Novel Bioactive Peptides from Meretrix meretrix Protect Caenorhabditis elegans against Free Radical-Induced Oxidative Stress through the Stress Response Factor DAF-16/FOXO

Snake Venom-Inspired Novel Peptides Protect Caenorhabditis elegans against Paraquat-Induced Parkinson's Pathology

The in vivo protective mechanisms of two low-molecular-mass (∼1.4 kDa) novel custom peptides (CPs) against paraquat-induced neurodegenerative dysfunction in the Caenorhabditis elegans model were deciphered. CPs prevented the paraquat from binding to the nerve ring adjacent to the pharynx in C. elegans (wild-type) by stable and high-affinity binding to the tyrosine-protein kinase receptor CAM-1, resulting in significant inhibition of paraquat-induced toxicity by reducing the production of reactive oxygen species, mitochondrial membrane depolarization, and chemosensory dysfunction. The CPs inhibited paraquat-induced dopaminergic neuron degeneration and alpha-synuclein protein expression, the hallmarks of Parkinson's disease, in transgenic BZ555 and NL5901 strains of C. elegans. Transcriptomic, functional proteomics, and quantitative reverse transcription-polymerase chain reaction analyses show that CPs prevented the increased expression of the genes involved in the skn-1 downstream pathway, thereby restoring paraquat-mediated oxidative stress, apoptosis, and neuronal damage in C. elegans. The ability of CPs to repair paraquat-induced damage was demonstrated by a network of gene expression profiles, illustrating the molecular relationships between the regulatory proteins.

In silico and in vivo discovery of antioxidant sea cucumber peptides with antineurodegenerative properties

Since oxidative stress is often associated with neurodegenerative diseases, antioxidants are likely to confer protection against neurodegeneration. Despite an increasing number of food-derived peptides being identified as antioxidants, their antineurodegenerative potentials remain largely unexplored. Here, a sea cucumber peptide preparation - the peptide-rich fraction of <3 kDa (UF<3K) obtained by ultrafiltration from Apostichopus japonicus protein hydrolyzate - was found to protect PC12 cells and Caenorhabditis elegans from neurodegeneration by reducing oxidative stress and apoptosis, demonstrating its in vitro and in vivo neuroprotective effects. As many food-originated peptides are cryptides (cryptic peptides - short amino acid sequences encrypted in parent proteins) released in quantities by protein hydrolysis, UF<3K was subjected to sequencing analysis. As expected, a large repertoire of peptides were identified in UF<3K, establishing a sea cucumber cryptome (1238 peptides in total). Then 134 peptides were randomly selected from the cryptome (>10%) and analyzed for their antioxidant activities using a number of in silico bioinformatic programs as well as in vivo experimental assays in C. elegans. From these results, a novel antioxidant peptide - HoloPep#362 (FETLMPLWGNK) - was shown to not only inhibit aggregation of neurodegeneration-associated polygluatmine proteins but also ameliorate behavioral deficits in proteotoxicity nematodes. Proteomic analysis revealed an increased expression of several lysosomal proteases by HoloPep#362, suggesting proteostasis maintenance as a mechanism for its antineurodegenerative action. These findings provide an insight into the health-promoting potential of sea cucumber peptides as neuroprotective nutraceuticals and also into the importance of training in silico peptide bioactivity prediction programs with in vivo experimental data.

Preparation of Auricularia auricula polysaccharides and their protective effect on acute oxidative stress injury of Caenorhabditis elegans

This research enhanced the extraction procedure for Auricularia auricula crude polysaccharides by utilizing a modified Fenton reagent as a solvent, and obtained A. auricula polysaccharides (AAPs-VH) via alcohol precipitation and deproteinization. The HPLC profile revealed that the purified AAPs-VH using Sepharose 6FF was mainly a heteropolysaccharide, consisting primarily of mannose, glucuronic acid, glucose, and xylose. The Mw and Mn of the purified AAPs-VH were 87.646 kDa and 48.854 kDa, respectively. The FT-IR and NMR spectra revealed that the purified AAPs-VH belonged to pyranose and were mainly formed by (1 → 3)-linked-β-D glucan formation. In vivo experiments conducted with Caenorhabditis elegans, AAPs-VH was found to notably influence the lifespan, improve the antioxidant system, and decrease the level of cell apoptosis. This might be achieved by up-regulating the expression of genes in the IIS and TOR pathways. The study concludes that the modified Fenton reagent can increase Auricularia auricula polysaccharide solubleness and active sites, which may be an essential prompt for future studies.

