Catechin induced longevity in C. elegans: from key regulator genes to disposable soma

HDAC1/2 inhibitor therapy improves multiple organ systems in aged mice

Aging increases the risk of age-related diseases, imposing substantial healthcare and personal costs. Targeting fundamental aging mechanisms pharmacologically can promote healthy aging and reduce this disease susceptibility. In this work, we employed transcriptome-based drug screening to identify compounds emulating transcriptional signatures of long-lived genetic interventions. We discovered compound 60 (Cmpd60), a selective histone deacetylase 1 and 2 (HDAC1/2) inhibitor, mimicking diverse longevity interventions. In extensive molecular, phenotypic, and bioinformatic assessments using various cell and aged mouse models, we found Cmpd60 treatment to improve age-related phenotypes in multiple organs. Cmpd60 reduces renal epithelial-mesenchymal transition and fibrosis in kidney, diminishes dementia-related gene expression in brain, and enhances cardiac contractility and relaxation for the heart. In sum, our two-week HDAC1/2 inhibitor treatment in aged mice establishes a multi-tissue, healthy aging intervention in mammals, holding promise for therapeutic translation to promote healthy aging in humans.

Hypsizygus marmoreus extract exhibited antioxidant effects to promote longevity and stress resistance in Caenorhabditis elegans

In this study, we explored the lifespan extension effect of a popular edible mushroom, Hypsizygus marmoreus, using the model organism Caenorhabditis elegans (C. elegans). The results showed that Hypsizygus marmoreus extract (HME) could increase the lifespan of C. elegans and ameliorate the healthspan by improving motility, attenuating lipofuscin accumulation, and enhancing the ability to withstand oxidative and heat stress. Then, we found noteworthy enhancements in SOD and CAT activities and reactive oxygen species (ROS) scavenging activity in vivo. Combined with the up-regulation of the expression of antioxidant genes (skn-1, sod-1, sod-3, mev-1, and gst-4), HME may function as an antioxidant in nematodes, which may be closely related to its phenolic compounds. Furthermore, we found that HME promoted the transfer of the transcription factor SKN-1 to the nucleus but had no impact on the lifespan of skn-1 mutants, indicating that SKN-1 was essential for Hypsizygus marmoreus to exert beneficial biological effects in C. elegans. Our findings elucidated that dietary supplementation with Hypsizygus marmoreus might have beneficial anti-aging effects and contribute to exploring the lifespan extension and underlying mechanisms of Hypsizygus marmoreus in C. elegans.

Dietary antioxidants and lifespan: Relevance of environmental conditions, diet, and genotype of experimental models

The rise of life expectancy in current societies is not accompanied, to date, by a similar increase in healthspan, which represents a great socio-economic problem. It has been suggested that aging can be manipulated and then, the onset of all age-associated chronic disorders can be delayed because these pathologies share age as primary underlying risk factor. One of the most extended ideas is that aging is consequence of the accumulation of molecular damage. According to the oxidative damage theory, antioxidants should slow down aging, extending lifespan and healthspan. The present review analyzes studies evaluating the effect of dietary antioxidants on lifespan of different aging models and discusses the evidence on favor of their antioxidant activity as anti-aging mechanisms. Moreover, possible causes for differences between the reported results are evaluated.

DAF-16 is involved in colonic metabolites of ferulic acid-promoted longevity and stress resistance of Caenorhabditis elegans

BACKGROUND

Ferulic acid (FA) is a dietary polyphenol widely found in plant tissues. It has long been considered to have health-promoting qualities. However, the biological properties of dietary polyphenols depend largely on their absorption during digestion, and the effects of their intestinal metabolites on human health have attracted the interest of researchers. This study evaluated the effects of three main colonic metabolites of FA - 3-(3,4-dihydroxyphenyl)propionic acid (3,4diOHPPA), 3-(3-hydroxyphenyl)propionic acid (3OHPPA) and 3-phenylpropionic acid (3PPA) - on longevity and stress resistance in Caenorhabditis elegans.

RESULTS

Our results showed that 3,4diOHPPA, 3OHPPA and 3PPA extended the lifespan under normal conditions in C. elegans whereas FA did not. High doses of 3,4diOHPPA (0.5 mmol L^-1 ), 3OHPPA (2.5 mmol L^-1 ) and 3PPA (2.5 mmol L^-1 ) prolonged the mean lifespan by 11.2%, 13.0% and 10.6%, respectively. Moreover, 3,4diOHPPA, 3OHPPA and 3PPA treatments promoted stress tolerance against heat, UV irradiation and paraquat. Furthermore, three metabolites ameliorated physical functions, including reactive oxygen species and malondialdehyde levels, motility and pharyngeal pumping rate. The anti-aging activities mediated by 3,4diOHPPA, 3OHPPA and 3PPA depend on the HSF-1 and JNK-1 linked insulin/IGF-1 signaling pathway, which converge onto DAF-16.

CONCLUSION

The current findings suggest that colonic metabolites of FA have the potential for use as anti-aging bioactivate compounds. © 2022 Society of Chemical Industry.

The effects of polyphenols against oxidative stress in Caenorhabditis elegans are determined by coexisting bacteria

INTRODUCTION

Increasing evidence supports the role of gut microbiota in many aspects of human health, including immune, metabolic and neurobehavioral traits. Several studies have focused on how different components of the diet, such as polyphenols, can modulate the composition and function of the gut microbiota leading to health benefits.

METHODS

The effects on the resistance against thermally induced oxidative stress of C. elegans grown in the presence of flavonoids (quercetin or epicatechin) and fed different probiotic strains, namely Lactobacillus plantarum CLC17, Bifidobacterium longum NCIMB 8809 and Enterococcus faecium CECT 410, were explored.

RESULTS

Feeding C. elegans with the assayed bacteria in the absence of flavonoids did not significantly affect body size and fertility of the worms neither improve their resistance against oxidative stress compared to E. coli controls. However, increased resistance to stress was found when C. elegans was cultivated in the presence of both L. plantarum and flavonoids, but not with B. longum or E. faecium. An exploratory study revealed the presence of glycosylated and sulfated metabolites together with the aglycone in worms treated with quercetin and fed any of the different assayed LAB strains. However, in the assays with epicatechin a differential metabolite, tentatively identified as 5-(4'-hydroxyphenyl)-γ-valerolactone 3'-O-glucoside, was detected in the worms fed L. plantarum but not with the other bacteria.

CONCLUSION

The obtained results indicated that the interactions bacteria/polyphenol play a key role in the effects produced in C. elegans regarding resistance against oxidative stress, although those effects cannot be only explained by the ability of bacteria to metabolize polyphenols, but other mechanisms should also be involved.

