Ameliorative effect of aspalathin from rooibos (Aspalathus linearis) on acute oxidative stress in Caenorhabditis elegans

Unveiling the impact of aging on BBB and Alzheimer's disease: Factors and therapeutic implications

Alzheimer's disease (AD) is a highly prevalent neurodegenerative condition that has devastating effects on individuals, often resulting in dementia. AD is primarily defined by the presence of extracellular plaques containing insoluble β-amyloid peptide (Aβ) and neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein (P-tau). In addition, individuals afflicted by these age-related illnesses experience a diminished state of health, which places significant financial strain on their loved ones. Several risk factors play a significant role in the development of AD. These factors include genetics, diet, smoking, certain diseases (such as cerebrovascular diseases, obesity, hypertension, and dyslipidemia), age, and alcohol consumption. Age-related factors are key contributors to the development of vascular-based neurodegenerative diseases such as AD. In general, the process of aging can lead to changes in the immune system's responses and can also initiate inflammation in the brain. The chronic inflammation and the inflammatory mediators found in the brain play a crucial role in the dysfunction of the blood-brain barrier (BBB). Furthermore, maintaining BBB integrity is of utmost importance in preventing a wide range of neurological disorders. Therefore, in this review, we discussed the role of age and its related factors in the breakdown of the blood-brain barrier and the development of AD. We also discussed the importance of different compounds, such as those with anti-aging properties, and other compounds that can help maintain the integrity of the blood-brain barrier in the prevention of AD. This review builds a strong correlation between age-related factors, degradation of the BBB, and its impact on AD.

Translation of preclinical ethnomedicine data in LMICs: the example of rooibos

All disease, but especially non-communicable diseases, are related to dysfunction of one or more regulatory systems. In developing countries, long-term management of patients with chronic diseases has many challenges and is generally not financially viable, but Africa in particular, which is rich in diverse ethnomedicines presents a more feasible long-term therapeutic approach in this niche. However, despite comprehensive preclinical investigations on numerous plant-derived candidate medicines, only a small portion of these reach the patient as recognised medicines. In this review, we use the example of rooibos (Aspalathus linearis (Burm.f.) R. Dahlgren)-which is globally consumed as aromatic, caffeine-free tea-to illustrate the hurdles that need to be overcome in the low-to middle-income countries, before progression of ethnomedicines to official treatment regimens can be achieved. In terms of methodology, regulatory system focused rooibos papers indexed on PubMed for the past three decades (n = 112) were accessed. Papers reporting duplication of previous results were excluded, as well as review papers. Topics covered includes the high standard of ethnomedicine drug discovery and efficacy testing research performed in Africa (and South Africa in particular in the case of rooibos), the potential bias in terms of preclinical research focus, ethnomedicine ownership and the requirement for independent clinical trial coordination and/or management.

Pharmacological activity of Aspalathus linearis extracts: pre-clinical research in view of prospective neuroprotection

OBJECTIVES

Rooibos tea, a very popular everyday beverage made of Aspalathus linearis plant material and containing multiple polyphenolic compounds, reveals an expectation to positively affect various processes observed in the pathogenesis of neurodegenerative diseases as in the case of consumption of other polyphenol-abundant food products.

METHODS

This review is based on available data from pre-clinical in vitro and in vivo studies and presents a broad report on the pharmacological activity of the A. linearis extracts relevant for neurodegenerative diseases.

RESULTS

Flavonoids present in herbal infusions are absorbed from gastro-intestinal tract and may affect the central nervous system. The experimental investigations yield the results indicating to supporting role of A. linearis in the prevention of neurodegeneration, primarily owing to anti-oxidative and anti-inflammatory properties, anti-hyperglycaemic and anti-hyperlipidaemic effects as well as favourable impact on neurotransmission with following cognitive and behavioural after-math.

DISCUSSION

The multiple pharmacological activities and safety of Aspalathus linearis extracts are commented in the manuscript. The continuous rooibos tea consumption seems to be safe (despite anecdotal liver irritation); however, there is a risk of herbal-drug interactions.

Rooibos tea-in the cross fire of ROS, mitochondrial dysfunction and loss of proteostasis-positioned for healthy aging

Impaired mitochondrial function and loss of cellular proteostasis control are key hallmarks of aging and are implicated in the development of neurodegenerative diseases. A common denominator is the cell's inability to handle reactive oxygen species (ROS), leading to major downstream oxidative damage that exacerbates neuronal dysfunction. Although we have progressed in understanding the molecular defects associated with neuronal aging, many unanswered questions remain. How much ROS is required to serve cellular function before it becomes detrimental and how does the cell's oxidative status impact mitochondrial function and protein degradation through autophagy? How does ROS regulate autophagy? Aspalathus linearis, also commonly known as rooibos, is an endemic South African plant that is gaining globally acclaim for its antioxidant properties and its role as functional medicinal beverage. In this article we dissect the role of rooibos in the context of the cell's ROS handling capacity, mitochondrial function and autophagy activity. By addressing the dynamic relationship between these critical interconnected systems, and by evaluating the functional properties of rooibos, we unravel its position for preserving cell viability and promoting healthy aging.

Effects of Vegetal Extracts and Metabolites against Oxidative Stress and Associated Diseases: Studies in Caenorhabditis elegans

Oxidative stress is a natural physiological process where the levels of oxidants, such as reactive oxygen species (ROS) and nitrogen (RNS), exceed the strategy of antioxidant defenses, culminating in the interruption of redox signaling and control. Oxidative stress is associated with multiple pathologies, including premature aging, neurodegenerative diseases, obesity, diabetes, atherosclerosis, and arthritis. It is not yet clear whether oxidative stress is the cause or consequence of these diseases; however, it has been shown that using compounds with antioxidant properties, particularly compounds of natural origin, could prevent or slow down the progress of different pathologies. Within this context, the Caenorhabditis elegans (C. elegans) model has served to study the effect of different metabolites and natural compounds, which has helped to decipher molecular targets and the effect of these compounds on premature aging and some diseases such as neurodegenerative diseases and dyslipidemia. This article lists the studies carried out on C. elegans in which metabolites and natural extracts have been tested against oxidative stress and the pathologies associated with providing an overview of the discoveries in the redox area made with this nematode.