The role of Caenorhabditis elegans in the discovery of natural products for healthy aging

Covering: 2012 to 2023The human population is aging. Thus, the greatest risk factor for numerous diseases, such as diabetes, cancer and neurodegenerative disorders, is increasing worldwide. Age-related diseases do not typically occur in isolation, but as a result of multi-factorial causes, which in turn require holistic approaches to identify and decipher the mode of action of potential remedies. With the advent of C. elegans as the primary model organism for aging, researchers now have a powerful in vivo tool for identifying and studying agents that effect lifespan and health span. Natural products have been focal research subjects in this respect. This review article covers key developments of the last decade (2012-2023) that have led to the discovery of natural products with healthy aging properties in C. elegans. We (i) discuss the state of knowledge on the effects of natural products on worm aging including methods, assays and involved pathways; (ii) analyze the literature on natural compounds in terms of their molecular properties and the translatability of effects on mammals; (iii) examine the literature on multi-component mixtures with special attention to the studied organisms, extraction methods and efforts regarding the characterization of their chemical composition and their bioactive components. (iv) We further propose to combine small in vivo model organisms such as C. elegans and sophisticated analytical approaches ("wormomics") to guide the way to dissect complex natural products with anti-aging properties.

APPA Increases Lifespan and Stress Resistance via Lipid Metabolism and Insulin/IGF-1 Signal Pathway in Caenorhabditis elegans

Animal studies have proven that 1-acetyl-5-phenyl-1H-pyrrol-3-yl acetate (APPA) is a powerful antioxidant as a novel aldose reductase inhibitor independently synthesized by our laboratory; however, there is no current information on APPA's anti-aging mechanism. Therefore, this study examined the impact and mechanism of APPA's anti-aging and anti-oxidation capacity using the Caenorhabditis elegans model. The results demonstrated that APPA increases C. elegans' longevity without affecting the typical metabolism of Escherichia coli OP50 (OP50). APPA also had a non-toxic effect on C. elegans, increased locomotor ability, decreased the levels of reactive oxygen species, lipofuscin, and fat, and increased anti-stress capacity. QRT-PCR analysis further revealed that APPA upregulated the expression of antioxidant genes, including sod-3, gst-4, and hsp-16.2, and the critical downstream transcription factors, daf-16, skn-1, and hsf-1 of the insulin/insulin-like growth factor (IGF) receptor, daf-2. In addition, fat-6 and nhr-80 were upregulated. However, the APPA's life-prolonging effects were absent on the daf-2, daf-16, skn-1, and hsf-1 mutants implying that the APPA's life-prolonging mechanism depends on the insulin/IGF-1 signaling system. The transcriptome sequencing also revealed that the mitochondrial route was also strongly associated with the APPA life extension, consistent with mev-1 and isp-1 mutant life assays. These findings aid in the investigation of APPA's longevity extension mechanism.

A preliminary study of the chemical composition and bioactivity of Bombax ceiba L. flower and its potential mechanism in treating type 2 diabetes mellitus using ultra-performance liquid chromatography quadrupole-time-flight mass spectrometry and network pharmacology analysis