A comprehensive and current review on the role of flavonoids in lung cancer-Experimental and theoretical approaches

BACKGROUND

It is well-known that flavonoids, which can be easily obtained from many fruits and vegetables are widely preferred in the treatment of some important diseases. Some researchers noted that these chemical compounds exhibit high inhibition effect against various cancer types. Many experimental studies proving this ability of the flavonoids with high antioxidant activity are available in the literature.

PUROPOSE

The main aim of this review is to summarize comprehensively anticancer properties of flavonoids against the lung cancer in the light of experimental studies and well-known theory and electronic structure principles. In this review article, more detailed and current information about the using of flavonoids in the treatment of lung cancer is presented considering theoretical and experimental approaches.

STUDY DESIGN

In addition to experimental studies including the anticancer effects of flavonoids, we emphasized the requirement of the well-known electronic structure principle in the development of anticancer drugs. For this aim, Conceptual Density Functional Theory should be considered as a powerful tool. Searching the databases including ScienceDirect, PubMed and Web of Science, the suitable reference papers for this project were selected.

METHODS

Theoretical tools like DFT and Molecular Docking provides important clues about anticancer behavior and drug properties of molecular systems. Conceptual Density Functional Theory and CDFT based electronic structure principles and rules like Hard and Soft Acid-Base Principle (HSAB), Maximum Hardness Principle, Minimum Polarizability, Minimum Electrophilicity Principles and Maximum Composite Hardness Rule introduced by one of the authors of this review are so useful to predict the mechanisms and powers of chemical systems. Especially, it cannot be ignored the success of HSAB Principle in the explanations and highlighting of biochemical interactions.

RESULTS

Both theoretical analysis and experimental studies confirmed that flavonoids have higher inhibition effect against lung cancer. In addition to many superior properties like anticancer activity, antimicrobial activity, antioxidant activity, antidiabetic effect of flavonoids, their toxicities are also explained with the help of published popular papers. Action modes of the mentioned compounds are given in detail.

CONCLUSION

The review includes detailed information about the mentioned electronic structure principles and rules and their applications in the cancer research. In addition, the epidemiology and types of lung cancer anticancer activity of flavonoids in lung cancer are explained in details.

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.

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.

Bioactive Phytochemicals with Anti-Aging and Lifespan Extending Potentials in Caenorhabditis elegans

In the forms of either herbs or functional foods, plants and their products have attracted medicinal, culinary, and nutraceutical applications due to their abundance in bioactive phytochemicals. Human beings and other animals have employed those bioactive phytochemicals to improve health quality based on their broad potentials as antioxidant, anti-microbial, anti-carcinogenic, anti-inflammatory, neuroprotective, and anti-aging effects, amongst others. For the past decade and half, efforts to discover bioactive phytochemicals both in pure and crude forms have been intensified using the Caenorhabditis elegans aging model, in which various metabolic pathways in humans are highly conserved. In this review, we summarized the aging and longevity pathways that are common to C. elegans and humans and collated some of the bioactive phytochemicals with health benefits and lifespan extending effects that have been studied in C. elegans. This simple animal model is not only a perfect system for discovering bioactive compounds but is also a research shortcut for elucidating the amelioration mechanisms of aging risk factors and associated diseases.

Caenorhabditis elegans as a model for obesity research

Caenorhabditis elegans, a free-living nematode, is an animal model that has been extensively employed in a variety of research fields, including in the study of obesity. Its favorable features include its compact size, short life cycle, large brood size, easy handling, low cost, availability of complete genetic information, 65% conserved human diseases-associated genes, relatively easy genetic manipulation, and research using Caenorhabditis elegans does not require approvals by the Institutional Animal Care and Use Committee. These advantages make Caenorhabditis elegans a great in vivo model for life science research including obesity research. In this review, we provide graphic overviews of Caenorhabditis elegans' basic anatomy, growth conditions, routes of compound delivery, and fat metabolism, both synthesis and degradation pathways, including major signaling pathways involved. Our aim is to provide an overview for researchers interested in applying C. elegans as an in vivo model for the screening and identification of anti-obesity bioactive compounds prior to testing in vertebrate animal models.

Anti-aging properties of phytoconstituents and phyto-nanoemulsions and their application in managing aging-related diseases

Aging is spontaneous and inevitable process in all living beings. It is a complex natural phenomenon that manifests as a gradual decline of physiological functions and homeostasis. Aging inevitably leads to age-associated injuries, diseases, and eventually death. The research on aging-associated diseases aimed at delaying, preventing or even reversing the aging process are of great significance for healthy aging and also for scientific progress. Numerous plant-derived compounds have anti-aging effects, but their therapeutic potential is limited due to their short shelf-life and low bioavailability. As the novel delivery system, nanoemulsion can effectively improve this defect. Nanoemulsions enhance the delivery of drugs to the target site, maintain the plasma concentration for a longer period, and minimize adverse reaction and side effects. This review describes the importance of nanoemulsions for the delivery of phyto-derived compounds and highlights the importance of nanoemulsions in the treatment of aging-related diseases. It also covers the methods of preparation, fate and safety of nanoemulsions, which will provide valuable information for the development of new strategies in treatment of aging-related diseases.

Physiological Dose of EGCG Attenuates the Health Defects of High Dose by Regulating MEMO-1 in Caenorhabditis elegans

EGCG, as a dietary-derived antioxidant, has been extensively studied for its beneficial health effects. Nevertheless, it induces the transient increase in ROS and leads to the hormetic extension of lifespan. How exactly biology-benefiting effects with the minimum severe adverse are realized remains unclear. Here, we showed that physiological dose of EGCG could help moderate remission in health side effects exposed to high doses, including shortened lifespan, reduced body size, decreased pharyngeal pumping rate, and dysfunctional body movement in C. elegans. Furthermore, we found this result was caused by the physiological dose of EGCG to block the continued ROS accumulation and triggered acclimation responses after stressor removal. Also, in this process, we observed that EGCG downregulated the key redox protein MEMO-1 to activate the feedback loop of NADPH oxidase-mediated redox signaling. Our data indicates that the feedback signal induced by NADPH oxidase may contribute to the health-protective mechanism of dietary polyphenols in vivo.

Goji berry (Lycium barbarum L.) juice reduces lifespan and premature aging of Caenorhabditis elegans: Is it safe to consume it?

Goji berry fruit is considered a healthy food. However, studies on its effects on aging and safety are rare. This study is the first to evaluate the effects of goji berry juice (GBJ) on oxidative stress, metabolic markers, and lifespan of Caenorhabditis elegans. GBJ caused toxicity, reduced the lifespan of C. elegans by 50%, and increased the reactive oxygen species (ROS) production by 45-50% at all tested concentrations (1-20 mg/µL) of GBJ. Moreover, the highest concentration of GBJ increased lipid peroxidation by 80% and altered the antioxidant enzymes. These effects could be attributed to a pro-oxidant effect induced by GBJ polyphenols and carotenoids. Moreover, GBJ increased lipofuscin, glucose levels, number of apoptotic bodies, and lipase activity. The use of mutant strains demonstrated that these effects observed in the worms treated with GBJ were not associated with the Daf-16/FOXO or SKN-1 pathways. Our findings revealed that GBJ (mainly the highest concentration) exerted toxic effects and promoted premature aging in C. elegans. Therefore, its consumption should be carefully considered until further studies in mammals are conducted.