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

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

Polygonati Rhizoma Polysaccharide Prolongs Lifespan and Healthspan in Caenorhabditis elegans

Polygonati Rhizoma is the dried rhizome of Polygonatum kingianum coll.et hemsl., Polygonatum sibiricum Red. or Polygonatum cyrtonema Hua, and has a long history of medication. Raw Polygonati Rhizoma (RPR) numbs the tongue and stings the throat, while prepared Polygonati Rhizoma (PPR) can remove the numbness of the tongue, and at the same time enhance its functions of invigorating the spleen, moistening the lungs and tonifying the kidneys. There are many active ingredients in Polygonati Rhizoma (PR), among which polysaccharide is one of the most important active ingredients. Therefore, we studied the effect of Polygonati Rhizoma polysaccharide (PRP) on the lifespan of Caenorhabditis elegans (C. elegans) and found that polysaccharide in PPR (PPRP) was more effective than Polysaccharide in RPR (RPRP) in prolonging the lifespan of C. elegans, reducing the accumulation of lipofuscin, and increasing the frequency of pharyngeal pumping and movement. The further mechanism study found that PRP can improve the anti-oxidative stress ability of C. elegans, reduce the accumulation of reactive oxygen species (ROS) in C. elegans, and improve the activity of antioxidant enzymes. The results of quantitative real-time PCR(q-PCR) experiments suggested that PRP may prolong the lifespan of C. elegans by down-regulating daf-2 and activating daf-16 and sod-3, and the transgenic nematode experiments were consistent with its results, so it was hypothesized that the mechanism of age delaying effect of PRP was related to daf-2, daf-16 and sod-3 of the insulin signaling pathway. In short, our research results provide a new idea for the application and development of PRP.

Aspalathin and Other Rooibos Flavonoids Trapped α-Dicarbonyls and Inhibited Formation of Advanced Glycation End Products In Vitro

The excessive dietary intake of simple sugars and abnormal metabolism in certain diseases contribute to the increased production of α-dicarbonyls (α-DCs), such as methylglyoxal (MGO) and glyoxal (GO), the main precursors of the formation of advanced glycation end products (AGEs). AGEs play a vital role, for example, in the development of cardiovascular diseases and diabetes. Aspalathus linearis (Burman f.) R. Dahlgren (known as rooibos tea) exhibits a wide range of activities beneficial for cardio-metabolic health. Thus, the present study aims to investigate unfermented and fermented rooibos extracts and their constituents for the ability to trap MGO and GO. The individual compounds identified in extracts were tested for the capability to inhibit AGEs (with MGO or GO as a glycation agent). Ultra-high-performance liquid chromatography coupled with an electrospray ionization mass spectrometer (UHPLC-ESI-MS) was used to investigate α-DCs' trapping capacities. To evaluate the antiglycation activity, fluorescence measurement was used. The extract from the unfermented rooibos showed a higher ability to capture MGO/GO and inhibit AGE formation than did the extract from fermented rooibos, and this effect was attributed to a higher content of dihydrochalcones. The compounds detected in the extracts, such as aspalathin, nothofagin, vitexin, isovitexin, and eriodictyol, as well as structurally related phloretin and phloroglucinol (formed by the biotransformation of certain flavonoids), trapped MGO, and some also trapped GO. AGE formation was inhibited the most by isovitexin. However, it was the high content of aspalathin and its higher efficiency than that of metformin that determined the antiglycation and trapping properties of green rooibos. Therefore, A. linearis, in addition to other health benefits, could potentially be used as an α-DC trapping agent and AGE inhibitor.

Cyanidin-3-O-glucoside promotes stress tolerance and lifespan extension of Caenorhabditis elegans exposed to polystyrene via DAF-16 pathway

Microplastic pollution has attracted growing attention due to its prevalent and persistent exposure to general population through the food chain, but few reports have focused on the toxicological prevention of polystyrene (PS). Using the wild-type and mutant strains, this study explored the impacts of PS and cyanidin-3-O-glucoside (C3G) on stress tolerance and lifespan of Caenorhabditis elegans (C. elegans). In N2 nematodes, PS exposure initiated the oxidative stress and subsequent lifespan reduction, while these adverse impacts could be positively improved by C3G treatment. Considering the pivotal role of DAF-16 pathway in stress tolerance and lifespan regulation, the expression of the daf-16 gene and its downstream antioxidant genes (clt-2, hsp-16.1, sod-3, sod-5) were examined, and found to be significantly enhanced by C3G. Since the sod-3 gene was up-regulated the most fold by C3G, the activity of SOD enzyme that encoded by the sod-3 was examined, and could be obviously enhanced upon C3G treatment. This explained the improved oxidative stress and delayed oxidation-associated aging after C3G intervention. Nevertheless, these positive effects of C3G were weakened in daf-16(-) mutant strain (with deleted DAF-16 gene), for which the beneficial effects of C3G in promoting stress resistance and lifespan extension were inhibited. These findings suggested that the DAF-16 gene and its downstream antioxidant genes, have participated in C3G's regulations on redox balance and lifespan that impacted by nano-polystyrene particles. This study highlighted the link between dietary components and environmentally driven disturbance.