This study aimed to preliminary investigate the phytochemistry, bioactivity, hypoglycemic potential, and mechanism of action of Bombax ceiba L. flower (BCF), a wild edible and food plant in China. By using methanol extraction and liquid-liquid extraction, the crude extract (CE) of BCF and its petroleum ether (PE), dichloromethane (DCM), ethyl acetate (EtOAc), n-butanol (n-BuOH), and aqueous (AQ) fractions were obtained, and their chemical components and biological activities were evaluated. Further high-performance liquid chromatography (HPLC) analysis was carried out to identify and quantify the active constituents of BFC and its five fractions, and the phytochemical composition of the best-performing fraction was then analyzed by ultra-performance liquid chromatography quadrupole-time-flight mass spectrometry (UPLC/Q-TOF-MS). Finally, a network pharmacology strategy based on the chemical profile of this fraction was applied to speculate its main hypoglycemic mechanism. Results revealed the excellent biological activities of BCF, especially the EtOAc fraction. In addition to the highest total flavonoid content (TFC) (367.72 μg RE/mg E) and total phenolics content (TPC) (47.97 μg GAE/mg E), EtOAc showed the strongest DPPH⋅ scavenging ability (IC₅₀ value = 29.56 μg/mL), ABTS⋅⁺ scavenging ability (IC₅₀ value = 84.60 μg/mL), and ferric reducing antioxidant power (FRAP) (889.62 μg FeSO₄/mg E), which were stronger than the positive control BHT. EtOAc also exhibited the second-best α-glucosidase inhibitory capacity and second-best acetylcholinesterase (AChE) inhibitory capacity with the IC₅₀ values of 2.85 and 3.27 mg/mL, respectively. Also, EtOAc inhibited HepG2, MCF-7, Raw264.7, and A549 cell with IC₅₀ values of 1.08, 1.62, 0.77, and 0.87 mg/mL, which were the second or third strongest in all fractions. Additionally, HPLC analysis revealed significant differences in the compounds’ abundance between different fractions. Among them, EtOAc had the most detected compounds and the highest content. According to the results of UPLC/Q-TOF-MS, 38 compounds were identified in EtOAc, including 24 phenolic acids and 6 flavonoids. Network pharmacological analysis further confirmed 41 potential targets of EtOAc in the treatment of type 2 diabetes, and intracellular receptor signaling pathways, unsaturated fatty acid, and DNA transcription pathways were the most possible mechanisms. These findings suggested that BCF was worthwhile to be developed as an antioxidant and anti-diabetic food/drug.

Caenorhabditis elegans as an emerging model in food and nutrition research: importance of standardizing base diet

As a model organism that has helped revolutionize life sciences, Caenorhabditis elegans has been increasingly used in nutrition research. Here we explore the tradeoffs between pros and cons of its use as a dietary model based primarily on literature review from the past decade. We first provide an overview of its experimental strengths as an animal model, focusing on lifespan and healthspan, behavioral and physiological phenotypes, and conservation of key nutritional pathways. We then summarize recent advances of its use in nutritional studies, e.g. food preference and feeding behavior, sugar status and metabolic reprogramming, lifetime and transgenerational nutrition tracking, and diet-microbiota-host interactions, highlighting cutting-edge technologies originated from or developed in C. elegans. We further review current challenges of using C. elegans as a nutritional model, followed by in-depth discussions on potential solutions. In particular, growth scales and throughputs, food uptake mode, and axenic culture of C. elegans are appraised in the context of food research. We also provide perspectives for future development of chemically defined nematode food ("NemaFood") for C. elegans, which is now widely accepted as a versatile and affordable in vivo model and has begun to show transformative potential to pioneer nutrition science.

A Peptide HEPFYGNEGALR from Apostichopus japonicus Alleviates Acute Alcoholic Liver Injury by Enhancing Antioxidant Response in Male C57BL/6J Mice

Liver-related disease caused by alcohol is a frequent disorder of the hepatic tract. Heavy consumption of alcohol in a short period causes oxidative damage to the liver. Sea cucumber is abundant in nutrients and its various extracts have been studied for antioxidant properties. One peptide was isolated and identified from Apostichopus japonicus in our recent study. We investigated the benefits of the peptide in a model of acute ethanol-induced male C57BL/6J mice. Dietary intake of the peptide could attenuate hepatomegaly, hepatitis and the accumulation of lipid droplets, and increase antioxidant enzyme activities in mice with acute alcoholic liver injury. The results indicated that a 20 mg/kg peptide supplement could activate the Nrf2/HO-1 pathway and block the nuclear translocation of NF-κB to alleviate oxidative stress and inflammation. In addition, the preventive effects of peptide supplementation may be related to autophagy. This study suggests that dietary supplementation with a sea cucumber-derived peptide is one of the potential candidates to alleviate acute alcoholic liver injury.

