Silymarin promotes longevity and alleviates Parkinson’s associated pathologies in Caenorhabditis elegans

Inhibition of cytotoxic fibril formation of α-synuclein and human insulin by Silymarin from the Silybum marianum

Silymarin (SIL), the extract obtained from the seeds of milk thistle (Silybum marianum), contains several flavonolignans with a broad range of therapeutic properties such as antioxidant, anti-inflammatory, and neuroprotective effects. Despite several studies indicating the neuroprotective effects of SIL in relating to neurodegenerative diseases (NDs), there is no report regarding the anti-amyloidogenic activity and the mechanism of action of SIL in vitro. Here, we have extracted SIL from the seeds of milk thistle (SIL A), followed by investigating its potential, in comparison with SIL purchased from Sigma company (SIL B), in modulating fibrillogenesis and cytotoxicity of human insulin and α-synuclein (α-syn) amyloid fibrils. The obtained results indicated the potency of both SIL A and SIL B in inhibiting the assembly process and related cytotoxicity of both proteins but via different mechanisms, including inhibition of amyloid fibrillation with the appearance of short fibrils for human insulin and redirecting the assembly process of α-syn toward the formation of small globular structures. The higher inhibitory effects of SIL B may be attributed to its higher silybin content, which is responsible for the most biological, including anti-amyloidogenic, activities of SIL B. Nanonization increased the capacity of both SILs to inhibit fibrillation and related cytotoxicity of both proteins. Taken together, these results may suggest SIL A as a potent candidate relating to NDs and highlight nanonization as a promising approach to increase its anti-amyloidogenic properties.

Unlocking the Neuroprotective Potential of Silymarin: A Promising Ally in Safeguarding the Brain from Alzheimer's Disease and Other Neurological Disorders

Medicinal plants and their phytochemicals have been extensively employed worldwide for centuries to address a diverse range of ailments, boasting a history that spans several decades. These plants are considered the source of numerous medicinal compounds. For instance, silymarin is a polyphenolic flavonoid extract obtained from the milk thistle plant or Silybum marianum which has been shown to have significant neuroprotective effects and great therapeutic benefits. Neurodegenerative diseases (NDs) are a class of neurological diseases that have become more prevalent in recent years, and although treatment is available, there is no complete cure developed yet. Silymarin utilizes a range of molecular mechanisms, including modulation of MAPK, AMPK, NF-κB, mTOR, and PI3K/Akt pathways, along with various receptors, enzymes, and growth factors. These mechanisms collectively contribute to its protective effects against NDs such as Alzheimer's disease, Parkinson's disease, and depression. Despite its safety and efficacy, silymarin faces challenges related to bioavailability and aqueous solubility, hindering its development as a clinical drug. This review highlights the molecular mechanisms underlying silymarin's neuroprotective effects, suggesting its potential as a promising therapeutic strategy for NDs.

Unlocking the possibilities of therapeutic potential of silymarin and silibinin against neurodegenerative Diseases-A mechanistic overview

Silymarin, a bioflavonoid derived from the Silybum marianum plant, was discovered in 1960. It contains C25 and has been extensively used as a therapeutic agent against liver-related diseases caused by alcohol addiction, acute viral hepatitis, and toxins-inducing liver failure. Its efficacy stems from its role as a potent anti-oxidant and scavenger of free radicals, employed through various mechanisms. Additionally, silymarin or silybin possesses immunomodulatory characteristics, impacting immune-enhancing and immune-suppressive functions. Recently, silymarin has been recognized as a potential neuroprotective therapy for various neurological conditions, including Parkinson's and Alzheimer's diseases, along with conditions related to cerebral ischemia. Its hepatoprotective qualities, primarily due to its anti-oxidant and tissue-regenerating properties, are well-established. Silymarin also enhances health by modifying processes such as inflammation, β-amyloid accumulation, cellular estrogenic receptor mediation, and apoptotic machinery. While believed to reduce oxidative stress and support neuroprotective mechanisms, these effects represent just one aspect of the compound's multifaceted protective action. This review article further delves into the possibilities of potential therapeutic advancement of silymarin and silibinin for the management of neurodegenerative disorders via mechanics modules.

