Panax ginseng extract improves the scopolamine-induced disruption of 8-arm radial maze performance in rats

Cognition enhancing effect of panax ginseng in Korean volunteers with mild cognitive impairment: a randomized, double-blind, placebo-controlled clinical trial

This study aimed to investigate the cognition-enhancing effect of Panax ginseng. A randomized, double-blind, placebo-controlled clinical trial was conducted to address the cognition-enhancing effects of Panax ginseng. A total of 90 Korean volunteers with mild cognitive impairment participated in this study. All subjects were allocated randomly into ‘Ginseng’ group or ‘Placebo’ group. All subjects were administered 3g of Panax ginseng powder or starch (placebo) for 6 months. The Korean version of the Mini-Mental Status Examination (K-MMSE), Korean version of Instrumental Activities of Daily Living (K-IADL), and Seoul Neuropsychological Screening Battery (SNSB) were used to assess the changes in cognitive function at the end of the 6 month study period. The subjects of the ‘Ginseng’ group improved significantly on the Rey Complex Figure Test (RCFT) immediate recall (P = 0.0405 and P = 0.0342 in per-protocol (PP) and intention-to-treat (ITT) analysis, respectively) and on the RCFT 20-min delayed recall (P = 0.0396 and P = 0.0355 in PP and ITT analysis, respectively) compared with ‘placebo’ group throughout the 6 months of Panax ginseng administration. There were no serious adverse events. These results suggest that Panax ginseng has a cognition-enhancing effect.

The Use of Ginseng as an Adjunct in Treatment-Resistant Depression

The treatment of depression has evolved over the past several years since the evolution of tricyclic antidepressants (TCAs) to the serotonin selective reuptake inhibitors (SSRIs). However, some patients are resistant to various medications, and various adjunctive medications have been added to the original medication, to promote a therapeutic response. This case report describes a woman, with a long history of treatment-resistant depression, who was treated with a combination of an SSRI and ginseng.

Black ginseng-enriched Chong-Myung-Tang extracts improve spatial learning behavior in rats and elicit anti-inflammatory effects in vitro

Background

Chong-Myung-Tang (CMT) extract is widely used in Korea as a traditional herbal tonic for increasing memory capacity in high-school students and also for numerous body ailments since centuries. The use of CMT to improve the learning capacity has been attributed to various plant constituents, especially black ginseng, in it. Therefore, in this study, we have first investigated whether black ginseng-enriched CMT extracts affected spatial learning using the Morris water maze (MWM) test. Their molecular mechanism of action underlying improvement of learning and memory was examined in vitro.

Methods

We used two types of black ginseng-enriched CMT extracts, designated as CM-1 and CM-2, and evaluated their efficacy in the MWM test for spatial learning behavior and their anti-inflammatory effects in BV2 microglial cells.

Results

Our results show that both black ginseng-enriched CMT extracts improved the learning behavior in scopolamine-induced impairment in the water maze test. Moreover, these extracts also inhibited nitric oxide production in BV2 cells, with significant suppression of expression of proinflammatory cytokines, especially inducible nitric oxide synthase, cyclooxygenase-2, and interleukin-1β. The protein expression of mitogen-activated protein kinase and nuclear factor-κB pathway factors was also diminished by black ginseng-enriched CMT extracts, indicating that it not only improves the memory impairment, but also acts a potent anti-inflammatory agent for neuroinflammatory diseases.

Conclusion

Our research for the first time provides the scientific evidence that consumption of black ginseng-enriched CMT extract as a brain tonic improves memory impairment. Thus, our study results can be taken as a reference for future neurobehavioral studies.

Administration of red ginseng ameliorates memory decline in aged mice

Background

It has been known that ginseng can be applied as a potential nutraceutical for memory impairment; however, experiments with animals of old age are few.