Flavonoids from Lycium barbarum Leaves Exhibit Anti-Aging Effects through the Redox-Modulation

Lycium barbarum leaves are a kind of vegetable, and modern nutrition studies have found that they have an anti-aging function. Our study aims to investigate the anti-aging effects of Lycium barbarum leaf flavonoid (LBLF) extracts and its underlying molecular mechanism. LBLFs were purified using D101 and polyamide resin, characterized by ultraperformance liquid chromatography coupled with mass spectrometry, and administered to hydrogen peroxide (H₂O₂)-treated human umbilical vein endothelial cells (HUVECs) and Caenorhabditis elegans. Appropriate enrichment conditions were optimized through dynamic adsorption and desorption experiments, the content of flavonoids reached 909.84 mg/g, rutin and kaempferol being the main ones. LBLFs attenuated H₂O₂-induced HUVEC apoptosis, decreased reactive oxygen species and malondialdehyde production levels, increased superoxide dismutase, glutathione peroxidase and catalase activities. Furthermore, pre-treatment with LBLF increased mRNA expression of erythropoietin (EPO) and heme oxygenase-1 (HO-1) via the mitogen-activated protein kinase (MAPK) signaling pathway in HUVECs. Compared with 100 µM rutin monomer, LBLF prolonged the lifespan of Caenorhabditis elegans, enhanced their mobility in middle life stages and upregulated expression of sod-2, gcs-1 and skn-1 genes, which indicated that the anti-aging effects of LBLF were due to its redox-modulation.

Oxidative Stress Protection by Canary Seed (Phalaris canariensis L.) Peptides in Caco-2 Cells and Caenorhabditis elegans

During oxidative stress, degenerative diseases such as atherosclerosis, Alzheimer’s, and certain cancers are likely to develop. Recent research on canary seed (Phalaris canariensis) peptides has demonstrated the high in vitro antioxidant potential. Thus, this study aimed to assess the cellular and in vivo antioxidant capacity of a low-molecular-weight (<3 kDa) canary seed peptide fraction (CSPF) using Caco-2 cells and the Caenorhabditis elegans model. The results show that the CSPF had no cytotoxicity effect on Caco-2 cells at any tested concentration (0.3−2.5 mg/mL). Additionally, the cellular antioxidant activity (CAA) of the CSPF was concentration-dependent, and the highest activity achieved was 80% by the CSPF at 2.5 mg/mL. Similarly, incubation with the CSPF significantly mitigated the acute and chronic oxidative damage, extending the lifespan of the nematodes by 88 and 61%, respectively. Furthermore, it was demonstrated that the CSPF reduced the accumulation of reactive oxygen species (ROS) to safe levels after sub-lethal doses of pro-oxidant paraquat. Quantitative real-time PCR revealed that the CSPF increased the expression of oxidative-stress-response-related gene GST-4. Overall, these results show that the CSPFs relied on GST-4 upregulation and scavenging of free radicals to confer oxidative stress protection and suggest that a CSPF can be used as a natural antioxidant in foods for health applications.

Caenorhabditis elegans as an in vivo model for food bioactives: A review

Caenorhabditis elegans (C. elegans) is being widely explored as an in vivo model to study the effects of food bioactives. These nematodes are largely advantageous over other in vivo models as they are relatively inexpensive, have a short generation time, and have a completely sequenced genome, among other advantages. C. elegans is a commonly used model to study diseases such as Alzheimer's and Parkinson's disease; however, researchers are finding they can also give insight into the health promoting effect of food-derived bioactive compounds. As consumers become more aware of the health benefits of the foods that they consume, the study of bioactive properties of foods and food constituents is becoming an important source of information. This review focuses on the advantages of using C. elegans as a model such as their short lifespans, high level of gene conservation relative to humans, and large number of progenies per reproductive cycle. They are also easily manipulated in order to perform controlled experiments on synchronous populations. Through review of recent literature, it is clear that C. elegans can be used to study a range of food derived compounds such as bioactive peptides, phenolic compounds, carbohydrates, and lipids. This review also provides information on potential challenges associated with working with this nematode. These challenges include the need for a sterile environment, potential inaccuracy when determining if the nematodes are dead, and the simplicity of the organism making it not suitable for all studies.

Aesculin offers increased resistance against oxidative stress and protective effects against Aβ-induced neurotoxicity in Caenorhabditis elegans

