Network-based identification and mechanism exploration of active ingredients against Alzheimer's disease via targeting endoplasmic reticulum stress from traditional chinese medicine

Alzheimer's disease is a neurodegenerative disease that leads to dementia and poses a serious threat to the health of the elderly. Traditional Chinese medicine (TCM) presents as a promising novel therapeutic therapy for preventing and treating dementia. Studies have shown that natural products derived from kidney-tonifying herbs can effectively inhibit AD. Furthermore, endoplasmic reticulum (ER) stress is a critical factor in the pathology of AD. Regulation of ER stress is a crucial approach to prevent and treat AD. Thus, in this study, we first collected kidney-tonifying herbs, integrated chemical ingredients from multiple TCM databases, and constructed a comprehensive drug-target network. Subsequently, we employed the endophenotype network (network proximity) method to identify potential active ingredients in kidney-tonifying herbs that prevented AD via regulating ER stress. By combining the predicted outcomes, we discovered that 32 natural products could ameliorate AD pathology via regulating ER stress. After a comprehensive evaluation of the multi-network model and systematic pharmacological analyses, we further selected several promising compounds for in vitro testing in the APP-SH-SY5Y cell model. Experimental results showed that echinacoside and danthron were able to effectively reduce ER stress-mediated neuronal apoptosis by inhibiting the expression levels of BIP, p-PERK, ATF6, and CHOP in APP-SH-SY5Y cells. Overall, this study utilized the endophenotype network to preliminarily decipher the effective material basis and potential molecular mechanism of kidney-tonifying Chinese medicine for prevention and treatment of AD.

Discovery of cinnamamide/ester triazole hybrids as potential treatment for Alzheimer's disease

Developing multitargeted ligands as promising therapeutics for Alzheimer's disease (AD) has been considered important. Herein, a novel class of cinnamamide/ester-triazole hybrids with multifaceted effects on AD was developed based on the multitarget-directed ligands strategy. Thirty-seven cinnamamide/ester-triazole hybrids were synthesized, with most exhibiting significant inhibitory activity against Aβ-induced toxicity at a single concentration in vitro. The most optimal hybrid compound 4j inhibited copper-induced Aβ toxicity in AD cells. its action was superior to that of donepezil and memantine. It also moderately inhibited intracellular AChE activity and presented favorable bioavailability and blood-brain barrier penetration with low toxicity in vivo. Of note, it ameliorated cognitive impairment, neuronal degeneration, and Aβ deposition in Aβ1-42-injured mice. Mechanistically, the compound regulated APP processing by promoting the ADAM10-associated nonamyloidogenic signaling and inhibiting the BACE1-mediated amyloidogenic pathway. Moreover, it suppressed intracellular AChE activity and tau phosphorylation. Therefore, compound 4j may be a promising multitargeted active molecule against AD.

Longevity and anti-aging effects of curcumin supplementation

Aging is a gradual and irreversible process that is accompanied by an overall decline in cellular function and a significant increase in the risk of age-associated disorders. Generally, delaying aging is a more effective method than treating diseases associated with aging. Currently, researchers are focused on natural compounds and their therapeutic and health benefits. Curcumin is the main active substance that is present in turmeric, a spice that is made up of the roots and rhizomes of the Curcuma longa plant. Curcumin demonstrated a positive impact on slowing down the aging process by postponing age-related changes. This compound may have anti-aging properties by changing levels of proteins involved in the aging process, such as sirtuins and AMPK, and inhibiting pro-aging proteins, such as NF-κB and mTOR. In clinical research, this herbal compound has been extensively examined in terms of safety, efficacy, and pharmacokinetics. There are numerous effects of curcumin on mechanisms related to aging and human diseases, so we discuss many of them in detail in this review.

P-hydroxybenzaldehyde protects Caenorhabditis elegans from oxidative stress and β-amyloid toxicity

Introduction

Gastrodia elata is the dried tuber of the orchid Gastrodia elata Bl. It is considered a food consisting of a source of precious medicinal herbs, whose chemical composition is relatively rich. Gastrodia elata and its extracted fractions have been shown to have neuroprotective effects. P-hydroxybenzaldehyde (p-HBA), as one of the main active components of Gastrodia elata, has anti-inflammatory, antioxidative stress, and cerebral protective effects, which has potential for the treatment of Alzheimer's disease (AD). The aim of this study was to verify the role of p-HBA in AD treatment and to investigate its mechanism of action in depth based using the Caenorhabditis elegans (C. elegans) model.

Methods

In this study, we used paralysis, lifespan, behavioral and antistress experiments to investigate the effects of p-HBA on AD and aging. Furthermore, we performed reactive oxygen species (ROS) assay, thioflavin S staining, RNA-seq analysis, qPCR validation, PCR Array, and GFP reporter gene worm experiment to determine the anti-AD effects of p-HBA, as well as in-depth studies on its mechanisms.