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

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

Hibiscus, Rooibos, and Yerba Mate for Healthy Aging: A Review on the Attenuation of In Vitro and In Vivo Markers Related to Oxidative Stress, Glycoxidation, and Neurodegeneration

The world is currently undergoing a demographic change towards an increasing number of elderly citizens. Aging is characterized by a temporal decline in physiological capacity, and oxidative stress is a hallmark of aging and age-related disorders. Such an oxidative state is linked to a decrease in the effective mechanisms of cellular repair, the incidence of post-translational protein glycation, mitochondrial dysfunction, and neurodegeneration, just to name some of the markers contributing to the establishment of age-related reduction-oxidation, or redox, imbalance. Currently, there are no prescribed therapies to control oxidative stress; however, there are strategies to elevate antioxidant defenses and overcome related health challenges based on the adoption of nutritional therapies. It is well known that herbal teas such, as hibiscus, rooibos, and yerba mate, are important sources of antioxidants, able to prevent some oxidation-related stresses. These plants produce several bioactive metabolites, have a pleasant taste, and a long-lasting history as safe foods. This paper reviews the literature on hibiscus, rooibos, and yerba mate teas in the context of nutritional strategies for the attenuation of oxidative stress-related glycoxidation and neurodegeneration, and, here, Alzheimer’s Disease is approached as an example. The focus is given to mechanisms of glycation inhibition, as well as neuroprotective in vitro effects, and, in animal studies, to frame interest in these plants as nutraceutical agents related to current health concerns.

Vitexin and Isovitexin Act Through Inhibition of Insulin Receptor to Promote Longevity and Fitness in Caenorhabditis elegans

SCOPE

Vitexin and isovitexin are natural plant nutraceuticals for human health and longevity. This research investigated the underlying mechanism of vitexin and isovitexin on aging and health. The vital role of DAF-2/IGFR was illustrated in the insulin/insulin-like growth signaling pathway (IIS) modulated by vitexin and isovitexin.

METHODS AND RESULTS

In vitro, in vivo models and molecular docking methods were performed to explore the antiaging mechanism of vitexin and isovitexin. Vitexin and isovitexin (50 and 100 μM) extended the lifespan of C. elegans. The declines of pharyngeal pumping and body bending rates, and the increase of intestinal lipofuscin accumulation, three markers of aging, were postponed by vitexin and isovitexin. These compounds inhibited the IIS pathway in a daf-16-dependent manner, subsequently increasing the expression of DAF-16 downstream proteins and genes in nematodes. Molecular docking studies demonstrated that these compounds might inhibit insulin signal transduction by binding to the crucial amino acid residue ARG1003 in the pocket of the insulin-like growth factor-1 receptor (IGFR). Western blot indicated that IGFR, PI3K and AKT kinase expressions in senescent cells is decreased after vitexin and isovitexin treatment.

CONCLUSION

Vitexin and isovitexin might inhibit IIS pathway by occupying the ATP-binding site pocket of IGFR, subsequently decreasing IGFR expression, thereby promoting longevity and fitness. This article is protected by copyright. All rights reserved.

Metabolomics-Based Profiling of Clerodendrum speciosum (Lamiaceae) Leaves Using LC/ESI/MS-MS and In Vivo Evaluation of Its Antioxidant Activity Using Caenorhabditis elegans Model

We investigated the antioxidant activity of the total methanol extract of C. speciosum leaves (CST), the ethyl acetate (CSE), and the remaining aqueous (CSR) fractions in vitro, in vivo using Caenorhabditis elegans model, and in silico. LC-ESI-MS/MS analysis was employed for metabolic profiling of CST. ADME/TOPAKT prediction was performed to determine the potential pharmacokinetic, pharmacodynamic, and toxicity properties of the major identified phytoconstituents. All examined samples showed considerable antioxidant activity where CST, CSE, and CSR displayed EC₅₀ values of 27.1, 16.2, and 21.3 µg/mL, respectively, in 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) assay, whereas they showed 11.44, 16.27, and 12.16 Fe²⁺ equivalents/mg of sample, respectively, in ferric reducing antioxidant power (FRAP) assay. CST, CSE, and CSR displayed total phenolic content of 262, 326, and 289 mg GAE/g sample, respectively. In vivo antioxidant study revealed that CST at 150 μg/mL increased the survival rate of C. elegans by 71.88% compared to untreated group. Regarding intracellular reactive oxygen species (ROS), worms treated with 150 μg/mL of CSE exhibited 60.42% reduction of ROS compared to the untreated group. Quantitation of hsp-16.2/GFP expression in Caenorhabditis elegans showed that worms treated with 150 μg/mL of CSR exerted 40.43% reduction in fluorescence with respect to the untreated group. LC-ESI-MS/MS of CST revealed the presence of sixteen secondary metabolites belonging mainly to polyphenolics with phenyl propanoids constituting the major detected class. The in silico study showed that rosmarinic acid displayed the best fitting within the active sites of Daf-2 protein with considerable safety profile and limited pharmacokinetic and pharmacodynamic that could be slightly enhanced by certain treatment.

Ginkgo seed extract promotes longevity and stress resistance of Caenorhabditis elegans

Ginkgo seeds are a traditional food in China valued for their nutritional and health benefits. However, little is known about the anti-aging and health-promoting effects of ginkgo seed products. Here, we showed that ginkgo seed powder extract (GSP-E) is abundant in alkaloids and flavonoids, and can extend the lifespan of Caenorhabditis elegans. GSP-E improved most physiological indicators related to aging of C. elegans, including locomotor activity, reproductive capacity, and resistance to oxidation and heat. Moreover, GSP-E reduced the accumulation of lipofuscin and reactive oxygen species (ROS) in C. elegans. Further studies demonstrated that GSP-E improved longevity and stress resistance by mediating lipid metabolism and autophagy, as well as by regulating gene expression (e.g., FASN-1, POD-2, GPX-7, FAT-5). GSP-E has an anti-amyloid effect and delayed amyloid-induced paralysis of C. elegans. These findings could support the utilization of ginkgo seed as a potential dietary supplement for the health food industry, and provide a novel health-promoting resource against aging and aging-related diseases.