Dauer larva-derived extracellular vesicles extend the life of Caenorhabditis elegans

There is growing evidence that extracellular vesicles (EVs) play a functional role in tissue repair and anti-aging by transferring the contents of donor cells to recipient cells. We hypothesized that Dauer (C. elegans), known as "ageless" nematodes, can also secrete extracellular vesicles and influence the lifespan of C. elegans. Here, we isolated EVs of dauer larvae (dauer EVs). Dauer EVs were characterized using transmission electron microscopy, nanoparticle tracking analysis (NTA), and Western blot analysis. Wild-type C. elegans were fed in the presence or absence of dauer EVs and tested for a range of phenotypes, including longevity, mobility and reproductive capacity. Results showed that dauer EVs increased the average lifespan of nematodes by 15.74%, improved mobility, slowed age-related pigmentation as well as body length, and reduced the accumulation of reactive oxygen species and lipids, while not impairing nematode reproductive capacity. These findings suggest that dauer EVs can extend the lifespan of C. elegans as well as the healthy lifespan by reducing ROS accumulation, with potential anti-aging capacity.

Mechanistic Insights into the Pharmacological Significance of Silymarin

Medicinal plants are considered the reservoir of diverse therapeutic agents and have been traditionally employed worldwide to heal various ailments for several decades. Silymarin is a plant-derived mixture of polyphenolic flavonoids originating from the fruits and akenes of Silybum marianum and contains three flavonolignans, silibinins (silybins), silychristin and silydianin, along with taxifolin. Silybins are the major constituents in silymarin with almost 70–80% abundance and are accountable for most of the observed therapeutic activity. Silymarin has also been acknowledged from the ancient period and is utilized in European and Asian systems of traditional medicine for treating various liver disorders. The contemporary literature reveals that silymarin is employed significantly as a neuroprotective, hepatoprotective, cardioprotective, antioxidant, anti-cancer, anti-diabetic, anti-viral, anti-hypertensive, immunomodulator, anti-inflammatory, photoprotective and detoxification agent by targeting various cellular and molecular pathways, including MAPK, mTOR, β-catenin and Akt, different receptors and growth factors, as well as inhibiting numerous enzymes and the gene expression of several apoptotic proteins and inflammatory cytokines. Therefore, the current review aims to recapitulate and update the existing knowledge regarding the pharmacological potential of silymarin as evidenced by vast cellular, animal, and clinical studies, with a particular emphasis on its mechanisms of action.

Onion Vinegar Quality Evaluation and its Alleviate Oxidative Stress Mechanism in Caenorhabditis elegans Via SKN-1

Recently, there has been renewed interest in biorefining of agricultural onion into functional products. In this study, onion vinegar (OV) are prepared by a two-stage semi-continuous fermentation method, and its content of total flavonoids (3.01 mg/mL) and polyphenols (976.76 μg/mL) is superior to other commercial vinegars. OV possesses a high radical scavenging activity and enhances the antioxidant enzyme activities in vivo, alleviating intracellular oxidative stress in Caenorhabditis elegans. Treated by OV, the 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH·), diammonium 2,2'-azino-bis (3-ethylbenzo thiazoline-6-sulfonic acid) (ABTS⁺·) and 2-phenyl-4,4,5,5- tetramethylimidazoline-1-oxyl 3-Oxide (PTIO·) free radicals clearance rates are 88.76, 98.76 and 90.54%, respectively in vitro. Whereas the glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) enzyme activities in C. elegans reach 271.57, 129.26, and 314.68%, respectively. Using RNAi and RT-PCR, it has been further confirmed that OV modulates transcription factor SKN-1, the nuclear factor erythroid 2-related factor 2 (Nrf2) homologous, in C. elegans, enhancing the resistance of C. elegans against sodium arsenite stress. Lifespan analysis reveals that 1 mL OV extends the maximum lifespan of the nematode to 26 days. Evidence is presented which shows that OV increases the lifespan of C. elegans by activating the SKN-1 signaling pathway. Overall, the OV is a well functional condiment, enhancing the value-added of onion.