Results

p-HBA was able to delay paralysis, improve mobility and resistance to stress, and delay aging in the AD nematode model. Further mechanistic studies showed that ROS and lipofuscin levels, Aβ aggregation, and toxicity were reduced after p-HBA treatment, suggesting that p-HBA ameliorated Aβ-induced toxicity by enhancing antioxidant and anti-aging activity and inhibiting Aβ aggregation. p-HBA had a therapeutic effect on AD by improving stress resistance, as indicated by the down-regulation of NLP-29 and UCR-11 expression and up-regulation of PQN-75 and LYS-3 expression. In addition, the gene microarray showed that p-HBA treatment played a positive role in genes related to AD, anti-aging, ribosomal protein pathway, and glucose metabolism, which were collectively involved in the anti-AD mechanism of p-HBA. Finally, we also found that p-HBA promoted nuclear localization of DAF-16 and increased the expression of SKN-1, SOD-3, and GST-4, which contributed significantly to inhibition of Aβ toxicity and enhancement of antioxidative stress.

Conclusion

Our work suggests that p-HBA has some antioxidant and anti-aging activities. It may be a viable candidate for the treatment and prevention of Alzheimer's disease.

Development of dietary small molecules as multi-targeting treatment strategies for Alzheimer's disease

Cognitive dysfunction can occur both in normal aging and age-related neurological disorders, such as mild cognitive impairment and Alzheimer's disease (AD). These disorders have few treatment options due to side effects and limited efficacy. New approaches to slow cognitive decline are urgently needed. Dietary interventions (nutraceuticals) have received considerable attention because they exhibit strong neuroprotective properties and may help prevent or minimize AD symptoms. Biological aging is driven by a series of interrelated mechanisms, including oxidative stress, neuroinflammation, neuronal apoptosis, and autophagy, which function through various signaling pathways. Recent clinical and preclinical studies have shown that dietary small molecules derived from natural sources, including flavonoids, carotenoids, and polyphenolic acids, can modulate oxidative damage, cognitive impairments, mitochondrial dysfunction, neuroinflammation, neuronal apoptosis, autophagy dysregulation, and gut microbiota dysbiosis. This paper reviews research on different dietary small molecules and their bioactive constituents in the treatment of AD. Additionally, the chemical structure, effective dose, and specific molecular mechanisms of action are comprehensively explored. This paper also discusses the advantages of using nanotechnology-based drug delivery, which significantly enhances oral bioavailability, safety, and therapeutic effect, and lowers the risk of adverse effects. These agents have considerable potential as novel and safe therapeutic agents that can prevent and combat age-related AD.

Research progress on the regulation of oxidative stress by phenolics: the role of gut microbiota and Nrf2 signaling pathway

In recent years, the increase in high-calorie diets and sedentary lifestyles has made obesity a global public health problem. An unbalanced diet promotes the production of proinflammatory cytokines and causes redox imbalance in the body. Phenolics have potent antioxidant activity and cytoprotective ability. They can scavenge free radicals and reactive oxygen species, and enhance the activity of antioxidant enzymes, thus combating the body's oxidative stress. They can also improve the body's inflammatory response, enhance the enzyme activity of lipid metabolism, and reduce the contents of cholesterol and triglyceride. Most phenolics are biotransformed and absorbed into the blood after the action by gut microbiota; these metabolites then undergo phase I and II metabolism and regulate oxidative stress by scavenging free radicals and increasing expression of antioxidant enzymes. Phenolics induce the expression of genes encoding antioxidant enzymes and phase II detoxification enzymes by stimulating Nrf2 to enter the nucleus and bind to the antioxidant response element after uncoupling from Keap1, thereby promoting the production of antioxidant enzymes and phase II detoxification enzymes. The absorption rate of phenolics in the small intestine is extremely low. Most phenolics reach the colon, where they interact with the microbiota and undergo a series of metabolism. Their metabolites will reach the liver via the portal vein and undergo conjugation reactions. Subsequently, the metabolites reach the whole body to exert biological activity by traveling with the systemic circulation. Phenolics can promote the growth of probiotics, reduce the ratio of Firmicutes/Bacteroidetes (F/B), and improve intestinal microecological imbalance. This paper reviews the nutritional value, bioactivity, and antioxidant mechanism of phenolics in the body, aiming to provide a scientific basis for the development and utilization of natural antioxidants and provide a reference for elucidating the mechanism of action of phenolics for regulating oxidative stress in the body. © 2023 Society of Chemical Industry.

Caffeic acid activates mitochondrial UPR to resist pathogen infection in Caenorhabditis elegans via the transcription factor ATFS-1

Mitochondria play roles in the resistance of Caenorhabditis elegans against pathogenic bacteria by regulating mitochondrial unfolded protein response (UPRmt). Caffeic acid (CA) (3,4-dihydroxy cinnamic acid) is a major phenolic compound present in several plant species, which exhibits biological activities such as antioxidant, anti-fibrosis, anti-inflammatory, and anti-tumor properties. However, whether caffeic acid influences the innate immune response and the underlying molecular mechanisms remains unknown. In this study, we find that 20 µM caffeic acid enhances innate immunity to resist the Gram-negative pathogen Pseudomonas aeruginosa infection in C. elegans. Meanwhile, caffeic acid also inhibits the growth of pathogenic bacteria. Furthermore, caffeic acid promotes host immune response by reducing the bacterial burden in the intestine. Through genetic screening in C. elegans, we find that caffeic acid promotes innate immunity via the transcription factor ATFS-1. In addition, caffeic acid activates the UPRmt and immune response genes for innate immune response through ATFS-1. Our work suggests that caffeic acid has the potential to protect patients from pathogen infection.