The soma-germline communication: implications for somatic and reproductive aging

Aging is characterized by a functional decline in most physiological processes, including alterations in cellular metabolism and defense mechanisms. Increasing evidence suggests that caloric restriction extends longevity and retards age-related diseases at least in part by reducing metabolic rate and oxidative stress in a variety of species, including yeast, worms, flies, and mice. Moreover, recent studies in invertebrates – worms and flies, highlight the intricate interrelation between reproductive longevity and somatic aging (known as disposable soma theory of aging), which appears to be conserved in vertebrates. This review is specifically focused on how the reproductive system modulates somatic aging and vice versa in genetic model systems. Since many signaling pathways governing the aging process are evolutionarily conserved, similar mechanisms may be involved in controlling soma and reproductive aging in vertebrates.

Catechinic acid, a natural polyphenol compound, extends the lifespan of Caenorhabditis elegans via mitophagy pathways

Catechinic acid (CA), widely present in tea and fruits, has vital biological and pharmacological properties. CA plays an important role in the regulation of lifespan. However, the mechanism behind its anti-aging properties remains poorly characterized. In the present study, Caenorhabditis elegans (C. elegans) was used as a model organism. It was found that CA induced mitophagy which prevented the accumulation of dysfunctional mitochondria with age and profoundly extended lifespan. Notably, CA significantly improved the fitness of aging worms, particularly the treatment slowed age-related decline in observed spontaneous movements. Furthermore, CA was found to eliminate dysfunctional mitochondria in the gut and muscle cells, and demonstrated that the lifespan-prolonging effects of CA can be attributed to mitophagy along with the likely regulation of the genes bec-1 and pink-1. The results of this study indicated that pharmacologically induced mitophagy has a profound impact on aging, providing a novel therapeutic intervention against aging and age-related diseases.

Antistress and anti-aging activities of Caenorhabditis elegans were enhanced by Momordica saponin extract

BACKGROUND

Momordica saponin extract (MSE) was found to not only improve longevity and neuroprotection but also alleviate fat accumulation in Caenorhabditis elegans in our previous study. However, the lipid-lowering activity of MSE alone could not fully explain its ability to improve health, so the antistress effects of MSE were further studied.

METHODS

Using C. elegans as an in vivo animal, the lifespan of MSE-treated C. elegans under various stressors (H₂O₂, paraquat and heat) and normal conditions was studied. Furthermore, the antioxidant activities of MSE were discussed. To study the underlying mechanisms, the expression of stress resistance genes and the resistance of related mutants to H₂O₂ stress were tested.

RESULTS

MSE significantly improved the lifespan of C. elegans under stress and normal conditions. Meanwhile, the mobility of C. elegans was also improved. Moreover, the activities of SOD and CAT and the ratio of GSH/GSSG were elevated. Consistently, the levels of ROS and lipid oxidation (the NEFA and MDA content) were reduced. Furthermore, MSE treatment upregulated the expression of the sod-3, sod-5, clt-1, clt-2, hsp-16.1 and hsp-16.2 genes. All biomarkers indicated that the antistress and anti-aging activities of MSE were due to its strong antioxidant activities. Finally, MSE induced nuclear DAF-16::GFP localization. Studies with mutants revealed that skn-1 and hsf-1 were involved in the activity of MSE, which might upregulate the expression of downstream stress-responsive genes.

CONCLUSIONS

Therefore, in addition to its lipid-lowering property, the ability of MSE to improve healthspan was also attributed to the stress resistance effect. Together, MSE might serve as a lead nutraceutical in geriatric research.

Phenotypic Screening in C. elegans as a Tool for the Discovery of New Geroprotective Drugs

Population aging is one of the largest challenges of the 21st century. As more people live to advanced ages, the prevalence of age-related diseases and disabilities will increase placing an ever larger burden on our healthcare system. A potential solution to this conundrum is to develop treatments that prevent, delay or reduce the severity of age-related diseases by decreasing the rate of the aging process. This ambition has been accomplished in model organisms through dietary, genetic and pharmacological interventions. The pharmacological approaches hold the greatest opportunity for successful translation to the clinic. The discovery of such pharmacological interventions in aging requires high-throughput screening strategies. However, the majority of screens performed for geroprotective drugs in C. elegans so far are rather low throughput. Therefore, the development of high-throughput screening strategies is of utmost importance.

5'-Hydroxy-6, 7, 8, 3', 4'-pentamethoxyflavone extends longevity mediated by DR-induced autophagy and oxidative stress resistance in C. elegans

5'-Hydroxy-6, 7, 8, 3', 4'-pentamethoxyflavone (5-HPF), a polymethoxyflavone compound found in dikamali gum, has been shown to exert a range of beneficial effects on health. We have previously reported that 5-HPF improves the cholinergic dysfunction and also possesses antioxidant properties in Caenorhabditis elegans. In this study, we have identified the effect of 5-HPF on the worm lifespan and its underlying molecular mechanisms. Out of the five tested pharmacological doses of 5-HPF, viz. 6.25, 12.5, 25, 50, and 100 μM, the 50 μM dose maximally extended the mean life of C. elegans by 28%. The present study revealed that 5-HPF supplementation leads to dietary restriction (DR)-like effects in the worms without altering bacterial metabolism. The analysis of mutant animals fed with 5-HPF suggested that the extended lifespan of C. elegans depends upon multiple DR-related signaling pathways, with NRF2 and FOXA being critical factors. Further investigation into the mechanistic aspects indicated that 5-HPF utilizes autophagy pathway induced by DR through the upregulation of autophagy genes bec-1 and lgg-1, evident from the increase in autophagic puncta in the seam cells of lgg-1::gfp tagged worms. This study identifies the longevity-promoting activity of 5-HPF in C. elegans regulated by oxidative stress-resistance genes and DR-induced autophagy pathway.

