Dihydromyricetin Improves Cognitive Impairments in d-Galactose-Induced Aging Mice through Regulating Oxidative Stress and Inhibition of Acetylcholinesterase

Galactose Impairs Motor Performance and Cerebellar Signaling in Young Male Wistar Rats

Galactosemias are a group of inborn errors of galactose metabolism that causes different motor symptoms such as ataxia, tremor, and fine motor dysfunction. The objective was to investigate the cerebellar damage caused by an acute galactose administration. Thirty-day-old male and female Wistar rats were used. Animals were randomized into the following groups: I) galactose group, receiving a single subcutaneous administration of galactose; II) control group, receiving the vehicle solution under the same conditions. One, 3 or 24 h after administration, the animals were evaluated in the Rotarod test. A lower motor performance was observed in male rats 3 h after a galactose administration. This effect was not seen in females or with galactose exposure for 1 or 24 h. The activities of acetylcholinesterase and choline acetyltransferase were found unaltered in the cerebellum of males 3 h after galactose injection. We also found lower TH levels in cerebellar hemispheres and higher TH levels in cerebellar vermis 3 h after galactose administration in male rats, without differences in MAO-A or MAO-B activities. Galactose administration resulted in lower p-CREB(Ser133) and GAD67 levels in cerebellar hemispheres, without altering these parameters in cerebellar vermis of male rats. Finally, a decrease in TrkB-FL immunocontent (but not of TrkB-T levels) was observed in male cerebellar hemispheres. The absence of neurochemical alterations 1 h or 24 h after galactose administration indicates a transient effect for this hexose. The signs and symptoms of galactosemic patients underscore the need to study galactose effects in males and females and in various brain areas. Our findings enhance the understanding of therapeutic mechanisms of catecholaminergic drugs, which are proposed as a potential therapy for galactosemia.

Dihydromyricetin: an emerging compound with comprehensive effects on multiple systems

Dihydromyricetin (DHM or DMY) is a flavonoid derived from natural sources with a range of confirmed biological benefits. It exhibits anti-inflammatory, antioxidant, anti-tumor, and anti-viral activities. DHM is recognized for its high biosafety, making it a promising subject for further research. This article offers a comprehensive overview of DHM's pharmacological properties, mechanisms, and recent research developments in the cardiovascular, urinary, digestive, nervous, and respiratory systems. The review summarizes DHM's biological effects and associated signaling pathways, providing novel insights for its clinical application.

Role of Neural Circuits in Cognitive Impairment

Cognitive impairment refers to abnormalities in learning, memory and cognitive judgment, mainly manifested as symptoms such as decreased memory, impaired orientation and reduced computational ability. As the fundamental unit of information processing in the brain, neural circuits have recently attracted great attention due to their functions in regulating pain, emotion and behavior. Furthermore, a growing number of studies have suggested that neural circuits play an important role in cognitive impairment. Neural circuits can affect perception, attention and decision-making, they can also regulate language skill, thinking and memory. Pathological conditions crucially affecting the integrity and preservation of neural circuits and their connectivity will heavily impact cognitive abilities. Nowadays, technological developments have led to many novel methods for studying neural circuits, such as brain imaging, optogenetic techniques, and chemical genetics approaches. Therefore, neural circuits show great promise as a potential target in mitigating cognitive impairment. In this review we discuss the pathogenesis of cognitive impairment and the regulation and detection of neural circuits, thus highlighting the role of neural circuits in cognitive impairment. Hence, therapeutic agents against cognitive impairment may be developed that target neural circuits important in cognition.

Ferulic Acid-Loaded Nanostructure Maintains Brain Levels of ACh, Glutamate, and GABA and Ameliorates Anxiety and Memory Impairments Induced by the D-Galactose Aging Process in Rats

Population aging is a global reality driven by increased life expectancy. This demographic phenomenon is intrinsically linked to the epidemic of cognitive disorders such as dementia and Alzheimer's disease, posing challenges for elderly and their families. In this context, the search for new therapeutic strategies to prevent or minimize cognitive impairments becomes urgent, as these deficits are primarily associated with oxidative damage and increased neuroinflammation. Ferulic acid (FA), a natural and potent antioxidant compound, is proposed to be nanoencapsulated to target the central nervous system effectively with lower doses and an extended duration of action. Here, we evaluated the effects of the nanoencapsulated FA on d-galactose (d-Gal)- induced memory impairments. Male Wistar adult rats were treated with ferulic acid-loaded nanocapsules (FA-Nc) or non-encapsulated ferulic acid (D-FA) for 8 weeks concurrently with d-Gal (150 mg/kg s.c.) injection. As expected, our findings showed that d-Gal injection impaired memory processes and increased anxiety behavior, whereas FA-Nc treatment ameliorated these behavioral impairments associated with the aging process induced by d-Gal. At the molecular level, nanoencapsulated ferulic acid (FA-Nc) ameliorated the decrease in ACh and glutamate induced by d-galactose (d-Gal), and also increased GABA levels in the dorsal hippocampus, indicating its therapeutic superiority. Additional studies are needed to elucidate the mechanisms underlying our current promising outcomes. Nanoscience applied to pharmacology can reduce drug dosage, thereby minimizing adverse effects while enhancing therapeutic response, particularly in neurodegenerative diseases associated with aging. Therefore, the strategy of brain-targeted drug delivery through nanoencapsulation can be effective in mitigating aging-related factors that may lead to cognitive deficits.

