Holothuria scabra extracts possess anti-oxidant activity and promote stress resistance and lifespan extension in Caenorhabditis elegans

2-Butoxytetrahydrofuran, Isolated from Holothuria scabra, Attenuates Aggregative and Oxidative Properties of α-Synuclein and Alleviates Its Toxicity in a Transgenic Caenorhabditis elegans Model of Parkinson's Disease

Aggregative α-synuclein and incurring oxidative stress are pivotal cascading events, leading to dopaminergic (DAergic) neuronal loss and contributing to clinical manifestations of Parkinson's disease (PD). Our previous study demonstrated that 2-butoxytetrahydrofuran (2-BTHF), isolated from Holothuria scabra (H. scabra), could inhibit amyloid-β aggregation and its ensuing toxicity, which leads to Alzheimer's disease. In the present study, we found that 2-BTHF also attenuated the aggregative and oxidative activities of α-synuclein and lessened its toxicity in a transgenic Caenorhabditis elegans (C. elegans) PD model. Such worms treated with 100 μM of 2-BTHF showed substantial reductions in α-synuclein accumulation and DAergic neurodegeneration. Mechanistically, 2-BTHF, at this concentration, significantly decreased aggregation of monomeric α-synuclein and restored locomotion and dopamine-dependent behaviors. Molecular docking exhibited potential bindings of 2-BTHF to HSF-1 and DAF-16 transcription factors. Additionally, 2-BTHF significantly increased the mRNA transcripts of genes encoding proteins involved in proteostasis, including the molecular chaperones hsp-16.2 and hsp-16.49, the ubiquitination/SUMOylation-related ubc-9 gene, and the autophagy-related genes atg-7 and lgg-1. Transcriptomic profiling revealed an additional mechanism of 2-BTHF in α-synuclein-expressing worms, which showed upregulation of PPAR signaling cascades that mediated fatty acid metabolism. 2-BTHF significantly restored lipid deposition, upregulated the fat-7 gene, and enhanced gcs-1-mediated glutathione synthesis in the C. elegans PD model. Taken together, this study demonstrated that 2-BTHF could abrogate aggregative and oxidative properties of α-synuclein and attenuate its toxicity, thus providing a possible therapeutic application for the treatment of α-synuclein-induced PD.

Campomanesia adamantium O Berg. fruit, native to Brazil, can protect against oxidative stress and promote longevity

Campomanesia adamantium O. Berg. is a fruit tree species native to the Brazilian Cerrado biome whose fruits are consumed raw by the population. The present study determined the chemical composition of the C. adamantium fruit pulp (FPCA) and investigated its in vitro antioxidant potential and its biological effects in a Caenorhabditis elegans model. The chemical profile obtained by LC-DAD-MS identified 27 compounds, including phenolic compounds, flavonoids, and organic carboxylic acids, in addition to antioxidant lipophilic pigments and ascorbic acid. The in vitro antioxidant activity was analysed by the radical scavenging method. In vivo, FPCA showed no acute reproductive or locomotor toxicity. It promoted protection against thermal and oxidative stress and increased the lifespan of C. elegans. It also upregulated the antioxidant enzymes superoxide dismutase and glutathione S-transferase and activated the transcription factor DAF-16. These results provide unprecedented in vitro and in vivo evidence for the potential functional use of FPCA in the prevention of oxidative stress and promotion of longevity.

The Structural Characteristics and Bioactivity Stability of Cucumaria frondosa Intestines and Ovum Hydrolysates Obtained by Different Proteases

The study aimed to investigate the effects of alcalase, papain, flavourzyme, and neutrase on the structural characteristics and bioactivity stability of Cucumaria frondosa intestines and ovum hydrolysates (CFHs). The findings revealed that flavourzyme exhibited the highest hydrolysis rate (51.88% ± 1.87%). At pH 2.0, the solubility of hydrolysate was the lowest across all treatments, while the solubility at other pH levels was over 60%. The primary structures of hydrolysates of different proteases were similar, whereas the surface hydrophobicity of hydrolysates was influenced by the types of proteases used. The hydrolysates produced by different proteases were also analyzed for their absorption peaks and antioxidant activity. The hydrolysates of flavourzyme had β-fold absorption peaks (1637 cm^-1), while the neutrase and papain hydrolysates had N-H bending vibrations. The tertiary structure of CFHs was unfolded by different proteases, exposing the aromatic amino acids and red-shifting of the λ-peak of the hydrolysate. The alcalase hydrolysates showed better antioxidant activity in vitro and better surface hydrophobicity than the other hydrolysates. The flavourzyme hydrolysates displayed excellent antioxidant stability and pancreatic lipase inhibitory activity during gastrointestinal digestion, indicating their potential use as antioxidants in the food and pharmaceutical industries.