Caernohabditis elegans as a Model Organism to Evaluate the Antioxidant Effects of Phytochemicals

The nematode Caenorhabditis elegans was introduced as a model organism in biological research by Sydney Brenner in the 1970s. Since then, it has been increasingly used for investigating processes such as ageing, oxidative stress, neurodegeneration, or inflammation, for which there is a high degree of homology between C. elegans and human pathways, so that the worm offers promising possibilities to study mechanisms of action and effects of phytochemicals of foods and plants. In this paper, the genes and pathways regulating oxidative stress in C. elegans are discussed, as well as the methodological approaches used for their evaluation in the worm. In particular, the following aspects are reviewed: the use of stress assays, determination of chemical and biochemical markers (e.g., ROS, carbonylated proteins, lipid peroxides or altered DNA), influence on gene expression and the employment of mutant worm strains, either carrying loss-of-function mutations or fluorescent reporters, such as the GFP.

Plant and fungal products that extend lifespan in Caenorhabditis elegans

The nematode Caenorhabditis elegans is a useful model to study aging due to its short lifespan, ease of manipulation, and available genetic tools. Several molecules and extracts derived from plants and fungi extend the lifespan of C. elegans by modulating aging-related pathways that are conserved in more complex organisms. Modulation of aging pathways leads to activation of autophagy, mitochondrial biogenesis and expression of antioxidant and detoxifying enzymes in a manner similar to caloric restriction. Low and moderate concentrations of plant and fungal molecules usually extend lifespan, while high concentrations are detrimental, consistent with a lifespan-modulating mechanism involving hormesis. We review here molecules and extracts derived from plants and fungi that extend the lifespan of C. elegans, and explore the possibility that these natural substances may produce health benefits in humans.

Assessment of the In Vivo Antioxidant Activity of an Anthocyanin-Rich Bilberry Extract Using the Caenorhabditis elegans Model

Anthocyanins have been associated with several health benefits, although the responsible mechanisms are not well established yet. In the present study, an anthocyanin-rich extract from bilberry (Vaccinium myrtillus L.) was tested in order to evaluate its capacity to modulate reactive oxygen species (ROS) production and resistance to thermally induced oxidative stress, using the nematode Caenorhabditis elegans as an in vivo model. The assays were carried out with the wild-type N2 strain and the mutant strains daf-16(mu86) I and hsf-1(sy441), which were grown in the presence of two anthocyanin extract concentrations (5 and 10 μg/mL in the culture medium) and further subjected to thermal stress. The treatment with the anthocyanin extract at 5 μg/mL showed protective effects on the accumulation of ROS and increased thermal resistance in C. elegans, both in stressed and non-stressed young and aged worms. However, detrimental effects were observed in nematodes treated with 10 μg/mL, leading to a higher worm mortality rate compared to controls, which was interpreted as a hormetic response. These findings suggested that the effects of the bilberry extract on C. elegans might not rely on its direct antioxidant capacity, but other mechanisms could also be involved. Additional assays were performed in two mutant strains with loss-of-function for DAF-16 (abnormal DAuer Formation factor 16) and HSF-1 (Heat Shock Factor 1) transcription factors, which act downstream of the insulin/insulin like growth factor-1 (IGF-1) signaling pathway. The results indicated that the modulation of these factors could be behind the improvement in the resistance against thermal stress produced by bilberry anthocyanins in young individuals, whereas they do not totally explain the effects produced in worms in the post-reproductive development stage. Further experiments are needed to continue uncovering the mechanisms behind the biological effects of anthocyanins in living organisms, as well as to establish whether they fall within the hormesis concept.

The Mechanisms Behind the Biological Activity of Flavonoids

Flavonoids are phenolic compounds widely distributed in the human diet. Their intake has been associated with a decreased risk of different diseases such as cancer, immune dysfunction or coronary heart disease. However, the knowledge about the mechanisms behind their in vivo activity is limited and still under discussion. For years, their bioactivity was associated with the direct antioxidant and radical scavenging properties of phenolic compounds, but nowadays this assumption is unlikely to explain their putative health effects, or at least to be the only explanation for them. New hypotheses about possible mechanisms have been postulated, including the influence of the interaction of polyphenols and gut microbiota and also the possibility that flavonoids or their metabolites could modify gene expression or act as potential modulators of intracellular signaling cascades. This paper reviews all these topics, from the classical view as antioxidants in the context of the Oxidative Stress theory to the most recent tendencies related with the modulation of redox signaling pathways, modification of gene expression or interactions with the intestinal microbiota. The use of C. elegans as a model organism for the study of the molecular mechanisms involved in biological activity of flavonoids is also discussed.

Butiá fruit extract (Butia eriospatha) protects against oxidative damage and increases lifespan on Caenorhabditis elegans

Butiá (Butia eriospatha) is a fruit of a palm tree belonging to the family Arecaceae, native to South America. The aim of this study was to evaluate the antioxidant potential of butiá extract using Caenorhabditis elegans as animal model. Initially, we performed survival experiments, reproduction, resistance to oxidative stress (post or pre-treatment with paraquat or hydrogen peroxide), longevity, superoxide dismutase, and catalase GFP reporters' expression. We observed that butiá extract did not affect the worms' survival. Similarly, egg laying also showed no significant difference between treatments. None of the extract concentrations tested was able to significantly protect or reverse paraquat-induced oxidative stress. However, they were able to reverse the oxidative damage induced by hydrogen peroxide. In addition, butiá extract increased C. elegans lifespan under stress and not per se. Our results demonstrate that the Butiá is able to extend the lifespan of the nematode C. elegans and that this effect may be mediated by an induced resistance to oxidative stress. PRACTICAL APPLICATIONS: The practical applications of this research are to expand and bring scientific knowledge to the population about the benefits of the consumption of this native fruit from the southern region of Brazil. Many fruits and other plant foods are consumed and spread with benefits without proper scientific proof of these benefits. This fruit is widely cultivated and its production and consumption can be expanded from these results. Still, we point out that this is the first time that the benefits of this fruit are studied.

Can an entomopathogenic nematode serve, as proxy for strongyles, in assessing the anthelmintic effects of phenolic compounds?

