Ganoderma atrum polysaccharide attenuates oxidative stress induced by d-galactose in mouse brain

Mitigation of oxidative stress-induced aging by extracellular polysaccharides from Lactiplantibacillus plantarum R6-1 from Sayram ketteki

Oxidative stress within the body is associated with aging, playing a crucial role in its progression. Polysaccharides from lactic acid bacteria are well recognized for their antioxidant effects, potentially improving the aging process. This study investigated the characterization and antioxidant activities of extracellular polysaccharides (EPS-1: 59,978 Da, 40.9 % mannose, 4.5 % ribose, 5.8 % glucuronic acid, 44.1 % glucose, 2.9 % galactose; EPS-2: 25,686 Da, 22.9 % mannose, 5.4 % ribose, 5.5 % glucuronic acid, 59.6 % glucose, 5.4 % galactose) produced by Lactiplantibacillus plantarum R6-1. The results showed that EPS could increase the survival rates of Caco-2 cells exposed to hydrogen peroxide and mitigate the D-galactose (D-Gal)-induced oxidative stress in mice. Administration of EPS activated the hepatic nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in mice. Subsequently, this pathway activated various oxidation-related enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. Meanwhile, EPS regulated mouse intestinal microbiota by increasing the relative abundance of beneficial bacteria secreting anti-inflammatory factors, such as Norank_f_Muribaculaceae and Dubosiella, and restoring the imbalance of Firmicutes to Bacteroidetes caused by oxidative stress. This study shows that L. plantarum R6-1's EPS exhibited the ability to concurrently influence both the liver and intestinal microbiota of mice, thereby achieving an anti-oxidative effect through their interconnected interactions.

Polygonatum sibiricum polysaccharide ameliorates skeletal muscle aging via mitochondria-associated membrane-mediated calcium homeostasis regulation

BACKGROUND

Sarcopenia, an age-related disease, is characterized by a gradual loss of muscle mass, strength, and function. It has been linked to abnormal organelle function in myotubes, including the mitochondria and endoplasmic reticulum (ER). Recent studies revealed that mitochondria-associated membranes (MAM), the sites connecting mitochondria and the ER, may be implicated in skeletal muscle aging. In this arena, the potential of Polygonatum sibiricum polysaccharide (PSP) emerges as a beacon of hope. PSP, with its remarkable antioxidant and anti-senescence properties, is on the cusp of a therapeutic revolution, offering a promising strategy to mitigate the impacts of sarcopenia.

PURPOSE

The objective of this research is to explore the effects of PSP on age-related muscle dysfunction and the underlying mechanisms involved both in vivo and in vitro.

METHODS

In this investigation, we used in vitro experiments using D-galactose (D-gal)-induced aging in C2C12 myotubes and in vivo experiments on aged mice. Key indices were assessed, including reactive oxygen species (ROS) levels, mitochondrial function, the expression of aging-related markers, and the key proteins of mitochondria and MAM fraction. Differentially expressed genes (DEGs) related to mitochondria and ER were identified, and bioinformatic analyses were performed to explore underlying mechanisms. Muscle mass and function were determined to evaluate the quantity and quality of skeletal muscle in vivo.

RESULTS

PSP treatment effectively mitigated oxidative stress and mitochondrial malfunction caused by D-gal in C2C12 myotubes, preserving mitochondrial fitness and reducing MAM formation. Besides, PSP attenuated D-gal-induced increases in Ca2+ concentrations intracellularly by modulating the calcium-related proteins, which were also confirmed by gene ontology (GO) analysis of DEGs. In aged mice, PSP increased muscle mass and improved grip strength, hanging time, and other parameters while reducing ROS levels and increasing antioxidant enzyme activities in skeletal muscle tissue.

CONCLUSION

PSP offers protection against age-associated muscle impairments. The proposed mechanism suggests that modulation of calcium homeostasis via regulation of the MAM results in a favorable functional outcome during skeletal muscle aging. The results of this study highlight the prospect of PSP as a curative intervention for sarcopenia and affiliated pathological conditions, warranting further investigation.