Aesculin, a coumarin compound, is one of the major active ingredients of traditional Chinese herbal medicine Qinpi (Cortex Fraxini), which has been reported to exhibit antioxidative, anti-inflammatory and neuroprotective properties against oxidative stress and cellular apoptosis. However, the regulatory mechanisms remain poorly characterized in vivo. This research was performed to explore the underlying molecular mechanisms behind aesculin response conferring oxidative stress resistance, and the protective effects on amyloid-β (Aβ)-mediated neurotoxicity in Caenorhabditis elegans. Study indicated that aesculin plays the protective roles for C. elegans against oxidative stress and Aβ-mediated neurotoxicity and reduces the elevated ROS and MDA contents through enhancement of antioxidant defenses. The KEGG pathway analysis suggested that the differentially expressed genes are mainly involved in longevity regulating pathway, and the nuclear translocation of DAF-16 and the RNAi of daf-16 and hsf-1 indicated that DAF-16 and HSF-1 play critical roles in integrating upstream signals and inducing the expressions of stress resistance-related genes. Furthermore, the up-regulated expressions of their target genes such as sod-3 and hsp-16.2 were confirmed in transgenic GFP reporter strains CF1553 and CL2070, respectively. These results indicated that the regulators DAF-16 and HSF-1 elevate the stress resistance of C. elegans by modulating stress-responsive genes. Further experiments revealed that aesculin is capable of suppressing Aβ-induced oxidative stress and apoptosis and improves chemosensory behavior dysfunction in Aβ-transgenic nematodes. In summary, this study suggested that aesculin offers increased resistance against oxidative stress and protective effects against Aβ-induced neurotoxicity through activation of stress regulators DAF-16 and HSF-1 in nematodes.

Neuroprotective Effects of Palmatine via the Enhancement of Antioxidant Defense and Small Heat Shock Protein Expression in Aβ-Transgenic Caenorhabditis elegans

Palmatine is a naturally occurring isoquinoline alkaloid that has been reported to display neuroprotective effects against amyloid-β- (Aβ-) induced neurotoxicity. However, the mechanisms underlying the neuroprotective activities of palmatine remain poorly characterized in vivo. We employed transgenic Caenorhabditis elegans models containing human Aβ_1-42 to investigate the effects and possible mechanisms of palmatine-mediated neuroprotection. Treatment with palmatine significantly delayed the paralytic process and reduced the elevated reactive oxygen species levels in Aβ-transgenic C. elegans. In addition, it increased oxidative stress resistance without affecting the lifespan of wild-type C. elegans. Pathway analysis suggested that the differentially expressed genes were related mainly to aging, detoxification, and lipid metabolism. Real-time PCR indicated that resistance-related genes such as sod-3 and shsp were significantly upregulated, while the lipid metabolism-related gene fat-5 was downregulated. Further studies demonstrated that the inhibitory effects of palmatine on Aβ toxicity were attributable to the free radical-scavenging capacity and that the upregulated expression of resistance-related genes, especially shsp, whose expression was regulated by HSF-1, played crucial roles in protecting cells from Aβ-induced toxicity. The research showed that there were significantly fewer Aβ deposits in transgenic CL2006 nematodes treated with palmatine than in control nematodes. In addition, our study found that Aβ-induced toxicity was accompanied by dysregulation of lipid metabolism, leading to excessive fat accumulation in Aβ-transgenic CL4176 nematodes. The alleviation of lipid disorder by palmatine should be attributed not only to the reduction in fat synthesis but also to the inhibition of Aβ aggregation and toxicity, which jointly maintained metabolic homeostasis. This study provides new insights into the in vivo neuroprotective effects of palmatine against Aβ aggregation and toxicity and provides valuable targets for the prevention and treatment of AD.

Antiaging Potential of Peptides from Underused Marine Bioresources

Aging is a biological process that occurs under normal conditions and in several chronic degenerative diseases. Bioactive natural peptides have been shown to improve the effects of aging in cell and animal models and in clinical trials. However, few reports delve into the enormous diversity of peptides from marine organisms. This review provides recent information on the antiaging potential of bioactive peptides from underused marine resources, including examples that scavenge free radicals in vitro, inhibit cell apoptosis, prolong the lifespan of fruit flies and Caenorhabditis elegans, suppress aging in mice, and exert protective roles in aging humans. The underlying molecular mechanisms involved, such as upregulation of oxidase activity, inhibition of cell apoptosis and MMP-1 expression, restoring mitochondrial function, and regulating intestinal homeostasis, are also summarized. This work will help highlight the antiaging potential of peptides from underused marine organisms which could be used as antiaging foods and cosmetic ingredients in the near future.

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.

