New polysaccharide from Nerium indicum protects neurons via stress kinase signaling pathway

Mechanisms and structure-activity relationships of polysaccharides in the intervention of Alzheimer's disease: A review

Alzheimer's disease (AD) is a complex neurodegenerative disease. Despite several decades of research, the development of effective treatments and responses for Alzheimer's disease remains elusive. The utilization of polysaccharides for Alzheimer's disease became more popular due to their beneficial characteristics, notably their multi-target activity and low toxicity. This review mainly focuses on the researches of recent 5 years in the regulation of AD by naturally derived polysaccharides, systematically lists the possible intervention pathways of polysaccharides from different mechanisms, and explores the structure-activity relationship between polysaccharide structural activities, so as to provide references for the intervention and treatment of AD by polysaccharides.

A New Ultra-Performance Liquid Chromatographic Method for the Quantification of Vitamin C in Fresh and Dried Goji Berries (Lycium barbarum L.) Cultivated in Turkey

BACKGROUND

The potential background of the study is related to comprehensive detection of the content of vitamin C with an actual chromatographic method.

OBJECTIVE

Vitamin C is of vital importance in terms of human life and health due to its polyfunctional activity such as antioxidant activity and antiviral effect with other biological functions. In this regard, it may be necessary to update analytical methods or develop up-to-date analytical methods to accurately estimate the amount of vitamin C in natural samples. In this study, a new ultra-performance liquid chromatography with photodiode array detection (UPLC-PDA) method has been developed for the determination of vitamin C content in fresh and dried goji berries (Lycium barbarum L.), which are cultivated in Turkey.

METHOD

The chromatographic elution of vitamin C in natural fruit samples was achieved on an ACQUITY UPLC BEH C18 (1.7 µm, 2.1 mm × 100 mm) column using methanol and 0.1 M H3PO4 pH 2.15 (20:80, v/v), which are mobile phase. UPLC determination was done at the 242.8 nm. Flow rate was 0.20 mL/min at a column temperature of 30°C. Linearity range of the calibration graph was found to be at 5-30 µg/mL. The validity of the newly developed UPLC method was tested by analyzing individual test samples and added samples.

RESULTS

Applicability of the validated UPLC method was verified by the quantitative analysis of vitamin C content in both fresh and dried goji berries.

CONCLUSIONS

We believe that the newly developed and validated UPLC method would be a useful and promising approach for simple quantitative analysis of goji berry samples for vitamin C.

HIGHLIGHTS

In previous studies, no UPLC-PDA method was reported for the analysis of vitamin C in goji berries. The method provided a good repeatability for the analysis of real samples.

Protective Effect of Nerium Oleander Distillate and Tarantula Cubensis Alcoholic Extract on Cancer Biomarkers on Colon and Liver Tissues of Rats with Experimental Colon Cancer

BACKGROUND

Colon cancers are among the three major cancer types that result in death. The research for effective treatment continues.

OBJECTIVE

The aim of this study is to determine the effects of Tarantula cubensis alcoholic extract (TCAE) and Nerium oleander (NO) distillate on the levels of midkine, TGF-β, VEGF, AFP, COX-2, IGF and caspase 3 in liver and colon tissues of experimentally induced colon cancer in rats.

METHOD

The liver and colon tissues of the rats were divided into Control, Colon Cancer (AZM), AZM+TCAE and AZM+NO groups and they were homogenized. The levels of midkine, TGF-β, VEGF, AFP, COX-2, IGF and caspase 3 in the colon and liver tissues were measured by ELISA kits.

RESULTS

All parameters levels of colon and liver tissues in the AZM group were generally higher (p<0.05) than the Control group. TCAE and NO prevented (p<0.05) the increases in midkine, TGF-β, VEGF, AFP, COX-2, IGF and caspase-3 levels in the colon. NO prevented increase of all parameters except for IGF level, while TCAE prevented (p<0.05) the increase of all values apart from COX-2 and IGF levels in the liver.

CONCLUSION

NO and TCAE may prevented at the specified marker levels of colon in the AZM induced colon cancer. The increases the level of parameters in the liver are not as severe as in the colon, due to the 18-week study period may not be sufficient for liver metastasis formationIn the future molecular studies should be done to determine the mechanisms and pathways of them more clearly.

Polysaccharide from Schisandra chinensis acts via LRP-1 to reverse microglia activation through suppression of the NF-κB and MAPK signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra chinensis (Turcz.) Baill (S. Chinensis), a traditional Chinese medicine frequently used in the traditional treatment of dementia, its polysaccharide component has been widely reported.

