Mechanism of Lycium barbarum polysaccharides on primary cultured rat hippocampal neurons

Effects of natural source polysaccharides on neurological diseases: A review

With the aging of society and changes in lifestyle, the incidence of neurological diseases (NDs) has been increasing year by year, bringing a heavy burden to patients and society. Although the efficacy of chemical drugs in the treatment of NDs is remarkable, there are problems such as high side effects and high costs. Therefore, finding mild and efficient drugs for NDs treatment has become an urgent clinical need. Natural source polysaccharides (NSPs) are macromolecules with unique bioactivity and low toxicity characteristics, which have great potential to become novel therapeutic agents for NDs. In the present study, the pharmacological activities and potential molecular mechanisms of NSPs to alleviate NDs are systematically reviewed from the perspectives of inflammation, oxidative stress, apoptosis, neuronal cell autophagy, neurotoxicity, and sedation-hypnosis. In addition, the limitations of the existing studies were analyzed and discussed, and the future research direction was suggested. This study may provide scientific basis for the research and development of therapeutic agents for NDs based on NSPs.

Neuroprotective effects of Lycium barbarum polysaccharide on light-induced oxidative stress and mitochondrial damage via the Nrf2/HO-1 pathway in mouse hippocampal neurons

Light at night (LAN) induced cognitive impairment associated with oxidative stress in mice has been reported. Lycium barbarum polysaccharide (LBP) exhibits anti-tumor, anti-oxidant and neuroprotective effects, yet the neuroprotective effect on light-induced neuron damage still unclear. Here, mice exposed to LAN displayed cognitive impairment and depressive like behavior, which was reversed by LBP treatment. Meanwhile, LBP alleviated light-induced higher apoptosis and mitochondrial damage in HT-22 cells. Also, LBP prevented the decreased of mitochondrial membrane permeabilization (MMP) level in light-treated cells. Additionally, LBP demonstrated its antioxidant potential by reducing ROS production and malondialdehyde (MDA) level, while simultaneously enhancing the levels of superoxide dismutase (SOD) and glutathione peroxidases (GSH-Px) in both light-treated mice and HT-22 cells. Furthermore, the mRNA and protein expression of Nrf2 (NF-E2-related factor 2), heme oxygenease-1 (HO-1), and NAD(P)H quinone oxidoreductase (NQO1) were decreased in both light-treated mice and cells. Additionally, LBP treatment reversed light-induced the inhibition of Nrf2/HO-1 signaling pathway in both mice and cells. Moreover, Nrf2 antagonist ML385 significantly eliminated the neuroprotection of LBP on cell apoptosis, oxidative stress and mitochondrial damage in light-treated cells. These results indicate that LBP can rescue light-induced neurotoxicity in mice and HT-22 cells by activating the Nrf2/HO-1 signaling pathway.

Anti-Aging of the Nervous System and Related Neurodegenerative Diseases With Chinese Herbal Medicine

Human beings have always pursued a prolonged lifespan, while the aging of the nervous system is associated with a large variety of diseases. Pathological aging of the nervous system results in a series of neurodegenerative diseases and can cause disability and death in the elderly. Therefore, there is an urgent need for the prevention and treatment of nervous system aging. Chinese herbal medicines have a long history, featuring rich and safe ingredients, and have great potential for the development of anti-aging treatment. We searched the publications on PubMed with key words "anti-aging of the nervous system" and "Chinese herbal medicine" in recent 10 years, and found sixteen Chinese herbal medicines. Then by comparing their popularity of use as well as active components based on the research articles, five common Chinese herbal medicines namely Ginseng Radix, Lycii Fructus, Astragali Radix, Coptidis Rhizoma and Ginkgo Folium, were confirmed to be the most related to anti-nervous system aging and neural degenerative diseases. At the same time, the active ingredients, research models, action mechanisms and curative effects of these five common Chinese herbal medicines were reviewed. From the five common Chinese herbal medicines reviewed in this paper, many encouraging effects of Chinese herbal medicines on treating nervous system aging and related diseases were revealed and more potent herbs would be explored with the help of the proposed possible mechanisms.

