Aster glehni Extract Ameliorates Scopolamine-Induced Cognitive Impairment in Mice

Neuroprotective effects of Petiveria alliacea on scopolamine-induced learning and memory impairment mouse model

ETHNOPHARMACOLOGY RELEVANCE

Petiveria alliacea L., commonly known as macura and gully root, is an important medicinal plant used in the Caribbean and Central America to treat ailments associated to the central nervous system, including poor memory.

AIM OF THE STUDY

To assess the effects of the P. alliacea leaves methanol fraction (PMF) on a scopolamine-induced learning and memory impairment mouse model related to acetylcholinesterase activity and oxidative stress.

MATERIAL AND METHODS

After PMF administration at doses of 500 or 900 mg/kg, cognitive ability was evaluated using the Morris water maze (MWM), Y-maze (YM) and novel object recognition (NOR) tests. The mouse brain tissue was further assessed for acetylcholinesterase activity and antioxidant activity. Levels of oxidative stress were also evaluated by measuring malondialdehyde (MDA) and glutathione activity. Acute toxicity was also evaluated.

RESULTS

PMF led to memory improvement in the behavioral tests in mice with scopolamine-induced cognitive impairment. Moreover, PMF inhibited acetylcholinesterase activity and showed antioxidant potential that in turn attenuated cholinergic degradation. Additionally, PMF increased glutathione levels and glutathione reductase activity and reduced MDA levels in the brain. Moreover, no acute toxicity was detected with the use of PMF.

CONCLUSION

In a mouse model of scopolamine-induced cognitive deficit, PMF exhibited protective effects, decreasing oxidative damage and regulating cholinergic function in the brain bearing significant memory enhancing potency. These data suggest that PMF is a promising candidate for developing therapies for neurodegenerative disorders.

Humulus lupulus L. Extract Protects against Senior Osteoporosis through Inhibiting Amyloid β Deposition and Oxidative Stress in APP/PS1 Mutated Transgenic Mice and Osteoblasts

As aging progresses, β-amyloid (Aβ) deposition and the resulting oxidative damage are key causes of aging diseases such as senior osteoporosis (SOP). Humulus lupulus L. (hops) is an important medicinal plant widely used in the food, beverage and pharmaceutical industries due to its strong antioxidant ability. In this study, APP/PS1 mutated transgenic mice and Aβ-injured osteoblasts were used to evaluate the protective effects of hops extracts (HLE) on SOP. Mice learning and memory levels were assessed by the Morris water maze. Mice femurs were prepared for bone micro-structures and immunohistochemistry experiments. The deposition of Aβ in the hippocampus, cortex and femurs were determined by Congo red staining. Moreover, protein expressions related to antioxidant pathways were evaluated by Western blotting. It was found that HLE markedly improved learning abilities and ameliorated memory impairment of APP/PS1 mice, as well as regulated antioxidant enzymes and bone metabolism proteins in mice serum. Micro-CT tests indicated that HLE enhanced BMD and improved micro-architectural parameters of mice femur. More importantly, it was discovered that HLE significantly reduced Aβ deposition both in the brain and femur. Further in vitro results showed HLE increased the bone mineralization nodule and reduced the ROS level of Aβ-injured osteoblasts. Additionally, HLE increased the expression of antioxidant related proteins Nrf2, HO-1, NQO1, FoxO1 and SOD-2. These results indicated that Humulus lupulus L. extract could protect against senior osteoporosis through inhibiting Aβ deposition and oxidative stress, which provides a reference for the clinical application of hops in the prevention and treatment of SOP.

Extract of Aster glehni ameliorates potassium oxonate-induced hyperuricemia by modulating renal urate transporters and renal inflammation by suppressing TLR4/MyD88 signaling

Recent studies suggest that Aster glehni extract (AGE) reduces hyperuricemia by preventing xanthine oxidase activity. However, its effect on renal urate transporters responsible for modulating urate excretion has not been examined. This study investigated whether AGE affects gene expressions of urate transporters using potassium oxonate (PO)-induced hyperuricemia rats. Furthermore, the underlying mechanisms of AGE were explored to ameliorate renal inflammation and injury by PO. AGE effectively restored PO-induced dysregulation of renal urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), ATP-binding cassette transporter subfamily G member 2 (ABCG2), organic anion transporter 1 (OAT1), and organic cation transporter 1 (OCT1), resulting in increasing urate excretion. Additionally, AGE suppressed toll-like receptor 4/myeloid differentiation factor 88 (TLR4/MyD88) signaling, phosphorylation of nuclear factor kappa B (NF-κB), and renal production of IFN-γ, IL-1β, TNF-α, and IL-6. These results suggest that AGE may ameliorate PO-induced hyperuricemia by modulating renal transporters, and further renal inflammation via inhibiting the TLR4/MyD88/NF-κB signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01153-5.