AIM OF THE STUDY

In this paper, we studied whether SCP2-1, a natural product of homogeneous polysaccharide from S. Chinensis, could improve M1 and M2 polarization and inhibit neuroinflammation through lipoprotein receptor-related protein-1 (LRP-1), and futher exerted anti-inflammatory and neuroprotective effects.

MATERIALS AND METHODS

SCP2-1 was obtained from crude polysaccharide of S. Chinensis, BV2 microglia cells and mice stimulated by LPS were served to detect the positive role of SCP2-1 in M1/M2 polarization. The concentration of cytokine expression, IL-1β, TNF-α, IL-12 and IL-6 for M1 polarization and TGF-β, IL-10, IL-4 and Arg-1 for M2 polarization, in the BV2 and hippocampus were tested by ELISA kits. CD86 and CD206, as surface markers of M1 and M2, were tested by flow cytometry. We examined the expression of LRP-1 in BV2 cells and mouse hippocampus. The addition of siRNA for LRP-1 demonstrated the important role of LRP-1 in the neuroprotection of SCP2-1. Western blot was used to detect the activation of various mitogen-activated protein kinase (MAPKs) pathway, i.e. the phosphorylation of JNK and ERK proteins, and nuclear translocation of nuclear factor κB (NF-κB). H.E. staining was used to observe Histopathological changes.

RESULTS

SCP2-1 could reverse M1/M2 polarization in vitro culture and suppressed M1 polarization in the hippocampus of mice stimulated with LPS. After LPS stimulation, poor levels of LRP-1, hyperactivation of the JNK and NF-κB was appeared, which could improve by SCP2-1. The addition of siRNA for LRP-1 suppressed the protection of SCP2-1 in BV2 microglial cells. More importantly, SCP2-1 could improve LPS-induced cognitive dysfunction in mice in Y-maze and NOR test.

CONCLUSIONS

SCP2-1 could improve M1/M2 polarization, especially inhibit M1 polarization, and ameliorate the cognition of mice in Y-maze and NOR test. SCP2-1 play a neuroprotective role through LRP-1 to reverse activation of microglia via suppressing the overactive NF-κB and JNK pathway.

Research advances in the treatment of Alzheimer's disease with polysaccharides from traditional Chinese medicine

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the loss of patients' memory and their cognitive abilities and the mechanism is not completely clear. Although a variety of drugs have been approved for the AD treatment, substances which can prevent and cure AD are still in great need. The effect of polysaccharides from traditional Chinese medicine (TCM) on anti-AD has gained great progress and attained more and more attention in recent years. In this review, research advances in TCM-polysaccharides on AD made in this decade are summarized.

Systematic Review of Chemical Constituents in the Genus Lycium (Solanaceae)

The Lycium genus is widely used as a traditional Chinese medicine and functional food. Many of the chemical constituents of the genus Lycium were reported previously. In this review, in addition to the polysaccharides, we have enumerated 355 chemical constituents and nutrients, including 22 glycerogalactolipids, 29 phenylpropanoids, 10 coumarins, 13 lignans, 32 flavonoids, 37 amides, 72 alkaloids, four anthraquinones, 32 organic acids, 39 terpenoids, 57 sterols, steroids, and their derivatives, five peptides and three other constituents. This comprehensive study could lay the foundation for further research on the Lycium genus.

Epimedium Polysaccharide Alleviates Polyglutamine-Induced Neurotoxicity in Caenorhabditis elegans by Reducing Oxidative Stress

Epimedium has been traditionally used to treat a variety of medical conditions, including neurological disorders. In this study, an acidic polysaccharide EbPS-A1 is isolated from Epimedium brevicornum and found to contain mainly galacturonic acid, galactose, and rhamnose but also arabinose and glucuronic acid. Using Caenorhabditis elegans models, we show that EbPS-A1 is capable of inhibiting behavioral dysfunction mediated by polyglutamine (polyQ), which is implicated in several neurodegenerative disorders such as Huntington's disease. Interestingly, EbPS-A1 does not inhibit polyQ aggregation or extend lifespan in the nematodes; it does, however, improve the survival under increased oxidative stress of both polyQ and wild-type nematodes intoxicated by paraquat. Further studies reveal that EbPS-A1 is capable of not only scavenging free radicals in vitro but also reducing reactive oxygen species levels, enhancing antioxidant enzyme activities, and decreasing lipid peroxidation product in C. elegans models. Together, these results suggest that the protective effect of Epimedium polysaccharide against polyQ-mediated neurotoxicity is likely due to its antioxidant function.