Flavonoids from the mung bean coat promote longevity and fitness in Caenorhabditis elegans

Mung beans possess health benefits related to their bioactive ingredients, mainly flavonoids, which are highly concentrated in the coat. However, the anti-aging effects of mung beans are rarely reported. In this work, we found that mung bean coat extract (MBCE), rich in vitexin and isovitexin, extended the lifespan and promoted the health of Caenorhabditis elegans (C. elegans) without any disadvantages. Moreover, MBCE enhanced the resistance to heat and oxidation of C. elegans by reducing the accumulation of intracellular reactive oxygen species and up-regulating the expression of stress-resistant genes or proteins. Further studies demonstrated that MBCE improved longevity, stress-resistance and fitness by mediating the mitochondrial function, mimicking calorie restriction, and altering histone modification. These findings provide direct evidence for the anti-aging effects of mung beans and new insights into the innovations and applications of mung beans for the healthcare industry.

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

The nematode Caernohabditis 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.

Isoorientin: A dietary flavone with the potential to ameliorate diverse metabolic complications

Isoorientin is a natural C-glucosyl flavone that is generating a lot of interest due to its multiple pharmacological activities. Increasing experimental data have shown that the robust antioxidant and anti-inflammatory properties of isoorientin remain important in ameliorating a number of metabolic complications. In fact, plants rich in isoorientin have demonstrated strong ameliorative properties against complications such as hyperglycemia, hyperlipidemia, and insulin resistance. However, while such evidence is accumulating, it has not been reviewed to better inform on the therapeutic potential of this flavone in improving human health. This review examines and extrapolates available literature on the potential beneficial or detrimental effects associated with the use of isoorientin in mitigating metabolic diseases, with a specific focus on diabetes, obesity, and insulin resistance, including associated complications. The discussion includes effective doses in various experimental settings and proposed molecular mechanisms by which isoorientin may exert its therapeutic effects. In addition, the protective effects of extracts of a number of isoorientin-rich plants against metabolic complications will be highlighted.

Analyzing the Synergistic Effects of Antioxidants in Combating Photoaging Using Model Nematode, Caenorhabditis elegans

Aging, a universal and unique process, occurs both intrinsically (chronological) and extrinsically (photoaging). Ultraviolet-A (UV-A)-mediated stress is a growing health hazard to mankind as it is the major cause of photoaging, which could lead to much damage of skin cells and tissues ranging from tan, burn, or even cancer. The present study focuses on the role of antioxidants and other natural compounds which have been widely used in oral/topical applications to combat and delay the effects of photoaging using model nematode Caenorhabditis elegans. Compounds like green tea extract, naringenin, and naringin, which are known for their antioxidant properties, were able to extend life span and healthspan of the nematode in normal as well as under UV-A-mediated stress conditions. Regulation of both the stress-responsive genes (skn-1 and sir-2.1) and the aging-regulating genes (daf-2 and age-1) was attributable for these conditions. Interestingly, it was observed that these compounds when combined in equal ratios by weight worked synergistically to combat the aging process. Pronounced synergistic effects were observed during UV-A-mediated stress conditions, suggesting that these could be used as potential antiphotoaging compounds which will be of greater significance for health-based research.

In Vivo Pharmacological and Anti-inflammatory Evaluation of Xerophyte Plantago sempervirens Crantz

Known for centuries throughout the world, Plantago species have long been used as traditional herbal remedies for many diseases related to inflammatory conditions of the skin, respiratory and digestive tract, or even malignancy. This study is aimed first at investigating the in vitro antioxidant and regenerative effects of Plantago sempervirens Crantz hydroalcoholic extract followed by an in vivo experiment using a turpentine oil-induced inflammation model. The in vitro evaluation for antioxidant activity was performed using classical assays such as DPPH and TEAC scavenging assays but also EPR, and the total phenolic content was determined using the Folin-Ciocalteu reagent. The wound healing assay was performed on human cells (Human EA.hy926). Besides, the prooxidant activity was determined using a method which involves in situ free radical generation by laccase and the oxidation of haemoglobin. On turpentine oil-induced inflammation in rats, the in vivo effects of three doses of P. sempervirens extracts (100%, 50%, and 25%) were assessed by measuring oxidative stress (MDA, TOS, OSI, NO, CAT, and SOD) and inflammatory (CRP, WBC, and NEU) parameters. Having a rich polyphenolic content, the xerophyte P. sempervirens exhibited a strong in vitro antioxidant activity by scavenging radicals, enhancing cell regeneration, and reducing oxidative stress markers. Diluted P. sempervirens extract (25%) exhibited the best antioxidant, wound healing, and anti-inflammatory activity.

A proanthocyanidin-rich extract from Cassia abbreviata exhibits antioxidant and hepatoprotective activities in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Cassia abbreviata is a small to medium sized branched umbrella-shaped deciduous tree. It is widely spread in the tropics, especially in Africa, having a long history in traditional medicine for the treatment of numerous conditions such as headaches, diarrhea, constipation, some skin diseases, malaria, syphilis, pneumonia, stomach troubles, uterine pains, and against gonorrhea.

AIM OF THE STUDY

We investigated the phytochemical constituents of a root extract from Cassia abbreviata using HPLC-PDA-ESI-MS/MS. We also determined the antioxidant activities in vitro and in vivo using the nematode Caenorhabditis elegans as a model organism. The hepatoprotective activities in case of D-galactosamine (D-GaIN)-induced hepatotoxicity were studied in a rat model.