Neuroprotective Effects of Polysaccharides and Gallic Acid from Amauroderma rugosum against 6-OHDA-Induced Toxicity in SH-SY5Y Cells

The pharmacological activity and medicinal significance of Amauroderma rugosum (AR) have rarely been documented. We examined the antioxidant and neuroprotective effects of AR on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in an SH-SY5Y human neuroblastoma cell model of Parkinson's disease (PD) and explored the active ingredients responsible for these effects. The results showed that the AR aqueous extract could scavenge reactive oxygen species and reduce SH-SY5Y cell death induced by 6-OHDA. In addition, the AR aqueous extract increased the survival of Caenorhabditis elegans upon juglone-induced toxicity. Among the constituents of AR, only polysaccharides and gallic acid exhibited antioxidant and neuroprotective effects. The AR aqueous extract reduced apoptosis and increased the expression of phospho-Akt, phospho-mTOR, phospho-MEK, phospho-ERK, and superoxide dismutase-1 in 6-OHDA-treated SH-SY5Y cells. The polysaccharide-rich AR extract was slightly more potent than the aqueous AR extract; however, it did not affect the expression of phospho-Akt or phospho-mTOR. In conclusion, the AR aqueous extract possessed antioxidant and neuroprotective properties against 6-OHDA-induced toxicity in SH-SY5Y cells. The mechanism of action involves the upregulation of the Akt/mTOR and MEK/ERK-dependent pathways. These findings indicate the potential utility of AR and its active ingredients in preventing or treating neurodegenerative disorders associated with oxidative stress such as PD.

Corrigendum: Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: a review

[This corrects the article DOI: 10.3389/fimmu.2023.1147641.].

Unveiling the Therapeutic Potentials of Mushroom Bioactive Compounds in Alzheimer's Disease

Alzheimer's disease (AD) stands as a prevailing neurodegenerative condition (NDs), leading to the gradual deterioration of brain cells and subsequent declines in memory, thinking, behavior, and emotion. Despite the intensive research efforts and advances, an effective curative treatment for the disease has not yet been found. Mushrooms, esteemed globally for their exquisite flavors and abundant nutritional benefits, also hold a wealth of health-promoting compounds that contribute to improving AD health. These compounds encompass polysaccharides, proteins, lipids, terpenoids, phenols, and various other bioactive substances. Particularly noteworthy are the potent neuroprotective small molecules found in mushrooms, such as ergothioneine, erinacine, flavonoids, alkaloids, ergosterol, and melanin, which warrant dedicated scrutiny for their therapeutic potential in combating AD. This review summarizes such positive effects of mushroom bioactive compounds on AD, with a hope to contribute to the development of functional foods as an early dietary intervention for this neurodegenerative disease.

Multiple Metabolites Derived from Mushrooms and Their Beneficial Effect on Alzheimer's Diseases

Mushrooms with edible and medicinal potential have received widespread attention because of their diverse biological functions, nutritional value, and delicious taste, which are closely related to their rich active components. To date, many bioactive substances have been identified and purified from mushrooms, including proteins, carbohydrates, phenols, and vitamins. More importantly, molecules derived from mushrooms show great potential to alleviate the pathological manifestations of Alzheimer's disease (AD), which seriously affects the health of elderly people. Compared with current therapeutic strategies aimed at symptomatic improvement, it is particularly important to identify natural products from resource-rich mushrooms that can modify the progression of AD. This review summarizes recent investigations of multiple constituents (carbohydrates, peptides, phenols, etc.) isolated from mushrooms to combat AD. In addition, the underlying molecular mechanisms of mushroom metabolites against AD are discussed. The various mechanisms involved in the antiAD activities of mushroom metabolites include antioxidant and anti-neuroinflammatory effects, apoptosis inhibition, and stimulation of neurite outgrowth, etc. This information will facilitate the application of mushroom-derived products in the treatment of AD. However, isolation of new metabolites from multiple types of mushrooms and further in vivo exploration of the molecular mechanisms underlying their antiAD effect are still required.

Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: A review

Polysaccharides extracted from natural resources have attracted extensive attention in biomedical research and pharmaceutical fields, due to their medical values in anti-tumor, immunomodulation, drug delivery, and many other aspects. At present, a variety of natural polysaccharides have been developed as adjuvant drugs in clinical application. Benefit from their structural variability, polysaccharides have great potential in regulating cellular signals. Some polysaccharides exert direct anti-tumor effects by inducing cell cycle arrest and apoptosis, while the majority of polysaccharides can regulate the host immune system and indirectly inhibit tumors by activating either non-specific or specific immune responses. As the essential of microenvironment in the process of tumor development has been gradually revealed, some polysaccharides were found to inhibit the proliferation and metastasis of tumor cells via tumoral niche modulation. Here, we focused on natural polysaccharides with biomedical application potential, reviewed the recent advancement in their immunomodulation function and highlighted the importance of their signaling transduction feature for the antitumor drug development.