Relevance of bioassay of biologically active substances (BAS) with geroprotective properties in the model of the nematode Caenorhabditis elegans in experiments in vivo

Aging is a process global in nature. The age of living organisms contributes to the appearance of chronic diseases, which not only reduce the quality of life, but also significantly damage it. Modern medicines can successfully fight multiple diseases and prolong life. At the same time, medications have a large number of side effects. New research indicates that bioactive phytochemicals have great potential for treating even the most severe diseases and can become an alternative to medicines. Despite many studies in this area, the effects of many plant ingredients on living organisms are poorly understood. Analysis of the mechanisms through which herbal preparations influence the aging process helps to select the right active substances, determine the optimal doses to obtain the maximum positive effect. It is preferable to check the effectiveness of plant extracts and biologically active components with geroprotective properties in vivo. For these purposes, live model systems such as Rattus rattus, Mus musculus, Drosophila melanogaster, and Caenorhabditis elegans are used. These models help to comprehensively study the impact of the developed new drugs on the aging process. The model organism C. elegans is gaining increasing popularity in these studies because of its many advantages. This review article discusses the advantages of the nematode C. elegans as a model organism for studying the processes associated with aging. The influence of various BAS and plant extracts on the increase in the life span of the nematode, on the increase in its stress resistance and on other markers of aging is also considered. The review showed that the nematode C. elegans has a number of advantages over other organisms and is a promising model system for studying the geroprotective properties of BAS.

Silymarin mitigates bile duct obstruction-induced cholemic nephropathy

Bile duct obstruction or cholestasis can occur by several diseases or xenobiotics. Cholestasis and the accumulation of the bile constituents in the liver primarily damage this organ. On the other hand, extrahepatic organs are also affected by cholestasis. The kidney is the most affected tissue during cholestatic liver injury. Cholestasis-associated renal injury is known as cholemic nephropathy (CN). Several lines of evidence specify the involvement of oxidative stress and mitochondrial impairment in the pathogenesis of CN. The current study aimed to assess the role of silymarin as a potent antioxidant on CN-induced oxidative stress and mitochondrial dysfunction in the kidney. Bile duct ligated (BDL) rats were treated with silymarin (10 and 100 mg/kg, oral) for seven consecutive days. A significant increase in reactive oxygen species (ROS), lipid peroxidation, protein carbonylation, and oxidized glutathione (GSSG) levels were evident in the kidney of BDL animals. Moreover, reduced glutathione (GSH) content and total antioxidant capacity were significantly decreased in the kidney of cholestatic rats. Mitochondrial depolarization, decreased mitochondrial dehydrogenases activity, mitochondrial permeabilization, and depleted ATP stores were detected in the kidney mitochondria isolated from BDL animals. Kidney histopathological alterations, as well as serum and urine levels of renal injury biomarkers, were also significantly different in the BDL group. It was found that silymarin treatment significantly ameliorated CN-induced renal injury. The antioxidant effects of silymarin and its positive impact on mitochondrial indices seem to play a significant role in its renoprotective effects during cholestasis.

Role of Flavonoids in Neurodegenerative Diseases: Limitations and Future Perspectives

BACKGROUND

Flavonoids, a group of natural dietary polyphenols, are known for their beneficial effects on human health. By virtue of their various pharmacological effects, like anti-oxidative, antiinflammatory, anti-carcinogenic and neuroprotective effects, flavonoids have now become an important component of herbal supplements, pharmaceuticals, medicinals and cosmetics. There has been enormous literature supporting neuroprotective effect of flavonoids. Recently their efficacy in various neurodegenerative diseases, like Alzheimer's disease and Parkinson diseases, has received particular attention.

OBJECTIVE

The mechanism of flavanoids neuroprotection might include antioxidant, antiapoptotic, antineuroinflammatory and modulation of various cellular and intracellular targets. In in-vivo systems, before reaching to brain, they have to cross barriers like extensive first pass metabolism, intestinal barrier and ultimately blood brain barrier. Different flavonoids have varied pharmacokinetic characteristics, which affect their pharmacodynamic profile. Therefore, brain accessibility of flavonoids is still debatable.

METHODS

This review emphasized on current trends of research and development on flavonoids, especially in neurodegenerative diseases, possible challenges and strategies to encounter using novel drug delivery system.

RESULTS

Various flavonoids have elicited their therapeutic potential against neurodegenerative diseases, however by using nanotechnology and novel drug delivery systems, the bioavailability of favonoids could be enhanced.

CONCLUSION

This study bridges a significant opinion on medicinal chemistry, ethanopharmacology and new drug delivery research regarding use of flavonoids in management of neurodegeneration.