Exploring the effects of the dietary fiber compound mediated by a longevity dietary pattern on antioxidation, characteristic bacterial genera, and metabolites based on fecal metabolomics

BACKGROUND

Age-related dysbiosis of the microbiota has been linked to various negative health outcomes. This study aims to investigate the effects of a newly discovered dietary fiber compound (DFC) on aging, intestinal microbiota, and related metabolic processes. The DFC was identified through in vitro fermentation screening experiments, and its dosage and composition were determined based on a longevity dietary pattern.

METHODS

Aged SPF C57BL/6 J mice (65 weeks old) and young mice (8 weeks old) were divided into three groups: a subgroup without dietary fiber (NDF), a low DFC dose subgroup (LDF, 10% DFC), and a high DFC dose subgroup (HDF, 20% DFC). The total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD) activity, malondialdehyde (MDA) content, and glutathione peroxidase (GSH-Px) activity in liver and serum samples of the mice were measured according to the manufacturer's protocol. The expression levels of characteristic bacterial genera and fecal metabolite concentrations in mice were determined using quantitative real-time PCR (qPCR) and nuclear magnetic resonance hydrogen spectroscopy (1H NMR). Metabolomics analysis was further conducted to identify biological functions and potential pathways related to aging.

RESULTS

After an 8-weeks dietary intervention, DFC supplementation significantly attenuated age-related weight loss, organ degeneration, and oxidative stress. And promoted the growth of Lactobacillus and Bifidobacterium and inhibited the growth of Escherichia coli (E. coli) and Bacteroides (p < 0.05) in the intestinal tracts of aged mice. Metabolomic analysis identified glycolipid and amino acid metabolic pathway biomarkers associated with aging that were differentially regulated by DFC consumption. Correlation analysis between the identified microbial flora and the biomarkers revealed potential mechanistic links between altered microbial composition and metabolic activity with aging markers.

CONCLUSIONS

In conclusion, this study revealed an important mechanism by which DFC consumption impacts healthspan and longevity, shedding light on optimizing dietary fiber or developing fiber-based interventions to improve human health.

miR-34a/TAN1/CREB Axis Engages in Alleviating Oligodendrocyte Trophic Factor-Induced Myelin Repair Function and Astrocyte-Dependent Neuroinflammation in the Early Stages of Alzheimer's Disease: The Anti-Neurodegenerative Effect of Treadmill Exercise

Reduced myelin stability observed in the early stages of Alzheimer's disease leads to spatial learning and memory impairment. Exercise has been shown to protect nerves, reduce the risk of Alzheimer's disease, and strengthen synaptic connectivity. However, the underlying mechanisms of how exercise can promote myelin repair and coordinate inflammation and proliferation are still uncertain. In this study, we conducted histological and biochemical assays of cortical lysates after behavioral testing to detect pathological changes, myelin sheath thickness, and mRNA and protein levels. It is notable that D-galactose model mice exhibited elevated miRNA-34a levels, overactive astrocytes, decreased myelin staining scores, increased apoptosis, and decreased synaptic plasticity in the brain. Significantly, after eight weeks of exercise, we observed improvements in LFB scores, NeuN( +) neuron counts, and myelin basic protein (MBP) expression. Additionally, exercise promoted the expression of oligodendrocyte markers Olig2 and PDFGR-α associated with brain proliferation, and improved spatial cognitive function. Furthermore, it decreased the inflammation caused by astrocyte secretions (TNF-α, Cox-2, CXCL2). Interestingly, we also observed downregulation of miR-34a and activation of the TAN1/PI3K/CREB signaling pathway. Our data shed light on a previously unsuspected mechanism by which exercise reduces miR-34a levels and protects neuronal function and survival by preventing excessive demyelination and inflammatory infiltration in the CNS.