Review of studies on polysaccharides, lignins and small molecular compounds from three Polygonatum Mill. (Asparagaceae) spp. in crude and processed states

Since ancient times, Polygonatum Mill. (Asparagaceae) has been utilized as a medicinal and culinary resource in China. Its efficacy in treating various illnesses has been well documented. Traditional processing involves the Nine-Steam-Nine-Bask method, which results in a reduction of toxicity and enhanced effectiveness of Polygonatum. Many substances, such as polysaccharides, lignins, saponins, homoisoflavones, alkaloids, and others, have been successfully isolated from Polygonatum. This review presents the research progress on the chemical composition of three crude and processed Polygonatum, including Polygonatum sibiricum Redouté (P. sibiricum), Polygonatum kingianum Collett & Hemsl (P. kingianum), and Polygonatum cyrtonema Hua (P. cyrtonema). The review also includes the pharmacology of Polygonatum, specifically on the pharmacology of polysaccharides both before and after processing. Its objective is to provide a foundation for uncovering the significance of the processing procedure, and to facilitate the development and utilization of Polygonatum in clinical practice.

Insights into the Neuroprotective Potential of Epicatechin: Effects against Aβ-Induced Toxicity in Caenorhabditis elegans

Medical therapies to avoid the progression of Alzheimer's disease (AD) are limited to date. Certain diets have been associated with a lower incidence of neurodegenerative diseases. In particular, the regular intake of foods rich in polyphenols, such as epicatechin (EC), could help prevent or mitigate AD progression. This work aims to explore the neuroprotective effects of EC using different transgenic strains of Caenorhabditis elegans, which express human Aβ1-42 peptides and contribute to elucidating the mechanisms involved in the effects of EC in AD. The performed assays indicate that this flavan-3-ol was able to reduce the signs of β-amyloid accumulation in C. elegans, improving motility and chemotaxis and increasing survival in transgenic strain peptide producers compared to nematodes not treated with EC. The neuroprotective effects exhibited by EC in C. elegans could be explained by the modulation of inflammation and stress-associated genes, as well as autophagy, microgliosis, and heat shock signaling pathways, involving the regulation of cpr-5, epg-8, ced-7, ZC239.12, and hsp-16 genes. Overall, the results obtained in this study support the protective effects of epicatechin against Aβ-induced toxicity.

D-pinitol ameliorated H2O2-induced oxidative damage in PC12 cells and prolonged the lifespan by IIS pathway in Caenorhabditis elegans

D-pinitol (DP) has been extensively regarded as the main active component of legumes for anti-aging. In this study, we intended to explore the anti-aging mechanism of DP, utilizing computer modeling techniques. The results demonstrated that DP significantly delayed H2O2-induced cellular senescence. Model PC12 cells treated with DP exhibited increased cell viability, increased antioxidant enzyme activity (SOD, CAT), and reduced ROS and MDA levels. Furthermore, DP was discovered to have a positive effect on healthy longevity. In C. elegans, DP treatment enhanced lifespan, stress capacity, antioxidant capacity (T-SOD/CAT/GSH-Px/MDA/ROS), and altered aging-related indicators of lipofuscin accumulation, pharyngeal pump rate, motility, and reproduction. Moreover, DP could reduce the toxicity Aβ in transgenic C. elegans CL4176, CL2355, and CL2331. Further mechanistic studies indicated DP increased transcription factor (daf-16, skn-1, hsf-1) expression of insulin/insulin-like growth factor-1 signaling (IIS) pathway. As expected, DP also extended the downstream target genes of the three transcription factors (sod-3, ctl-1, ctl-2, gst-4, hsp-16.1, and hsp-16.2). Further mutant lifespan experiments, network pharmacology, and molecular docking revealed that DP might be life-extending through the IIS pathway. DP deserves extensive investigation and development as a potential anti-aging drug in the future.

Hesperidin ameliorates Amyloid-β toxicity and enhances oxidative stress resistance and lifespan of Caenorhabditis elegans through acr-16 mediated activation of the autophagy pathway

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease in aged populations. Aberrant amyloid-beta accumulation is a common pathological feature in AD patients. Dysfunction of autophagy and impairment of α7nAChR functioning are associated with enhanced amyloid-beta (Aβ) accumulation in AD patients. Hesperidin, a flavone glycoside found primarily in citrus species, is known to have anti-inflammatory, antioxidant, and neuroprotective effects. However, the underlying molecular mechanisms of hesperidin as an antiaging and anti-Aβ phytochemical were unclear. In this study, we found that hesperidin upregulates the acr-16 expression level in C. elegans as evidenced by increased GFP-tagged ACR-16 and GFP-tagged pmyo-3:ACR-16 expression in muscle and ventral nerve cord. Further, hesperidin upregulates the autophagy genes in wild-type N2, evident by increased GFP-tagged LGG-1 foci. However, hesperidin failed to upregulate the autophagy genes level in acr-16 mutant worms that suggests autophagy activation is mediated through acr-16. In addition, hesperidin showed antiaging and anti-oxidative effects, as evidenced by positive changes in different markers necessary for health span and lifespan. Additionally, hesperidin could upregulate acr-16 and autophagy genes (lgg-1 & bec-1) and ameliorates Aβ-induced toxicity as observed with reduce ROS accumulation, paralysis rate, and enhanced lifespan even in worms AD model CL4176 and CL2006 strain. Our finding suggests that hesperidin significantly enhances oxidative stress resistance, prolongs the lifespan, and protects against Aβ-induced toxicity in C. elegans. Thus, acr-16 mediated autophagy and antioxidation is associated with anti-aging and anti-Aβ effect of hesperidin.