Silymarin and neurodegenerative diseases: Therapeutic potential and basic molecular mechanisms

BACKGROUND

Neurodegenerative diseases (NDDs) are primarily characterized by selective neuronal loss in the brain. Alzheimer's disease as the most common NDDs and the most prevalent cause of dementia is characterized by Amyloid-beta deposition, which leads to cognitive and memory impairment. Parkinson's disease is a progressive neurodegenerative disease characterized by the dramatic death of dopaminergic neuronal cells, especially in the SNc and caused alpha-synuclein accumulation in the neurons. Silymarin, an extract from seeds of Silybum marianum, administered mostly for liver disorders and also had anti-oxidant and anti-carcinogenic activities.

PURPOSE

The present comprehensive review summarizes the beneficial effects of Silymarin in-vivo and in-vitro and even in animal models for these NDDs.

METHODS

A diagram model for systematic review is utilized for this search. The research is conducted in the following databases: PubMed, Web of Science, Scopus, and Science Direct.

RESULTS

Based on the inclusion criteria, 83 studies were selected and discussed in this review.

CONCLUSION

Lastly, we review the latest experimental evidences supporting the potential effects of Silymarin, as a neuroprotective agent in NDDs.

Potential of Caenorhabditis elegans as an antiaging evaluation model for dietary phytochemicals: A review

Aging is an inevitable process characterized by the accumulation of degenerative damage, leading to serious diseases that affect human health. Studies on aging aim to develop pre-protection or therapies to delay aging and age-related diseases. A preventive approach is preferable to clinical treatment not only to reduce investment but also to alleviate pain in patients. Adjusting daily diet habits to improve the aging condition is a potentially attractive strategy. Fruits and vegetables containing active compounds that can effectively delay the aging process and reduce or inhibit age-related degenerative diseases have been identified. The signaling pathways related to aging in Caenorhabditis elegans are evolutionarily conserved; thus, studying antiaging components by intervening senescence process may contribute to the prevention and treatment of age-related diseases in humans. This review focuses on the effects of food-derived extracts or purified substance on antiaging in nematodes, as well as the underlying mechanisms, on the basis of several major signaling pathways and key regulatory factors in aging. The aim is to provide references for a healthy diet guidance and the development of antiaging nutritional supplements. Finally, challenges in the use of C. elegans as the antiaging evaluation model are discussed, together with the development that potentially inspire novel strategies and research tools.

A Bioactive compound Shatavarin IV-mediated longevity as revealed by dietary restriction-induced autophagy in Caenorhabditis elegans

Plant-based dietary supplements that delay aging are of significant interest now a days because these naturally occurring bioactive molecules effectively provide pharmaceuticals/neutraceuticals to deal with diseases related to the advanced life expectancy. In this paper, we aimed to investigate the effect of Shatavarin IV (SIV), a steroidal saponin isolated from Asparagus racemosus Willd. on dietary restriction (DR) induced longevity in Caenorhabditis elegans. SIV significantly increased the lifespan to 18% which is independent of antimicrobial activity and reduced the aging by-product, lipofuscin along with increased locomotion, and chemotaxis behavior in wild type worms. The longevity effect has been dependent on eat-2, which was further validated via reduced pharyngeal pumping rate that established the effect similar to DR induced longevity. Moreover, like eat-2 mutant worms, SIV reduces the total progeny number of wild type worm along with a significant alleviation of stored fat, which reconfirms the involvement of eat-2 mediated longevity. Further, it was also observed that DR induced longevity mechanism by SIV requires mTOR which works in PHA-4/FOXA dependent manner. In addition to this, the role of autophagy mechanism concerning SIV mediated DR was confirmed via bec-1, unc-51, and lgg-1. The longevity effect achieved by SIV was also dependent on SKN-1/NRF-2 and partially dependent on DAF-16/FOXO. Furthermore, the DR-induced longevity by SIV was found to be independent of hsf-1 exhibiting non-significant alteration in the mRNA expression of downstream target genes hsp-16.2 and hsp-70. Altogether, this study provides first-hand information on the pro-longevity effect of SIV in worms that have been mediated by the DR-regulating gene induced autophagy.

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.