Antioxidant and Anticancer Activities of Sand Sea Cucumber (Holothuria scabra) Extracts using Wet Rendering Extraction Method

Antioxidant and anticancer activities of sand sea cucumber Holothuria scabra (dried and fresh) extracts were studied. The highest extraction yield of sea cucumber H. scabra (3.9%) was obtained using dried H. scabra at 60oC. The highest antioxidant activity was found in fresh H. scabra extract at 60°C with an IC50 value of 629.89 ± 0.15 µg/mL using the ABTS method, and the highest antioxidant activity by DPPH method was found in dried H. scabra extract at 70°C with an IC50 value of 32017.18 ± 0.82 µg/mL. The best antioxidant activity based on FRAP and TBARS methods was found in fresh H. scabra extracts at 80°C, respectively. The highest total phenol and flavonoid contained in dried H. scabra extract were 317.54 ± 8.91 mg GAE/100 g sample and 247.56 ± 11.70 mg QE/100 g sample. H. scabra extracts inhibited more than 50% of the growth of the MDA-MB-231 cell line at concentrations of 25 and 50 μg/mL except for dried H. scabra extracts at 80°C. Similarly, the extracts showed the highest cytotoxic effect up to 100% at the highest concentration (100 μg/mL) except for dried H. scabra extracts at 70°C and 80°C.

Holothuria scabra extracts confer neuroprotective effect in C. elegans model of Alzheimer's disease by attenuating amyloid-β aggregation and toxicity

Background and aim

Alzheimer's disease (AD) is the most common aged-related neurodegenerative disorder that is associated with the toxic amyloid-β (Aβ) aggregation in the brain. While the efficacies of available drugs against AD are still limited, natural products have been shown to possess neuroprotective potential for prevention and therapy of AD. This study aimed to investigate the neuroprotective effects of H. scabra extracts against Aβ aggregation and proteotoxicity in C. elegans model of Alzheimer's diseases.

Experimental procedure

Whole bodies (WB) and body wall (BW) of H. scabra were extracted and fractionated into ethyl acetate (WBEA, BWEA), butanol (WBBU, BWBU), and ethanol (BWET). Then C. elegans AD models were treated with these fractions and investigated for Aβ aggregation and polymerization, biochemical and behavioral changes, and level of oxidative stress, as well as lifespan extension.

Results and conclusion

C. elegans AD model treated with H. scabra extracts, especially triterpene glycoside-rich ethyl acetate and butanol fractions, exhibited significant reduction of Aβ deposition. These H. scabra extracts also attenuated the paralysis behavior and improved the neurological defects in chemotaxis caused by Aβ aggregation. Immunoblot analysis revealed decreased level of Aβ oligomeric forms and the increased level of Aβ monomers after treatments with H. scabra extracts. In addition, H. scabra extracts reduced reactive oxygen species and increased the mean lifespan of the treated AD worms. In conclusion, this study demonstrated strong evidence of anti-Alzheimer effects by H. scabra extracts, implying that these extracts can potentially be applied as natural preventive and therapeutic agents for AD.

Taxonomy classification by EVISE

Alzheimer's disease, Neurodegenerative disorder, Traditional medicine, Experimental model systems, Molecular biology.

Neuroprotective effects of a medium chain fatty acid, decanoic acid, isolated from H. leucospilota against Parkinsonism in C. elegans PD model