Mitochondria Related Pathway Is Essential for Polysaccharides Purified from Sparassis crispa Mediated Neuro-Protection against Glutamate-Induced Toxicity in Differentiated PC12 Cells

The present study aims to explore the neuro-protective effects of purified Sparassis crispa polysaccharides against l-glutamic acid (l-Glu)-induced differentiated PC12 (DPC12) cell damages and its underlying mechanisms. The Sparassis crispa water extract was purified by a DEAE-52 cellulose anion exchange column and a Sepharose G-100 column. A fraction with a molecular weight of 75 kDa and a diameter of 88.9 nm, entitled SCWEA, was obtained. SCWEA was identified with a triple helix with (1→3)-linked Rha in the backbone, and (1→2) linkages and (1→6) linkages in the side bone. Our results indicated that the pre-treatment of DPC12 cells with SCWEA prior to l-Glu exposure effectively reversed the reduction on cell viability (by 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay) and reduced l-Glu-induced apoptosis (by Hoechst staining). SCWEA decreased the accumulation of intracellular reactive oxygen species, blocked Ca²⁺ influx and prevented depolarization of the mitochondrial membrane potential in DPC12 cells. Furthermore, SCWEA normalized expression of anti-apoptotic proteins in l-Glu-explored DPC12 cells. These results suggested that SCWEA protects against l-Glu-induced neuronal apoptosis in DPC12 cells and may be a promising candidate for treatment against neurodegenerative disease.

Sertraline increases the survival of retinoic acid induced neuronal cells but not glial cells from human mesenchymal stem cells

An increase in the number of viable in vitro differentiated neuronal cells is important for their use in clinics. A proportion of differentiated cells lose their viability before being used, and therefore we decided to use a pharmacological agent, sertraline, to increase neural cell differentiation and their survival. Purified endometrial stem cells (EnSCs) were examined for neuronal and glial cell specific markers after retinoic acid (RA) and sertraline treatment via RT-PCR, immunocytochemistry and Western blot analysis. The survival of differentiated cells was measured by MTT assay and the frequency of apoptosis, demonstrated by caspase-3-like activity. EnSCs were differentiated into neuronal cells after RA induction. Sertraline increased neuronal cell differentiation by 1.2-fold and their survival by 1.4-fold, and decreased from glial cell differentiation significantly. The findings indicate that sertraline could be used to improve the in vitro differentiation process of stem cells into neuronal cells, and may be involved in regenerative pharmacology in future.

Polysaccharides from medicinal herbs as potential therapeutics for aging and age-related neurodegeneration

Recent studies have uncovered important aging clues, including free radicals, inflammation, telomeres, and life span pathways. Strategies to regulate aging-associated signaling pathways are expected to be effective in the delay and prevention of age-related disorders. For example, herbal polysaccharides with considerable anti-oxidant and anti-inflammation capacities have been shown to be beneficial in aging and age-related neurodegenerative diseases. Polysaccharides capable of reducing cellular senescence and modulating life span via telomere and insulin pathways have also been found to have the potential to inhibit protein aggregation and aggregation-associated neurodegeneration. Here we present the current status of polysaccharides in anti-aging and anti-neurodegenerative studies.

In-vitro evaluation of selected Egyptian traditional herbal medicines for treatment of Alzheimer disease

BACKGROUND

Egyptians recognized the healing power of herbs and used them in their medicinal formulations. Nowadays, "Attarin" drug shops and the public use mainly the Unani medicinal system for treatment of their health problems including improvement of memory and old age related diseases. Numerous medicinal plants have been described in old literature of Arabic traditional medicine for treatment of Alzheimer's disease (AD) (or to strengthen memory).

METHODS

In this study, some of these plants were evaluated against three different preliminary bioassays related to AD to explore the possible way of their bio-interaction. Twenty three selected plants were extracted with methanol and screened in vitro against acetylcholinesterase (AChE) and cycloxygenase-1 (COX-1) enzymes. In addition, anti-oxidant activity using DPPH was determined.