Targeting Protein Aggregates with Natural Products: An Optional Strategy for Neurodegenerative Diseases

Protein aggregation is one of the hallmarks of aging and aging-related diseases, especially for the neurodegenerative diseases (NDs) such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Amyotrophic lateral sclerosis (ALS), and others. In these diseases, many pathogenic proteins, such as amyloid-β, tau, α-Syn, Htt, and FUS, form aggregates that disrupt the normal physiological function of cells and lead to associated neuronal lesions. Protein aggregates in NDs are widely recognized as one of the important targets for the treatment of these diseases. Natural products, with their diverse biological activities and rich medical history, represent a great treasure trove for the development of therapeutic strategies to combat disease. A number of in vitro and in vivo studies have shown that natural products, by virtue of their complex molecular scaffolds that specifically bind to pathogenic proteins and their aggregates, can inhibit the formation of aggregates, disrupt the structure of aggregates and destabilize them, thereby alleviating conditions associated with NDs. Here, we systematically reviewed studies using natural products to improve disease-related symptoms by reducing or inhibiting the formation of five pathogenic protein aggregates associated with NDs. This information should provide valuable insights into new directions and ideas for the treatment of neurodegenerative diseases.

Curcumin supplementation increases longevity and antioxidant capacity in Caenorhabditis elegans

Curcumin is well known as a potent antioxidant and free radical scavenger and has great potential for anti-aging applications. In this study, we investigate the molecular mechanism of curcumin in prolonging the lifespan of C. elegans. Four concentrations of curcumin (10, 25, 50, and 100 µM) were administered, and the optimal treatment concentration was determined by analyzing the nematode lifespan, physiology, and biochemistry. Additionally, RNA-seq and qRT-PCR were performed to explore the antioxidant effect of curcumin and its underlying mechanism. Results revealed that curcumin could significantly improve the survival capacity of C. elegans without influencing its growth. Curcumin was observed to significantly decrease the levels of reactive oxygen species (ROS) under extreme conditions such as heat stress and paraquat stress. In addition, curcumin increased the amount of nematode mitochondrial DNA (mtDNA) replication. RNA-seq results revealed that the underlying mechanism of curcumin in C. elegans is related to the mitogen-activated protein kinase (MAPK) pathway. qRT-PCR results confirmed that the expression of oxidative stress-related genes (sod-1, sod-2, sod-3, gst-4) was increased, and the expression of MAPK signaling pathway-related genes (sek-1, pmk-1, nsy-1) was significantly downregulated. Furthermore, the administration of curcumin extended the lifespan of nematodes, potentially through the enhancement of oxidative stress resistance and the downregulation of the MAPK signaling pathway. These findings improve our understanding of both lifespan extension and the potential mechanism of curcumin in C. elegans.

Lonicera japonica polysaccharides improve longevity and fitness of Caenorhabditis elegans by activating DAF-16

Polysaccharide is one of the main active ingredients in Lonicera japonica Thunb. (L. japonica). In this study, we examined the anti-aging activities of L.japonica polysaccharides (LJPs) and further explored the mechanisms. Polysaccharides from L.japonica including the crude LJP (CLJP) and the purified fraction (LJP-2-1) were characterized. The molecular weights of CLJP and LJP-2-1 were 1450 kDa and 1280 kDa, respectively. Meanwhile, CLJP was mainly composed of galacturonic acid (23.57 %), galactose (23.45 %) and arabinose (23.45 %). LJP-2-1 was mainly composed of galacturonic acid (51.25 %) and arabinose (22.89 %). In Caenorhabditis elegans (C. elegans), LJPs maximally prolonged mean lifespan by 13.97 %, promoted fitness with increased motility by 40.92 % and pharyngeal pumping by 25.72 %, and decreased lipofuscin accumulation by 38.9 % with intact body length and fecundity. Moreover, CLJP extended the mean lifespan of nematodes under oxidative and heat stress by 16.76 % and 14.05 % respectively by activating stress-related genes and the antioxidant system. Further, CLJP required DAF-16 to prolong the lifespan of nematodes. CLJP upregulated the expression of daf-16 and its targeted downstream genes, including sod-3, gst-4 and hsp-16.2. Moreover, nuclear accumulation of DAF-16 was promoted upon CLJP treatment. Together, our data uncover the role of LJPs in extending lifespan and healthspan through DAF-16.

Health-Promoting Activities and Associated Mechanisms of Polygonati Rhizoma Polysaccharides

Polygonati Rhizoma, a typical homology of medicine and food, possesses remarkable anti-fatigue, anti-aging, metabolic regulatory, immunomodulatory, anti-inflammatory, neuroprotective, anti-diabetes, and anti-cancer effects. Among bioactive phytochemicals in Polygonati Rhizoma, polysaccharides play important roles in the health-promoting activities through the mechanisms mentioned above and potential synergistic effects with other bioactives. In this review, we briefly introduce the updated biosynthesis of polysaccharides, the purification method, the structure characterization, and food applications, and discuss in detail the biological activities of Polygonati Rhizoma polysaccharides and associated mechanisms, aiming at broadening the usage of Polygonati Rhizoma as functional food and medicine.