MATERIALS AND METHODS

HPLC-PDA-ESI-MS/MS analysis allowed the identification of the secondary metabolites of the methanol extract. DPPH and FRAP assays were used to determine the antioxidant activities in vitro. Using the C. elegans model, survival rates under juglone induced oxidative stress, intracellular ROS content, quantification of Phsp-16.2: GFP expression and subcellular DAF-16: GFP localization were investigated to determine the antioxidant activities in vivo. The in vivo hepatoprotective potential of the root extract was evaluated for D-galactosamine (D-GaIN)-induced hepatotoxicity in rats. The activity of the liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT), in addition to liver peroxidation product malondialdehyde (MDA) and glutathione content (GSH), as well as albumin and total bilirubin concentration, were determined. A histopathological study was also performed.

RESULTS AND CONCLUSIONS

C. abbreviata root extract is rich in polyphenolics, particularly proanthocyanidins. HPLC-PDA-ESI-MS/MS analysis resulted in the identification of 57 compounds on the bases of their mass spectra. (epi)-Catechin, (epi)-afzelechin, (epi)-guibourtinidol, and (ent)-cassiaflavan monomers as well as their dimers, trimers, and their diastereomers are the main components of the extract. The total phenolic content amounted for 474mg/g root extract expressed as gallic acid equivalent using the Folin-Ciocalteu method. The extract exhibited powerful antioxidant activity with EC₅₀ of 6.3μg/mL in DPPH and 19.15mM FeSO₄ equivalent/mg sample in FRAP assay. In C. elegans model, the extract (200μg/mL) was able to increase the survival rate by 44.56% and reduced the ROS level to 61.73%, compared to control group. Pretreatment of rats with 100mg extract/kg (b. wt.) reduced MDA by 47.36% and elevated GSH by 59.1%. The extract caused a significant reduction of ALT, AST and GGT activities by 11%, 35.7% and 65%, respectively. The findings of this study suggest that the proanthocyanidin-rich extract from C. abbreviata may be an interesting candidate for hepatoprotective activity in case of hepatocellular injury.

Calycophyllum spruceanum (Benth.), the Amazonian "Tree of Youth" Prolongs Longevity and Enhances Stress Resistance in Caenorhabditis elegans

The tree popularly known in Brazil as mulateiro or pau-mulato (Calycophyllum spruceanum (Benth.) K. Schum.) is deeply embedded in the herbal medicine of the Amazon region. Different preparations of the bark are claimed to have anti-aging, antioxidant, antimicrobial, emollient, wound healing, hemostatic, contraceptive, stimulant, and anti-diabetic properties. The current study aims to provide the first step towards a science-based evidence of the beneficial effects of C. spruceanum in the promotion of longevity and in the modulation of age-related markers. For this investigation, we used the model system Caenorhabditis elegans to evaluate in vivo antioxidant and anti-aging activity of a water extract from C. spruceanum. To chemically characterize the extract, HPLC MS (High Performance Liquid Chromatography Mass Spectrometry)/MS analyses were performed. Five secondary metabolites were identified in the extract, namely gardenoside, 5-hydroxymorin, cyanidin, taxifolin, and 5-hydroxy-6-methoxycoumarin-7-glucoside. C. spruceanum extract was able to enhance stress resistance and to extend lifespan along with attenuation of aging-associated markers in C. elegans. The demonstrated bioactivities apparently depend on the DAF-16/FOXO pathway. The data might support the popular claims of mulateiro as the “tree of youth”, however more studies are needed to clarify its putative benefits to human health.

Senna singueana: Antioxidant, Hepatoprotective, Antiapoptotic Properties and Phytochemical Profiling of a Methanol Bark Extract

Natural products are considered as an important source for the discovery of new drugs to treat aging-related degenerative diseases and liver injury. The present study profiled the chemical constituents of a methanol extract from Senna singueana bark using HPLC-PDA-ESI-MS/MS and 36 secondary metabolites were identified. Proanthocyanidins dominated the extract. Monomers, dimers, trimers of (epi)catechin, (epi)gallocatechin, (epi)guibourtinidol, (ent)cassiaflavan, and (epi)afzelechin represented the major constituents. The extract demonstrated notable antioxidant activities in vitro: In DPPH (EC50 of 20.8 µg/mL), FRAP (18.16 mM FeSO₄/mg extract) assays, and total phenolic content amounted 474 mg gallic acid equivalent (GAE)/g extract determined with the Folin-Ciocalteu method. Also, in an in vivo model, the extract increased the survival rate of Caenorhabditis elegans worms pretreated with the pro-oxidant juglone from 43 to 64%, decreased intracellular ROS inside the wild-type nematodes by 47.90%, and induced nuclear translocation of the transcription factor DAF-16 in the transgenic strain TJ356. Additionally, the extract showed a remarkable hepatoprotective activity against d-galactosamine (d-GalN) induced hepatic injury in rats. It significantly reduced elevated AST (aspartate aminotransferase), and total bilirubin. Moreover, the extract induced a strong cytoplasmic Bcl-2 expression indicating suppression of apoptosis. In conclusion, the bark extract of S. sengueana represents an interesting candidate for further research in antioxidants and liver protection.