Methods

To determine the memory enhancing effect of red ginseng, C57BL/6 mice (21 mo old) were given experimental diet pellets containing 0.12% red ginseng extract (approximately 200 mg/kg/d) for 3 mo. Young and old mice (4 mo and 21 mo old, respectively) were used as the control group. The effect of red ginseng, which ameliorated memory impairment in aged mice, was quantified using Y-maze test, novel objective test, and Morris water maze. Red ginseng ameliorated age-related declines in learning and memory in older mice. In addition, red ginseng's effect on the induction of inducible nitric oxide synthase and proinflammatory cytokines was investigated in the hippocampus of aged mice.

Results

Red ginseng treatment suppressed the production of age-processed inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-α, and interleukin-1β expressions. Moreover, it was observed that red ginseng had an antioxidative effect on aged mice. The suppressed glutathione level in aged mice was restored with red ginseng treatment. The antioxidative-related enzymes Nrf2 and HO-1 were increased with red ginseng treatment.

Conclusion

The results revealed that when red ginseng is administered over long periods, age-related decline of learning and memory is ameliorated through anti-inflammatory activity.

Actoprotective effect of ginseng: improving mental and physical performance

Actoprotectors are preparations that increase the mental performance and enhance body stability against physical loads without increasing oxygen consumption. Actoprotectors are regarded as a subclass of adaptogens that hold a significant capacity to increase physical performance. The focus of this article is studying adaptogen herbs of genus Panax (P. ginseng in particular) and their capabilities as actoprotectors. Some animal experiments and human studies about actoprotective properties of genus Panax attest that P. ginseng (administered as an extract) significantly increased the physical and intellectual work capacities, and the data provided suggests that ginseng is a natural source of actoprotectors. Preparations of ginseng can be regarded as potential actoprotectors which give way to further research of its influence on physical and mental work capacity, endurance and restoration after exhaustive physical loads while compared with reference actoprotectors.

Comparative study of korean white, red, and black ginseng extract on cholinesterase inhibitory activity and cholinergic function

This study evaluated cholineresterase inhibitory activity of Korean white ginseng extract (WGE), red ginseng extract (RGE), and black ginseng extract (BGE) and the cholinergic effect on scopolamine (SCOP)-induced amnesic mice. WGE, RGE, and BGE inhibited acetylcholineserase (AChE), as well as butyrylcholineserase (BuChE) in a concentration-dependent manner. BGE presented strong inhibition of AChE with an IC50 value of 1.72 mg/mL, followed by WGE (5.89 mg/mL), RGE (6.30 mg/mL), respectively. The inhibitory activity of the three ginseng extracts on BuChE showed similar values among the groups. To better understand the mechanisms of the possible effect of ginseng extract on the cholinergic function, this study assessed the expression of the cholinergic markers of choline acetyltransferase (ChAT) and AChE using western blot and RT-PCR analysis in the brains of amnesic mice. Treatment with ginseng extracts led to inhibition of AChE expression and, the activation of ChAT expression in the hippocampus and the cerebral cortex of amnesic mice as induced by SCOP. The results suggest that ginseng extracts including BGE, appear to modulate the metabolism of acetylchoine (ACh), which would greatly increase synaptic ACh levels and most potently revert SCOP-induced amnesia.

Ginsenoside Rg1 restores the impairment of learning induced by chronic morphine administration in rats