Sea cucumbers are marine organism that have long been used for food and traditional medicine in Asian countries. Recently, we have shown that ethyl acetate fraction (HLEA) of the crude extract of the black sea cucumber, Holothuria leucospilota, could alleviate Parkinsonism in Caenorhabditis elegans PD models. In this study, we found that the effective neuroprotective activity is attributed to HLEA-P1 compound chemically isolated and identified in H. leucospilota ethyl acetate. We reported here that HLEA-P1 could attenuate DAergic neurodegeneration, improve DAergic-dependent behaviors, reduce oxidative stress in 6-OHDA-induced C. elegans. In addition, HLEA-P1 reduced α-synuclein aggregation, improved behavior deficit and recovered lipid deposition in transgenic C. elegans overexpressing α-synuclein. We also found that HLEA-P1 activates nuclear localization of DAF-16 transcription factor of insulin/IGF-1 signaling (IIS) pathway. Treatment with 25 μg/ml of HLEA-P1 upregulated transcriptional activity of DAF-16 target genes including anti-oxidant genes (such as sod-3) and small heat shock proteins (such as hsp16.1, hsp16.2, and hsp12.6) in 6-OHDA-induced worms. In α-synuclein-overexpressed C. elegans strain, treatment with 5 μg/ml of HLEA-P1 significantly activated mRNA expression of sod-3 and hsp16.2. Chemical analysis demonstrated that HLEA-P1 compound is decanoic acid/capric acid. Taken together, our findings revealed that decanoic acid isolated from H. leucospilota exerts anti-Parkinson effect in C. elegans PD models by partly modulating IIS/DAF-16 pathway.

2-Butoxytetrahydrofuran and Palmitic Acid from Holothuria scabra Enhance C. elegans Lifespan and Healthspan via DAF-16/FOXO and SKN-1/NRF2 Signaling Pathways

Extracts from a sea cucumber, Holothuria scabra, have been shown to exhibit various pharmacological properties including anti-oxidation, anti-aging, anti-cancer, and anti-neurodegeneration. Furthermore, certain purified compounds from H. scabra displayed neuroprotective effects against Parkinson's and Alzheimer's diseases. Therefore, in the present study, we further examined the anti-aging activity of purified H. scabra compounds in a Caenorhabditis elegans model. Five compounds were isolated from ethyl acetate and butanol fractions of the body wall of H. scabra and characterized as diterpene glycosides (holothuria A and B), palmitic acid, bis (2-ethylhexyl) phthalate (DEHP), and 2-butoxytetrahydrofuran (2-BTHF). Longevity assays revealed that 2-BTHF and palmitic acid could significantly extend lifespan of wild type C. elegans. Moreover, 2-BTHF and palmitic acid were able to enhance resistance to paraquat-induced oxidative stress and thermal stress. By testing the compounds' effects on longevity pathways, it was shown that 2-BTHF and palmitic acid could not extend lifespans of daf-16, age-1, sir-2.1, jnk-1, and skn-1 mutant worms, indicating that these compounds exerted their actions through these genes in extending the lifespan of C. elegans. These compounds induced DAF-16::GFP nuclear translocation and upregulated the expressions of daf-16, hsp-16.2, sod-3 mRNA and SOD-3::GFP. Moreover, they also elevated protein and mRNA expressions of GST-4, which is a downstream target of the SKN-1 transcription factor. Taken together, the study demonstrated the anti-aging activities of 2-BTHF and palmitic acid from H. scabra were mediated via DAF-16/FOXO insulin/IGF and SKN-1/NRF2 signaling pathways.

Hawthorn fruit extract ameliorates H2O2-induced oxidative damage in neuronal PC12 cells and prolongs the lifespan of Caenorhabditis elegans via the IIS signaling pathway

Hawthorn (Crataegus pinnatifida) fruit has a long history of use as traditional Chinese medicine and is shown to have many health benefits including antioxidant and anti-aging. In this study, the anti-aging mechanism of hawthorn fruit extract (HFE) is predicted by network pharmacology and further verified in H₂O₂-induced PC12 cells and Caenorhabditis elegans. Network pharmacology predicted that the antiaging mechanism of HFE is mainly involved in phosphoinositide 3-kinase (PI3K)/AKT and the insulin/insulin-like growth factor-1 (IIS) signaling pathway. HFE significantly improved cell viability, increased superoxide dismutase, catalase, and glutathione peroxidase activity, decreased lactate dehydrogenase release, the level of reactive oxygen species (ROS), and malondialdehyde content in H₂O₂-induced PC12 cells (p < 0.05). HFE significantly increased the mean lifespan of C. elegans by 28.43% (100 μg mL^-1) and enhanced the stress resistance to H₂O₂, paraquat, juglone, ultraviolet radiation, and heat shock. HFE also suppressed the accumulation of aging pigments, improved the body bending ability, increased antioxidant enzyme activities, and reduced the contents of ROS and malondialdehyde. In addition, relevant gene expression, lifespan experiments with mutant strains, and molecular docking studies supported the results that HFE might extend lifespan through the IIS signal pathway.