As gastro-intestinal nematodes (GINs) become increasingly resistant to chemical anthelmintics, and because consumers scrutinize chemical residues in animal products, the use of herbal anthelmintics and in particular, phenolic compounds, has become attractive. Most life stages of GINs cannot be grown in the lab as they are obligatory parasites, which limits our understanding of the effects of phenolic compounds on their parasitic stages of life. We hypothesized that a species phylogenetically close to GINs and grown in vitro, the insect-parasitic nematode Heterorhabditis bacteriophora (Rhabditida; Heterorhabditiade), when fed with Photorhabdus luminescens exposed to plant phenolics, can serve, as proxy for strongyles, in assessing the anthelmintic effects of phenolic compounds. We compared the development of H. bacteriophora infective juveniles (IJ) and the exsheathment rate of L3 larvae of the strongyle Teladorsagia circumcincta and Trichostrongylus colubriformis when exposed to catechin, rutin, chlorogenic and gallic acids, and myricetin. Gallic acid had the highest impact in terms of IJ mortality but the highest impairment of IJ development to adulthood was imposed by myricetin. The studied compounds were not lethal to GINs stricto sensu but we consider that the practical implications of total exsheathment inhibition and mortality on GIN populations are similar. Catechin and rutin had similar effects on rhabditid and strongyles: they imposed ca. 90% lethality of IJs at concentrations higher than 1200 ppm and the remaining live IJs did not develop further, and they also totally inhibited strongyle L3 exsheathment in a dose-response fashion. Gallic acid was 100% lethal to IJs exposed above 300 ppm and chlorogenic acid caused 87% mortality above 1200 ppm, with no development for the surviving IJs but for all lower concentrations, all the IJs developed to adult stages. Likewise, gallic and chlorogenic acids did not affect the exsheatment of GIN L3 larvae. Therefore, a discrepancy between the effects of gallic and chlorogenic acids on the development of rhabditid IJs and exsheathment of GIN L3 larvae was found only when they were exposed to high concentrations. A dose-response of IJ lethality to myricetin was found, with no IJ development between 150 and 2400 ppm; but contrary to the other compounds, myricetin also impaired IJ development of IJs above 10 ppm in a dose-response manner and showed dose-responses in the L3 exsheathment. Apart for the high rates of lethality imposed on IJs by gallic and chlorogenic acids at high concentration, these results suggest that H. bacteriophora fed P. luminescens exposed to phenolics shows potential to serve as model in studies of the anthelmintic effects of phenolics in GIN.

Epigallocatechin gallate prevents senescence by alleviating oxidative stress and inflammation in WI-38 human embryonic fibroblasts

Increased levels of oxidative stress and inflammation are the underlying mechanisms behind the aging process and age-related diseases. The purpose of our research is to explore whether epigallocatechin gallate (EGCG) can extend replicative life span by preventing the oxidative stress and inflammatory effects of WI-38 fibroblasts and the involved mechanisms in vitro. WI-38 cells were treated with different concentrations of EGCG (0, 25, 50 and 100 μM) at population doubling (PD) 25. At late-stage cells, we determined the age-associated genes with signaling through transcriptome sequencing. The expression profile of the targets in WI-38 fibroblasts was confirmed by bioinformatics analysis, qPCR and western blot. We found that EGCG markedly decreased reactive oxygen species (ROS), and inflammation factors, tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and significantly increased cell proliferation at PD 35 and 45. EGCG treatments significantly decreased p53 and retinoblastoma (Rb) expressions, markedly increased p-Rb and E2F2 expressions as well as antioxidant enzymes and superoxide dismutase (SOD) 1 and SOD2 content, and obviously decreased the expressions of inflammation factors IL-32, TNF-α expressions at PD 45 WI-38 cells. Moreover, the effects were changed by EGCG treatment by p53 siRNA or overexpression. These findings in our studies reveal that EGCG treatments improved senescence and enhanced the replicative life span through alleviating oxidative stress and inflammation in WI-38 fibroblasts.

Epimedium flavonoids mitigate proteotoxicity and extend healthspan via DAF-16 in C. elegans

Objective: Epimedium flavonoids (EF), the raw extract of medicinal herb Epimedium, have been shown to have broad beneficial effects in the elderly including those with neurodegeneration. The goal of this study is to investigate whether EF is protective against proteotoxicity and whether it extends healthspan in C. elegans.

Methods: Animals were treated with EF supplemented in the growth medium. Two C. elegans models of human proteotoxic disease, CL4176 expressing an aggregated amyloid-[Formula: see text] (1–42) peptide (A[Formula: see text]1–42) and AM140 expressing a polyglutamine (polyQ) protein, were exploited to test the anti-proteotoxicity of EF. Proteotoxicity-induced paralysis in CL4176 and AM140 was evaluated. Lifespan, stress resistance, and locomotion were tested in wild-type N2 C. elegans. Lifespan assays were also performed in CF1038, a daf-16 null mutant strain. DAF-16 nuclear translocation was analyzed in TJ356, a strain expressing a functional DAF-16::GFP fusion protein. The mRNA levels of downstream targets of DAF-16 were measured by qPCR.

Results: EF significantly reduced A[Formula: see text]1–42- and polyQ-induced paralysis in CL4176 and AM140, indicating the anti-proteotoxic potency of EF. EF significantly extended the lifespan and promoted stress resistance and locomotion in N2, demonstrating a healthspan extension effect of EF. DAF-16 nuclear localization and its downstream targets, sod-3 and hsp-16.2 mRNA levels, were significantly elevated with EF. EF did not increase the lifespan of daf-16 null mutant CF1038, revealing a DAF-16-dependent mechanism of EF effect on lifespan.

Conclusion: We found that EF, a natural extract from a widely used medicinal herb Epimedium, protects against proteotoxicity and extends the healthspan via DAF-16 in C. elegans. Our work may provide molecular insights into the clinical benefits of EF and Epimedium.

Phenolic Compounds from Populus alba L. and Salix subserrata Willd. (Salicaceae) Counteract Oxidative Stress in Caenorhabditis elegans

Utilizing bioassay- and TLC-guided column chromatography, fifteen secondary metabolites from Populus alba and eight compounds from Salix subserrata were isolated, including a novel plant metabolite salicyl ether and characterized using ultralviolet light (UV) absorbance, mass spectrometry (MS), ¹H-, ¹³C-NMR (nuclear magnetic resonance), heteronuclear single quantum coherence spectroscopy (HSQC) and heteronuclear multiple bond correlation (HMBC). The extracts, their sub-fractions and the isolated compounds exhibited promising antioxidant activities in vitro in DPPH and FRAP assays. Also, the extracts of P. alba leaf (PL), shoots (PS), and S. subserrata leaf (SL) demonstrated substantial antioxidant activities in vivo in the multicellular model organism Caenorhabditis elegans. For the first time, the isolated secondary metabolites, aromadendrin, tremuloidin, salicin, isorhamnetin-3-O-β-d-rutinoside, gallocatechin, triandrin, and chrysoeriol-7-O-glucuronide were investigated. They exhibited substantial antioxidant activities in vivo. Salicin, isorhamnetin-3-O-β-d-rutinoside and gallocatechin, in particular, protected the worms against a lethal dose of the pro-oxidant juglone (80 µM), decreased the endogenous reactive oxygen species (ROS) level to 45.34%, 47.31%, 68.09% and reduced juglone- induced hsp-16.2::GFP (green fluorescence protein) expression to 79.62%, 70.17%, 26.77%, respectively. However, only gallocatechin induced higher levels of sod-3 expression. These findings support the traditional use of Populus alba and Salix subserrata for treating inflammation especially when ROS are involved.