Anti-Aging and Antioxidant Potential of Paullinia cupana var. sorbilis: Findings in Caenorhabditis elegans Indicate a New Utilization for Roasted Seeds of Guarana

Background: Roasted seeds of Amazonian guarana (Paullinia cupana var. sorbilis; Sapindaceae) are popular in South America due to their stimulant activity on the central nervous system (CNS). Rich in purine alkaloids, markedly caffeine, the seeds are extensively used in the Brazilian beverage industry for the preparation of soft drinks and as additives in energy drinks. Methods: To investigate the putative anti-aging and antioxidant activity of guarana, we used the model organism Caenorhabditis elegans. Chemical analyses were performed using high-performance liquid chromatography (HPLC) and electrospray ionization-mass spectrometry (ESI-MS/MS). Results: When tested in the model system Caenorhabditis elegans, the water extract from roasted guarana seeds enhanced resistance against oxidative stress, extended lifespan and attenuated aging markers such as muscle function decline and polyQ40 aggregation. Conclusions: In the current study, we demonstrate that guarana extracts can work as a powerful antioxidant in vivo; moreover, guarana extracts exhibit anti-aging properties. Our results suggest that the biological activities of guarana go beyond the extensively reported CNS stimulation.

Chlorophyll enhances oxidative stress tolerance inCaenorhabditis elegansand extends its lifespan

Green vegetables are thought to be responsible for several beneficial properties such as antioxidant, anti-mutagenic, and detoxification activities. It is not known whether these effects are due to chlorophyll which exists in large amounts in many foods or result from other secondary metabolites. In this study, we used the model systemCaenorhabditis elegansto investigate the anti-oxidative and anti-aging effects of chlorophyllin vivo. We found that chlorophyll significantly improves resistance to oxidative stress. It also enhances the lifespan ofC. elegansby up to 25% via activation of the DAF-16/FOXO-dependent pathway. The results indicate that chlorophyll is absorbed by the worms and is thus bioavailable, constituting an important prerequisite for antioxidant and longevity-promoting activities inside the body. Our study thereby supports the view that green vegetables may also be beneficial for humans.

Aspalathin, a dihydrochalcone C-glucoside, protects H9c2 cardiomyocytes against high glucose induced shifts in substrate preference and apoptosis

SCOPE

Energy deprivation in the myocardium is associated with impaired heart function. This study aims to investigate if aspalathin (ASP) can ameliorate hyperglycemic-induced shift in substrate preference and protect the myocardium against cell apoptosis.

METHODS AND RESULTS

H9c2 cells were exposed to, either normal (5.5 mM) or high (33 mM) glucose concentrations for 48 h. Thereafter, cells exposed to 33 mM glucose were treated with metformin (1 μM) or ASP (1 μM), as well as a combination of metformin and ASP for 6 h. In vitro studies revealed that ASP improved glucose metabolism by decreasing fatty acid uptake and subsequent β-oxidation through the decreased expression of adenosine monophosphate-activated protein kinase threonine 172 (pAMPK (Thr172)) and carnitine palmitoyltransferase 1 (CPT1), while increasing acetyl-CoA carboxylase (ACC) and glucose transporter 4 (GLUT4) expression. ASP inhibited high glucose induced loss of membrane potential in H9c2 cells as observed by an increase in 5' ,6,6'-tetrachloro-1,1',3,3' -tetraethylbenzimidazolyl-carbocyanine iodide (JC-1) ratio (orange\red fluorescence) and decreased apoptosis by reducing intracellular reactive oxygen species and DNA nick formation, while increasing glutathione, superoxide dismutase, uncoupling protein 2 (UCP2), and Bcl-2\Bax ratio.

CONCLUSION

Our study provides evidence that ASP increases glucose oxidation and modulates fatty acid utilization producing a favorable substrate shift in H9c2 cardiomyocytes exposed to high glucose. Such a favorable shift will be of importance in the protection of cardiomyocytes in the diabetic heart.

Lifespan Extending and Stress Resistant Properties of Vitexin from Vigna angularis in Caenorhabditis elegans

Several theories emphasize that aging is closely related to oxidative stress and disease. The formation of excess ROS can lead to DNA damage and the acceleration of aging. Vigna angularis is one of the important medicinal plants in Korea. We isolated vitexin from V. angularis and elucidated the lifespan-extending effect of vitexin using the Caenorhabditis elegans model system. Vitexin showed potent lifespan extensive activity and it elevated the survival rates of nematodes against the stressful environments including heat and oxidative conditions. In addition, our results showed that vitexin was able to elevate antioxidant enzyme activities of worms and reduce intracellular ROS accumulation in a dose-dependent manner. These studies demonstrated that the increased stress tolerance of vitexin-mediated nematode could be attributed to increased expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). In this work, we also studied whether vitexin-mediated longevity activity was associated with aging-related factors such as progeny, food intake, growth and movement. The data revealed that these factors were not affected by vitexin treatment except movement. Vitexin treatment improved the body movement of aged nematode, suggesting vitexin affects healthspan as well as lifespan of nematode. These results suggest that vitexin might be a probable candidate which could extend the human lifespan.

Modes of Action of Herbal Medicines and Plant Secondary Metabolites

Plants produce a wide diversity of secondary metabolites (SM) which serve them as defense compounds against herbivores, and other plants and microbes, but also as signal compounds. In general, SM exhibit a wide array of biological and pharmacological properties. Because of this, some plants or products isolated from them have been and are still used to treat infections, health disorders or diseases. This review provides evidence that many SM have a broad spectrum of bioactivities. They often interact with the main targets in cells, such as proteins, biomembranes or nucleic acids. Whereas some SM appear to have been optimized on a few molecular targets, such as alkaloids on receptors of neurotransmitters, others (such as phenolics and terpenoids) are less specific and attack a multitude of proteins by building hydrogen, hydrophobic and ionic bonds, thus modulating their 3D structures and in consequence their bioactivities. The main modes of action are described for the major groups of common plant secondary metabolites. The multitarget activities of many SM can explain the medical application of complex extracts from medicinal plants for more health disorders which involve several targets. Herbal medicine is not a placebo medicine but a rational medicine, and for several of them clinical trials have shown efficacy.