Betulinic acid increases lifespan and stress resistance via insulin/IGF-1 signaling pathway in Caenorhabditis elegans

Numerous studies reported that betulinic acid (BA), a natural product extracted from birch bark, exhibited various beneficial effects in vitro. However, its pharmacological activities in aging are rarely understood. In this study, Caenorhabditis elegans was deployed as a whole animal model to investigate the impacts of BA on lifespan and stress resistance. Wild-type C. elegans were fed in the presence or absence of BA and tested for a series of phenotypes, including longevity, mobility, reproductive capacity, pharyngeal pumping, heat stress, and oxidative stress. BA at the optimal dose (50 μg/mL) extended the lifespan, improved the healthspan, and significantly evoked the increased oxidative stress resistance in C. elegans. Incorporating the genetic analysis with different types of longevity mutants, DAF-16, the downstream effector of the Insulin/IGF-1 receptor signaling, was revealed to mediate the protective effects of BA on lifespan and antioxidant activity. Together, these data showcased the potential of BA in promoting healthy aging, which shall facilitate its further development in the food and pharmaceutical industries.

Pharmaceutical and nutraceutical activation of FOXO3 for healthy longevity

Life expectancy has increased substantially over the last 150 years. Yet this means that now most people also spend a greater length of time suffering from various age-associated diseases. As such, delaying age-related functional decline and extending healthspan, the period of active older years free from disease and disability, is an overarching objective of current aging research. Geroprotectors, compounds that target pathways that causally influence aging, are increasingly recognized as a means to extend healthspan in the aging population. Meanwhile, FOXO3 has emerged as a geroprotective gene intricately involved in aging and healthspan. FOXO3 genetic variants are linked to human longevity, reduced disease risks, and even self-reported health. Therefore, identification of FOXO3-activating compounds represents one of the most direct candidate approaches to extending healthspan in aging humans. In this work, we review compounds that activate FOXO3, or influence healthspan or lifespan in a FOXO3-dependent manner. These compounds can be classified as pharmaceuticals, including PI3K/AKT inhibitors and AMPK activators, antidepressants and antipsychotics, muscle relaxants, and HDAC inhibitors, or as nutraceuticals, including primary metabolites involved in cell growth and sustenance, and secondary metabolites including extracts, polyphenols, terpenoids, and other purified natural compounds. The compounds documented here provide a basis and resource for further research and development, with the ultimate goal of promoting healthy longevity in humans.

In vivo Assessment of Cold Atmospheric Pressure Plasma Technology on the Bioactivity of Spirulina

The present study challenges the in vivo assessment of cold atmospheric pressure plasma (CAPP) technology on the bioactive activity (antioxidant/antiaging and antimicrobial potential) of Spirulina powder, using Caenorhabditis elegans as an animal model. Surface microdischarge cold atmospheric pressure plasma (SMD-CAPP) treatment was 3.3 W discharge power for 7 min. C. elegans lifespan and egg laying were used as indicators of antioxidant/antiaging potential of Spirulina (1 mg/mL), when grown with Spirulina CP-treated [E_SCP] and untreated [E_S], compared with a control [E_0] (non-supplemented with Spirulina). According to our results, under both Spirulina supplemented media [E_SCP and E_S] and for the first 17 days, nematodes experienced an increase in lifespan but without significant differences (p > 0.05) between control and Spirulina CP-treated. Regarding the in vivo assay of the antimicrobial potential of Spirulina against Salmonella enterica serovar Typhimurium (infected worms), no significant differences (p > 0.05) were found between the three exposure scenarios (control [S_0]; Spirulina supplemented media [S_S]; CP-treated Spirulina supplemented media [S_SCP]). According to present results, CAPP-treatment do not influence negatively the lifespan of C. elegans but a reduction in the Spirulina antiaging potential was found. No in vivo modifications in antimicrobial activity seem to be linked to CAPP-processed Spirulina.