Traditional Chinese medicine in treating ischemic stroke by modulating mitochondria: A comprehensive overview of experimental studies

Ischemic stroke has been a prominent focus of scientific investigation owing to its high prevalence, complex pathogenesis, and difficulties in treatment. Mitochondria play an important role in cellular energy homeostasis and are involved in neuronal death following ischemic stroke. Hence, maintaining mitochondrial function is critical for neuronal survival and neurological improvement in ischemic stroke, and mitochondria are key therapeutic targets in cerebral stroke research. With the benefits of high efficacy, low cost, and high safety, traditional Chinese medicine (TCM) has great advantages in preventing and treating ischemic stroke. Accumulating studies have explored the effect of TCM in preventing and treating ischemic stroke from the perspective of regulating mitochondrial structure and function. In this review, we discuss the molecular mechanisms by which mitochondria are involved in ischemic stroke. Furthermore, we summarized the current advances in TCM in preventing and treating ischemic stroke by modulating mitochondria. We aimed to provide a new perspective and enlightenment for TCM in the prevention and treatment of ischemic stroke by modulating mitochondria.

Neuroprotective Effects of Lycium barbarum Berry on Neurobehavioral Changes and Neuronal Loss in the Hippocampus of Mice Exposed to Acute Ionizing Radiation

Background: Brain exposure to ionizing radiation during the radiotherapy of brain tumor or metastasis of peripheral cancer cells to the brain has resulted in cognitive dysfunction by reducing neurogenesis in hippocampus. The water extract of Lycium barbarum berry (Lyc), containing water-soluble Lycium barbarum polysaccharides and flavonoids, can protect the neuronal injury by reducing oxidative stress and suppressing neuroinflammation. Reseach Design: To demonstrate the long-term radioprotective effect of Lyc, we evaluated the neurobehavioral alterations and the numbers of NeuN, calbindin (CB), and parvalbumin (PV) immunopositive hippocampal neurons in BALB/c mice after acute 5.5 Gy radiation with/without oral administration of Lyc at the dosage of 10 g/kg daily for 4 weeks. Results: The results showed that Lyc could improve irradiation-induced animal weight loss, depressive behaviors, spatial memory impairment, and hippocampal neuron loss. Immunohistochemistry study demonstrated that the loss of NeuN-immunopositive neuron in the hilus of the dentate gyrus, CB-immunopositive neuron in CA1 strata radiatum, lacunosum moleculare and oriens, and PV-positive neuron in CA1 stratum pyramidum and stratum granulosum of the dentate gyrus after irradiation were significantly improved by Lyc treatment. Conclusion: The neuroprotective effect of Lyc on those hippocampal neurons may benefit the configuration of learning related neuronal networks and then improve radiation induced neurobehavioral changes such as cognitive impairment and depression. It suggests that Lycium barbarum berry may be an alternative food supplement to prevent radiation-induced neuron loss and neuropsychological disorders.

Effects of long-term consumption of polysaccharides from the fruit of Lycium barbarum on host's health

Polysaccharides from the fruit of Lycium barbarum (LBPs) are functional molecules with diverse biological functions in vivo and in vitro. This study investigated the long-term consumption of LBPs on host's health in BALB/c mice. Six-week-old male mice (n = 10 each group) were fed either a normal control (NC) diet or supplemented with 200 mg/kg (body weight)/d of LBPs for 14 weeks. Compared with the NC diet, the LBPs diet enhanced the expression of mucin 2 and Claudin5, improved the intestinal barrier morphologically, moreover, promoted the growth of Lactobacillus and strongly increased the production of short-chain fatty acids and IgA (p < 0.05). Feeding LBPs increased the levels of superoxide dismutase and reduced glutathione in the serum, liver and spleen while decreased the levels of alanine aminotransferase and lysozyme in serum and spleen. Besides, the LBPs diet increased the expression of cytokines including tumor necrosis factor α and interleukin-6 and related mRNA but decreased the level of lysozyme. To sum up, chronic intake of LBPs in BALB/c mice improved the oxidation resistance, changed the immune status especially promoted the intestinal immunity. These results may have important implications for LBPs as functional food supplement and for realizing the potential value of LBPs for host's health.

