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

Current Perspective in the Discovery of Anti-aging Agents from Natural Products

Aging is a process characterized by accumulating degenerative damages, resulting in the death of an organism ultimately. The main goal of aging research is to develop therapies that delay age-related diseases in human. Since signaling pathways in aging of Caenorhabditis elegans (C. elegans), fruit flies and mice are evolutionarily conserved, compounds extending lifespan of them by intervening pathways of aging may be useful in treating age-related diseases in human. Natural products have special resource advantage and with few side effect. Recently, many compounds or extracts from natural products slowing aging and extending lifespan have been reported. Here we summarized these compounds or extracts and their mechanisms in increasing longevity of C. elegans or other species, and the prospect in developing anti-aging medicine from natural products.

Effects of Bu Shen Yi sui capsule on NogoA/NgR and its signaling pathways RhoA/ROCK in mice with experimental autoimmune encephalomyelitis

Background

Axon growth inhibitory factors NogoA/Nogo receptor (NgR) and its signaling pathways RhoA/Rho kinase (ROCK) play a critical role in the repair of nerve damage in multiple sclerosis (MS). Bu Shen Yi Sui Capsule (BSYSC) is an effective Chinese formula utilized to treat MS in clinical setting and noted for its potent neuroprotective effects. In this study, we focus on the effects of BSYSC on promoting nerve repair and the underlying mechanisms in mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS.

Methods

The EAE mouse model was induced by injecting subcutaneously with myelin oligodendrocyte glycoprotein (MOG) _35–55 supplemented with pertussis toxin. BSYSC was orally administrated at dose of 3.0 g/kg once a day for 40 days. The levels of protein gene product (PGP) 9.5, p-Tau, growth associated protein (GAP) -43, KI67 and Nestin in the brain or spinal cord on 20 and 40 day post-induction (dpi) were detected via immunofluorescence and Western blot analysis. Furthermore, NogoA/NgR and RhoA/ROCK signaling molecules were studied by qRT-PCR and Western blot analysis.

Results

Twenty or 40 days of treatment with BSYSC increased markedly PGP9.5 and GAP-43 levels, reduced p-Tau in the brain or spinal cord of mice with EAE. In addition, BSYSC elevated significantly the expression of KI67 and Nestin in the spinal cord 40 dpi. Further study showed that the activation of NogoA/NgR and RhoA/ROCK were suppressed by the presence of BSYSC.

Conclusions

BSYSC could attenuate axonal injury and promote repair of axonal damage in EAE mice in part through the down-regulation of NogoA/NgR and RhoA/ROCK signaling pathways.

The Protective Effect of Lavender Essential Oil and Its Main Component Linalool against the Cognitive Deficits Induced by D-Galactose and Aluminum Trichloride in Mice

Lavender essential oil (LO) is a traditional medicine used for the treatment of Alzheimer's disease (AD). It was extracted from Lavandula angustifolia Mill. This study was designed to investigate the effects of lavender essential oil (LO) and its active component, linalool (LI), against cognitive impairment induced by D-galactose (D-gal) and AlCl₃ in mice and to explore the related mechanisms. Our results revealed that LO (100 mg/kg) or LI (100 mg/kg) significantly protected the cognitive impairments as assessed by the Morris water maze test and step-though test. The mechanisms study demonstrated that LO and LI significantly protected the decreased activity of superoxide dismutase (SOD), glutathione peroxidase (GPX), and protected the increased activity of acetylcholinesterase (AChE) and content of malondialdehyde (MDA). Besides, they protected the suppressed nuclear factor-erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression significantly. Moreover, the decreased expression of synapse plasticity-related proteins, calcium-calmodulin-dependent protein kinase II (CaMKII), p-CaMKII, brain-derived neurotrophic factor (BDNF), and TrkB in the hippocampus were increased with drug treatment. In conclusion, LO and its active component LI have protected the oxidative stress, activity of cholinergic function and expression of proteins of Nrf2/HO-1 pathway, and synaptic plasticity. It suggest that LO, especially LI, could be a potential agent for improving cognitive impairment in AD.