Global knowledge on the commercial sea cucumber Holothuria scabra

Holothuria scabra is one of the most intensively studied holothuroids, or sea cucumbers (Echinodermata: Holothuroidea), having been discussed in the literature since the early 19th century. The species is important for several reasons: (1) it is widely distributed and historically abundant in several shallow soft-bottom habitats throughout the Indo-Pacific, (2) it has a high commercial value on the Asian markets, where it is mainly sold as a dried product (beche-de-mer) and (3) it is the only tropical holothuroid species that can currently be mass-produced in hatcheries. Over 20 years have elapsed since the last comprehensive review on H. scabra published in 2001. Research on H. scabra has continued to accumulate, fuelled by intense commercial exploitation, and further declines in wild stocks over the entire distribution range. This review compiles data from over 950 publications pertaining to the biology, ecology, physiology, biochemical composition, aquaculture, fishery, processing and trade of H. scabra, presenting the most complete synthesis to date, including scientific papers and material published by local institutions and/or in foreign languages. The main goal of this project was to summarize and critically discuss the abundant literature on this species, making it more readily accessible to all stakeholders aiming to conduct fundamental and applied research on H. scabra, or wishing to develop aquaculture, stock enhancement and management programs across its geographic range.

Anti-aging effects of the fermented anthocyanin extracts of purple sweet potato on Caenorhabditis elegans

Anthocyanins have anti-inflammatory, anticarcinogenic and antioxidant properties and anti-aging effects as well as potential application as pigments. The metabolism of anthocyanins in fermented food has attracted increasing attention. However, the effect of lactic acid bacteria (LAB) fermentation on its anti-aging activity remains mostly unknown. The current study aimed to investigate the compositions, antioxidant activities and anti-aging effect of fermented purple sweet potato anthocyanins (FSPA) on aging Caenorhabditis elegans compared to raw purple sweet potato anthocyanins (PSPA). Results showed that anthocyanins were degraded into more bioavailable phenolic acids by Weissella confusa fermentation. PSPA and FSPA can extend the lifespan of C. elegans by 26.7% and 37.5%, respectively, through improving the activity of antioxidant enzymes as well as decreasing MDA content, ROS levels and lipofuscin accumulation. Pretreatment of the worms with PSPA and FSPA induced their potential to resist to thermal tolerance and oxidative stress, and FSPA exerted a higher anti-stress effect than PSPA. Moreover, FSPA supplementation upregulated the mRNA expressions of genes daf-16, hsp-16.2, sir-2.1, skn-1 and sod-3 and downregulated the expression of daf-2 in the nematodes, whereas PSPA only induced the increase in the expressions of sir-2.1, skn-1 and sod-3. Overall, FSPA can improve stress resistance and extend the lifespan of C. elegans by both insulin/IGF-1 signaling pathway and dietary restriction pathway, providing a theoretical basis for the application of PSPA in fermented food as functional pigments.

Naringenin prolongs lifespan and delays aging mediated by IIS and MAPK in Caenorhabditis elegans

Naringenin (NN) is one of the most abundant flavonoids in citrus and grapefruits and has been shown to have antioxidant properties in vitro. The purpose of the study is to examine the antioxidant and anti-aging activities of NN in C. elegans, and to further explore the molecular mechanism. The results showed that NN enhanced the lifespan under normal and oxidative stress induced by H₂O₂. After treatment with NN, locomotion capability was improved and aging pigment accumulation was suppressed. NN also delayed the paralysis and reversed the defective chemotaxis behavior induced by Aβ protein. Meanwhile, the treatment with NN enhanced the activities of antioxidant enzymes and reduced the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA) content. The possible targets and pathways interacting with NN were predicted by network pharmacology. Real-time PCR analysis indicated that NN upregulated the expression levels of daf-16, sek-1 and skn-1, downregulated the expression levels of daf-2, age-1 and akt-1, and further activated sod-3, ctl-1, ctl-2, gst-4 and mtl-1. Moreover, the selected mutant strains were used and molecular docking was conducted to further suggest that IIS and MAPK pathways could be involved in the NN-mediated longevity-promoting effect.

Diterpene glycosides from Holothuria scabra exert the α-synuclein degradation and neuroprotection against α-synuclein-Mediated neurodegeneration in C. elegans model

ETHNOPHARMACOLOGICAL RELEVANCE

Holothuria (Metriatyla) scabra Jaeger (H. scabra), sea cucumber, is the marine organism that has been used as traditional food and medicine to gain the health benefits since ancient time. Although our recent studies have shown that crude extracts from H. scabra exhibited neuroprotective effects against Parkinson's disease (PD), the underlying mechanisms and bioactive compounds are still unknown.