Anti-aging effects and mechanisms of anthocyanins and their intestinal microflora metabolites

Aging, a natural and inevitable physiological process, is the primary risk factor for all age-related diseases; it severely threatens the health of individuals and places a heavy burden on the public health-care system. Thus, strategies to extend the lifespan and prevent and treat age-related diseases have been gaining increasing scientific interest. Anthocyanins (ACNs) are a subclass of flavonoids widely distributed in fruits and vegetables. Growing evidence suggests that ACNs delay aging and relieve age-related diseases. However, owing to the low bioavailability of ACNs, their gut metabolites have been proposed to play a critical role in mediating health benefits. In this review, we introduce the biological fate of ACNs after consumption and highlight ACNs metabolites (phenolic acids) from intestinal microorganisms. Additionally, ACNs and gut metabolites exhibit outstanding anti-aging ability in Caenorhabditis elegans, Drosophila melanogaster, and mouse models, probably associated with increasing antioxidation, anti-inflammation, protein homeostasis, antiglycation, mitochondrial function, and inhibition of insulin/IGF-1 signaling (IIS). ACNs and gut metabolites have great application prospects as functional foods and drugs to delay aging and manage age-related diseases. Further investigation should focus on the interaction between ACNs and gut microbiota, including clarifying the complex metabolic pathway and maximizing the health effects of ACNs.

Cryptotanshinone Alleviates Oxidative Stress and Reduces the Level of Abnormally Aggregated Protein in Caenorhabditis elegans AD Models

Alzheimer's disease (AD) is one of the leading causes of dementia. As the first common neurodegenerative disease, there are no effective drugs that can reverse the progression. The present study is to report the anti-AD effect of cryptotanshinone (CTS), a natural product isolated from Salvia castanea. It is found that it can alleviate AD-like features associated with Aβ_1-42 toxicity in muscle cells as well as neuronal cells of Caenorhabditis elegans (C. elegans). Further studies showed that CTS reduced the level of reactive oxygen species (ROS) in nematodes, up-regulated the expression of sod-3, and enhanced superoxide dismutase activity. Cryptotanshinone reduced the level of Aβ monomers and highly toxic oligomers in C. elegans while inhibiting the abnormal aggregation of polyglutamine protein. In addition, CTS upregulated the expression of hsp-16.2 and downregulated the expression of ace-2. These results suggested that CTS could alleviate oxidative stress and reduce the level of abnormally aggregated proteins and has the potential to be developed as an anti-AD drug candidate.

Artemisia selengensis Turcz. leaf extract promotes longevity and stress resistance in Caenorhabditis elegans

BACKGROUND

Artemisia selengensis Turcz. (AST) is a common edible and medicinal herb possessing extensive biological activities and various health-promoting functions. However, the anti-aging effects of AST have been neglected. This work evaluated the effects of AST leaf extract (ASTE) on stress tolerance and longevity in Caenorhabditis elegans.

RESULTS

ASTE treatment enhanced stress resistance and significantly extended the lifespan of C. elegans. Moreover, ASTE prolonged the healthspan by increasing body bending and pharyngeal pumping rates, and by reducing the intestinal lipofuscin level and accumulation of intracellular reactive oxygen species (ROS). Caffeoylquinic acids in ASTE, especially dicaffeoylquinic acids, were the major components responsible for these benefits. The mechanism underlying the anti-aging effect of ASTE occurred by activating insulin/insulin-like growth factor, SIR-2.1 signaling and mitochondrial dysfunction pathways, which in turn induced the activity of the transcription factors DAF-16/FOXO and SKN-1/Nrf2.

CONCLUSION

These findings provide direct evidence for the anti-aging effects of AST and reveal its potential on promoting healthy aging. © 2022 Society of Chemical Industry.

Two new catechins from Zijuan green tea enhance the fitness and lifespan of Caenorhabditis elegans via insulin-like signaling pathways

Green tea polyphenols show positive effects on human health and longevity. However, knowledge of the antiaging properties of green tea is limited to the major catechin epigallocatechin gallate (EGCG). The search for new ingredients in tea with strong antiaging activity deserves further study. Here we isolated and identified two new catechins from Zijuan green tea, named zijuanin E (1) and zijuanin F (2). Their structures were identified by extensive high-resolution mass spectroscopy (HR-MS), nuclear magnetic resonance (NMR), ultraviolet-vis (UV), infrared (IR) and circular dichroism (CD) spectroscopic analyses, and their ¹³C NMR and CD data were calculated. We used the nematode Caenorhabditis elegans (C. elegans) to analyze the health benefits and longevity effects of 1 and 2. Compounds 1 and 2 (100 μM) remarkably prolonged the lifespan of C. elegans by 67.2% and 56.0%, respectively, delaying the age-related decline of phenotypes, enhancing stress resistance, and reducing ROS and lipid accumulation. Furthermore, 1 and 2 did not affect the lifespan of daf-16, daf-2, sir-2.1, and skn-1 mutant worms, suggesting that they might work via the insulin/IGF and SKN-1/Nrf2 signaling pathways. Meanwhile, 1 and 2 also exhibited strong antioxidant activity in vitro. Surface plasmon resonance (SPR) evidence suggests that zijuanins E and F have strong human serum albumin (HSA) binding ability. Together, zijuanins E and F represent a new valuable class of tea components that promote healthspan and could be developed as potential dietary therapies against aging.