Protective effects of baicalin in a Caenorhabditis elegans model of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder of the central nervous system. However, the pathogenetic mechanisms of PD are far from understood. The aim of this study was to determine the protective effect of baicalin in a Caenorhabditis elegans model of PD. C. elegans worms were stimulated for 24 h with 6-hydroxydopamine (6-OHDA, 50 mM) and treated with or without baicalin (1, 10, or 100 μM). At all tested concentrations, baicalin improved the reversal and omega turn behavioral phenotypes, as well as the survival, of 6-OHDA-stimulated worms. It also inhibited 6-OHDA-induced oxidative stress by decreasing malondialdehyde levels, increasing superoxide dismutase, glutathione reductase, catalase, and glutathione levels and up-regulating mRNA expression of the antioxidant-related genes sod-1, sod-2, sod-3, daf-2, and daf-16. Additionally, it significantly decreased the expression of the apoptosis-related gene ced-3 and increased that of the anti-apoptosis-related gene ced-9. The expression levels of cleaved caspase-3 and B-cell lymphoma 2 in 6-OHDA-treated worms were reversed by baicalin. Apoptosis was suppressed by 6-OHDA in loss-of-function strains via the p38 mitogen-activated protein kinase (MAPK) signaling pathway. Furthermore, the apoptotic effects of 6-OHDA were blocked in sek-1 and pmk-1 mutants. Finally, the mRNA expression of sek-1 and pmk-1 and the protein expression of p38 MAPK and stress-activated protein kinase/extracellular signal-regulated kinase 1 were up-regulated by 6-OHDA and reversed by baicalin. Baicalin may protect against 6-OHDA injury by inhibiting apoptosis and decreasing oxidative stress through the p38 MAPK signaling pathway.

Ferulic Acid Supplementation Increases Lifespan and Stress Resistance via Insulin/IGF-1 Signaling Pathway in C. elegans

Ferulic acid (FA) is a naturally-occurring well-known potent antioxidant and free radical scavenger. FA supplementation is an effective strategy to delay aging, but the underlying mechanism remains unknown. In the present study, we examined the effects of FA on lifespan extension and its mechanism of FA in Caenorhabditis elegans (C. elegans). Results suggested that FA increased the lifespan of C. elegans, rather than altering the growth of E. coli OP50. Meanwhile, FA promoted the healthspan of C. elegans by improving locomotion and reducing fat accumulation and polyQ aggregation. FA increased the resistance to heat and oxidative stress through reducing ROS. The upregulating of the expression of the hlh-30, skn-1, and hsf-1 were involved in the FA-mediated lifespan extension. Furthermore, FA treatment had no impact on the lifespan of daf-2, hlh-30, skn-1, and hsf-1 mutants, confirming that insulin/IGF-1 signaling pathway and multiple longevity mechanisms were associated with the longevity mechanism of FA. We further found that mitochondrial signaling pathway was modulation involved in FA-mediated lifespan extension. With the results from RNA-seq results and mutants lifespan assay. These findings contribute to our knowledge of the lifespan extension and underlying mechanism of action of FA in C. elegans.

Sea Cucumber-Derived Peptides Alleviate Oxidative Stress in Neuroblastoma Cells and Improve Survival in C. elegans Exposed to Neurotoxic Paraquat

Oxidative stress results when the production of oxidants outweighs the capacity of the antioxidant defence mechanisms. This can lead to pathological conditions including cancer and neurodegeneration. Consequently, there is considerable interest in compounds with antioxidant activity, including those from natural sources. Here, we characterise the antioxidant activity of three novel peptides identified in protein hydrolysates from the sea cucumber Apostichopus japonicus. Under oxidative stress conditions, synthetic versions of the sea cucumber peptides significantly compensate for glutathione depletion, decrease mitochondrial superoxide levels, and alleviate mitophagy in human neuroblastoma cells. Moreover, orally supplied peptides improve survival of the Caenorhabditis elegans after treatment with paraquat, the latter of which leads to the production of excessive oxidative stress. Thus, the sea cucumber peptides exhibit antioxidant activity at both the cellular and organism levels and might prove attractive as nutritional supplements for healthy ageing.

Marine natural products

This review covers the literature published between January and December in 2018 for marine natural products (MNPs), with 717 citations (706 for the period January to December 2018) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1554 in 469 papers for 2018), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. The proportion of MNPs assigned absolute configuration over the last decade is also surveyed.

Enzymatic preparation of Crassostrea oyster peptides and their promoting effect on male hormone production

ETHNOPHARMACOLOGICAL RELEVANCE

Crassostrea gigas Thunberg and other oysters have been traditionally used in China as folk remedies to invigorate the kidney and as natural aphrodisiacs to combat male impotence.