Rg1, as a ginsenoside extracted from Panax ginseng, could ameliorate spatial learning impairment. Previous studies have demonstrated that Rg1 might be a useful agent for the prevention and treatment of the adverse effects of morphine. The aim of this study was to investigate the effect of Rg1 on learning impairment by chronic morphine administration and the mechanism responsible for this effect. Male rats were subcutaneously injected with morphine (10 mg/kg) twice a day at 12 hour intervals for 10 days, and Rg1 (30 mg/kg) was intraperitoneally injected 2 hours after the second injection of morphine once a day for 10 days. Spatial learning capacity was assessed in the Morris water maze. The results showed that rats treated with Morphine/Rg1 decreased escape latency and increased the time spent in platform quadrant and entering frequency. By implantation of electrodes and electrophysiological recording in vivo, the results showed that Rg1 restored the long-term potentiation (LTP) impaired by morphine in both freely moving and anaesthetised rats. The electrophysiological recording in vitro showed that Rg1 restored the LTP in slices from the rats treated with morphine, but not changed LTP in the slices from normal saline- or morphine/Rg1-treated rats; this restoration could be inhibited by N-methyl-D-aspartate (NMDA) receptor antagonist MK801. We conclude that Rg1 may significantly improve the spatial learning capacity impaired by chonic morphine administration and restore the morphine-inhibited LTP. This effect is NMDA receptor dependent.

Panax ginseng enhances cognitive performance in Alzheimer disease

Recent experimental evidences suggest protective and trophic effects of ginseng in the memory function of Alzheimer disease (AD). Thus, we investigated the clinical efficacy of Panax ginseng in the cognitive performance of AD patients in an open-label study. Consecutive AD patients were randomly assigned to the ginseng (n=58) or the control group (n=39), and the ginseng group was treated with Panax ginseng powder (4.5 g/d) for 12 weeks. Cognitive performances were monitored using the mini-mental state examination (MMSE) and Alzheimer disease assessment scale (ADAS) during 12 weeks of the ginseng treatment and at 12 weeks after the ginseng discontinuation. MMSE and ADAS scales showed no baseline difference between the groups. After ginseng treatment, the cognitive subscale of ADAS and the MMSE score began to show improvements and continued up to 12 weeks (P=0.029 and P=0.009 vs. baseline, respectively). After discontinuing ginseng, the improved ADAS and MMSE scores declined to the levels of the control group. These results suggest that Panax ginseng is clinically effective in the cognitive performance of AD patients.

Panax Ginseng in combination with brewers' yeast (Gerivet) as a stimulant for geriatric dogs: a controlled-randomized blinded study

The study was performed on two groups of dogs, one (n = 41) given Ginseng (Panax Ginseng) together with brewers' yeast (Saccharomyces cerevisae) and the other (n = 39) given only brewers' yeast (control group, but not a true placebo), for 8 weeks. Using a questionnaire and three visual analogue scales, the blinded owners evaluated the dogs before the trial, weekly for the 8 weeks of the trial and twice, at 12th and 16th weeks, after the trial (follow-up). At 8th, 12th and 16th weeks the owners also answered questions concerning what treatment their dogs likely had been getting, willingness to continue medication and the dogs' general status. The changes from baseline to the end of the treatment period in the variable scores were calculated for each dog and used in statistics. Panax Ginseng plus yeast significantly improved all evaluated variables within the group. Four of the seven primary (mentally) outcome measures were significant when comparing the changes in the Ginseng group with the control group, and six of the seven were significant when compared to an external group. As the secondary (physical) outcome measures were significantly better in both the Ginseng and the control group compared to the external group, it indicates that brewers' yeast is the ingredient that has impact on physical performance. No significant changes in blood- or urine analyses and no side effects were seen.

Effect of Tremella fuciformis on the neurite outgrowth of PC12h cells and the improvement of memory in rats

We investigated the neuritogenic effects of Tremella fuciformis (TF), which has been valued in traditional Chinese medicine as a remedy with nutritive and tonic actions, on PC12h cells. The cognitive improving effects of TF on scopolamine-induced (2 mg/kg, s.c.) amnesia in rats were also evaluated with using the Morris water maze task and by performing choline acetyltransferase (ChAT) immunohistochemistry. The water extract of TF (0.01-1 microg/ml) promoted neurite outgrowth of the PC12h cells in a dose dependent manner. TF was highly efficient at the concentration range of 0.1-1 microg/ml. Oral daily treatment with TF (100 or 400 mg/kg) for 14 consecutive days significantly reversed the scopolamine-induced deficit in learning and memory, and it alleviated decrease in cholinergic immunoreactivity induced by scopolamine in the medial septum and hippocampus. The results demonstrate that the promotion of neuritogenesis in neuronal culture cells by TF water extract is related with its activity for improving the performance of rats on a spatial learning and memory task. Moreover, the impairments of spatial learning and memory may be attributable to the decrease in activation of the septohippocampal cholinergic system and that TF ameliorated learning and memory deficits partly through its increasing the central cholinergic activity. Therefore, TF could represent a potentially useful agent that is able to improve the function of impaired cognitive processes.

