in animal models. This work presents the behavioral effects of an aqueous standardized extract of Justicia pectoralis (SEJP) in animal models, such as the elevated plus maze (EPM), light/dark, open field, rota rod and pentobarbital sleep time. The extract was administered intragastrically to male mice at single doses of 50, 100 and 200 mg/kg, while diazepam 1 or 2 mg/kg was used as a standard drug and flumazenil 2.5 mg/kg was used to evaluate the participation of benzodiazepinic receptors. The results showed that, similar to diazepam (1 mg/kg), SEJP significantly modified all the observed parameters in the EPM test, without altering the general motor activity in the open field, rota rod and pentobarbital sleep time tests. Flumazenil reversed not only the diazepam effect but also the SEJP effect. In the same way, all doses of SEJP increased the time of permanence in the light box in the light/dark test. The results showed that SEJP presented an anxiolytic‐like effect, disproving sedative effects. Copyright © 2010 John Wiley & Sons, Ltd.