AIM OF THE STUDY

Erectile dysfunction (ED) has become a major health problem for the global ageing population. The aim of this study is therefore to evaluate the effect of peptide-rich preparations from C. gigas oysters on ED and related conditions as increasing evidence suggests that peptides are important bioactive components of marine remedies and seafood.

MATERIALS AND METHODS

Crassostrea oyster peptide (COP) preparations COP1, COP2 and COP3 were obtained from C. gigas oysters by trypsin, papain or sequential trypsin-papain digestion, respectively. The contents of testosterone, cyclic adenosine monophosphate (cAMP) and nitric oxide (NO) and the activity of nitric oxide synthase (NOS) in mice and/or cells were measured by enzyme-linked immunosorbent assays. Real-time PCR was used to assess the expression of genes associated with sex hormone secretion pathways. The model animal Caenorhabditis elegans was also used to analyze the gene expression of a conserved steroidogenic enzyme. In silico analysis of constituent peptides was performed using bioinformatic tools based on public databases.

RESULTS

The peptide-rich preparation COP3, in which >95% peptides were <3000 Da, was found to increase the contents of male mouse serum testosterone and cAMP, both of which are known to play important roles in erectile function, and to increase the activity of mouse penile NOS, which is closely associated with ED. Further investigation using mouse Leydig-derived TM3 cells demonstrates that COP3 was able to stimulate the production of testosterone as well as NO, a pivotal mediator of penile erection. Real-time PCR analysis reveals that COP3 up-regulated the expression of Areg and Acvr2b, the genes known to promote sex hormone secretion, but not Fst, a gene involved in suppressing follicle-stimulating hormone release. Furthermore, COP3 was also shown to up-regulate the expression of let-767, a well-conserved C. elegans gene encoding a protein homologous to human 17-β-hydroxysteroid dehydrogenases. Preliminary bioinformatic analysis using the peptide sequences in COP3 cryptome identified 19 prospective motifs, each of which occurred in more than 10 peptides.

CONCLUSIONS

In this paper, Crassostrea oyster peptides were prepared by enzymatic hydrolysis and were found for the first time to increase ED-associated biochemical as well as molecular biology parameters. These results may help to explain the ethnopharmacological use of oysters and provide an important insight into the potentials of oyster peptides in overcoming ED-related health issues.

Caffeic acid protects against Aβ toxicity and prolongs lifespan in Caenorhabditis elegans models

Caffeic acid may alleviate Aβ-induced toxicity and increase lifespan by increasing signaling pathway-associated oxidative stress and regulating metabolism in C. elegans.

Lipopolysaccharide exposure induces oxidative damage in Caenorhabditis elegans: protective effects of carnosine

Background

The present study was designed to investigate the protective effects and mechanisms of carnosine on lipopolysaccharide (LPS)-induced injury in Caenorhabditis elegans.

Methods

C. elegans individuals were stimulated for 24 h with LPS (100 μg/mL), with or without carnosine (0.1, 1, 10 mM). The survival rates and behaviors were determined. The activities of superoxide dismutase (SOD), glutathione reductase (GR), and catalase (CAT) and levels of malondialdehyde (MDA) and glutathione (GSH) were determined using the respective kits. Reverse transcription polymerase chain reaction (RT-PCR) was performed to validate the differential expression of sod-1, sod-2, sod-3, daf-16, ced-3, ced-9, sek-1, and pmk-1. Western blotting was used to determine the levels of SEK1, p38 mitogen-activated protein kinase (MAPK), cleaved caspase3, and Bcl-2. C. elegans sek-1 (km2) mutants and pmk-1 (km25) mutants were used to elucidate the role of the p38 MAPK signaling pathway.

Results

Carnosine improved the survival of LPS-treated C. elegans and rescued behavioral phenotypes. It also restrained oxidative stress by decreasing MDA levels and increasing SOD, GR, CAT, and GSH levels. RT-PCR results showed that carnosine treatment of wild-type C. elegans up-regulated the mRNA expression of the antioxidant-related genes sod-1, sod-2, sod-3, and daf-16. The expression of the anti-apoptosis-related gene ced-9 and apoptosis-related gene ced-3 was reversed by carnosine. In addition, carnosine treatment significantly decreased cleaved caspase3 levels and increased Bcl-2 levels in LPS-treated C. elegans. Apoptosis in the loss-of-function strains of the p38 MAPK signaling pathway was suppressed under LPS stress; however, the apoptotic effects of LPS were blocked in the sek-1 and pmk-1 mutants. The expression levels of sek-1 and pmk-1 mRNAs were up-regulated by LPS and reversed by carnosine. Finally, the expression of p-p38MAPK and SEK1 was significantly increased by LPS, which was reversed by carnosine.