Combined metabolomics and proteomics to reveal beneficial mechanisms of Dendrobium fimbriatum against gastric mucosal injury

As a dietary and medicinal plant, Dendrobium fimbriatum (DF) is widely utilized in China for improving stomach disease for centuries. However, the underlying mechanisms against gastric mucosal injury have not been fully disclosed. Here, metabolomics and proteomics were integrated to clarify the in-depth molecular mechanisms using cyclophosphamide-induced gastric mucosal injury model in mice. As a result, three metabolic pathways, such as creatine metabolism, arginine and proline metabolism, and pyrimidine metabolism were hit contributing to DF protective benefits. Additionally, γ-L-glutamyl-putrescine, cytosine, and thymine might be the eligible biomarkers to reflect gastric mucosal injury tatus, and DF anti-gastric mucosal injury effects were mediated by the so-called target proteins such as Ckm, Arg1, Ctps2, Pycr3, and Cmpk2. This finding provided meaningful information for the molecular mechanisms of DF and also offered a promising strategy to clarify the therapeutic mechanisms of functional foods.

Bioactive components of mushrooms: Processing effects and health benefits

Mushrooms have been recognized for their culinary attributes for long and were relished in the most influential civilizations in history. Currently, they are the focus of renewed research because of their therapeutic abilities. Nutritional benefits from mushrooms are in the form of a significant source of essential proteins, dietary non-digestible carbohydrates, unsaturated fats, minerals, as well as various vitamins, which have enhanced its consumption, and also resulted in the development of various processed mushroom products. Mushrooms are also a crucial ingredient in traditional medicine for their healing potential and curative properties. The literature on the nutritional, nutraceutical, and therapeutic potential of mushrooms, and their use as functional foods for the maintenance of health was reviewed, and the available literature indicates the enormous potential of the bioactive compounds present in mushrooms. Future research should be focused on the development of processes to retain the mushroom bioactive components, and valorization of waste generated during processing. Further, the mechanisms of action of mushroom bioactive components should be studied in detail to delineate their diverse roles and functions in the prevention and treatment of several diseases.

Anti-aging Effect of Ganoderma (Lingzhi) with Health and Fitness

Although Ganoderma (Lingzhi in Chinese) has been used as an elixir for thousands of years, its anti-aging effects still need to be clarified. Aging is related to immunoregulation, oxidation stress, and free radical product. Till now, Ganoderma exert life span elongation activities by inhibiting ROS production, lipid peroxidation, and advanced oxidation protein products; increasing production of mitochondrial electron transport complexes, SOD, CAT, GSH and GSH-Px, DPPH, and ABTS radical scavenger activities; and having immunomodulatory and antioxidant activity by increasing radical scavenging activity and ferric reducing antioxidant power. Ganoderma's anti-aging effect on human remains a mystery, and its potential mechanisms underlying anti-aging effect for its clinical application still need to be elucidated.

Activation of the miR-34a-Mediated SIRT1/mTOR Signaling Pathway by Urolithin A Attenuates D-Galactose-Induced Brain Aging in Mice

Despite tremendous advances in modern medicine, effective prevention or therapeutic strategies for age-related neurodegenerative diseases such as Alzheimer's disease (AD) remain limited. Currently, accumulating evidence has demonstrated that microRNAs (miRNAs) are increasingly associated with age-related diseases and are emerging as promising therapeutic targets. Urolithin A, a metabolite compound resulting from the transformation of ellagitannins by gut bacteria, has been reported to have anti-oxidant, anti-inflammatory, and anti-apoptotic properties. The present study primarily focused on the ameliorative effect of urolithin A on aging mice and on the exploration of the potential mechanisms of such an ameliorative effect on cognitive impairment and brain aging. In this study, we first tested the neuroprotective effect of urolithin A using an in vitro H2O2-induced PC12 cell oxidative damage model. The in vivoD-gal-induced brain aging model showed that urolithin A significantly suppressed the upregulation of miR-34a induced by D-gal. Moreover, target genes associated with miR-34a were also examined. Urolithin A supplementation ameliorated apoptosis induced by D-gal and rescued miR-34a overexpression-induced impaired autophagy in brain aging mice after a 2-month administration. Furthermore, urolithin A activated autophagy by upregulating the SIRT1 signaling pathway and downregulating the mTOR signaling pathway. In conclusion, urolithin A may exert neuroprotective effects and may aid in preventing D-gal-induced brain aging through activation of the miR-34a-mediated SIRT1/mTOR signaling pathway.