Flavonoids Regulate Lipid Droplets Biogenesis in Drosophila melanogaster

Lipid droplets (LDs), cytosolic fat storage organelles, are emerging as major regulators of lipid metabolism, trafficking, and signaling in various cells and tissues. LDs are altered in cardiovascular and neuronal disorders, inflammation, obesity, and cancer. Flavonoids comprise different classes of molecules, characterized by a well-known antioxidant activity and a beneficial effect in several diseases. However, the cellular mechanism by which different classes of flavonoids improve health is poorly understood, in particular as far as LDs biogenesis is concerned. Here we used Drosophila melanogaster as a model system to investigate the effects of a selected group of flavonoids on larval tissues by examining LDs biogenesis. In our study, fruit flies were grown in xanthohumol-, isoquercetin-, and genistein-enriched food and larval tissues were analyzed using a LD marker. Total mRNA expression of two main enzymes (minotaur and midway) responsible for triacylglycerides synthesis was evaluated after treatments. Among the flavonoids analyzed, xanthohumol and isoquercetin resulted to be potent regulators of LDs biogenesis in a tissue-specific manner, inducing fat storage decrease in fat bodies and accumulation of LDs in nerves. Since LDs have been suggested to play a protective role against intracellular stress in nonadipocyte cells, our data support the hypothesis that some phytochemicals could act as strong modulators of LDs biogenesis in vivo. The knowledge of how different flavonoids act on lipid metabolism in different tissues can help to manage the use of phytochemicals with the aim of selectively ameliorating specific neuronal and metabolic diseases’ manifestations.

Bioavailability and Biological Effects of 2- O-β-d-Glucopyranosyl-carboxyatractyligenin from Green Coffee in Caenorhabditis elegans

Targeted analysis of Coffea arabica and Coffea canephora green coffees (total sample size n = 57) confirmed 2- O-β-d-glucopyranosyl-carboxyatractyligenin (6) as the quantitatively dominating carboxyatractyligenin derivative. Its abundance in Arabicas (2425 ± 549 nmol/g, n = 48) exceeded that in Robustas (34 ± 12 nmol/g, n = 9) roughly by a factor of 70. Coffee processing involving heat (e.g., steam treatment and decaffeination) reduced concentrations of 6 and increased those of the decarboxylated derivative. The bioavailability of compound 6 in Caenorhabditis elegans was demonstrated by ultraperformance liquid chromatography-tandem mass spectrometry analysis of extracts prepared from nematode cultures incubated in a liquid medium containing 6. A toxicity assay performed to assess the impact of 6 in vivo showed a 20-fold higher median lethal dose (LD₅₀ = 11.7 ± 1.2 mM) concentration compared to that of the known phytotoxic adenine-nucleotide transporters inhibitor carboxyatractyloside (2, LD₅₀ = 0.61 ± 0.05 mM), whereas 1 mM 6 and 0.1 mM 2 were sufficient to decrease the survival of wild type C. elegans, already 10-20-fold lower doses reduced reproduction. Because the insulin/insulin-like growth factors signaling cascade (IIS) is a key regulator of life span and stress resistance, the impact of compound 6 on the survival of long-living daf-2 C. elegans was tested. As the susceptibility of these nematodes to 6 was as high as that in wild type, an impact on central metabolic processes independent of IIS was suggested. Analysis of the in vivo adenosine triphosphate (ATP) content of adult C. elegans revealed no changes after 1 and 24 h, but a 50% reduction after treatment with 1 mM 6 during the entire postembryonic development. These data speak for a developmental-stage-dependent modulation of the ATP pool by 6.

Antioxidant Characterization and Biological Effects of Grape Pomace Extracts Supplementation in Caenorhabditis elegans

The aim of this work was to evaluate the biological activity of four grape pomace (GP) extracts that are rich in polyphenols using C. elegans as an in vivo model. Different concentrations of the GP extracts were assessed for their effects on the resistance of C. elegans against thermally induced oxidative stress, accumulation of reactive oxygen species (ROS), and lifespan. The cultivation of C. elegans with relatively low concentrations of GP extracts increased their resistance against thermal stress and prolonged their lifespan, while high levels displayed detrimental effects. In the studied extracts, maximum protection was observed for levels of polyphenols around 7 to 9 µg gallic acid equivalents per cultivation plate. The obtained results suggested that small changes in the ROS levels could have beneficial effects, although further studies are required to fully understand the impact of the extracts and assayed doses on ROS levels to explain the mechanism that is involved in the observed effects.

Epicatechin modulates stress-resistance in C. elegans via insulin/IGF-1 signaling pathway

The nematode Caenorhabditis elegans has been used to examine the influence of epicatechin (EC), an abundant flavonoid in the human diet, in some stress biomarkers (ROS production, lipid peroxidation and protein carbonylation). Furthermore, the ability of EC to modulate the expression of some key genes in the insulin/IGF-1 signaling pathway (IIS), involved in longevity and oxidative or heat shock stress response, has also been explored. The final aim was to contribute to the elucidation of the mechanisms involved in the biological effects of flavonoids. The results showed that EC-treated wild-type C. elegans exhibited increased survival and reduced oxidative damage of biomolecules when submitted to thermal stress. EC treatment led to a moderate elevation in ROS levels, which might activate endogenous mechanisms of defense protecting against oxidative insult. The enhanced stress resistance induced by EC was found to be mediated through the IIS pathway, since assays in daf-2, age-1, akt-1, akt-2, sgk-1, daf-16, skn-1 and hsf-1 loss of function mutant strains failed to show any heat-resistant phenotype against thermal stress when treated with EC. Consistently, EC treatment upregulated the expression of some stress resistance associated genes, such as gst-4, hsp-16.2 and hsp-70, which are downstream regulated by the IIS pathway.

Toxicity of phenolic compounds to entomopathogenic nematodes: A case study with Heterorhabditis bacteriophora exposed to lentisk (Pistacia lentiscus) extracts and their chemical components

Insects show adaptive plasticity by ingesting plant secondary compounds, such as phenolic compounds, that are noxious to parasites. This work examined whether exposure to phenolic compounds affects the development of insect parasitic nematodes. As a model system for parasitic life cycle, we used Heterorhabditis bacteriophora (Rhabditida; Heterorhabditiade) grown with Photorhabdita luminescens supplemented with different concentrations of plant phenolic extracts (0, 600, 1200, 2400 ppm): a crude ethanol extract of lentisk (Pistacia lentiscus) or lentisk extract fractionated along a scale of hydrophobicity with hexane, chloroform and ethyl acetate; and flavonoids (myricetin, catechin), flavanol-glycoside (rutin) or phenolic acids (chlorogenic and gallic acids). Resilience of the nematode to phenolic compounds was stage-dependent, with younger growth stages exhibiting less resilience than older growth stages (i.e., eggs < young juveniles < young hermaphrodites < infective juveniles < mature hermaphrodites). At high concentrations, all of the phenolic compounds studied were lethal to eggs and young juveniles. The nematodes were able to survive in the presence of medium and low concentrations of all studied compounds, but very few of those treatments allowed for reproduction beyond the infective juvenile stage and, at low concentrations, the crude 70% ethanol extract, chloroform and hexane extracts, and myricetin were associated with some impaired reproduction. The ethyl-acetate fraction and gallic acid were extremely lethal to the young stages and allowed almost no development beyond the infective juvenile stage. We conclude that exposure of infective juveniles to phenolics before they infect insects and post-infection exposure of other nematode developmental stages may affect the initiation of the infection, suggesting that the chemistry of dietary phenolics may limit H. bacteriophora's infection of insects.