Diterpenoid Caesalmin C Delays Aβ-Induced Paralysis Symptoms via the DAF-16 Pathway in Caenorhabditis elegans

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease in the world. However, there is no effective drug to cure it. Caesalmin C is a cassane-type diterpenoid abundant in Caesalpinia bonduc (Linn.) Roxb. In this study, we investigated the effect of caesalmin C on Aβ-induced toxicity and possible mechanisms in the transgenic Caenorhabditis elegans AD model. Our results showed that caesalmin C significantly alleviated the Aβ-induced paralysis phenotype in transgenic CL4176 strain C. elegans. Caesalmin C dramatically reduced the content of Aβ monomers, oligomers, and deposited spots in AD C. elegans. In addition, mRNA levels of sod-3, gst-4, and rpt-3 were up-regulated, and mRNA levels of ace-1 were down-regulated in nematodes treated with caesalmin C. The results of the RNAi assay showed that the inhibitory effect of caesalmin C on the nematode paralysis phenotype required the DAF-16 signaling pathway, but not SKN-1 and HSF-1. Further evidence suggested that caesalmin C may also have the effect of inhibiting acetylcholinesterase (AchE) and upregulating proteasome activity. These findings suggest that caesalmin C delays the progression of AD in C. elegans via the DAF-16 signaling pathway and that it could be developed into a promising medication to treat AD.

Neuroprotective Effects of Oligosaccharides in Rehmanniae Radix on Transgenic Caenorhabditis elegans Models for Alzheimer’s Disease

Rehmanniae Radix (RR, the dried tuberous roots of Rehmannia glutinosa (Gaertn.) DC.) is an important traditional Chinese medicine distributed in Henan, Hebei, Inner Mongolia, and Northeast in China. RR is frequently used to treat diabetes mellitus, cardiovascular disease, osteoporosis and aging-related diseases in a class of prescriptions. The oligosaccharides and catalpol in RR have been confirmed to have neuroprotective effects. However, there are few studies on the anti-Alzheimer’s disease (AD) effect of oligosaccharides in Rehmanniae Radix (ORR). The chemical components and pharmacological effects of dried Rehmannia Radix (DRR) and prepared Rehmannia Radix (PRR) are different because of the different processing methods. ORR has neuroprotective potential, such as improving learning and memory in rats. Therefore, this study aimed to prove the importance of oligosaccharides in DRR (ODRR) and PRR (OPRR) for AD based on the Caenorhabditis elegans (C. elegans) model and the different roles of ODRR and OPRR in the treatment of AD. In this study, we used paralysis assays, lifespan and stress resistance assays, bacterial growth curve, developmental and behavioral parameters, and ability of learning and memory to explore the effects of ODRR and OPRR on anti-AD and anti-aging. Furthermore, the accumulation of reactive oxygen species (ROS); deposition of Aβ; and expression of amy-1, sir-2.1, daf-16, sod-3, skn-1, and hsp-16.2 were analyzed to confirm the efficacy of ODRR and OPRR. OPRR was more effective than ODRR in delaying the paralysis, improving learning ability, and prolonging the lifespan of C. elegans. Further mechanism studies showed that the accumulation of ROS, aggregation, and toxicity of Aβ were reduced, suggesting that ORR alleviated Aβ-induced toxicity, in part, through antioxidant activity and Aβ aggregation inhibiting. The expression of amy-1 was downregulated, and sir-2.1, daf-16, sod-3, and hsp-16.2 were upregulated. Thus, ORR could have a possible therapeutic effect on AD by modulating the expression of amy-1, sir-2.1, daf-16, sod-3, and hsp-16.2. Furthermore, ORR promoted the nuclear localization of daf-16 and further increased the expression of sod-3 and hsp-16.2, which significantly contributed to inhibiting the Aβ toxicity and enhancing oxidative stress resistance. In summary, the study provided a new idea for the development of ORR.

Natural Bioactive Products and Alzheimer’s Disease Pathology: Lessons from Caenorhabditis elegans Transgenic Models

Alzheimer’s disease (AD) is an age-dependent, progressive disorder affecting millions of people. Currently, the therapeutics for AD only treat the symptoms. Although they have been used to discover new products of interest for this disease, mammalian models used to investigate the molecular determinants of this disease are often prohibitively expensive, time-consuming and very complex. On the other hand, cell cultures lack the organism complexity involved in AD. Given the highly conserved neurological pathways between mammals and invertebrates, Caenorhabditis elegans has emerged as a powerful tool for the investigation of the pathophysiology of human AD. Numerous models of both Tau- and Aβ-induced toxicity, the two prime components observed to correlate with AD pathology and the ease of performing RNA interference for any gene in the C. elegans genome, allow for the identification of multiple therapeutic targets. The effects of many natural products in main AD hallmarks using these models suggest promising health-promoting effects. However, the way in which they exert such effects is not entirely clear. One of the reasons is that various possible therapeutic targets have not been evaluated in many studies. The present review aims to explore shared therapeutical targets and the potential of each of them for AD treatment or prevention.