AIM OF THE STUDY

In the present study, we examined the efficacy of purified compounds from H. scabra and their underlying mechanism on α-synuclein degradation and neuroprotection against α-synuclein-mediated neurodegeneration in a transgenic Caenorhabditis elegans PD model.

MATERIAL AND METHODS

The H. scabra compounds (HSEA-P1 and P2) were purified and examined for their toxicity and optimal dose-range by food-clearance and lifespan assays. The α-synuclein degradation and neuroprotection against α-synuclein-mediated neurodegeneration were determined using transgenic C. elegans model, Punc-54::α-syn and Pdat-1:: α-syn; Pdat-1::GFP, respectively, and then further investigated by determining the behavioral assays including locomotion rate, basal slowing rate, ethanol avoidance, and area-restricted searching. The underlying mechanisms related to autophagy were clarified by quantitative PCR and RNAi experiments.

RESULTS

Our results showed that HSEA-P1 and HSEA-P2 significantly diminished α-synuclein accumulation, improved motility deficits, and recovered the shortened lifespan. Moreover, HSEA-P1 and HSEA-P2 significantly protected dopaminergic neurons from α-synuclein toxicity and alleviated dopamine-associated behavioral deficits, i.e., basal slowing, ethanol avoidance, and area-restricted searching. HSEA-P1 and HSEA-P2 also up-regulated autophagy-related genes, including beclin-1/bec-1, lc-3/lgg-1, and atg-7/atg-7. RNA interference (RNAi) of these genes in transgenic α-synuclein worms confirmed that lc-3/lgg-1 and atg-7/atg-7 were required for α-synuclein degradation and DAergic neuroprotection activities of HSEA-P1 and HSEA-P2. NMR and mass spectrometry analysis revealed that the HSEA-P1 and HSEA-P2 contained diterpene glycosides.

CONCLUSION

These findings indicate that diterpene glycosides extracted from H. scabra decreases α-synuclein accumulation and protects α-synuclein-mediated DAergic neuronal loss and its toxicities via lgg-1 and atg-7.

Trilobatin, a Component from Lithocarpus polystachyrus Rehd., Increases Longevity in C. elegans Through Activating SKN1/SIRT3/DAF16 Signaling Pathway

Trilobatin (TLB) is an effective component from Lithocarpus polystachyrus Rehd. Our previous study revealed that TLB protected against oxidative injury in neuronal cells by AMPK/Nrf2/SIRT3 signaling pathway. However, whether TLB can delay aging remains still a mystery. Therefore, the present study was designed to investigate the possible longevity-enhancing effect of TLB, and further to explore its underlying mechanism in Caenorhabditis elegans (C. elegans). The results showed that TLB exerted beneficial effects on C. elegans, as evidenced by survival rate, body movement assay and pharynx-pumping assay. Furthermore, TLB not only significantly decreased ROS and MDA levels, but also increased anti-oxidant enzyme activities including CAT and SOD, as well as its subtypes SOD2 andSOD3, but not affect SOD1 activity, as evidenced by heat and oxidative stress resistance assays. Whereas, the anti-oxidative effects of TLB were almost abolished in SKN1, Sir2.3, and DAF16 mutant C. elegans. Moreover, TLB augmented the fluorescence intensity of DAF16: GFP, SKN1:GFP, GST4:GFP mutants, indicating that TLB increased the contents of SKN1, SIRT3 and DAF16 due to fluorescence intensity of these mutants, which were indicative of these proteins. In addition, TLB markedly increased the protein expressions of SKN1, SIRT3 and DAF16 as evidenced by ELISA assay. However, its longevity-enhancing effect were abolished in DAF16, Sir2.3, SKN1, SOD2, SOD3, and GST4 mutant C. elegans than those of non-TLB treated controls. In conclusion, TLB effectively prolongs lifespan of C. elegans, through regulating redox homeostasis, which is, at least partially, mediated by SKN1/SIRT3/DAF16 signaling pathway.