Protective effects of polysaccharides on cerebral ischemia: A mini-review of the mechanisms

Cerebral ischemia, a common cerebrovascular disease, is one of the great threats to human health. Nowadays, many drugs used in the treatment of cerebral ischemia such as clot busting drugs, antiplatelet drugs, and neuroprotective drugs have limits. It is urgent finding new effective treatments for the patients. Researches have confirmed that many kinds of polysaccharides from natural resources possess therapeutic effects on cerebral ischemia, but are still lack of a comprehensively understanding. In this paper, based on the pathophysiology of cerebral ischemic injury, we summarize the latest discoveries and advancements of 29 kinds of polysaccharides, focusing on their ameliorating effects on cerebral ischemia and the underlying mechanisms. Several mechanisms are involved, mainly including antioxidant activities, anti-inflammatory activities, regulating neuron apoptosis, as well as resisting nitrosative stress injury. Besides, polysaccharides show protective effects through certain signaling pathways including PI3K/Akt, MAPK, and NF-κB, PARP-1/AIF, JNK3/c-Jun/Fas-L, and Nrf2/HO-1 signaling pathways. The main goal of this mini-review is to emphasize the important roles of polysaccharides in attenuating cerebral ischemic injury through the elucidation of mechanisms.

Anxiolytic, antioxidant, and neuroprotective effects of goji berry polysaccharides in ovariectomized rats: experimental evidence from behavioral, biochemical, and immunohistochemical analyses

Recent studies have indicated that polysaccharides, the main component of the Lycium barbarum L. fruit, have beneficial effects (e.g., anxiolytic, antioxidant, and neuroprotective) on humans and rodents. However, the effects of different dosages of such polysaccharides on ovariectomized rats and their underlying mechanisms in the brain have not been evaluated in the literature. Here, we aimed to evaluate the effects of the high and low doses of polysaccharides obtained from Lycium barbarum fruits (HD-LBP and LD-LBP, respectively) on anxious behaviors via behavioral (using the OFT and EPM), biochemical (using ELISA), and immunohistochemical (using immunohistochemical staining) measures in detail. Two weeks after ovariectomy, the rats were randomly assigned to either the treatment conditions [control (DW, 3 mL/kg, p.o., per day), LD-LBP (20 mg/kg, 3 mL/kg, p.o., per day), HD-LBP (200 mg/kg, 3 mL/kg, p.o., per day), 17 β-ES (1 mg/kg, 3 mL/kg, p.o., per day), DZ(1 mg/kg, 3 mL/kg, p.o., per day)] or operation type [SHAM (pseudo-ovariectomized) and OVX (ovariectomized)]. The treatments were applied for 30 consecutive days, and then serum and brain tissue samples of all rats were collected. Biochemical (SOD, CAT, GPX, MDA, and 17 β-ES) and immunohistochemical (BDNF, SER, and apoptosis) analyses of the samples were performed as well. The rats administered HD-LBP and LD-LBP were less anxious than the control groups. The HD-LBP-treated rats had high levels of SOD and low levels of MDA in their serum samples. Moreover, HD-LBP and drug-treated groups had a high number of SER receptors and BDNF-positive cells and a low number of TUNEL-positive cells in their hippocampal brain tissues. The HD-LBP treatments decrease anxious behavior by increasing antioxidant enzyme activities, hippocampal SER and BDNF neurotransmitter levels and decreasing the TUNEL-positive cell count of ovariectomized rats. Given these findings, we suggest that menopause-induced symptoms of anxiety can be reduced by polysaccharides obtained from goji berry fruits, and that these findings will be beneficial for the production studies of natural herbal-origin antianxiety (anxiolytic) drugs in the future.

Lycium barbarum polysaccharides attenuates the apoptosis of hippocampal neurons induced by sevoflurane

Following the application of inhalational anesthetics, including sevoflurane, patients may suffer from neural injury. The present study was conducted to explore the mechanism involved in Lycium barbarum polysaccharides (LBP) treatment of sevoflurane injured hippocampal neurons. Primary hippocampal neurons were isolated from Sprague Dawley embryonic rats. The Cell Counting Kit-8 (CCK-8) assay was used to detect cell viability. Furthermore, flow cytometry (FCM) was used to determine cell proliferation and apoptosis rates. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were applied to detect the expression levels of apoptosis-related factors, including activated-Caspase-3, B-cell lymphoma/leukemia-2 (Bcl-2) and Bcl-2 associated X (Bax), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) and total ERK1/2. The results showed that LBP promoted cell viability and cell proliferation but inhibited cell apoptosis in neurons injured with 3% sevoflurane, in dose-dependent manners (100, 200 and 400 µg/ml). LBP increased the expression levels of Bcl-2 and p-ERK1/2, and decreased levels of activated-Caspase-3 and Bax in a dose-dependent manner in hippocampal neurons that were injured with sevoflurane. In addition, ERK1/2 inhibitor reversed the above phenomenon in 400 µg/ml LBP and 3% sevoflurane-treated hippocampal neurons. Therefore, the present study indicated that LBP protected hippocampal neurons from sevoflurane injury, including aberrant cell apoptosis, via the ERK1/2 pathway.