Silymarin-albumin nanoplex: Preparation and its potential application as an antioxidant in nervous system in vitro and in vivo

In this study, we formulated silymarin-HSA nanoplex and assayed its ability to reduce LPS-induced toxicity in vitro and in vivo. Silymarin molecules were encapsulated into HSA nanoplex and the loading efficiency and characterization of fabricated nanoplex were performed by using HPLC, TEM, SEM, DLS, FTIR analysis, and theoretical studies. Afterwards, their protective effect against LPS (20 µg/ml) -induced toxicity in SH-SY5Y cells was investigated by MTT, ROS, and apoptosis assays. For in vivo experiments, rats were pre-treated with either silymarin or silymarin -HSA nanoplex (200 mg/kg) orally for 3 days and at third day received LPS by IP at a dose of 0.5 mg/kg, 150 min before scarification followed by SOD and CAT activity assay. The formulation of silymarin-HSA nanoplex showed a spherical shape with an average diameter between 50 nm and 150 nm, hydrodynamic radius of 188.3 nm, zeta potential of -26.6 mV, and a drug loading of 97.3%. In LPS-treated cells, pretreatments with silymarin-HSA noncomplex recovered the cell viability and decreased the ROS level and corresponding apoptosis more significantly than free silymarin. In rats, it was also depicted that, silymarin-HSA noncomplex can increase the SOD and CAT activity in brain tissue at LPS-triggered oxidative stress model more significantly than the free counterpart. Therefore, nanoformulation of silymarin improved its capability to reduce LPS-induced oxidative stress by restoring cell viability and elevation of SOD and CAT activity in vitro and in vivo, respectively. In conclusion, formulation of silymarin may hold a great promise in the development of antioxidant agents.

Green kiwifruit extracts protect motor neurons from death in a spinal muscular atrophy model in Caenorhabditis elegans

Kiwifruit is considered a functional food and a good source of nutraceuticals. Among the possible beneficial effects of kiwifruit species, a neuroprotective activity exerted in rats with learning and memory impairment induced by exposure to different chemicals was reported. We sought to investigate the neuroprotective activities of kiwifruit toward spinal muscular atrophy (SMA). To this purpose, we have used a recently developed Caenorhabditis elegans SMA model, displaying an age-dependent degeneration of motor neurons detected as locomotory defects, disappearance of fluorescent markers, and apoptotic death of targeted neurons. Although an anti-nematode activity is reported for kiwifruit, it has been verified that neither green (Actinidia deliciosa, cultivar Hayward) nor gold (Actinidia chinensis, cultivar Hort 16A) kiwifruit extracts cause detectable effects on wild-type C. elegans growth and life cycle. Conversely, green kiwifruit extracts have a clear effect on the C. elegans SMA model by partially rescuing the degeneration and death of motor neurons and the locomotion impairment. The gold species does not show the same effect. The components responsible for the neuroprotection are macromolecules with a molecular weight higher than 3 kDa, present in the green and not in the yellow kiwifruit. In conclusion, this is the first study reporting a protective activity of green kiwifruit toward motor neurons. In addition, we demonstrate that C. elegans is an animal model suitable to study the biological activities contained in kiwifruit. Therefore, this model can be exploited for future investigations aimed at identifying kiwifruit molecules with potential applications in the field of human health.

Studying Parkinson’s disease using Caenorhabditis elegans models in microfluidic devices

Parkinson’s disease (PD) is a progressive neurological disorder associated with the loss of dopaminergic neurons (DNs) in the substantia nigra and the widespread accumulation of α-synuclein (α-syn) protein, leading to motor impairments and eventual cognitive dysfunction. In-vitro cell cultures and in-vivo animal models have provided the opportunity to investigate the PD pathological hallmarks and identify different therapeutic compounds. However, PD pathogenesis and causes are still not well understood, and effective inhibitory drugs for PD are yet to be discovered. Biologically simple but pathologically relevant disease models and advanced screening technologies are needed to reveal the mechanisms underpinning protein aggregation and PD progression. For instance, Caenorhabditis elegans (C. elegans) offers many advantages for fundamental PD neurobehavioral studies including a simple, well-mapped, and accessible neuronal system, genetic homology to humans, body transparency and amenability to genetic manipulation. Several transgenic worm strains that exhibit multiple PD-related phenotypes have been developed to perform neuronal and behavioral assays and drug screening. However, in conventional worm-based assays, the commonly used techniques are equipment-intensive, slow and low in throughput. Over the past two decades, microfluidics technology has contributed significantly to automation and control of C. elegans assays. In this review, we focus on C. elegans PD models and the recent advancements in microfluidic platforms used for manipulation, handling and neurobehavioral screening of these models. Moreover, we highlight the potential of C. elegans to elucidate the in-vivo mechanisms of neuron-to-neuron protein transfer that may underlie spreading Lewy pathology in PD, and its suitability for in-vitro studies. Given the advantages of C. elegans and microfluidics technology, their integration has the potential to facilitate the investigation of disease pathology and discovery of potential chemical leads for PD.