A comprehensive review of vine tea: Origin, research on Materia Medica, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Vine tea is a popular folk tea that has been consumed in China for more than 1200 years. It is often used in ethnic medicine by ethnic groups in southwest China with at least 35 aliases in 10 provinces. In coastal areas, vine tea is mostly used to treat heatstroke, aphtha, aphonia, toothache, etc. In contrast, in the southwest inland regions, vine tea is mostly used to clear away heat and toxic materials, antiphlogosis and relieving sore-throat, lowering blood pressure and lipid levels, and alleviating fatigue. Three main species have been used as the source of vine tea, Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla. Among them, the leaves of Nekemias grossedentata were considered as new food resource in complicance with regulations, according to the Food Safety Standards published by the Monitoring and Evaluation Department of the National Health and Family Planning Commission in China.

AIM OF THE STUDY

At present, the comprehensively summary of Materia Medica on the history and source of vine tea is currently unavailable. The current article summed up the Materia Medica, species origin and pharmacological effects of all 3 major species used in vine tea to fill the knowledge gaps. We also aim to provide a reference for future research on historical textual, resource development and medicinal utilization of vine tea.

MATERIALS AND METHODS

Adhering to the literature screening methodology outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), this review encompasses 148 scholarly research papers from three database, paper ancient books, local chronicles and folklore through field investigations. We then comprehensively summarized and discussed research progresses in scientific and application studies of vine tea.

RESULTS

The historical records indicated that vine tea could have been used as early as Southern and Northern Dynasties (AC 420-589). Nekemias grossedentata, Nekemias cantonensis and Nekemias megalophylla, were used to considered as vine tea in the ethnic medicine. The main phytochemicals found in three plants are flavonoids, polyphenols and terpenoids, among which dihydromyricetin (DHM) is the most important and most studied active substance. The key words "Ampelopsis grossedentata" (Synonym of Nekemias grossedentata) and "dihydromyricetin/DHM" showed the highest frequency over the last 27 year based on the research trend analysis. And the ethnopharmacology studies drawn the main activities of vine tea are antioxidant, antibacterial, hepatoprotective, neuroprotective and anti-atherosclerosis activities.

CONCLUSIONS

This review systematically summarized and discussed vine tea from the following five aspects, history, genetic relationship, phytochemistry, research trend and ethnopharmacology. Vine tea has a long historical usage in Chinese ethnic medicine. Its outstanding therapeutic efficacies have attracted extensive attention in other places in the world at present. Nekemias cantonensis and Nekemias megalophylla are quite similar to Nekemias grossedentata in terms of many aspects. However, the current research has a narrow focus on mainly Nekemias grossedentata and DHM. We propose that future studies could be carried out to determine the synergistic effect of multi-components and multi-targets of vine tea including all 3 species to provide valuable knowledge.

Theaflavin-3,3'-digallate ameliorates learning and memory impairments in mice with premature brain aging induced by D-galactose

Age-related neurodegenerative diseases accompanied by learning and memory deficits are growing in prevalence due to population aging. Cellular oxidative stress is a common pathomechanism in multiple age-related disorders, and various antioxidants have demonstrated therapeutic efficacy in patients or animal models. Many plants and plant extracts possess potent antioxidant activity, but the compounds responsible are frequently unknown. Identification and evaluation of these phytochemicals is necessary for optimal targeted therapy. A recent study identified theaflavin-3,3'-digallate (TFDG) as the most potent among a large series of phytochemical antioxidants. Here we examined if TFDG can mitigate learning and memory impairments in the D-galactose model of age-related neurodegeneration. Experimental mice were injected subcutaneously with D-galactose (120 mg/kg) for 56 days. In treatment groups, different doses of TFDG were administered daily by gavage starting on day 29 of D-galactose injection. Model mice exhibited poor learning and memory in the novel object recognition and Y-maze tests, reduced brain/body mass ratio, increased brain glutamate concentration and acetylcholinesterase activity, decreased brain acetylcholine concentration, and lower choline acetyltransferase, glutaminase, and glutamine synthetase activities. Activities of antioxidant enzymes glutathione peroxidase and superoxide dismutase were also reduced, while the concentration of malondialdehyde, a lipid peroxidation product, was elevated. Further, antioxidant genes Nrf2, Prx2, Gsh-px1, and Sod1 were downregulated in brain. Each one of these changes was dose-dependently reversed by TFDG. TFDG is an effective antioxidant response inducer and neuroprotectant that can restore normal neurotransmitter metabolism and ameliorate learning and memory dysfunction in the D-galactose model of age-related cognitive decline.

Ginseng under forest exerts stronger anti-aging effects compared to garden ginseng probably via regulating PI3K/AKT/mTOR pathway, SIRT1/NF-κB pathway and intestinal flora

BACKGROUND

Ginseng is deemed to be an effective anti-aging therapy. Evidence for differences in representative active ingredients and anti-aging effects between garden ginseng (GG) and ginseng under forest (FG) is insufficient.