Natural lignans from Arctium lappa as antiaging agents in Caenorhabditis elegans

Arctium lappa is a well-known traditional medicinal plant in China (TCM) and Europe that has been used for thousands of years to treat arthritis, baldness or cancer. The plant produces lignans as secondary metabolites, which have a wide range of bioactivities. Yet, their antiaging potential has not been explored. In this study, we isolated six lignans from A. lappa seeds, namely arctigenin, matairesinol, arctiin, (iso)lappaol A, lappaol C, and lappaol F. The antioxidant and antiaging properties of the isolated lignans were studied using Caenorhabditis elegans as a relevant animal model. All lignans at concentrations of 10 and 100 μM significantly extended the mean life span of C. elegans. The strongest effect was observed with matairesinol, which at a concentration of 100 μM extended the life span of worms by 25%. Additionally, we observed that five lignans are strong free radical-scavengers in vitro and in vivo and all lignans can improve survival of C. elegans under oxidative stress. Furthermore, the lignans can induce the nuclear translocation of the transcription factor DAF-16 and up-regulate its expression, suggesting that a possible underlying mechanism of the observed longevity-promoting activity of lignans depends on DAF-16 mediated signaling pathway. All lignans up-regulated the expression of jnk-1, indicating that lignans may promote the C. elegans longevity and stress resistance through a JNK-1-DAF-16 cascade. Our study reports new antiaging activities of lignans, which might be candidates for developing antiaging agents.

Thermal stress resistance and aging effects of Panax notoginseng polysaccharides on Caenorhabditis elegans

Panax notoginseng attract public attention due to their potential biomedical properties and corresponding health benefits. The present study investigated the anti-aging and thermal stress resistance effects of polysaccharides from P. notoginseng on Caenorhabditis elegans. Results showed polysaccharides had little scavenging ability of reactive oxygen species (ROS) in vitro, but significantly extended lifespan of C. elegans, especially the main root polysaccharide (MRP) which prolongs the mean lifespan of wild type worms by 21%. Further study demonstrated that the heat stress resistance effect of polysaccharides on C. elegans might be attributed to the elevation of antioxidant enzyme activities (both superoxide dismutase (SOD) and catalase (CAT)) and the reduction lipid peroxidation of malondialdehyde (MDA) level. Taken together, the results provided a scientific basis for the further exploitation of the mechanism of longer lifespan controlled by P. notoginseng polysaccharides on C. elegans. The P. notoginseng polysaccharides might be considered as a potential source to delay aging.

The Lignan Pinoresinol Induces Nuclear Translocation of DAF-16 in Caenorhabditis elegans but has No Effect on Life Span

The lignan pinoresinol is a constituent of flaxseed, sesame seeds and olive oil. Because of different molecular effects reported for this compound, e.g. antioxidative activity, pinoresinol is suggested to cause positive effects on humans. Because experimental data are limited, we have analysed the effects of the lignan on the nematode Caenorhabditis elegans: in spite of a strong antioxidative capacity detected in an in vitro assay, no antioxidative effects were detectable in vivo. In analogy to this result, no modulation of the sensitivity against thermal stress was detectable. However, incubation with pinoresinol caused an enhanced nuclear accumulation of the transcription factor DAF-16 (insulin/IGF-like signalling pathway). Using a strain with an enhanced oxidative stress level (mev-1 mutant), we clearly see an increase in stress resistance caused by this lignan, but no change in reactive oxygen species. Furthermore, we investigated the effects of pinoresinol on the life span of the nematode, but no modulation was found, neither in wild-type nor in mev-1 mutant nematodes. These results suggest that pinoresinol may exert pharmacologically interesting effects via modulation of the insulin-like signalling pathway in C. elegans as well as in other species like mammals due to the evolutionary conservation of this signalling pathway.

Caenorhabditis elegans as model system in pharmacology and toxicology: effects of flavonoids on redox-sensitive signalling pathways and ageing

Flavonoids are secondary plant compounds that mediate diverse biological activities, for example, by scavenging free radicals and modulating intracellular signalling pathways. It has been shown in various studies that distinct flavonoid compounds enhance stress resistance and even prolong the life span of organisms. In the last years the model organism C. elegans has gained increasing importance in pharmacological and toxicological sciences due to the availability of various genetically modified nematode strains, the simplicity of modulating genes by RNAi, and the relatively short life span. Several studies have been performed demonstrating that secondary plant compounds influence ageing, stress resistance, and distinct signalling pathways in the nematode. Here we present an overview of the modulating effects of different flavonoids on oxidative stress, redox-sensitive signalling pathways, and life span in C. elegans introducing the usability of this model system for pharmacological and toxicological research.

EPs7630(®) from Pelargonium sidoides increases stress resistance in Caenorhabditis elegans probably via the DAF-16/FOXO pathway

EPs7630(®) a water alcohol extract of the roots from Pelargonium sidoides contains several secondary metabolites including highly oxygenated coumarins, various phenolics and polyphenols. Using the DPPH assay to measure antioxidant activity a free radical scavenging activity of 14.7±0.85μg/ml (IC50) was determined. As an in vivo model Caenorhabditis elegans was applied to study the effect of EPs7630(®) on stress resistance. EPs7630(®) treatment reduces intracellular hsp-16.2::GFP expression (induced by the pro-oxidant juglone) indicating that the secondary metabolites of EPs7630(®) are bioavailable and exhibit antioxidant activities in vivo. Application of EPs7630(®) (50μg/ml) to the transgenic mutant TJ356 induced the migration of the transcription factor DAF-16 from cytosol to the nucleus, suggesting a prominent role of DAF-16/FOXO in the daf-2 pathway for stress resistance.