Chondroitin sulfate E alleviates β-amyloid toxicity in transgenic Caenorhabditis elegans by inhibiting its aggregation

Chondroitin sulfate E (CS-E), which is characterized by oversulfated disaccharide units, has been shown to regulate neuronal adhesion, neurite outgrowth and exert neuroprotective effects. In view of these findings, here we investigated the anti-Alzheimer's disease (AD) activities of CSE by using transgenic Caenorhabditis elegans model of Alzheimer's disease. The behavioral experiments demonstrated that CSE at the concentration of 1 mg/ml significantly delayed the worm paralysis caused by Aβ aggregation as compared with control group. Western blot analysis revealed that the level of small oligomers in the transgenic C. elegans was significantly reduced upon treatment with CSE. The number of Aβ plaque deposits in transgenic worm was significantly decreased. In addition, CSE also protected the worms from oxidative stress and rescued chemotaxis dysfunction in transgenic strain CL2355. Taken together, these data suggested that CSE could protect against Aβ-induced toxicity in C. elegans. These results offer valuable evidence for the future use of CSE in the development of agents for the treatment of AD.

Modeling Alzheimer's Disease in Caenorhabditis elegans

Alzheimer’s disease (AD) is the most frequent cause of dementia. After decades of research, we know the importance of the accumulation of protein aggregates such as β-amyloid peptide and phosphorylated tau. We also know that mutations in certain proteins generate early-onset Alzheimer’s disease (EOAD), and many other genes modulate the disease in its sporadic form. However, the precise molecular mechanisms underlying AD pathology are still unclear. Because of ethical limitations, we need to use animal models to investigate these processes. The nematode Caenorhabditis elegans has received considerable attention in the last 25 years, since the first AD models overexpressing Aβ peptide were described. We review here the main results obtained using this model to study AD. We include works studying the basic molecular mechanisms of the disease, as well as those searching for new therapeutic targets. Although this model also has important limitations, the ability of this nematode to generate knock-out or overexpression models of any gene, single or combined, and to carry out toxicity, recovery or survival studies in short timeframes with many individuals and at low cost is difficult to overcome. We can predict that its use as a model for various diseases will certainly continue to increase.

Facile synthesis of Cu N-lauroyl sarcosinate nanozymes with laccase-mimicking activity and identification of toxicity effects for C. elegans

Toxicity assessment of Caenorhabditis elegans Cu-Ls Nz with laccase-like activity.

Lipidome reveals the alleviation of krill oil on the impairment of acrylamide

Krill oil has rich content of polyunsaturated fatty acids and various biological functions. Previous researches have demonstrated that krill oil is helpful to improve the locomotion via antioxidation and regulation...

Amyloid β-but not Tau-induced neurotoxicity is suppressed by Manuka honey via HSP-16.2 and SKN-1/Nrf2 pathways in an in vivo model of Alzheimer's disease

Alzheimer's is a chronic degenerative disease of the central nervous system considered the leading cause of dementia in the world.

Small berries as health-promoting ingredients: a review on anti-aging effects and mechanisms in Caenorhabditis elegans

Aging is an inevitable, irreversible, and complex process of damage accumulation and functional decline, increasing the risk of various chronic diseases. However, for now no drug can delay aging process nor cure aging-related diseases. Nutritional intervention is considered as a key and effective strategy to promote healthy aging and improve life quality. Small berries, as one of the most common and popular fruits, have been demonstrated to improve cognitive function and possess neuroprotective activities. However, the anti-aging effects of small berries have not been systematically elucidated yet. This review mainly focuses on small berries' anti-aging activity studies involving small berry types, active components, the utilized model organism Caenorhabditis elegans (C. elegans), related signaling pathways, and molecular mechanisms. The purpose of this review is to propose effective strategies to evaluate the anti-aging effects of small berries and provide guidance for the development of anti-aging supplements from small berries.

p21-Activated kinase 1 (PAK1) in aging and longevity: An overview

The p21-activated kinases (PAKs) belong to serine/threonine kinases family, regulated by ∼21 kDa small signaling G proteins RAC1 and CDC42. The mammalian PAK family comprises six members (PAK1-6) that are classified into two groups (I and II) based on their domain architecture and regulatory mechanisms. PAKs are implicated in a wide range of cellular functions. PAK1 has recently attracted increasing attention owing to its involvement in oncogenesis, tumor progression, and metastasis as well as several life-limiting diseases and pathological conditions. In Caenorhabditis elegans, PAK1 functions limit the lifespan under basal conditions by inhibiting forkhead transcription factor DAF-16. Interestingly, PAK depletion extended longevity and attenuated the onset of age-related phenotypes in a premature-aging mouse model and delayed senescence in mammalian fibroblasts. These observations implicate PAKs as not only oncogenic but also aging kinases. Therefore, PAK-targeting genetic and/or pharmacological interventions, particularly PAK1-targeting, could be a viable strategy for developing cancer therapies with relatively no side effects and promoting healthy longevity. This review describes PAK family proteins, their biological functions, and their role in regulating aging and longevity using C. elegans. Moreover, we discuss the effect of small-molecule PAK1 inhibitors on the lifespan and healthspan of C. elegans.

Eugenol Elicits Prolongevity by Increasing Resistance to Oxidative Stress in C. elegans

AIM

To analyze the efficacy of eugenol on longevity by assessing its antioxidant effect using Caenorhabditis elegans as an animal model.

BACKGROUND

Eugenol is a major polyphenolic component of Ocimum sanctum (Tulsi) which attributes wide pharmacological activities and can serve as a biomarker. However, the possible effect of eugenol on longevity in Caenorhabditis elegans has not been reported.

OBJECTIVE

The objective of this investigation was to provide first scientific based results about effect of eugenol on longevity, slowing down of paralysis in Alzheimer's model and mechanism behind it in Caenorhabditis elegans animal model system.