Ginsenoside Rg3 Prevents Cognitive Impairment by Improving Mitochondrial Dysfunction in the Rat Model of Alzheimer's Disease

Ginseng, the roots and rhizomes of Panax ginseng C. A. Meyer, is used not only as a herbal medicine but also as a functional food to support body functions. Ginsenoside Rg3 (GRg3) is a major bioactive component in ginseng. In this study, the beneficial effects of GRg3 on rats with Alzheimer's disease (AD) were evaluated via the behavioral experiment and antioxidant capacity. Moreover, metabolomic analysis based on UPLC-QTOF-MS/MS and apoptosis analysis was used to obtain the change between AD and GRg3-administrated rats to assess the underlying mechanisms on improving mitochondrial dysfunction. Results showed that GRg3 could prevent the cognitive impairment of AD rats by improving the mitochondrial dysfunction. The potential mechanisms were related to regulate the abnormality of energy metabolism, electron transport chain, amino acid metabolism, purine metabolism, and antiapoptosis. These findings support the exploitation of GRg3 as an effective complementary and functional food to prevent and delay AD.

Evaluation of the protective effects of Ganoderma atrum polysaccharide on acrylamide-induced injury in small intestine tissue of rats

This research confirmed the protective effects of Ganoderma atrum polysaccharide (PSG-1) on acrylamide (AA) induced intestinal injury in rats.

Protective effects of astaxanthin on a combination of D-galactose and jet lag-induced aging model in mice

Oxidative stress caused free radical and mitochondrial damage plays a critical role in the progression of aging and age-related damage at the cellular and tissue levels. Antioxidant supplementation has received growing attention and the effects of antioxidant on aging are increasingly assessed in both animal and human studies. However, additional and more promising treatments that contribute to the expansion of anti-aging therapies are needed. Astaxanthin, a super antioxidant carotenoid and free radical scavenger, inhibits lipid peroxidation more potently than vitamin E. In the present study, we investigated the preventative effects of astaxanthin on aging using an accelerated aging model: mice chronically treated with a combination of D-galactose and jet lag. After 6 weeks of treatment, astaxanthin administration tended to protect the liver weight loss in aged mice. It is probably by upregulating the mRNA expression of galactose-1-phosphate uridyltransferase, which contribute to the enhancement of D-galactose metabolism. Astaxanthin supplementation also improved muscle endurance of aged mice in a swimming test. These results were associated with reduced oxidative stress in serum and increased anti-oxidative enzymes activities and mRNA expression in vivo. Moreover, astaxanthin reversed the dysregulation of aging-related gene expression caused by the combination of D-galactose and jet lag in the liver and kidney of mice. In conclusion, astaxanthin prevents liver weight loss, ameliorates locomotive muscular function, exerts significant anti-aging effects by reducing oxidative stress and improving the expression of age-related genes in D-galactose and jet lag-induced aging model.

Emerging Roles of Ganoderma Lucidum in Anti-Aging

Ganoderma lucidum is a white-rot fungus that has been viewed as a traditional Chinese tonic for promoting health and longevity. It has been revealed that several extractions from Ganoderma lucidum, such as Ethanol extract, aqueous extract, mycelia extract, water soluble extract of the culture medium of Ganoderma lucidum mycelia, Ganodermasides A, B, C, D, and some bioactive components of Ganoderma lucidum, including Reishi Polysaccharide Fraction 3, Ganoderma lucidum polysaccharides I, II, III, IV, Ganoderma lucidum peptide, Ganoderma polysaccharide peptide, total G. lucidum triterpenes and Ganoderic acid C1 could exert lifespan elongation or related activities. Although the use of Ganoderma lucidum as an elixir has been around for thousands of years, studies revealing its effect of lifespan extension are only the tip of the iceberg. Besides which, the kinds of extractions or components being comfrimed to be anti-aging are too few compared with the large amounts of Ganoderma lucidum extractions or constituients being discovered. This review aims to lay the ground for fully elucidating the potential mechanisms of Ganoderma lucidum underlying anti-aging effect and its clinical application.

Supplementation of lycopene attenuates oxidative stress induced neuroinflammation and cognitive impairment via Nrf2/NF-κB transcriptional pathway