Acteoside and Isoacteoside Protect Amyloid β Peptide Induced Cytotoxicity, Cognitive Deficit and Neurochemical Disturbances In Vitro and In Vivo

Acteoside and isoacteoside, two phenylethanoid glycosides, coexist in some plants. This study investigates the memory-improving and cytoprotective effects of acteoside and isoacteoside in amyloid β peptide 1-42 (Aβ 1-42)-infused rats and Aβ 1-42-treated SH-SY5Y cells. It further elucidates the role of amyloid cascade and central neuronal function in these effects. Acteoside and isoacteoside ameliorated cognitive deficits, decreased amyloid deposition, and reversed central cholinergic dysfunction that were caused by Aβ 1-42 in rats. Acteoside and isoacteoside further decreased extracellular Aβ 1-40 production and restored the cell viability that was decreased by Aβ 1-42 in SH-SY5Y cells. Acteoside and isoacteoside also promoted Aβ 1-40 degradation and inhibited Aβ 1-42 oligomerization in vitro. However, the memory-improving and cytoprotective effects of isoacteoside exceeded those of acteoside. Isoacteoside promoted exploratory behavior and restored cortical and hippocampal dopamine levels, but acteoside did not. We suggest that acteoside and isoacteoside ameliorated the cognitive dysfunction that was caused by Aβ 1-42 by blocking amyloid deposition via preventing amyloid oligomerization, and reversing central neuronal function via counteracting amyloid cytotoxicity.

Cognitive-enhancing and antioxidant activities of the aqueous extract from Markhamia tomentosa (Benth.) K. Schum. stem bark in a rat model of scopolamine

BACKGROUND

Plants of the genus Markhamia have been traditionally used by different tribes in various parts of West African countries, including Cameroun. Markhamia tomentosa (Benth.) K. Schum. (Bignoniaceae) is used as an antimalarial, anti-inflammatory, analgesic, antioxidant and anti-Alzheimer agent. The current study was undertaken in order to investigate its anti-amnesic and antioxidant potential on scopolamine-induced cognitive impairment and to determine its possible mechanism of action.

METHODS

Rats were pretreated with the aqueous extract (50 and 200 mg/kg, p.o.), for 10 days, and received a single injection of scopolamine (0.7 mg/kg, i.p.) before training in Y-maze and radial arm-maze tests. The biochemical parameters in the rat hippocampus were also assessed to explore oxidative status. Statistical analyses were performed using two-way ANOVA followed by Tukey's post hoc test. F values for which p < 0.05 were regarded as statistically significant.

RESULTS

In the scopolamine-treated rats, the aqueous extract improved memory in behavioral tests and decreased the oxidative stress in the rat hippocampus. Also, the aqueous extract exhibited anti-acetylcholinesterase activity.

CONCLUSIONS

These results suggest that the aqueous extract ameliorates scopolamine-induced spatial memory impairment by attenuation of the oxidative stress in the rat hippocampus.

Molecular pathways related to the longevity promotion and cognitive improvement of Cistanche tubulosa in Drosophila

BACKGROUND

The aging process, including physical dysfunction and age-related memory impairment (AMI), are considered to be correlated with cumulative oxidative damages and insulin/IGF-1 signaling pathway.

PURPOSE

The present study was to elucidate the in vivo effects on delaying aging and ameliorating AMI and underlying molecular mechanisms of Cistanche tubulosa (CT), a herb used in traditional Chinese medicine to improve sexual function and treat kidney dysfunction.

METHODS

The flies, treated and untreated with CT, were observed for lifespan, resistance to oxidative stress with H₂O₂ or paraquat, starvation assay, cognitive behaviors with T-maze, and transcript levels of target genes with quantitative RT-PCR.

RESULTS

Administering CT extended the mean and maximum lifespan and increased resistance to oxidative stress in flies. CT supplementation also enhanced memory formation in young flies and suppressed AMI upon aging. Several genes and signaling pathways, including the mechanistic target of rapamycin (mTOR) and Notch networks, have been identified as causing these pharmacological effects and alterations in the gene expression of glutamate receptors.

CONCLUSION

Our results indicate that CT supplementation may contribute to slowing aging phenotypes and alleviating cognitive behavioral decline in flies, indicating potential applicability for enhancing human health and reducing susceptibility to age-related disorders.

