Panaxcerol D from Panax ginseng ameliorates the memory impairment induced by cholinergic blockade or Aß25-35 peptide in mice.

Background: Alzheimer's disease (AD) has memory impairment associated with aggregation of amyloid plaques and neurofibrillary tangles in the brain. Although anti-amyloid ß (Aß) protein antibody and chemical drugs can be prescribed in the clinic, they show adverse effects or low effectiveness. Therefore, the development of a new drug is necessarily needed. We focused on the cognitive function of Panax ginseng and tried to find active ingredient(s). We isolated panaxcerol D, a kind of glycosyl glyceride, from the non-saponin fraction of P. ginseng extract. Methods: We explored effects of acute or sub-chronic administration of panaxcerol D on cognitive function in scopolamine- or Aß25-35 peptide-treated mice measured by several behavioral tests. After behavioral tests, we tried to unveil the underlying mechanism of panaxcerol D on its cognitive function by Western blotting. Results: We found that pananxcerol D reversed short-term, long-term and object recognition memory impairments. The decreased extracellular signal-regulated kinases (ERK) or Ca2+/calmodulin-dependent protein kinase II (CaMKII) in scopolamine-treated mice was normalized by acute administration of panaxcerol D. Glial fibrillary acidic protein (GFAP), caspase 3, NF-kB p65, synaptophysin and brain-derived neurotrophic factor (BDNF) expression levels in Aß25-35 peptide-treated mice were modulated by sub-chronic administration of panaxcerol D. Conclusion: Pananxcerol D could improve memory impairments caused by cholinergic blockade or Aß accumulation through increased phosphorylation level of ERK or its anti-inflammatory effect. Thus, panaxcerol D as one of non-saponin compounds could be used as an active ingredient of P. ginseng for improving cognitive function.

Oleanolic acid alleviates the extrapyramidal symptoms and cognitive impairment induced by haloperidol through the striatal PKA signaling pathway in mice.

Haloperidol, one of the representative typical antipsychotics, is on the market for schizophrenia but shows severe adverse effects such as extrapyramidal symptoms (EPS) or cognitive impairments. Oleanolic acid (OA) is known to be effective for tardive dyskinesia which is induced by long-term treatment with L-DOPA. This study aimed to investigate whether OA could ameliorate EPS or cognitive impairment induced by haloperidol. The balance beam, catalepsy response, rotarod and vacuous chewing movement (VCM) tests were performed to measure EPS and the novel object recognition test was used to estimate haloperidol-induced cognitive impairment. Levels of dopamine and acetylcholine, the phosphorylation levels of c-AMP-dependent protein kinase A (PKA) and its downstream signaling molecules were measured in the striatum. OA significantly attenuated EPS and cognitive impairment induced by haloperidol without affecting its antipsychotic properties. Valbenazine only ameliorated VCM. Also, OA normalised the levels of dopamine and acetylcholine in the striatum which were increased by haloperidol. Furthermore, the increased phosphorylated PKA, extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB) levels and c-FOS expression level induced by haloperidol were significantly decreased by OA in the striatum. In addition, cataleptic behaviour of haloperidol was reversed by sub-effective dose of H-89 with OA. These results suggest that OA can alleviate EPS and cognitive impairment induced by antipsychotics without interfering with antipsychotic properties via regulating neurotransmitter levels and the PKA signaling pathway in the striatum. Therefore, OA is a potential candidate for treating EPS and cognitive impairment induced by antipsychotics.

The effect of fecal microbiota transplantation on autistic-like behaviors in Fmr1 KO mice.

The importance of alterations in bidirectional communication between gut and brain has become obvious in neuropsychiatric disorders. Gastrointestinal (GI) disturbances are very common in autism spectrum disorders (ASD), and the GI microbiota profiles in children with ASD are significantly different from those in the general population. Fragile X syndrome (FXS) is an inheritable developmental disability in humans, and patients with FXS exhibit autistic behaviors such as mental retardation and impaired social communication or interaction. We hypothesized that an increase in specific gut microbiota by fecal microbiota transplantation (FMT) would mitigate autistic-like behaviors. To test this hypothesis, we measured the effects of FMT from normal mice to Fmr1 KO mice on autistic-like behaviors using several behavioral tests. Because the amounts of A. muciniphila in Fmr1 KO mice was very low, we assessed A. muciniphila population, tested the expression of MUC2, and analyzed goblet cells in the gut after the FMT. We found that FMT ameliorated autistic-like behaviors, especially memory deficits and social withdrawal, and we observed that the levels of A. muciniphila were normalized to wild-type levels. In addition, FMT attenuated the increased levels of TNFα and Iba1 in the brains of Fmr1 KO mice. These results suggest that FMT could be a useful tool for the treatments of cognitive deficits and social withdrawal symptoms observed in FXS or ASD because it increases the population of A. muciniphila and decreases TNFα and Iba1 levels.