Beneficial Effects of Cyclic Ether 2-Butoxytetrahydrofuran from Sea Cucumber Holothuria scabra against Aβ Aggregate Toxicity in Transgenic Caenorhabditis elegans and Potential Chemical Interaction

The pathological finding of amyloid-β (Aβ) aggregates is thought to be a leading cause of untreated Alzheimer’s disease (AD). In this study, we isolated 2-butoxytetrahydrofuran (2-BTHF), a small cyclic ether, from Holothuria scabra and demonstrated its therapeutic potential against AD through the attenuation of Aβ aggregation in a transgenic Caenorhabditis elegans model. Our results revealed that amongst the five H. scabra isolated compounds, 2-BTHF was shown to be the most effective in suppressing worm paralysis caused by Aβ toxicity and in expressing strong neuroprotection in CL4176 and CL2355 strains, respectively. An immunoblot analysis showed that CL4176 and CL2006 treated with 2-BTHF showed no effect on the level of Aβ monomers but significantly reduced the toxic oligomeric form and the amount of 1,4-bis(3-carboxy-hydroxy-phenylethenyl)-benzene (X-34)-positive fibril deposits. This concurrently occurred with a reduction of reactive oxygen species (ROS) in the treated CL4176 worms. Mechanistically, heat shock factor 1 (HSF-1) (at residues histidine 63 (HIS63) and glutamine 72 (GLN72)) was shown to be 2-BTHF’s potential target that might contribute to an increased expression of autophagy-related genes required for the breakdown of the Aβ aggregate, thus attenuating its toxicity. In conclusion, 2-BTHF from H. scabra could protect C. elegans from Aβ toxicity by suppressing its aggregation via an HSF-1-regulated autophagic pathway and has been implicated as a potential drug for AD.

Composition of peony petal fatty acids and flavonoids and their effect on Caenorhabditis elegans lifespan

The colorful petals of tree peony (Paeonia suffruticosa Andrews) are widely used as a source of additives in food, fragrances, and cosmetics. However, the nutritional composition of peony petals is undetermined, thereby limiting utility and product development. In this work, fresh petals of 15 traditional Chinese tree peony cultivars were selected to analyze the composition of soluble sugars, starch, and soluble protein. Extracted fatty acids (FAs) and flavonoids from petals were characterized by GC-MS and UPLC-triple-TOF-MS, respectively. The oxidative stress resistance (generated by paraquat) effects of petal extracts of three cultivars were also investigated in the model organism Caenorhabditis elegans. Our results showed that the petals were highly enriched in soluble sugars. 11 FAs were found in tree peony petals, and their compositions were similar to that of tree peony seeds. A total of 56 flavonoids were detected in tree peony petals, 28 of which were reported for the first time in tree peony petals, indicating that UPLC-triple-TOF-MS can improve the identification efficiency of flavonoids. Further analysis of tree peony petal metabolites indicated that anthocyanidin and flavonol composition might be used as specific chemotaxonomic biomarkers for cultivar classification. Flavonoids, linoleic acid, and α-linolenic acid (ALA) in petals might provide antioxidant activity. 150 mg/L of petal extracts of all three tested cultivars increased the lifespan of C. elegans. It was suggested that the petal extracts possessed anti-aging effects and oxidative stress resistance. These results highlight that tree peony petals can serve as natural antioxidant food resources in the future.

Terpenoids as Potential Geroprotectors

Terpenes and terpenoids are the largest groups of plant secondary metabolites. However, unlike polyphenols, they are rarely associated with geroprotective properties. Here we evaluated the conformity of the biological effects of terpenoids with the criteria of geroprotectors, including primary criteria (lifespan-extending effects in model organisms, improvement of aging biomarkers, low toxicity, minimal adverse effects, improvement of the quality of life) and secondary criteria (evolutionarily conserved mechanisms of action, reproducibility of the effects on different models, prevention of age-associated diseases, increasing of stress-resistance). The number of substances that demonstrate the greatest compliance with both primary and secondary criteria of geroprotectors were found among different classes of terpenoids. Thus, terpenoids are an underestimated source of potential geroprotectors that can effectively influence the mechanisms of aging and age-related diseases.