METHODS

The phenolic components of methanolic extract of Ocimum sanctum was analyzed by RP-HPLC. Worms were exposed to different concentrations of extract and one of its components -eugenol. Lifespan, health span, survival in CL4176 Alzheimer's model and molecular mechanism were analyzed.

RESULTS

Extract of Ocimum sanctumand eugenol increased lifespan and provided indemnity against pro-oxidants. It also significantly improved healthy ageing and slowed the progression of neurodegeneration in CL4176 Alzheimer's model of worm by increasing survival against prooxidants and slowing down the paralysis. Longevity effect was independent of the DAF-16 as observed by using DAF-16::GFP and daf-16 null mutant strains. These results implicate eugenol as a potent therapeutic compound which may curtail ageing and age related disorders like- Alzheimer's disease.

CONCLUSION

The present work demonstrated eugenol as a potential anti-ageing compound which may curtail ageing, improve heath span by enhancing resistance to oxidative stress and exerts its effect independent of DAF-16 pathway. So, it can be assumed that eugenol can be beneficial to humans as well, albeit further research is necessary before declaring it for human consumption.

Neuroprotective Potential of Mung Bean (Vigna radiata L.) Polyphenols in Alzheimer's Disease: A Review

Mung bean contains various neuroprotective polyphenols, so it might be a healthy food for Alzheimer's disease (AD) prevention. Totally, 19 major phenolic compounds were quantified in mung bean, including 10 phenolic acids and 9 flavonoids. After summarizing their contents and effective doses in rodent AD models, it was speculated that vitexin, isovitexin, sinapic acid, and ferulic acid might be the major bioactive compounds for mung bean-mediated neuroprotection. The mechanisms involved inhibition of β-amyloidogenesis, tau hyperphosphorylation, oxidative stress, and neuroinflammation, and promotion of autophagy and acetylcholinesterase enzyme activity. Notably, the neuroprotective phenolic profile in mung bean changed after germination, with decreased vitexin and isovitexin, and increased rutin, isoquercitrin, isorhamnetin, and caffeic acid detected. However, only studies of individual phenolic compounds in mung bean are published at present. Hence, further studies are needed to elucidate the neuroprotective activities and mechanisms of extractions of mung bean seeds and sprouts, and the synergism between different phenolic compounds.

A promising strategy for investigating the anti-aging effect of natural compounds: a case study of caffeoylquinic acids

Caffeoylquinic acids, as plant-derived polyphenols, exhibit multiple biological activities such as antioxidant, anti-inflammatory, and neuroprotective activities. However, only limited information about their effect on longevity is available. In the current study, molecular docking was employed to explore the interactions between six representative caffeoylquinic acids and the insulin-like growth factor-1 receptor (IGFR), which is an important target protein for longevity. The results indicated that all six compounds were embedded well in the active pocket of IGFR, and that 3,5-diCQA exhibited the strongest affinity to IGFR. Moreover, ASP1153, GLU1080, ASP1086, and ARG1003 were the key amino acid residues during the interaction of these 6 compounds with IGFR. Furthermore, the lifespan extension effect of caffeoylquinic acids was evaluated in a Caenorhabditis elegans (C. elegans) model. The results revealed that all the caffeoylquinic acids significantly extended the lifespan of wild-type worms, of which 3,5-diCQA was the most potent compound. Meanwhile, 3,5-diCQA enhanced the healthspan by increasing the body bending and pharyngeal pumping rates and reducing the intestinal lipofuscin level. Further studies demonstrated that 3,5-diCQA induced longevity effects by downregulating the insulin/insulin-like growth factor signaling (IIS) pathway. This study suggested that the combination of molecular docking and genetic analysis of specific worm mutants could be a promising strategy to reveal the anti-aging mechanisms of small molecule natural compounds.

Ginsenoside Prolongs the Lifespan of C. elegans via Lipid Metabolism and Activating the Stress Response Signaling Pathway

Panax ginseng is a valuable traditional Chinese medicine in Northeast China. Ginsenoside, the active component of ginseng, has not been investigated much for its effects on aging and its underlying mechanism(s) of action. Here, we investigated the effects of total ginsenoside (TG), a mixture of the primary active ginsenosides from Panax ginseng, on the lifespan of Caenorhabditis elegans (C. elegans). We found that TG extended the lifespan of C. elegans and reduced lipofuscin accumulation. Moreover, TG increased the survival of C. elegans in response to heat and oxidative stress via the reduction of ROS. Next, we used RNA-seq to fully define the antiaging mechanism(s) of TG. The KEGG pathway analysis showed that TG can prolong the lifespan and is involved in the longevity regulating pathway. qPCR showed that TG upregulated the expression of nrh-80, daf-12, daf-16, hsf-1 and their downstream genes. TG also reduced the fat accumulation and promoted lipid metabolism. Moreover, TG failed to extend the lifespan of daf-16 and hsf-1 mutants, highlighting their role in the antiaging effects of TG in C. elegans. The four main constitution of TG were then confirmed by HPLC and included ginsenoside Re, Rg1, Rg2 and Rd. Of the ginsenosides, only ginsenoside Rd prolonged the lifespan of C. elegans to levels comparable to TG. These findings provided mechanistic insight into the antiaging effects of ginsenoside in C. elegans.