Green Tea Extract Induces the Resistance of Caenorhabditis elegans against Oxidative Stress

Epidemiological studies on the effects of green tea consumption (Camellia sinensis) have demonstrated a reduction for the risk of age-related diseases. The investigation of the in vivo and in vitro antioxidant properties of an aqueous extract of green tea (GTE) was the aim of the current study. 2,2-Diphenyl-1-picrylhydrazyl (DPPH(•)) and superoxide anion radical (O₂(•-)) assays were used to estimate the GTE antioxidant activity. To investigate the protective effects of GTE against oxidative stress, wild-type N2 and transgenic strains (TJ374, hsp-16.2/GFP) of the model organism, Caenorhabditis elegans (C. elegans), were chosen. In the current study, the following catechins were identified by LC/ESI-MS: catechin, epicatechin, epicatechin gallate, gallocatechin, epigallocatechin and epigallocatechin gallate. GTE exhibited a free radical scavenging activity of DPPH(•) and O₂(•-) with IC50 8.37 and 91.34 µg/mL, respectively. In the C. elegans strain (TJ374, hsp-16.2/GFP), the expression of hsp-16.2/GFP was induced by a nonlethal dose of juglone, and the fluorescence density of hsp-16.2/GFP was measured. The hsp-16.2/GFP was reduced by 68.43% in the worms pretreated with 100 µg/mL GTE. N2 worms pretreated with 100 µg/mL GTE exhibited an increased survival rate of 48.31% after a lethal dose application of juglone. The results suggest that some green tea constituents are absorbed by the worms and play a substantial role to enhance oxidative stress resistance in C. elegans.

Natural compounds with anti-ageing activity

Ageing is a complex molecular process driven by diverse molecular pathways and biochemical events that are promoted by both environmental and genetic factors. Specifically, ageing is defined as a time-dependent decline of functional capacity and stress resistance, associated with increased chance of morbidity and mortality. These effects relate to age-related gradual accumulation of stressors that result in increasingly damaged biomolecules which eventually compromise cellular homeostasis. Nevertheless, the findings that genetic or diet interventions can increase lifespan in evolutionarily diverse organisms indicate that mortality can be postponed. Natural compounds represent an extraordinary inventory of high diversity structural scaffolds that can offer promising candidate chemical entities in the major healthcare challenge of increasing health span and/or delaying ageing. Herein, those natural compounds (either pure forms or extracts) that have been found to delay cellular senescence or in vivo ageing will be critically reviewed and summarized according to affected cellular signalling pathways. Moreover, the chemical structures of the identified natural compounds along with the profile of extracts related to their bioactive components will be presented and discussed. Finally, novel potential molecular targets for screening natural compounds for anti-ageing activity, as well as the idea that anti-ageing interventions represent a systemic approach that is also effective against age-related diseases will be discussed.

Anti-oxidative effects of Rooibos tea (Aspalathus linearis) on immobilization-induced oxidative stress in rat brain

Exposure to chronic psychological stress may be related to increased reactive oxygen species (ROS) or free radicals, and thus, long-term exposure to high levels of oxidative stress may cause the accumulation of oxidative damage and eventually lead to many neurodegenerative diseases. Compared with other organs, the brain appears especially susceptible to excessive oxidative stress due to its high demand for oxygen. In the case of excessive ROS production, endogenous defense mechanisms against ROS may not be sufficient to suppress ROS-associated oxidative damage. Dietary antioxidants have been shown to protect neurons against a variety of experimental neurodegenerative conditions. In particular, Rooibos tea might be a good source of antioxidants due to its larger proportion of polyphenolic compounds. An optimal animal model for stress should show the features of a stress response and should be able to mimic natural stress progression. However, most animal models of stress, such as cold-restraint, electric foot shock, and burn shock, usually involve physical abuse in addition to the psychological aspects of stress. Animals subjected to chronic restraint or immobilization are widely believed to be a convenient and reliable model to mimic psychological stress. Therefore, in the present study, we propose that immobilization-induced oxidative stress was significantly attenuated by treatment with Rooibos tea. This conclusion is demonstrated by Rooibos tea's ability to (i) reverse the increase in stress-related metabolites (5-HIAA and FFA), (ii) prevent lipid peroxidation (LPO), (iii) restore stress-induced protein degradation (PD), (iv) regulate glutathione metabolism (GSH and GSH/GSSG ratio), and (v) modulate changes in the activities of antioxidant enzymes (SOD and CAT).

Influence of resveratrol on oxidative stress resistance and life span in Caenorhabditis elegans

Objectives

Resveratrol (3,5,4′-trihydroxy-trans-stilbene), a polyphenol from red wine, has been reported to be beneficial in cases of ageing-related cardiovascular and neurodegenerative diseases owing to its property to reduce oxidative stress. Previous studies on the longevity promoting effect of resveratrol have been partly inconclusive, therefore we set out to investigate whether resveratrol at least promoted longevity in Caenorhabditis elegans under acute oxidative stress conditions.

Methods

C. elegans was cultured under standard conditions with or without resveratrol. After exposure to juglone-induced acute oxidative stress, the survival rate and hsp-16.2::GFP expression were measured. The influence of resveratrol on life span was recorded also under oxidative stress induced by high glucose concentrations in the growth medium.

Key findings

No extension of the normal life span of C. elegans was observed either in liquid or solid growth media containing different concentrations of resveratrol. However, resveratrol alleviated juglone-induced lethal oxidative stress, and significantly prolonged the life span of C. elegans under conditions of acute oxidative damage and oxidative stress caused by high concentrations of glucose.

Conclusions

Resveratrol, as an antioxidant, ameliorated oxidative stress in vivo but did not extend the life span of C. elegans under normal conditions. However, resveratrol did extend life span under conditions of oxidative stress.