A Hot Water Extract of Sideritis scardica Prolongs Life Span and Enhances Heat Shock Resistance in Caenorhabditis elegans

Sideritis scardica is a Lamiaceae plant that is endemic to the alpine zone of the Balkan Peninsula. The tea of S. scardica has been handed down as a “tea of longevity” in the Rhodope region of Bulgaria for an unknown amount of time. In this study, we prepared a hot water extract of S. scardica (SHWE) and examined its effects on both life span and stress response in living tissue using Caenorhabditis elegans and its transgenic mutants. The life span of wild-type N2 worms was prolonged by approximately 15% at the SHWE concentration of 5 µg/mL and approximately 22% at the SHWE concentration of 50 µg/mL, as compared with the control group. The effect of SHWE on the expression of heat shock protein 16.2 (HSP-16.2) under heat stress was investigated using TJ375 worms, a transgenic mutant of C. elegans. In the TJ375 worms pretreated with SHWE, the fluorescence intensity of green fluorescent protein fluorescence, which indicates the expression of HSP-16.2, was significantly increased. In the assay using TJ356 worms, the worms pretreated with SHWE did not show the translocation of DAF-16, a forkhead transcription factor class O homolog, from the cytoplasm to nucleus under heat stress. Additionally, under heat stress, the pretreatment of SHWE improved the survival rate of GR1307 worms, a knockout mutant of daf-16. These results indicate that SHWE enhances HSP-16.2 expression through a stress-response pathway (eg, HSF-1 pathway) other than the DAF-16 pathway, resulting in a prolonged life span of C. elegans under heat stress.

Saponin-rich extracts from Holothuria leucospilota mediate lifespan extension and stress resistance in Caenorhabditis elegans via daf-16

Saponins are secondary metabolite compounds that can be found in sea cucumbers (Holothuroidea spp.). However, little is known about how saponin-rich extracts from Holothuria leucospilota can delay and prolong the lifespan of the whole organism. In this study, anti-aging effects of H. leucospilota extracts were studied on Caenorhabditis elegans. NMR analysis revealed that body wall n-butanol-extract of H. leucospilota (BW-BU) is saponin-rich. BW-BU extracts exhibited antioxidant activities by 2,2'-diphenyl-2-picrylhydrazyl assay (EC₅₀  = 10.23 ± 0.12 mg/ml) and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid assay (EC₅₀  = 3.91 ± 0.04 mg/ml). BW-BU extracts increased lifespan of L4 and L1 C. elegans (5.92% and 15.76%, respectively), which also increased worm growth, stress resistance, and reduced biomarkers for aging. BW-BU extracts activated DAF-16 nuclear localization and upregulated daf-16 and DAF-16 target genes expression. Taken together, this study revealed the evidences on anti-aging activities of saponin-rich extracts from H. leucospilota, which can extend lifespan of C. elegans via daf-16. PRACTICAL APPLICATIONS: In recent years, age-associated chronic diseases have had a significant impact on quality of life. Many natural compounds exhibit anti-aging activities, especially in sea cucumber, H. leucospilota. Our results indicated that H. leucospilota is good for health. Extracts from H. leucospilota contain a bioactive compound that can be potentially used to promote longevity and disease prevention in aging.

Saponin-enriched extracts from body wall and Cuvierian tubule of Holothuria leucospilota reduce fat accumulation and suppress lipogenesis in Caenorhabditis elegans

BACKGROUND

Saponins have been shown to possess many pharmacological properties, including altered fat metabolism. The black sea cucumber, Holothuria leucospilota, is a marine animal that contains a specialized organ called a Cuvierian tubule that produces and secrete the bioactive saponins into the tubules and body wall. Therefore, the aims of this study are to investigate the anti-obesity effect of saponins extracted from body wall and Cuvierian tubules of H. leucospilota.

RESULTS

The butanol extracts of H. leucospilota body wall and Cuvierian tubules containing high amounts of saponins significantly reduced fat deposition and triglyceride levels in Caenorhabditis elegans fed with 50 mmol L^-1 glucose. Moreover, the saponin-enriched extracts of H. leucospilota significantly restored the lifespan of 2% glucose-fed worms (18.71%). Green fluorescence protein-labeled sbp-1 gene expression and nuclear translocation of daf-16 were also significantly decreased in H. leucospilota treatment. The saponin-enriched extracts downregulated the messenger RNA expressions of genes involved in fat storage and metabolism, including sbp-1, cebp, and daf-16 but upregulated the expression of nhr-49 gene.

CONCLUSION

Our results suggest that H. leucospilota-derived saponins may mediate the reduction of glucose-induced fat accumulation through sbp-1, cebp, daf-16 and nhr-9 pathways. Therefore, the H. leucospilota extracts could be used as nutraceuticals for anti-obesity prevention. © 2019 Society of Chemical Industry.