Conclusion

Carnosine treatment protected against LPS injury by decreasing oxidative stress and inhibiting apoptosis through the p38 MAPK pathway.

Antioxidant Peptides from Sepia esculenta Hydrolyzate Attenuate Oxidative Stress and Fat Accumulation in Caenorhabditis elegans

The hydrolysate of golden cuttlefish (Sepia esculenta) was prepared by using papain, and then, it was further separated by ultrafiltration, gel filtration chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). The peptide components of the active fraction were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and then two novel peptides, SeP2 (DVEDLEAGLAK, 1159.27 Da) and SeP5 (EITSLAPSTM, 1049.22 Da), were obtained and displayed significant alleviation effects on oxidative stress in Caenorhabditis elegans. Studies indicated that S. esculenta antioxidant peptides (SePs) increase superoxide dismutase (SOD) activity but reduce reactive oxygen species (ROS) and malondialdehyde (MDA) levelsin oxidation-damaged nematodes. Using transgenic CF1553 nematodes, the sod-3p::GFP expression in the worms treated with SePs was significantly higher than that of the control nematodes. Real-time PCR also demonstrated that the expression of stress-related genes such as sod-3 is up-regulated by SePs. Furthermore, studies showed that SePs could obviously decrease fat accumulation as well as reduce the elevated ROS and MDA levels in high-fat nematodes. Taken together, these results indicated that SePs are capable of the activation of antioxidant defense and the inhibition of free radicals and lipid peroxidation, play important roles in attenuating oxidative stress and fat accumulation in C. elegans, and might have the potential to be used in nutraceutical and functional foods.

Antioxidant and anti-aging effects of a sea cucumber protein hydrolyzate and bioinformatic characterization of its composing peptides

C. elegans-based activity guided and size-based isolation of antioxidant peptide fractions from a sea cucumber protein hydrolyzate and their bioinformatic characterization.

Glochidion zeylanicum leaf extracts exhibit lifespan extending and oxidative stress resistance properties in Caenorhabditis elegans via DAF-16/FoxO and SKN-1/Nrf-2 signaling pathways

BACKGROUND

Glochidion zeylanicum (GZ), a common plant in Thailand and Eastern Asia, is rich in antioxidants. However, the possible anti-aging and oxidative stress resistance properties of GZ leaf extracts (hexane and methanol extracts) have not been reported.

PURPOSE

We aimed to provide the first science-based evidence of the beneficial effects of GZ on anti-aging and oxidative stress resistance in the Caenorhabditis elegans model.

METHODS

The phytochemical composition of the hexane and methanol extracts were analyzed using GLC-MS and LC-MS. Fingerprinting analysis of the extract was performed by RP-HPLC. We determined total phenolics, flavonoids, and antioxidant properties via DPPH and ABTS assays. Oxidative stress resistance, anti-aging and lifespan were studied in C. elegans treated with leaf extracts.

RESULTS

GZ leaf extracts protected the worms against oxidative stress and attenuated ROS accumulation. The expression of stress-response genes, such as SOD-3, and GST-4 were up-regulated, whereas HSP-16.2 was down-regulated after GZ treatment. The oxidative stress resistance properties of GZ possibly involved the DAF-16/FoxO and SKN-1/Nrf-2 transcription factors. GZ leaf extracts improved pharyngeal pumping function and autofluorescent pigment attenuation suggesting anti-aging properties. GZ leaf extracts modulated the lifespan extension in C. elegans.

CONCLUSION

This study reports novel anti-aging and antioxidant activities of GZ leaf extracts, suggesting a novel bioactivity for a medicinally important plant and supplementary drug against oxidative stress.

Evaluation of the antioxidant effects of acid hydrolysates from Auricularia auricular polysaccharides using a Caenorhabditis elegans model

Caenorhabditis elegans is an important model organism for studying stress response mechanisms. In this paper, C. elegans was used to evaluate the antioxidant effects of acid hydrolysates from Auricularia auricular polysaccharides.