Polysaccharide IV from Lycium barbarum L. Improves Lipid Profiles of Gestational Diabetes Mellitus of Pregnancy by Upregulating ABCA1 and Downregulating Sterol Regulatory Element-Binding Transcription 1 via miR-33

Lycium barbarum L. (LBL) has beneficial effects on gestational diabetes mellitus (GDM) but the related mechanism remains unclear. Polysaccharides of LBL (LBLP) are the main bioactive components of LBL. miR-33, ATP-binding cassette transporter A1 (ABCA1) and sterol regulatory element-binding transcription 1 (SREBF1) affect lipid profiles, which are associated with GDM risk. LBLP may exert protective against GDM by affecting these molecules. Four LBLP fractions: LBLP-I, LBLP-II, LBLP-III, and LBLP-IV were isolated from LBL and further purified by using DEAE-Sephadex column. The effects of purified each fraction on pancreatic beta cells were comparatively evaluated. A total of 158 GDM patients were recruited and randomly divided into LBL group (LG) and placebo group (CG). miR-33 levels, lipid profiles, insulin resistance and secretory functions were measured. The association between serum miR-33 levels and lipid profiles were evaluated by using Spearman's rank-order correlation test. After 4-week therapy, LBL reduced miR-33 level, insulin resistance and increased insulin secretion of GDM patients. LBL increased the levels of ABCA1, high-density lipoprotein cholesterol (HDL-C) and reduced miR-33, SREBF1, low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglyceride (TG), and malondialdehyde. Homeostatic model assessment of β-cell function and insulin resistance was lower in LG than in CG, whereas homeostatic model assessment of β-cell function and insulin secretory function was higher in LG than in CG. There was a strong positive association between miR-33 level and TG, or TC and or LDL-C, and a strong negative association between miR-33 level and HDL-C. The levels of miR-33 had negative relation with ABCA1 and positive relation with SREBF1. ABCA1 has negative relation with TG, TC, and LDL-C and positive relation with HDL-C. Inversely, SREBF1 had positive relation with TG, TC, and LDL-C and negative relation with HDL-C. The main bioactive compound LBLP-IV of LBL increased insulin secretion of beta cells and the levels of ABCA1, and reduced miR-33 levels and SREBF1 in beta cells. However, LBLP-IV could not change the levels of these molecules anymore when miR-33 was overexpressed or silenced. LBLP-IV had the similar effects with LBL on beta cells while other components had no such effects. Thus, LBLP-IV from LBL improves lipid profiles by upregulating ABCA1 and downregulating SREBF1 via miR-33.

Gastrointestinal Absorption and Metabolic Dynamics of Jujuboside A, A Saponin Derived from the Seed of Ziziphus jujuba

Jujuboside A (JuA), an active saponin, is responsible for the anxiolytic and sedative effects of Zizyphi Spinosae Semen (ZSS). In this study, the gastrointestinal absorption and metabolic dynamics of JuA were investigated in vivo and in vitro. The results showed that the bioavailability was 1.32% in rats, indicating only a trace amount of JuA was able to be absorbed. Further investigation revealed that its poor bioavailability was not caused by malabsorption but by the metabolic process. JuA was hydrolyzed largely in the stomach before being absorbed into the different parts of the intestine (especially duodenum and colon), and the gastric environment played a vital role in this process. Furthermore, the metabolites, jujuboside B (JuB) and jujubogenin, exhibited significant effects on the expression and activation of γ-amino-butyric acid A (GABA(A)) receptors. Our findings demonstrate that the metabolites of the saponin, not the original molecule, should be responsible for the specific bioactivities.