RESULTS

Of the tested plant extracts; Adhatoda vasica and Peganum harmala showed inhibitory effect on AChE at IC50 294 μg/ml and 68 μg/ml respectively. Moreover, A. vasica interacted reversibly with the enzyme while P. harmala showed irreversible inhibition. Ferula assafoetida (IC50 3.2 μg/ml), Syzygium aromaticum (34.9 μg/ml) and Zingiber officinalis (33.6 μg/ml) showed activity against COX-1 enzyme. Potent radical scavenging activity was demonstrated by three plant extracts Terminalia chebula (EC50 2.2 μg/ml), T. arjuna (3.1 μg/ml) and Emblica officinalis (6.3 μg/ml).

CONCLUSION

Interestingly, differential results have been obtained which indicate the variability of the mode of actions for the selected plants. Additionally, the reversible interaction of A. vasica against AChE and the potent activity of F. assafoetida against COX-1 make them effective, new and promising agents for treatment of AD in the future, either as total extracts or their single bioactive constituents.

Neurologic effects of exogenous saccharides: a review of controlled human, animal, and in vitro studies

OBJECTIVES

Current research efforts are centered on delineating the novel health benefits of naturally derived saccharides, including growing interest in their abilities to influence neurologic health. We performed a comprehensive review of the literature to consolidate all controlled studies assessing various roles of exogenous saccharide compounds and polysaccharide-rich extracts from plants, fungi, and other natural sources on brain function, with a significant focus on benefits derived from oral intake.

METHODS

Studies were identified by conducting electronic searches on PubMed and Google Scholar. Reference lists of articles were also reviewed for additional relevant studies. Only articles published in English were included in this review.

RESULTS

Six randomized, double-blind, placebo-controlled clinical studies were identified in which consumption of a blend of plant-derived polysaccharides showed positive effects on cognitive function and mood in healthy adults. A separate controlled clinical study observed improvements in well-being with ingestion of a yeast beta-glucan. Numerous animal and in vitro studies have demonstrated the ability of individual saccharide compounds and polysaccharide-rich extracts to modify behavior, enhance synaptic plasticity, and provide neuroprotective effects.

DISCUSSION

Although the mechanisms by which exogenous saccharides can influence brain function are not well understood at this time, the literature suggests that certain naturally occurring compounds and polysaccharide-rich extracts show promise, when taken orally, in supporting neurologic health and function. Additional well-controlled clinical studies on larger populations are necessary, however, before specific recommendations can be made.

Inhibition of polyglutamine-mediated proteotoxicity by Astragalus membranaceus polysaccharide through the DAF-16/FOXO transcription factor in Caenorhabditis elegans

Late-onset neurodegenerative diseases are characterized by progressive accumulation of aggregation-prone proteins and global disruption of the proteostasis network, e.g. abnormal polyQ (polyglutamine) aggregation in Huntington's disease. Astragalus membranaceus polysaccharide (astragalan) has recently been shown to modulate aging and proteotoxic stress pathways. Using Caenorhabditis elegans models, we now show that astragalan not only reduces polyQ aggregation, but also alleviates the associated neurotoxicity. We also reveal that astragalan can extend the adult lifespan of wild-type and polyQ nematodes, indicating a connection of its anti-aging benefit with the toxicity-suppressing effect. Further examination demonstrates that astragalan can extend the lifespan of daf-2 and age-1, but not daf-16, mutant nematodes of the insulin-like aging and stress pathway, suggesting a lifespan-regulation signalling independent of DAF (abnormal dauer formation)-2/IGF-1R (insulin-like growth factor 1 receptor), but dependent on the DAF-16/FOXO (forkhead box O) transcription factor, a pivotal integrator of divergent signalling pathways related to both lifespan regulation and stress resistance. We also show that a subset of DAF-16 downstream genes are regulated by astragalan, including the DAF-16 transcriptional target gene scl-20, which is itself constitutively up-regulated in transgenic polyQ nematodes. These findings, together with our previous work on LEA (late embryogenesis abundant) proteins and trehalose, provide a revealing insight into the potential of stress and lifespan regulators in the prevention of proteotoxic disorders.

Botanical Drugs and Stem Cells

The potential to generate virtually any differentiated cell type from stem cells offers the possibility of creating new sources of cells for regenerative medicine. To realize this potential, it will be essential to control stem cell differentiation. Chinese herbal medicine is a major aspect of traditional Chinese medicine and is a rich source of unique chemicals. As such, individual herbs or extracts may play a role in the proliferation and differentiation of stem cells. In this review, we discuss some of the Chinese herbal medicines that are used to treat human diseases such as neuronal degenerative diseases, cardiovascular diseases, and osteoporosis. We also describe the relationship between Chinese herbal medicines and stem cell regulation.