Epigallocatechin-3-Gallate Reduces Fat Accumulation in Caenorhabditis elegans

Epigallocatechin gallate (EGCG) is a polyphenol that is abundant in green tea. It has been reported that consumption of EGCG can contribute to weight loss, however, the underlying mechanism is not fully understood. To determine how EGCG reduces body fat, an organism model Caenorhabditis elegans was used, which is a useful animal model system in exploring crucial biological mechanisms that are readily applicable to humans. In this study, different strains were raised for two days on Escherichia coli OP 50 diet with or without 100 μM and 200 μM EGCG treatment. The current results showed that 100 μM and 200 μM EGCG significantly reduced the triglyceride content of wild type worms by 10% and 20% (P-value<0.01 and <0.001, respectively) compared to the control, respectively, without affecting its food intake and physiological behaviors. Additionally, EGCG could effectively reduce fat accumulation in C. elegans dependent on atgl-1 (encoding a homolog of adipose triglyceride lipase), which suggests that EGCG controls the body fat by inhibiting adipogenesis.

Killed Bifidobacterium longum enhanced stress tolerance and prolonged life span of Caenorhabditis elegans via DAF-16

Probiotics are bacteria among the intestinal flora that are beneficial for human health. Bifidobacterium longum (BL) is a prototypical probiotic that is widely used in yogurt making, supplements and others. Although various physiological effects of BL have been reported, those associated with longevity and anti-ageing still remain elusive. Here we aimed to elucidate the physiological effects of killed BL (BR-108) on stress tolerance and longevity of Caenorhabditis elegans and their mechanisms. Worms fed killed BL in addition to Escherichia coli (OP50) displayed reduced body length in a BL dose-dependent manner. When compared with those fed E. coli alone, these worms had a higher survival rate following heat stress at 35°C and hydrogen peroxide-induced oxidative stress. A general decrease in motility was observed over time in all worms; however, killed BL-fed ageing worms displayed increased movement and longer life span than those fed E. coli alone. However, the longevity effect was suppressed in sir-2.1, daf-16 and skn-1-deficient worms. Killed BL induced DAF-16 nuclear localisation and increased the expression of the DAF-16 target gene hsp-12.6. These results revealed that the physiological effects of killed BL in C. elegans were mediated by DAF-16 activation. These findings contradict previous observations with different Bifidobacterium and Lactobacillus strains, which showed the role for SKN-1 independently of DAF-16.

Targeting Protein Quality Control Mechanisms by Natural Products to Promote Healthy Ageing

Organismal ageing is associated with increased chance of morbidity or mortality and it is driven by diverse molecular pathways that are affected by both environmental and genetic factors. The progression of ageing correlates with the gradual accumulation of stressors and damaged biomolecules due to the time-dependent decline of stress resistance and functional capacity, which eventually compromise cellular homeodynamics. As protein machines carry out the majority of cellular functions, proteome quality control is critical for cellular functionality and is carried out through the curating activity of the proteostasis network (PN). Key components of the PN are the two main degradation machineries, namely the ubiquitin-proteasome and autophagy-lysosome pathways along with several stress-responsive pathways, such as that of nuclear factor erythroid 2-related factor 2 (Nrf2), which mobilises cytoprotective genomic responses against oxidative and/or xenobiotic damage. Reportedly, genetic or dietary interventions that activate components of the PN delay ageing in evolutionarily diverse organisms. Natural products (extracts or pure compounds) represent an extraordinary inventory of highly diverse structural scaffolds that offer promising activities towards meeting the challenge of increasing healthspan and/or delaying ageing (e.g., spermidine, quercetin or sulforaphane). Herein, we review those natural compounds that have been found to activate proteostatic and/or anti-stress cellular responses and hence have the potential to delay cellular senescence and/or in vivo ageing.

Current Perspective in the Discovery of Anti-aging Agents from Natural Products

Aging is a process characterized by accumulating degenerative damages, resulting in the death of an organism ultimately. The main goal of aging research is to develop therapies that delay age-related diseases in human. Since signaling pathways in aging of Caenorhabditis elegans (C. elegans), fruit flies and mice are evolutionarily conserved, compounds extending lifespan of them by intervening pathways of aging may be useful in treating age-related diseases in human. Natural products have special resource advantage and with few side effect. Recently, many compounds or extracts from natural products slowing aging and extending lifespan have been reported. Here we summarized these compounds or extracts and their mechanisms in increasing longevity of C. elegans or other species, and the prospect in developing anti-aging medicine from natural products.

Phytochemistry and Pharmacology of Phyllanthus niruri L.: A Review

Phyllanthus niruri, a typical member of family Euphorbiaceae, is a small annual herb found throughout the tropical and subtropical regions of both hemispheres. The genus Phyllanthus has been used in traditional medicine for its wide range of pharmacological activities like antimicrobial, antioxidant, anticancer, antiinflammatory, antiplasmodial, antiviral, diuretic and hepatoprotective. This review summarizes the information about morphological, biochemical, ethanobotanical, pharmacological, biological and toxicological activities with special emphasis on mechanism of anticancer activity of P. niruri. Gaps in previous studies such as taxonomic inconsistency of P. niruri, novel phytochemicals and their therapeutic properties, especially mechanisms of anticancerous activity and market products available, have been looked into and addressed. Scientific information related to 83 phytochemicals (including many novel compounds detected recently by the authors) has been provided in a very comprehensive manner. Copyright © 2017 John Wiley & Sons, Ltd.

Geroprotectors: A Unified Concept and Screening Approaches

Although the geroprotectors discovery is a new biomedicine trend and more than 200 compounds can slow aging and increase the lifespan of the model organism, there are still no geroprotectors on the market. The reasons may be partly related to the lack of a unified concept of geroprotector, accepted by the scientific community. Such concept as a system of criteria for geroprotector identification and classification can form a basis for an analytical model of anti-aging drugs, help to consolidate the efforts of various research initiatives in this area and compare their results. Here, we review the existing classification and characteristics of geroprotectors based on their effect on the survival of a group of individuals or pharmaceutics classes, according to the proposed mechanism of their geroprotective action or theories of aging. After discussing advantages and disadvantages of these approaches, we offer a new concept based on the maintenance of homeostatic capacity because aging can be considered as exponential shrinkage of homeostatic capacity leading to the onset of age-related diseases and death. Besides, we review the most promising current screening approaches to finding new geroprotectors. Establishing the classification of existing geroprotectors based on physiology and current understanding of the nature of aging is essential for putting the existing knowledge into a single system. This system could be useful to formulate standards for finding and creating new geroprotectors. Standardization, in turn, would allow easier comparison and combination of experimental data obtained by different research groups.