Oxidative stress, considered as a major culprit in brain aging, triggers cognitive and memory impairment. Lycopene (LYC), a carotenoid pigment, possesses potent antioxidative, anti-inflammatory, and neuroprotective properties. In the present study, the effects of LYC on oxidative stress-induced cognitive defects and the underlying mechanisms were determined. The behavioral tests, including Y-maze test, locomotor activity and Morris water maze test, revealed that chronic LYC supplementation (50 mg/kg bodyweight per day) alleviated d-galactose induced CD-1 male mice cognitive impairments. LYC ameliorated histopathological damage and restored brain derived neurotrophic factor (BDNF) levels in the hippocampus of mice. LYC also significantly elevated antioxidant enzymes activities and reduced levels of inflammatory cytokines in the d-galactose-treated mice serum. Moreover, LYC treatment activated the mRNA expressions of antioxidant enzymes HO-1 and NQO-1, and downregulated inflammatory cytokines IL-1β and TNF-α in mice hippocampus. Immunohistochemical results also demonstrated that LYC significantly restored the expression of glial cells inflammatory makers Iba-1 and GFAP. Furthermore, LYC attenuated neuronal oxidative damage through activation of Nrf2 signaling and inactivation of NF-κB translocation in a H₂O₂-induced SH-SY5Y cell model. Therefore, these results illustrated that LYC could ameliorate oxidative stress induced neuroinflammation and cognitive impairment possibly via mediating Nrf2/NF-κB transcriptional pathway.

Tumor Microenvironment as a New Target for Tumor Immunotherapy of Polysaccharides

Many researches show that polysaccharides derived from fungi and plants have strong pharmacological activities such as enhancing the organism immune and anti-tumor function, and have few toxic and side effects. So the polysaccharides show a wide application prospect in the prevention and therapy of tumor. The tumor microenvironment consists of tumor cells and tumor cells' surrounding environment. The tumor microenvironment not only plays a key role in the development of tumor, but also is a potential treasure for searching new ways to treat tumor. In this review, we summarized polysaccharides' regulation effects on tumor microenvironment progression and tried to give a new theoretical basis for the exploitation of polysaccharides with anti-tumor activity.

Rhein exhibits antioxidative effects similar to Rhubarb in a rat model of traumatic brain injury

Background

The brain is secondarily harmed by pathological, physiological, and biological reactions that are caused by traumatic brain injury (TBI). Rhein, a significant composition of Rhubarb, is a well-known traditional Chinese treatment method and has a strong oxidation-resisting characteristic, but Rhein’s mechanism remains unclear.

Methods

This study aimed to identify Rhein in the brain tissues of TBI model of rats, and confirm whether Rhein induced an antioxidative effect similar to its parent medicine, Rhubarb. First, the ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was applied to identify Rhein in the brain tissue of the controlled cortical impact (CCI) rats after intra-gastric administration of Rhubarb. Further, for the purpose of calculating the oxidant stress of the CCI rats, the malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and glutathione disulfide (GSSG), as well as the proportion of glutathione (GSH)/GSSG were measured in the brain tissues.

Results

The results showed that Rhein was absorbed in the brain tissues of CCI rats. Rhubarb and rhein elevated the SOD, CAT activities, GSH level, and GSH/GSSG ratio, and diminished the MDA and GSSG levels.

Conclusion

The data demonstrated that Rhubarb and Rhein had the potential to be used as a neuroprotective drug for TBI, and that Rhein induced an antioxidative effect similar to its parent medicine, Rhubarb.

The structure of mushroom polysaccharides and their beneficial role in health

Mushroom is a kind of fungus that has been popular for its special flavour and renowned biological values. The polysaccharide contained in mushroom is regarded as one of the primary bioactive constituents and is beneficial for health. The structural features and bioactivities of mushroom polysaccharides have been studied extensively. It is believed that the diverse biological bioactivities of polysaccharides are closely related to their structure or conformation properties. In this review, the structural characteristics, conformational features and bioactivities of several mushroom polysaccharides are summarized, and their beneficial mechanisms and the relationships between their structure and bioactivities are also discussed.

Ganoderma lucidum polysaccharides target a Fas/caspase dependent pathway to induce apoptosis in human colon cancer cells

Ganoderma lucidum polysaccharides (GLP) extracted from Ganoderma lucidum have been shown to induce cell death in some kinds of cancer cells. This study investigated the cytotoxic and apoptotic effect of GLP on HCT-116 human colon cancer cells and the molecular mechanisms involved. Cell proliferation, cell migration, lactate dehydrogenase (LDH) levels and intracellular free calcium levels ([Ca(2+)]i) were determined by MTT, wound-healing, LDH release and fluorescence assays, respectively. Cell apoptosis was observed by scanning and transmission electron microscopy. For the mechanism studies, caspase-8 activation, and Fas and caspase-3 expression were evaluated. Treatment of HCT-116 cells with various concentrations of GLP (0.625-5 mg/mL) resulted in a significant decrease in cell viability (P< 0.01). This study showed that the antitumor activity of GLP was related to cell migration inhibition, cell morphology changes, intracellular Ca(2+) elevation and LDH release. Also, increase in the levels of caspase-8 activity was involved in GLP-induced apoptosis. Western blotting indicated that Fas and caspase-3 protein expression was up-regulated after exposure to GLP. This investigation demonstrated for the first time that GLP shows prominent anticancer activities against the HCT-116 human colon cancer cell line through triggering intracellular calcium release and the death receptor pathway.