PURPOSE

The study was designed to systematically analyze the differences in the mechanistic protective effects of GG and FG on aging mice based on their compositional differences.

METHODS

The chemical ingredients in GG and FG were first determined. In vivo, D-galactose-induced aging mice were orally administered GG or FG (400 mg/kg/day) for 6 weeks. Behavioral parameters of mice were measured by the radial 8-arm maze, and the changes in body weight and organ indices were recorded. Blood, brain tissue, and feces were collected for biochemical analysis, histopathological staining, Western blotting, and 16S rDNA intestinal flora sequencing, respectively.

RESULTS

The absolute contents of total ginsenosides, polyphenols, crude polysaccharides, starch, and protein in GG were 0.71, 0.68, 1.15, 2.27, and 1.08 folds higher than those in FG, respectively; while FG exhibited a higher relative abundance of representative active ingredients (total ginsenosides, polyphenols, crude polysaccharides, and protein) but lower relative content of starch than GG. GG and FG improved hippocampal lesions and poor weight gain, organ indices, and behavioral indices, and prevented excessive oxidative stress and acetylcholinesterase activity in aging mice. What's more, GG and FG treatment ameliorated excessive apoptosis and inflammatory reaction in the aging brain by modulating apoptosis-related proteins, PI3K/AKT/mTOR pathway, and SIRT1/NF-κB pathway. GG and FG also restored the diversity and structure of gut microbiota, up-regulated the relative abundance of beneficial bacteria (e.g., Lactobacillus), and tended to exert key anti-aging effects via the microbiota-gut-brain axis. Notably, in vivo experiments confirmed that FG had a stronger anti-aging activity than GG.

CONCLUSION

FG exerts a more powerful anti-aging effect than GG by regulating oxidative stress, apoptosis, inflammation, and the microbe-gut-brain axis, possibly relying on the higher relative abundance of representative active ingredients (total ginsenosides, polyphenols, crude polysaccharides, and protein) in FG.

Protective Effects of Flavonoids against Alzheimer's Disease: Pathological Hypothesis, Potential Targets, and Structure-Activity Relationship

Alzheimer’s disease (AD) is a neurodegenerative disease with high morbidity and mortality, for which there is no available cure. Currently, it is generally believed that AD is a disease caused by multiple factors, such as amyloid-beta accumulation, tau protein hyperphosphorylation, oxidative stress, and inflammation. Multitarget prevention and treatment strategies for AD are recommended. Interestingly, naturally occurring dietary flavonoids, a class of polyphenols, have been reported to have multiple biological activities and anti-AD effects in several AD models owing to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties. In this review, we summarize and discuss the existing multiple pathogenic factors of AD. Moreover, we further elaborate on the biological activities of natural flavonoids and their potential mode of action and targets in managing AD by presenting a wide range of experimental evidence. The gathered data indicate that flavonoids can be regarded as prophylactics to slow the advancement of AD or avert its onset. Different flavonoids have different activities and varying levels of activity. Further, this review summarizes the structure–activity relationship of flavonoids based on the existing literature and can provide guidance on the design and selection of flavonoids as anti-AD drugs.

Anti-Aging Effect of Dietary Fiber Compound Mediated by Guangxi Longevity Diet Pattern on Natural Aging Mice

A series of previous studies by our team has shown that the Guangxi longevity diet pattern contributes to the improvement of human health, but the role of dietary fiber compounds (DFC) in the anti-aging of this diet pattern has not been studied in depth. Thus, mice were fed with 5%, 15%, and 30% of the characteristic dietary fiber compound (CDFC) (compounded according to the longevity diet pattern) for 8 weeks, and their learning memory capacity, antioxidant capacity, and inflammatory markers, as well as typical microorganisms in the intestinal tract were analyzed to investigate the anti-aging effects of the CDFC under the Guangxi longevity diet pattern on naturally aging mice. The results showed that CDFC had a bidirectional effect on body weight regulation; increased brain, spleen, and cardiac indices, of which the medium dose was the best. Meanwhile, CDFC also had a maintenance and improvement effect on learning and memory ability in aging mice, as well as improved antioxidant capacity and reduced inflammation level. The neuronal cell necrosis in the hippocampus of mice was effectively alleviated. The expression of Escherichia coli and Bacteroides was significantly reduced, and the expression of Bifidobacterium and Lactobacillus increased. In addition, the optimal amount of CDFC added from the level of experimental animals was in a certain interval above and below 15%. The combined results indicated that CDFC mediated by the Guangxi longevity dietary pattern had significant anti-aging effects, thus theoretically proving that dietary fiber compound contributes to human longevity.