Ginseng enhances contextual fear conditioning and neurogenesis in rats

Panax Ginseng is a commonly used galenical known to have an enhancing effect on learning. Neurogenesis in the hippocampus has been shown to be necessary for hippocampus/amygdala-dependent learning tasks. To investigate the role of Ginseng in neurogenesis and learning of rats, we administered both Ginseng and BrdU for five consecutive days. As a result, Ginseng increased the number of BrdU-positive cells in the dentate gyrus in a dose-dependent manner. Further, we administered one dose of BrdU after Ginseng treatment for five consecutive days, and the number of BrdU-positive cells did not increase significantly. However, when one dose of BrdU was given 1 day before the following five consecutive days of Ginseng treatment, the number of BrdU-positive cells markedly increased in the hippocampus. Therefore, it is likely that Ginseng enhances not proliferation but survival of newly generated neurons in the hippocampus. Second, we administered both Ginseng and BrdU to rats for five consecutive days. One day after the last Ginseng and BrdU co-administration, contextual fear conditioning (CFC) was conducted. Ginseng in a dose-dependent manner increased the % freezing time and the number of BrdU-positive cells in the dentate gyrus of rats that received CFC. Thus, an increase in CFC-related neurogenesis may be one mechanism of Ginseng's properties to enhance learning ability.

Effect of a Nutritive-Tonic Drink on Scopolamine-Induced Memory Impairment in Mice

The effects of a liquid nutritive and tonic drug (NTD) selected from a modification of the "Kai-xin-shou-yu-shen-qi-wan" prescription, on scopolamine-induced amnesia in mice were investigated using the passive avoidance and water-maze tasks. A popular NTD in Japan that contains 17 crude (natural) drug extracts together with synthetic drugs such as taurine, caffeine, various vitamins and ethanol, and the natural drug extracts is based on a prescription of "Kampo" origin in Chinese medicine. Scopolamine (0.4 mg/kg, i.p.) reduces the step-through latency of the passive avoidance test and fear reaction behavior at 24 and 48 h after treatment. A single oral administration of the NTD (10 ml/kg) increased the step-through latency and the fear reaction behavior score in scopolamine-treated mice. Administration of the natural drug extracts found in the NTD tended to extend the step-through latency in the retention test at 48 h, but not 24 h after the initial scopolamine trial. However, administration of the synthetic drugs found in the NTD did not improve either the step-through latency or the behavioral score. The NTD and the natural drug extracts also improved the scopolamine-induced spatial memory impairment as assessed using the Morris water-maze test. In contrast, the synthetic drugs did not affect the escape latencies. Both NTD and the synthetic drugs increased the locomotor activity in scopolamine-treated mice, whereas the natural drug extracts did not. These results suggest that NTD improves scopolamine-induced amnesia, and that this action is attributable to the natural drug extracts in the NTD.