Antioxidant and anti-ageing activities of mycelia zinc polysaccharide from Pholiota nameko SW-03

BACKGROUND

Edible fungi polysaccharides usually exhibit antioxidant activity, and zinc has been shown to have antioxidant properties. In the present work, Pholiota nameko SW-03 was used as a vector of zinc biotransformation in order to obtain mycelia zinc polysaccharide (MZPS), and the structural characterization and anti-ageing activity of MZPS were investigated.

RESULTS

Pholiota nameko SW-03 could accumulate zinc in the form of zinc-enriched polysaccharide, and the zinc content in MZPS was 16.39 ± 0.72 mg g(-1) . Three fractions (MZPS-1, MZPS-2 and MZPS-3) were successfully isolated. The main fraction (MZPS-2) with the highest antioxidant activity in vitro was composed of glucose, mannose, glucuronic acid, galactose, galacturonic acid and arabinose in a molar ratio of 172.59:5.29:4.61:4.20:1.01:1.00, with a weight-average molecular weight of 13.63 kDa. The anti-ageing capability was measured in d-galactose-induced ageing mice, and the results showed that MZPS could improve antioxidant status (superoxide dismutase, total antioxidant capability, malondialdehyde and lipid peroxide), indicating that MZPS had strong anti-ageing capability in vivo.

CONCLUSION

This study suggested that organification of zinc through edible fungi liquid fermentation provided a novel method to produce MZPS, which might be used as a natural antioxidant to slow the progression of ageing.

Ganoderma atrum Polysaccharide Ameliorates Hyperglycemia-Induced Endothelial Cell Death via a Mitochondria-ROS Pathway

The aim of the present study was to examine the role of Ganoderma atrum polysaccharide (PSG-1) in reactive oxygen species (ROS) generation and mitochondrial function in hyperglycemia-induced angiopathy. In this work, ROS scavenger, oxidizing agent tert-butylhydroperoxide (tBH), mitochondrial permeability transition pore (mPTP) blockers, and caspase inhibition are used to investigate whether PSG-1 may promote survival of human umbilical vein cells (HUVECs) through preventing the overproduction of ROS and mitochondrial dysfunction. Experimental results show that exposure of HUVECs to 35.5 mmol/L glucose increases the proportion of cells undergoing apoptosis. PSG-1, mPTP blocker, or caspase inhibition can reduce apoptosis and ROS generation. PSG-1 also increases mitochondrial Bcl-2 protein formation and mitochondrial membrane potential (ΔΨm) but inhibits Bax translocation, cytochrome c release, and caspase activation. In summary, vascular protection of PSG-1 can be mediated by a mitochondria-ROS pathway. ROS generation and mPTP induction are critical for high glucose-mediated apoptosis. PSG-1 ameliorates endothelial dysfunction by inhibiting oxidative stress and subsequent mitochondrial dysfunction.

Chemical features of Ganoderma polysaccharides with antioxidant, antitumor and antimicrobial activities

Ganoderma genus comprises one of the most commonly studied species worldwide, Ganoderma lucidum. However, other Ganoderma species have been also reported as important sources of bioactive compounds. Polysaccharides are important contributors to the medicinal properties reported for Ganoderma species, as demonstrated by the numerous publications, including reviews, on this matter. Yet, what are the chemical features of Ganoderma polysaccharides that have bioactivity? In the present manuscript, the chemical features of Ganoderma polysaccharides with reported antioxidant, antitumor and antimicrobial activities (the most studied worldwide) are analyzed in detail. The composition of sugars (homo- versus hetero-glucans and other polysaccharides), type of glycosidic linkages, branching patterns, and linkage to proteins are discussed. Methods for extraction, isolation and identification are evaluated and, finally, the bioactivity of polysaccharidic extracts and purified compounds are discussed. The integration of data allows deduction of structure-activity relationships and gives clues to the chemical aspects involved in Ganoderma bioactivity.