Green tea extract containing enhanced levels of epimerized catechins attenuates scopolamine-induced memory impairment in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Green tea has been used as a traditional medicine to control brain function and digestion. Recent works suggest that drinking green tea could prevent cognitive function impairment. During tea manufacturing processes, such as brewing and sterilization, green tea catechins are epimerized. However, the effects of heat-epimerized catechins on cognitive function are still unknown. To take this advantage, we developed a new green tea extract, high temperature processed-green tea extract (HTP-GTE), which has a similar catechin composition to green tea beverages. AIM OF THE STUDY: This study aimed to investigate the effect of HTP-GTE on scopolamine-induced cognitive dysfunction and neuronal differentiation, and to elucidate its underlying mechanisms of action. MATERIALS AND METHODS: The neuronal differentiation promoting effects of HTP-GTE in SH-SY5Y cells was assessed by evaluating neurite length and the expression level of synaptophysin. The DNA methylation status at the synaptophysin promoter was determined in differentiated SH-SY5Y cells and in the hippocampi of mice. HTP-GTE was administered for 10 days at doses of 30, 100 and 300 mg/kg (p.o.) to mice, and its effects on cognitive functions were measured by Y-maze and passive avoidance tests under scopolamine-induced cholinergic blockade state. RESULTS: HTP-GTE induced neuronal differentiation and neurite outgrowth via the upregulation of synaptophysin gene expression. These beneficial effects of HTP-GTE resulted from reducing DNA methylation levels at the synaptophysin promoter via the suppression of DNMT1 activity. The administration of HTP-GTE ameliorated cognitive impairments in a scopolamine-treated mouse model. CONCLUSIONS: These results suggest that HTP-GTE could alleviate cognitive impairment by regulating synaptophysin expression and DNA methylation levels. Taken together, HTP-GTE would be a promising treatment for the cognitive impairment observed in dysfunction of the cholinergic neurotransmitter system.

The effect of maslinic acid on cognitive dysfunction induced by cholinergic blockade in mice.

BACKGROUND AND PURPOSE: Alzheimer's disease (AD) is the most prevalent disease associated with cognitive dysfunction. Current AD therapeutic agents have several gastrointestinal or psychological adverse effects and therefore, novel therapeutic agents with fewer adverse effects must be developed. Previously, we demonstrated that oleanolic acid, which is similar in chemical structure to maslinic acid, ameliorates cognitive impairment through the activation of tropomyosin receptor kinase (TrkB)-ERK-cAMP response element-binding protein (CREB) phosphorylation and increased levels of brain-derived neurotrophic factor (BDNF). In the present study, we investigate the effect of maslinic acid on cholinergic blockade-induced memory impairment in mice. METHODS AND KEY RESULTS: Maslinic acid reversed scopolamine-induced memory impairment, as determined by the Y-maze, passive avoidance and Morris water maze tests. In addition, we also observed that ERK-CREB, PI3K and PKB (Akt) phosphorylation levels were increased by maslinic acid administration in the mouse hippocampus. Moreover, we determined that the effects of maslinic acid on scopolamine-induced memory impairment in the passive avoidance test were abolished by a specific TrkB receptor antagonist (ANA-12). Additionally, we observed similar temporal changes in the expression levels between BDNF and tissue plasminogen activator in the hippocampus. CONCLUSION AND IMPLICATIONS: These findings suggest that maslinic acid enhances cognitive function through the activation of BDNF and its downstream pathway signalling in the hippocampus and that it might be a potential therapeutic agent for cognitive decline, such as that observed in AD.

A botanical drug composed of three herbal materials attenuates the sensorimotor gating deficit and cognitive impairment induced by MK-801 in mice.

OBJECTIVES: A botanical drug derived from the ethanolic extract composed of Clematis chinensis Osbeck (Ranunculaceae), Trichosanthes kirilowii Maximowicz (Cucurbitaceae) and Prunella vulgaris Linné (Lamiaceae) has been used to ameliorate rheumatoid arthritis as an ethical drug in Korea. In our study, we investigated the effect of this herbal complex extract (HCE) on schizophrenia-like behaviours induced by MK-801. METHODS: HCE (30, 100 or 300 mg/kg, p.o) was orally administered to male ICR mice to a schizophrenia-like animal model induced by MK-801. We conducted an acoustic startle response task, an open-field task, a novel object recognition task and a social novelty preference task. KEY FINDINGS: We found that a single administration of HCE (100 or 300 mg/kg) ameliorated MK-801-induced abnormal behaviours including sensorimotor gating deficits and social or object recognition memory deficits. In addition, MK-801-induced increases in phosphorylated Akt and GSK-3ß expression levels in the prefrontal cortex were reversed by HCE (30, 100 or 300 mg/kg). CONCLUSIONS: These results imply that HCE ameliorates MK-801-induced dysfunctions in prepulse inhibition, social interactions and cognitive function, partly by regulating the Akt and GSK-3ß signalling pathways.

Theracurmin Ameliorates Cognitive Dysfunctions in 5XFAD Mice by Improving Synaptic Function and Mitigating Oxidative Stress.

As the elderly population is increasing, Alzheimer's disease (AD) has become a global issue and many clinical trials have been conducted to evaluate treatments for AD. As these clinical trials have been conducted and have failed, the development of new theraphies for AD with fewer adverse effects remains a challenge. In this study, we examined the effects of Theracurmin on cognitive decline using 5XFAD mice, an AD mouse model. Theracurmin is more bioavailable form of curcumin, generated with submicron colloidal dispersion. Mice were treated with Theracurmin (100, 300 and 1,000 mg/kg) for 12 weeks and were subjected to the novel object recognition test and the Barnes maze test. Theracurmin-treated mice showed significant amelioration in recognition and spatial memories compared those of the vehicle-treated controls. In addition, the antioxidant activities of Theracurmin were investigated by measuring the superoxide dismutase (SOD) activity, malondialdehyde (MDA) and glutathione (GSH) levels. The increased MDA level and decreased SOD and GSH levels in the vehicle-treated 5XFAD mice were significantly reversed by the administration of Theracurmin. Moreover, we observed that Theracurmin administration elevated the expression levels of synaptic components, including synaptophysin and post synaptic density protein 95, and decreased the expression levels of ionized calcium-binding adapter molecule 1 (Iba-1), a marker of activated microglia. These results suggest that Theracurmin ameliorates cognitive function by increasing the expression of synaptic components and by preventing neuronal cell damage from oxidative stress or from the activation of microglia. Thus, Theracurmin would be useful for treating the cognitive dysfunctions observed in AD.