The effects of the ethanol extract of Cordia myxa leaves on the cognitive function in mice

Background

Cordia myxa L. (Boraginaceae) is widely distributed in tropical regions and it’s fruits, leaves and stem bark have been utilized in folk medicine for treating trypanosomiasis caused by Trypanosoma cruzi. A population-based study showed that T. cruzi infection is associated with cognitive impairments. Therefore, if C. myxa has ameliorating activities on cognitive function, it would be useful for both T. cruzi infection and cognitive impairments.

Methods

In this study, we evaluated the effects of an ethanol extract of leaves of C. myxa (ELCM) on memory impairments and sensorimotor gating deficits in mice. The phosphorylation level of protein was observed by the Western blot analysis.

Results

The administration of ELCM significantly attenuated scopolamine-induced cognitive dysfunction in mice, as measured by passive avoidance test and novel object recognition test. Additionally, in the acoustic startle response test, we observed that the administration of ELCM ameliorated MK-801-induced prepulse inhibition deficits. We found that these behavioral outcomes were related with increased levels of phosphorylation phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) and glycogen synthase kinase 3 beta (GSK-3β) in the cortex and extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB) in the hippocampus by western blot analysis.

Conclusions

These results suggest that ELCM would be a potential candidate for treating cognitive dysfunction and sensorimotor gating deficits observed in individuals with neurodegenerative diseases.

Valerian essential oil for treating insomnia via the serotonergic synapse pathway

Valerian volatile oil can be used in the treatment of insomnia; however, the active components and mechanisms of action are currently unclear. Therefore, we used transcriptome sequencing and weight coefficient network pharmacology to predict the effective components and mechanism of action of valerian volatile oil in an insomnia model induced by intraperitoneal injection of para-Chlorophenylalanine (PCPA) in SD rats. Valerian essential oil was given orally for treatment and the contents of 5-hydroxytryptamine receptor 1 A (5-HT1AR), γ-aminobutyric acid (GABA), cyclic adenosine monophosphate (cAMP), and protein kinase A (PKA) in the hippocampus of rats in each group were detected by enzyme-linked immunosorbent assay (ELISA), western blot, Polymerase Chain Reaction (PCR), and immunohistochemistry. The results showed that after treatment with valerian essential oil, insomnia rats showed significantly prolonged sleep duration and alleviated insomnia-induced tension and anxiety. Regarding the mechanism of action, we believe that caryophyllene in valerian essential oil upregulates the 5-HT1AR receptor to improve the activity or affinity of the central transmitter 5-HT, increase the release of 5-HT, couple 5-HT with a G protein coupled receptor, convert adenosine triphosphate (ATP) into cAMP (catalyzed by ADCY5), and then directly regulate the downstream pathway. Following pathway activation, we propose that the core gene protein kinase PKA activates the serotonergic synapse signal pathway to increase the expression of 5-HT and GABA, thus improving insomnia symptoms and alleviating anxiety. This study provides a theoretical basis for the application of valerian volatile oil in health food.

Dual Beneficial Effects of α-Spinasterol Isolated from Aster pseudoglehnii on Glucose Uptake in Skeletal Muscle Cells and Glucose-Stimulated Insulin Secretion in Pancreatic β-Cells

Herein, we determined whether α-Spinasterol, a stigmastane-type phytosterol isolated from Aster pseudoglehnii, potentially impacts glucose uptake and glucose-stimulated insulin secretion in skeletal muscle cells and pancreatic β-cells, respectively. We observed that A. pseudoglehnii and its fractions enhanced glucose uptake, with no toxic effects on C2C12 cells, with the n-hexane fraction exhibiting the most potent effect. α-Spinasterol, isolated from the n-hexane fraction, enhanced glucose uptake with no toxic effects on C2C12 cells. Additionally, α-Spinasterol increased the expression of associated proteins, including insulin receptor substrate-1, AMP-activated protein kinase, and glucose transporter type 4, as determined by Western blotting. Furthermore, α-Spinasterol enhanced insulin secretion in response to high glucose concentrations, with no toxic effects on INS-1 cells; this effect was superior to that demonstrated by gliclazide (positive control), commonly prescribed to treat type 2 diabetes (T2D). α-Spinasterol enhanced the expression of associated proteins, including insulin receptor substrate-2, peroxisome proliferator-activated receptor γ, and pancreatic and duodenal homeobox 1, as determined using Western blotting. The insulin secretory effect of α-Spinasterol was enhanced by a K⁺ channel blocker and L-type Ca²⁺ channel agonist and was suppressed by a K⁺ channel activator and L-type Ca²⁺ channel blocker. α-Spinasterol isolated from A. pseudoglehnii may improve hyperglycemia by improving glucose uptake into skeletal muscle cells and enhancing insulin secretion in pancreatic β-cells. Accordingly, α-Spinasterol could be a potential candidate for anti-T2D therapy.