D-galactose induces a mitochondrial complex I deficiency in mouse skeletal muscle: potential benefits of nutrient combination in ameliorating muscle impairment

Accumulating research has shown that chronic D-galactose (D-gal) exposure induces symptoms similar to natural aging in animals. Therefore, rodents chronically exposed to D-gal are increasingly used as a model for aging and delay-of-aging pharmacological research. Mitochondrial dysfunction is thought to play a vital role in aging and age-related diseases; however, whether mitochondrial dysfunction plays a significant role in mice exposed to D-gal remains unknown. In the present study, we investigated cognitive dysfunction, locomotor activity, and mitochondrial dysfunction involved in D-gal exposure in mice. We found that D-gal exposure (125 mg/kg/day, 8 weeks) resulted in a serious impairment in grip strength in mice, whereas spatial memory and locomotor coordination remained intact. Interestingly, muscular mitochondrial complex I deficiency occurred in the skeletal muscle of mice exposed to D-gal. Mitochondrial ultrastructure abnormality was implicated as a contributing factor in D-gal-induced muscular impairment. Moreover, three combinations (A, B, and C) of nutrients applied in this study effectively reversed D-gal-induced muscular impairment. Nutrient formulas B and C were especially effective in reversing complex I dysfunction in both skeletal muscle and heart muscle. These findings suggest the following: (1) chronic exposure to D-gal first results in specific muscular impairment in mice, rather than causing general, premature aging; (2) poor skeletal muscle strength induced by D-gal might be due to the mitochondrial dysfunction caused by complex I deficiency; and (3) the nutrient complexes applied in the study attenuated the skeletal muscle impairment, most likely by improving mitochondrial function.

Reduced numbers of cortical GABA-immunoreactive neurons in the chronic D-galactose treatment model of brain aging

Chronic administration of d-galactose (d-gal) is widely used to mimic the process of brain aging; however, the neural mechanisms are still poorly understood. In this study, we investigated the effect of long-term d-gal treatment on the number of GABA-immunoreactive neurons in rat cerebral cortex and the behavioral correlates. After eight weeks of daily subcutaneous injection of d-gal (100mg/ml/kg), rats showed reduced exploratory activity and lower ambulation in the open field compared to controls. There was no significant reduction in total neurons in the cortex, but there was a marked decrease in the number of GABA-immunoreactive neurons in all cortical layers of d-gal-treated rats. The ratio of GABA-immunoreactive neurons to total neurons was significantly lower in all cortical layers of d-gal-treated rats, with greatest reductions in output layers III (39.9% reduction), V (46.3%), and VI (48.4%). Our study provides the first evidence that chronic d-gal treatment may decrease cortical GABAergic neurotransmission, especially in cerebral output layers. The reduction in GABA-immunoreactive cell number likely disrupts the intracortical excitatory/inhibitory balance and may contribute to the behavioral deficits observed in this aging model.

Ergothioneine protects against neuronal injury induced by β-amyloid in mice

β-Amyloid peptides (Aβ) are neurotoxic and contribute to the development of Alzheimer's disease (AD). Ergothioneine (EGT) has been shown to protect against loss of memory and learning abilities in mice. In this study, mice were orally fed EGT (0.5 or 2 mg/kg body weight) for 16 days before treatment (i.c.v) with a single dose of Aβ1-40 in the hippocampus. After resting for 12 days to restore the body weight, the mice were again fed EGT for additional 39 days. Active avoidance tests were conducted on days 37-39 (short-memory avoidance) and on days 37, 44 and 51 (long-memory avoidance). Water maze task was used to evaluate learning and memory abilities by acquisition test and retention test. In both long-memory avoidance and water maze tests, EGT significantly decreased the escape latency and increased the frequency of successful avoidance. Furthermore, EGT significantly prevented Aβ accumulation in the hippocampus and brain lipid peroxidation, restored acetylcholinesterase (AChE) activity, maintained glutathione/glutathione disulfide ratio and superoxide dismutase activity in brain tissues of Aβ1-40-teated mice. Thus, EGT can protect against Aβ-induced loss of memory and learning abilities in mice. Further studies are required to confirm the protective effects of EGT on the development or progression of AD.

Protective role of chrysin against oxidative stress in d-galactose-induced aging in an experimental rat model

AIM

To evaluate the putative protective role of chrysin, an isoflavone, on D-galactose-induced aging in an experimental rat model.

METHODS

Rats were divided into five groups of five each. Group I received 0.9% saline only. Groups II, III and IV received d-galactose (50 mg/kg bodyweight) intraperitoneally, additionally group III and group IV received chrysin (20 mg/kg bodyweight) and α-tocopherol acetate (200 mg/kg bodyweight), respectively. Group V received chrysin alone. The experiment period was for a period of 8 weeks. After the rats were killed, the tissue samples were analyzed for mean activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase, glucose-6-phosphate dehydrogenase, reduced glutathione, vitamin C, vitamin E, malondialdehyde and protein carbonyl. Histopathological studies were also carried out for morphological conformation.