Therapeutic effects of herbal extracts and constituents in animal models of psychiatric disorders

A search for novel pharmacotherapy from medicinal plants for psychiatric illnesses has progressed significantly in the past decade. This is reflected in the large number of herbal preparations for which psychotherapeutic potential has been evaluated in a variety of animal models. The objective of this review is to provide an overview of herbal extracts and constituents that have significant therapeutic effects in animal models of psychiatric illnesses. Eighty five individual herbs reviewed were classified as anxiolytic, antidepressant, neuroleptic, antidementia, or anti-substance abuse herbs. The full scientific name of each herb, herbal part used, active constituent, extract, dose range and route, animal model, possible mechanisms of action, and pertinent references are presented via synoptic tables. The herbal mixtures were also mentioned. A considerable number of herbal constituents whose behavioral effects and pharmacological actions have been well characterized may be good candidates for further investigations that may ultimately result in clinical use. The investigation of a large portion of the herbal extracts and herbal mixtures is in its infancy. Herbal remedies that have demonstrable psychotherapeutic activities have provided a potential to psychiatric pharmaceuticals and deserve increased attention in future studies.

Ginseng: potential for the enhancement of cognitive performance and mood

Ginseng has been used medicinally in the Far East for several millennia and is currently one of the most widely taken herbal products throughout the world. It has been attributed with a plethora of physiological effects that could potentially benefit cognitive performance or mood. Studies involving animals show that ginseng and its constituent ginsenosides can modulate indices of stress, fatigue, and learning. However, there is a lack of adequately controlled research showing behavioural effects following chronic administration to humans. Recent research has demonstrated that single doses of ginseng most notably engender cognitive benefits in terms of improved memory, but can also be associated with 'costs' in terms of attention task deficits following less mnemonically beneficial doses. A single dose of ginseng has also been shown to modulate cerebroelectrical (EEG) activity. It is suggested that ginseng would benefit from rigorous research further delineating its acute effects and exploring the relationship between acute effects and those seen during and following chronic administration regimens.

Ninjin-yoei-to (Ren-Shen-Yang-Rong-Tang) and Polygalae radix improves scopolamine-induced impairment of passive avoidance response in mice

We investigated the effect of Ninjin-yoei-to (Ren-Shen-Yang-Rong-Tang), a Japanese herbal medicine, and found that 1000 mg/kg p.o. improved the scopolamine-induced impairment of passive avoidance response in mice. Further, the same dose of Ninjin-yoei-to enhanced oxotremorine-induced tremors in mice. The water extract of Polygalae radix, one of the constituent herbs of Ninjin-yoei-to, at a dose of 100 mg/kg significantly improved the scopolamine-induced impairment of passive avoidance response and enhanced oxotremorine-induced tremors in mice. Moreover, the enhancement of oxotremorine-induced tremors by Ninjin-yoei-to (1000 mg/kg) and Polygalae radix (100 mg/kg) was completely antagonized by pretreatment of scopolamine hydrobromide (0.5 mg/kg). These results suggest that Ninjin-yoei-to may improve the scopolamine-induced impairment of passive avoidance response by enhancing the cholinergic system and that Polygalae radix may be involved in the action of Ninjin-yoei-to.

Ginsenoside Rb1 and Rg1 improve spatial learning and increase hippocampal synaptophysin level in mice

We investigated the cognition enhancing effects of ginsenoside Rb1 and Rg1. Mice were trained in a Morris water maze following injection (i.p.) of Rb1 (1 mg/kg) or Rg1 (1 mg/kg) for 4 days. Both Rb1- and Rg1-injected mice showed enhanced spatial learning compared to control animals. The hippocampus, but not the frontal cortex, of treated mice contained higher density of a synaptic marker protein, synaptophysin, compared to control mice. Electrophysiological recordings in hippocampal slices revealed that Rb1 or Rg1 injection did not change the magnitude of paired-pulse facilitation or long-term potentiation. Our results suggest that Rb1 and Rg1 enhance spatial learning ability by increasing hippocampal synaptic density without changing plasticity of individual synapses.