Ginsenosides attenuate d-galactose- and AlCl3-inducedspatial memory impairment by restoring the dysfunction of the neurotransmitter systems in the rat model of Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C.A.Mey. is a traditional Chinese herbal medicine, which has been used to treat Alzheimer's disease (AD) for thousands of years. Ginsenoside is one of the major compounds found in P. ginseng. This study aimed to explore the attenuation of spatial memory impairment by ginsenosides and its correlation with restoring the dysfunction of the neurotransmitter systems in AD model rats to understand the mechanism underlying the anti-AD effect of P. ginseng.

MATERIALS AND METHODS

In this study, the AD model was established by combining d-galactose (d-gal) with AlCl₃ (Al) for 60 days. From day 30, the ginsenosides group was intragastrically administered with ginsenosides for 30 days. The ethology of rats was tested through the Morris water maze test(MWM). Histopathological changes in the hippocampus of rats were observed through hematoxylin and eosin staining. The expressions of amyloid β peptide (Aβ) and phospho-tau (p-tau) in the hippocampus and cortex of rats were detected by immunohistochemistry. A liquid chromatography-mass spectrometry assay was used to measure neurotransmitter concentrations in the hippocampus, cortex, and blood.

RESULTS

Ginsenosides could significantly decrease the escape latency time and the average latency time in the place navigation test and increase the times of crossing the platform area, the percentage of residence time, and the distance in the original platform quadrant in the spatial probe test. Ginsenosides could repair the damage of the hippocampus and reduce the expressions of Aβ and p-tau. Ginsenosides could also increase γ-aminobutyric acid, acetylcholine, and dopamine levels and decrease glutamate and aspartic acid levels in the hippocampus and cortex and increase glycine and serotonin levels in the blood.

CONCLUSIONS

After effectively administrated, ginsenosides attenuate d-gal- and Al-induced spatial memory impairment. The possible mechanism of the beneficial effect is restoring the dysfunction of various neurotransmitters.

Positional Isomerization of Phenylethanoid Glycosides from Magnolia officinalis

Positional isomerization, an inducement leading to instability of phenylethanoid glycosides (PhGs) containing the caffeoyl moiety linked to C-3/4 of the central saccharide, is reported. Magnolosides M, A and F from Magnolia officinalis were found to be transformed into their isomers magnolosides A, D, M and B, respectively, which indicated that PhGs containing the caffeoyl moiety linking to C-3/4 of the central saccharide were unstable, and the caffeoyl group could be transferred to either C-4/3 or C-6 of the central saccharide. In addition, among the factors of temperature, solvent type and exposure time in solvent, temperature was found to play a critical role in initiation of positional isomerization of PhGs. In order to retard this isomerization, the temperature should be lower than 40°C during the final purification stages of PhGs.

Protective effects of hydroponic Teucrium polium on hippocampal neurodegeneration in ovariectomized rats

BACKGROUND

The hippocampus is a target of ovarian hormones, and is necessary for memory. Ovarian hormone loss is associated with a progressive reduction in synaptic strength and dendritic spine. Teucrium polium has beneficial effects on learning and memory. However, it remains unknown whether Teucrium polium ameliorates hippocampal cells spike activity and morphological impairments induced by estrogen deficiency.

METHODS

In the present study, we investigated the effects of hydroponic Teucrium polium on hippocampal neuronal activity and morpho-histochemistry of bilateral ovariectomized (OVX) rats. Tetanic potentiation or depression with posttetanic potentiation and depression was recorded extracellularly in response to ipsilateral entorhinal cortex high frequency stimulation. In morpho-histochemical study revealing of the activity of Ca2+-dependent acid phosphatase was observed. In all groups (sham-operated, sham + Teucrium polium, OVX, OVX + Teucrium polium), most recorded hippocampal neurons at HFS of entorhinal cortex showed TD-PTP responses.

RESULTS

After 8 weeks in OVX group an anomalous evoked spike activity was detected (a high percentage of typical areactive units). In OVX + Teucrium polium group a synaptic activity was revealed, indicating prevention OVX-induced degenerative alterations: balance of types of responses was close to norm and areactive units were not recorded. All recorded neurons in sham + Teucrium polium group were characterized by the highest mean frequency background and poststimulus activity. In OVX+ Teucrium polium group the hippocampal cells had recovered their size and shape in CA1 and CA3 field compared with OVX group where hippocampal cells were characterized by a sharp drop in phosphatase activity and there was a complete lack of processes reaction.