RESULTS

Tissue samples from D-galactose-exposed untreated rats showed significantly (P < 0.05) lower levels of enzymatic and non-enzymatic anti-oxidants, and significantly (P < 0.05) higher levels of malondialdehyde and protein carbonyl when compared with group I and group III rats. Oral administration of chrysin for a period of 8 weeks, concomitant with the exposure to D-galactose, appeared to protect against oxidative damage and maintained all parameters at near normal levels. Histopathological studies confirmed the oxidative damage caused by D-galactose alone in tissues and also showed the tissue protective role of chrysin in rats receiving D-galactose and chrysin.

CONCLUSION

These results suggest that chrysin protects against oxidative stress-induced tissue damage in D-galactose-induced aging in an experimental rat model.

Ganoderma atrum polysaccharide improves age-related oxidative stress and immune impairment in mice

The aim of the present study was to investigate whether oxidative stress and immune dysfunction could be attenuated by Ganoderma atrum polysaccharide (PSG-1) in d-galactose (d-gal)-induced aging mice, and provide evidence for its effects. The results showed that PSG-1 significantly decreased lipid peroxidation in liver, brain, and spleen, but concomitantly increased the activities of superoxide dismutase, catalase, and glutathione peroxidase compared with the d-gal group. Elevation of glutathione contents and attenuation of glutathione disulfide contents were also found in PSG-1-treated animals. Furthermore, the results showed that PSG-1 treatment increased basal lymphocyte proliferation as well as T cell and B cell proliferation and enhanced interleukin-2 production. Taken together, the results suggested that PSG-1 had potential as a novel agent to promote health and improve aging-associated pathologies, at least in part, via modification of the redox system and improvement of immune function.

Structural characterization and antioxidative activity of low-molecular-weights beta-1,3-glucan from the residue of extracted Ganoderma lucidum fruiting bodies

The major cell wall constituent of Ganoderma lucidum (G. lucidum) is β-1,3-glucan. This study examined the polysaccharide from the residues of alkaline-extracted fruiting bodies using high-performance anion-exchange chromatography (HPAEC), and it employed nuclear magnetic resonance (NMR) and mass spectrometry (MS) to confirm the structures. We have successfully isolated low-molecular-weight β-1,3-glucan (LMG), in high yields, from the waste residue of extracted fruiting bodies of G. lucidum. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay evaluated the capability of LMG to suppress H₂O₂-induced cell death in RAW264.7 cells, identifying that LMG protected cells from H₂O₂-induced damage. LMG treatment decreased H₂O₂-induced intracellular reactive oxygen species (ROS) production. LMG also influenced sphingomyelinase (SMase) activity, stimulated by cell death to induce ceramide formation, and then increase cell ROS production. Estimation of the activities of neutral and acid SMases in vitro showed that LMG suppressed the activities of both neutral and acid SMases in a concentration-dependent manner. These results suggest that LMG, a water-soluble β-1,3-glucan recycled from extracted residue of G. lucidum, possesses antioxidant capability against H₂O₂-induced cell death by attenuating intracellular ROS and inhibiting SMase activity.

Protein and DNA oxidation in different anatomic regions of rat brain in a mimetic ageing model

It has been reported that d-galactose administration causes an increase in oxidative and osmotic stresses in several tissues of rodents. In this study, we established a brain ageing model by using d-galactose and investigated the concentrations of oxidative stress markers on the hippocampus, parietal and frontal lobes of male Sprague-Dawley rats. A mimetic ageing model was established by injecting d-galactose (60 mg/kg/day/i.p.) in the experimental group for 42 days. At the end of this period, we tested spatial memory using the Morris water maze test. To investigate the magnitude of oxidative damage in proteins, lipids and DNA, we studied the concentrations of various oxidative stress parameters in the hippocampus, parietal and frontal lobes of the brain. Glial and neuronal cell oxidative damage was observed in each of the three anatomic regions. It was found that protein carbonyl groups and advanced oxidation product concentrations in the d-galactose applied group were significantly high in each of the three brain lobes compared with the control group. Thiol concentration was found to be decreased in the parietal lobe. A concurrent increase in lipid hydroperoxides was also observed in this lobe. On the other hand, 8-hydroxy-2'-deoxyguanosine concentration was significantly increased in the hippocampal lobe of rats in the experimental group when compared with the controls. The results obtained from the mimetic ageing model rats showed that various anatomical regions of brain have different susceptibility to oxidative damage of proteins, lipids and DNA.