Korean red ginseng saponins with low ratios of protopanaxadiol and protopanaxatriol saponin improve scopolamine-induced learning disability and spatial working memory in mice

The effects of two ginseng saponins having a different ratio of protopanaxadiol (PD) and protopanaxatriol saponins (PT) on the learning impairment induced by scopolamine, and learning and memory in mice were investigated in a passive avoidance task and a Morris water maze task. The ratio of PD and PT was 1.24 and 1.46, respectively. Before training, the ginseng saponins were administered intraperitoneally at doses of 50 and 100 mg/kg. The two saponins improved the scopolamine-induced learning impairment at different dosages in mice, 50 and 100 mg/kg, respectively. However, the two saponins did not show a favorable effect on learning and memory in normal mice. Korean red ginseng saponin with a low PD/PT ratio had an improving effect on spatial working memory, but the saponin with a high PD/PT ratio did not. This finding suggests that the PD/PT ratio of the ginseng saponins may be an important factor in the pharmacological role of red ginseng as a medicinal herb.

Medicinal plants and Alzheimer's disease: from ethnobotany to phytotherapy

The use of complementary medicines, such as plant extracts, in dementia therapy varies according to the different cultural traditions. In orthodox Western medicine, contrasting with that in China and the Far East for example, pharmacological properties of traditional cognitive- or memory-enhancing plants have not been widely investigated in the context of current models of Alzheimer's disease. An exception is Gingko biloba in which the gingkolides have antioxidant, neuroprotective and cholinergic activities relevant to Alzheimer's disease mechanisms. The therapeutic efficacy of Ginkgo extracts in Alzheimer's disease in placebo controlled clinical trials is reportedly similar to currently prescribed drugs such as tacrine or donepezil and, importantly, undesirable side effects of Gingko are minimal. Old European reference books, such as those on medicinal herbs, document a variety of other plants such as Salvia officinalis (sage) and Melissa officinalis (balm) with memory-improving properties, and cholinergic activities have recently been identified in extracts of these plants. Precedents for modern discovery of clinically relevant pharmacological activity in plants with long-established medicinal use include, for example, the interaction of alkaloid opioids in Papaver somniferum (opium poppy) with endogenous opiate receptors in the brain. With recent major advances in understanding the neurobiology of Alzheimer's disease, and as yet limited efficacy of so-called rationally designed therapies, it may be timely to re-explore historical archives for new directions in drug development. This article considers not only the value of an integrative traditional and modern scientific approach to developing new treatments for dementia, but also in the understanding of disease mechanisms. Long before the current biologically-based hypothesis of cholinergic derangement in Alzheimer' s disease emerged, plants now known to contain cholinergic antagonists were recorded for their amnesia- and dementia-inducing properties.

Non-ginsenoside nicotinic activity in ginseng species

Amongst the many different therapeutic applications of ginseng are beneficial effects on age-related cognitive impairments. Ageing in the brain is associated with a loss of nicotinic receptor binding and receptor stimulation increases binding. Stimulation of the CNS (central nervous system) nicotinic receptor is considered to be beneficial in relation to symptomatic treatment and neuroprotection in age-associated cognitive disorders which involve a further receptor loss. We assessed Panax ginseng, Panax quinquefolium and several chemical constituents of these plants for nicotinic activity based on displacement of 3H-(-)nicotine from human brain cerebral cortex membranes in vitro. Dose-dependent displacement was evident in crude ethanol extracts of Panax ginseng and Panax quinquefolium. Assay of an extract of Panax ginseng showed the plant to have affinity for both the nicotinic receptor, and to a lesser extent the muscarinic receptor (IC50 2.12 mg/mL and 5.25 mg/mL respectively). Activity was largely conserved after the extraction of choline and other water soluble quaternary ammonium compounds (QAC), indicating that the activity of the plant extracts was not due to choline. Displacement binding assay of some purified chemical constituents, including a number of ginsenosides, showed that these were not primarily responsible for Panax activity. The active chemical constituent has yet to be identified, but the demonstrated nicotinic activity of ginseng warrants further investigation with reference to therapeutic activity in age-related conditions such as dementia.