Flavonoids: an overview

Flavonoids, a group of natural substances with variable phenolic structures, are found in fruits, vegetables, grains, bark, roots, stems, flowers, tea and wine. These natural products are well known for their beneficial effects on health and efforts are being made to isolate the ingredients so called flavonoids. Flavonoids are now considered as an indispensable component in a variety of nutraceutical, pharmaceutical, medicinal and cosmetic applications. This is attributed to their anti-oxidative, anti-inflammatory, anti-mutagenic and anti-carcinogenic properties coupled with their capacity to modulate key cellular enzyme function. Research on flavonoids received an added impulse with the discovery of the low cardiovascular mortality rate and also prevention of CHD. Information on the working mechanisms of flavonoids is still not understood properly. However, it has widely been known for centuries that derivatives of plant origin possess a broad spectrum of biological activity. Current trends of research and development activities on flavonoids relate to isolation, identification, characterisation and functions of flavonoids and finally their applications on health benefits. Molecular docking and knowledge of bioinformatics are also being used to predict potential applications and manufacturing by industry. In the present review, attempts have been made to discuss the current trends of research and development on flavonoids, working mechanisms of flavonoids, flavonoid functions and applications, prediction of flavonoids as potential drugs in preventing chronic diseases and future research directions.

Anti-aging pharmacology: Promises and pitfalls

Life expectancy has grown dramatically in modern times. This increase, however, is not accompanied by the same increase in healthspan. Efforts to extend healthspan through pharmacological agents targeting aging-related pathological changes are now in the spotlight of geroscience, the main idea of which is that delaying of aging is far more effective than preventing the particular chronic disorders. Currently, anti-aging pharmacology is a rapidly developing discipline. It is a preventive field of health care, as opposed to conventional medicine which focuses on treating symptoms rather than root causes of illness. A number of pharmacological agents targeting basic aging pathways (i.e., calorie restriction mimetics, autophagy inducers, senolytics etc.) are now under investigation. This review summarizes the literature related to advances, perspectives and challenges in the field of anti-aging pharmacology.

A literature review of flavonoids and lifespan in model organisms

Epidemiological data on consumption of flavonoid-containing food points to the notion that some of these secondary plant metabolites may favour healthy ageing. The aim of the present paper was to review the literature on lifespan extension by flavonoids in worms, flies and mice. In most studies, worms and flies experienced lifespan extension when supplemented with flavonoids either as extracts or single compounds. Studies with mutant worms and flies give hints as to which gene products may be regulated by flavonoids and consequently enhance longevity. We discuss the data considering putative mechanisms that may underlie flavonoid action such as energy-restriction-like effects, inhibition of insulin-like-growth-factor signalling, induction of antioxidant defence mechanisms, hormesis as well as antimicrobial properties. However, it remains uncertain whether human lifespan could be prolonged by increased flavonoid intake.

Healthspan Pharmacology

The main goal of this paper is to present the case for shifting the focus of research on aging and anti-aging from lifespan pharmacology to what I like to call healthspan pharmacology, in which the desired outcome is the extension of healthy years of life rather than lifespan alone. Lifespan could be influenced by both genetic and epigenetic factors, but a long lifespan may not be a good indicator of an optimal healthspan. Without improving healthspan, prolonging longevity would have enormous negative socioeconomic outcomes for humans. Therefore, the goal of aging and anti-aging research should be to add healthy years to life and not merely to increase the chronological age. This article summarizes and compares two categories of pharmacologically induced lifespan extension studies in animal model systems from the last two decades-those reporting the effects of pharmacological interventions on lifespan extension alone versus others that include their effects on both lifespan and healthspan in the analysis. The conclusion is that the extrapolation of pharmacological results from animal studies to humans is likely to be more relevant when both lifespan and healthspan extension properties of pharmacological intervention are taken into account.

Oleanolic acid activates daf-16 to increase lifespan in Caenorhabditis elegans

Oleanolic acid (OA) is an active ingredient in natural plants. It has been reported to possess a variety of pharmacological activities, but very little is known about its effects of anti-aging. We investigate here whether OA has an impact on longevity in vivo, and more specifically, we have examined effects of OA on the lifespan and stress tolerance in Caenorhabditis elegans (C. elegans). Our results showed that OA could extend the lifespan, increase its stress resistance and reduce the intracellular reactive oxygen species (ROS) in wild-type worms. Moreover, we have found that OA-induced longevity may not be associated with the calorie restriction (CR) mechanism. Our mechanistic studies using daf-16 loss-of-function mutant strains (GR1307) indicated that the extension of lifespan by OA requires daf-16. In addition, OA treatment could also modulate the nuclear localization, and the quantitative real-time PCR results revealed that up-regulation of daf-16 target genes such as sod-3, hsp-16.2 and ctl-1 could prolong lifespan and increase stress response in C. elegans. This study overall uncovers the longevity effect of OA and its underpinning mechanisms.

Acacetin 7-O-α-l-rhamnopyranosyl (1-2) β-D-xylopyranoside Elicits Life-span Extension and Stress Resistance in Caenorhabditis elegans

The advancements in the field of gerontology have unraveled the signaling pathways that regulate life span, suggesting that it might be feasible to modulate aging. To this end, we isolated a novel phytomolecule Acacetin 7-O-α-l-rhamnopyranosyl (1-2) β-D-xylopyranoside (ARX) from Premna integrifolia and evaluated its antiaging effects in Caenorhabditis elegans The spectral data analysis revealed the occurrence of a new compound ARX. Out of the three tested pharmacological doses of ARX, viz. 5, 25, and 50 µM, the 25-µM dose was able to extend life span in C. elegans by more than 39%. The present study suggests that ARX affects bacterial metabolism, which in turn leads to dietary restriction (DR)-like effects in the worms. The effect of ARX on worms with mutations (mev-1, eat-2, sir-2.1, skn-1, daf-16, and hsf-1) indicates that ARX-mediated life-span extension involves mechanisms associated with DR and maintenance of cellular redox homeostasis. This study is the first time report on longevity-promoting activity of ARX in C. elegans mediated by stress and DR-regulating genes. This novel phytomolecule can contribute in designing therapeutics for managing aging and age-related diseases.