CONCLUSION

Thus, Teucrium polium reduced OVX-induce neurodegenerative alterations in entorhinal cortex-hippocamp circuitry and facilitated neuronal survival by modulating activity of neurotransmitters and network plasticity.

Acteoside Binds to Caspase-3 and Exerts Neuroprotection in the Rotenone Rat Model of Parkinson's Disease

Parkinson’s disease (PD) is characterized by the progressive degeneration of the dopaminergic neurons in the substantia nigra (SN) region. Acteoside has displayed multiple biological functions. Its potential role against PD and the underlying signaling mechanisms are largely unknown. Here, we showed that oral administration of acteoside significantly attenuated parkinsonism symptoms in rotenone-induced PD rats. Further, acteoside inhibited rotenone-induced α-synuclein, caspase-3 upregulation and microtubule-associated protein 2 (MAP2) downregulation in PD rats. The molecular docking and molecular dynamics (MD) simulation results indicated that acteoside may directly bind to and inhibit caspase-3. Acteoside formed hydrogen bonds with at least six residues of caspase-3: ThrA177, SerA178, GlyA238, SerB339, ArgB341 and TrpB348. In addition, a pi-pi interaction was formed between acteoside and caspase-3’s HisA237, which might further stabilize the complex. MD simulation results demonstrated that the binding affinity of the caspase-3-acteoside complex was higher than that of caspase-3 and its native ligand inhibitor. Together, we show that acteoside binds to caspase-3 and exerts neuroprotection in the rotenone rat model of PD.

Phenylethanoid Glycosides: Research Advances in Their Phytochemistry, Pharmacological Activity and Pharmacokinetics

Phenylethanoid glycosides (PhGs) are widely distributed in traditional Chinese medicines as well as in other medicinal plants, and they were characterized by a phenethyl alcohol (C₆-C₂) moiety attached to a β-glucopyranose/β-allopyranose via a glycosidic bond. The outstanding activity of PhGs in diverse diseases proves their importance in medicinal chemistry research. This review summarizes new findings on PhGs over the past 10 years, concerning the new structures, their bioactivities, including neuroprotective, anti-inflammatory, antioxidant, antibacterial and antivirus, cytotoxic, immunomodulatory, and enzyme inhibitory effects, and pharmacokinetic properties.

Neuroprotective effects of ginseng protein on PI3K/Akt signaling pathway in the hippocampus of D-galactose/AlCl3 inducing rats model of Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer disease (AD) is a progressive neurodegenerative disease, with progressive memory loss, cognitive deterioration, and behavioral disorders. Ginseng (Panax ginseng C.A. Meyer) is widely used in China to treat various kinds of nervous system disorders. The study aimed to explore the therapeutic effect of ginseng protein (GP) on Alzheimer's disease and its correlation with the PI3K/Akt signaling pathway to understand the mechanism underlying the neuroprotective effect of ginseng.

MATERIAL AND METHODS

The AD rat model was established by intraperitoneally injecting D-galactose [60mg/(kgd)] followed by intragastrically administering AlCl3 [40mg/(kgd)] for 90 days. From day 60, the GP groups were intragastrically administered with GP 0.05 or 0.1g/kg twice daily for 30 days. The ethology of rats was tested by Morris water maze test. The content of Aβ1-42 and p-tau in the hippocampus of rats was detected by enzyme-linked immunosorbent assay. The expression of mRNAs and proteins of PI3K, Akt, phosphorylated Akt (p-Akt), Bcl-2, and Bax in the hippocampus was detected by real-time quantitative reverse transcription polymerase chain reaction and Western blot assay.

RESULTS

GP was found to significantly improve the memory ability of AD rats and prolong the times of crossing the platform and the percentage of residence time in the original platform quadrant of spatial probe test. GP also reduced the content of Aβ1-42 and p-tau and improved the mRNA and protein expression of PI3K, p-Akt/Akt, and Bcl-2/Bax in the hippocampus.

CONCLUSIONS

GP could improve the memory ability and reduce the content of Aβ1-42 and p-tau in AD rats. The anti-AD effects of GP were in part mediated by PI3K/Akt signaling pathway activation.