A Mixture of Ginkgo biloba L. Leaf and Hericium erinaceus (Bull.) Pers. Fruit Extract Attenuates Scopolamine-Induced Memory Impairments in Mice

Alzheimer's disease (AD) is a neurodegenerative disease that is characterized by loss of memory and cognitive impairment via dysfunction of the cholinergic nervous system. In cholinergic dysfunction, it is well known that impaired cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) signaling are major pathological markers and are some of the strategies for the development of AD therapy. Therefore, this study is aimed at evaluating whether a mixture comprising Ginkgo biloba L. leaf (GL) and Hericium erinaceus (Bull.) Pers. (HE) fruit extract (GH mixture) alleviated cognitive impairment induced in a scopolamine-induced model. It was discovered that GH reduced neuronal apoptosis and promoted neuronal survival by activating BDNF signaling in an in vitro assay. In addition, the GH (p.o. 240 mg/kg) oral administration group significantly restored the cognitive deficits of the scopolamine-induced mouse group (i.p. 1.2 mg/kg) in the behavior tests such as Y-maze and novel object recognition task (NORT) tests. This mixture also considerably enhanced cholinergic system function in the mouse brain. Furthermore, GH markedly upregulated the expressed levels of extracellular signal-regulated kinase (ERK), CREB, and BDNF protein levels. These results demonstrated that GH strongly exerted a neuroprotective effect on the scopolamine-induced mouse model, suggesting that an optimized mixture of GL and HE could be used as a good material for developing functional foods to aid in the prevention of neurodegenerative diseases, including AD.

Evaluation of Subchronic Toxicity and Genotoxicity of Ethanolic Extract of Aster glehni Leaves and Stems

Aster glehni, a traditional plant on Ulleung Island in the Republic of Korea, has been recognized for its multiple medicinal properties. However, potential toxicity and safety analyses of A. glehni have not been previously investigated. Therefore, this study aimed to evaluate the safety profile of ethanolic extract of A. glehni leaves and stems (EAG) in terms of genotoxicity and subchronic oral animal toxicity under OECD guidelines and GLP conditions. Toxicological assessments were performed at doses of 1,250, 2,500, and 5,000 mg/kg/day in a 13-week oral repeated-dose toxicity study of EAG in male and female SD rats. In addition, an Ames test, an in vitro mammalian chromosomal aberration test, and a micronucleus test were performed. No toxicological changes in clinical signs, body weights, water and food consumption, urinalysis, hematology, clinical biochemistry, gross findings, and histopathological examinations were observed in subchronic oral animal toxicity. In addition, EAG gave negative results when evaluated using in vitro and in vivo genotoxicity tests. In conclusion, the no-observed-adverse-effect level (NOAEL) of EAG was considered to be 5,000 mg/kg/day, and no target organs were identified in both sexes of rats. EAG was also classified as nonmutagenic and nonclastogenic in genotoxicity testing. Collectively, these results show a lack of general toxicity and genotoxicity for EAG that supports clinical work for development as a herbal medicine.

CX3C-chemokine receptor 1 modulates cognitive dysfunction induced by sleep deprivation

Background:

Microglia plays an indispensable role in the pathological process of sleep deprivation (SD). Here, the potential role of microglial CX3C-chemokine receptor 1 (CX3CR1) in modulating the cognition decline during SD was evaluated in terms of microglial neuroinflammation and synaptic pruning. In this study, we aimed to investigat whether the interference in the microglial function by the CX3CR1 knockout affects the CNS's response to SD.

Methods:

Middle-aged wild-type (WT) C57BL/6 and CX3CR1^−/− mice were either subjected to SD or allowed normal sleep (S) for 8 h to mimic the pathophysiological changes of middle-aged people after staying up all night. After which, behavioral and histological tests were used to explore their different changes.

Results:

CX3CR1 deficiency prevented SD-induced cognitive impairments, unlike WT groups. Compared with the CX3CR1^−/− S group, the CX3CR1^−/− SD mice reported a markedly decreased microglia and cellular oncogene fos density in the dentate gyrus (DG), decreased expression of pro-inflammatory cytokines, and decreased microglial phagocytosis-related factors, whereas increased levels of anti-inflammatory cytokines in the hippocampus and a significant increase in the density of spines of the DG were also noted.

Conclusions:

These findings suggest that CX3CR1 deficiency leads to different cerebral behaviors and responses to SD. The inflammation-attenuating activity and the related modification of synaptic pruning are possible mechanism candidates, which indicate CX3CR1 as a candidate therapeutic target for the prevention of the sleep loss-induced cognitive impairments.

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.