Polysaccharides from wolfberry antagonizes glutamate excitotoxicity in rat cortical neurons

Glutamate excitotoxicity is involved in many neurodegenerative diseases including Alzheimer's disease (AD). Attenuation of glutamate toxicity is one of the therapeutic strategies for AD. Wolfberry (Lycium barbarum) is a common ingredient in oriental cuisines. A number of studies suggest that wolfberry has anti-aging properties. In recent years, there is a trend of using dried Wolfberry as food supplement and health product in UK and North America. Previously, we have demonstrated that a fraction of polysaccharide from Wolfberry (LBA) provided remarkable neuroprotective effects against beta-amyloid peptide-induced cytotoxicity in primary cultures of rat cortical neurons. To investigate whether LBA can protect neurons from other pathological factors such as glutamate found in Alzheimer brain, we examined whether it can prevent neurotoxicity elicited by glutamate in primary cultured neurons. The glutamate-induced cell death as detected by lactate dehydrogenase assay and caspase-3-like activity assay was significantly reduced by LBA at concentrations ranging from 10 to 500 microg/ml. Protective effects of LBA were comparable to memantine, a non-competitive NMDA receptor antagonist. LBA provided neuroprotection even 1 h after exposure to glutamate. In addition to glutamate, LBA attenuated N-methyl-D-aspartate (NMDA)-induced neuronal damage. To further explore whether LBA might function as antioxidant, we used hydrogen peroxide (H(2)O(2)) as oxidative stress inducer in this study. LBA could not attenuate the toxicity of H(2)O(2). Furthermore, LBA did not attenuate glutamate-induced oxidation by using NBT assay. Western blot analysis indicated that glutamate-induced phosphorylation of c-jun N-terminal kinase (JNK) was reduced by treatment with LBA. Taken together, LBA exerted significant neuroprotective effects on cultured cortical neurons exposed to glutamate.

Antagonizing beta-amyloid peptide neurotoxicity of the anti-aging fungus Ganoderma lucidum

Ganoderma lucidum (Leyss. ex Fr.) Karst. (Lingzhi) is a medicinal fungus used clinically in many Asian countries to promote health and longevity. Synaptic degeneration is another key mode of neurodegeneration in Alzheimer's disease (AD). Recent studies have shown the loss of synaptic density proteins in each individual neuron during the progression of AD. It was recently reported that beta-amyloid (Abeta) could cause synaptic dysfunction and contribute to AD pathology. In this study, we reported that aqueous extract of G. lucidum significantly attenuated Abeta-induced synaptotoxicity by preserving the synaptic density protein, synaptophysin. In addition, G. lucidum aqueous extract antagonized Abeta-triggered DEVD cleavage activities in a dose-dependent manner. Further studies elucidated that phosphorylation of c-Jun N-terminal kinase, c-Jun, and p38 MAP kinase was attenuated by G. lucidum in Abeta-stressed neurons. Taken together, the results prove a hypothesis that anti-aging G. lucidum can prevent harmful effects of the exterminating toxin Abeta in AD.

Characterizing the neuroprotective effects of alkaline extract of Lycium barbarum on β-amyloid peptide neurotoxicity

Lycium barbarum is an oriental medicinal herb that has long been used for its anti-aging and cell-protective properties. Previous studies have shown that aqueous extracts from L. barbarum exhibit neuroprotection via inhibiting pro-apoptotic signaling pathways. Other active components can also be accomplished by novel alkaline extraction method, which may give different profiles of water-soluble components. We hypothesize that another active component obtained by alkaline extraction method exerts different biological mechanisms to protect neurons. In this study, we aim to examine the neuroprotective effects from the alkaline extract of L. barbarum, namely LBB, to attenuate beta-amyloid (Abeta) peptide neurotoxicity. Primary cortical neurons were exposed to Abeta-peptides inducing apoptosis and neuronal cell death. Pretreatment of LBB significantly reduced the level of lactate dehydrogenase (LDH) release and the activity of caspase-3 triggered by Abeta. "Wash-out" procedures did not reduce its neuroprotective effects, suggesting that LBB may not bind directly to Abeta. We have further isolated three subfractions from LBB, namely LBB-0, LBB-I and LBB-II. LBB-I and LBB-II showed differential neuroprotective effects. Western blot analysis demonstrated that LBB-I and LBB-II markedly enhanced the phosphorylation of Akt. Taken together, our results suggested that the glycoconjugate isolated from novel alkaline extraction method can open up a new avenue for drug discovery in neurodegenerative diseases.