From the Cover: Harmane-Induced Selective Dopaminergic Neurotoxicity in Caenorhabditis elegans

Parkinson's disease (PD) is a debilitating neurodegenerative disease. Although numerous exposures have been linked to PD etiology, causative factors for most cases remain largely unknown. Emerging data on the neurotoxicity of heterocyclic amines suggest that this class of compounds should be examined for relevance to PD. Here, using Caenorhabditis elegans as a model system, we tested whether harmane exposure produced selective toxicity to dopamine neurons that is potentially relevant to PD. Harmane is a known tremorigenic β-carboline (a type of heterocyclic amine) found in cooked meat, roasted coffee beans, and tobacco. Thus, this compound represents a potentially important exposure. In the nematode model, we observed dopaminergic neurons to be selectively vulnerable, showing significant loss in terms of structure and function at lower doses than other neuronal populations. In examining mechanisms of toxicity, we observed significant harmane-induced decreases in mitochondrial viability and increased reactive oxygen species levels. Blocking transport through the dopamine transporter (DAT) was not neuroprotective, suggesting that harmane is unlikely to enter the cell through DAT. However, a mitochondrial complex I activator did partially ameliorate neurodegeneration. Further, mitochondrial complex I activator treatment reduced harmane-induced dopamine depletion, measured by the 1-nonanol assay. In summary, we have shown that harmane exposure in C. elegans produces selective dopaminergic neurotoxicity that may bear relevance to PD, and that neurotoxicity may be mediated through mitochondrial mechanisms.

Anti-Parkinson Potential of Silymarin: Mechanistic Insight and Therapeutic Standing

Parkinson's disease (PD) involves aggregation of α-synuclein and progressive loss of dopaminergic neurons. Pathogenesis of PD may also be related to one's genetic background. PD is most common among geriatric population and approximately 1-2% of population suffers over age 65 years. Currently no successful therapies are in practice for the management of PD and available therapies tend to decrease the symptoms of PD only. Furthermore, these are associated with diverse range of adverse effects profile. The neuroprotective effects of polyphenols are widely studied and documented. Among phytochemicals, silymarin is one of the most widely used flavonoids because of its extensive therapeutic properties and has been indicated in pathological conditions of prostate, CNS, lungs, skin, liver, and pancreas. Silymarin is a mixture of flavonolignans (silybin, isosilybin, and silychristin), small amount of flavonoids (taxifolin), fatty acids, and other polyphenolic compounds extracted from the dried fruit of Silybum marianum and is clinically used for hepatoprotective effects since ancient times. Neuroprotective effects of silymarin have been studied in various models of neurological disorders such as Alzheimer's disease, PD, and cerebral ischemia. The aim of the present study is to provide a comprehensive review of the recent literature exploring the effects of silymarin administration on the progression of PD. Reducing oxidative stress, inflammatory cytokines, altering cellular apoptosis machinery, and estrogen receptor machinery are mechanisms that are responsible for neuroprotection by silymarin, as discussed in this review. Additionally, because of poor aqueous solubility, the bioavailability of silymarin is low and only 23-47% of silymarin reaches systemic circulation after oral administration. Our primary focus is on the chemical basis of the pharmacology of silymarin in the treatment of PD and its mechanisms and possible therapeutic/clinical status while addressing the bioavailability limitation.

Anti-Parkinsonian effects of β-amyrin are regulated via LGG-1 involved autophagy pathway in Caenorhabditis elegans

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disease that is associated with aging and is characterized as a movement disorder. Currently, there is still no complete therapy for PD. In recent years, the identification and characterization of medicinal plants to cure or treat PD has gained increasing scientific interest.

PURPOSE

In this study, we investigated a pentacyclic triterpenoid compound, β-amyrin, which is found in many medicinal plants for its anti-Parkinsonian effects, using Caenorhabditis elegans (C. elegans) disease models and their underlying mechanisms.

METHODS

C. elegans treated or untreated with β-amyrin were investigated for oxidative stress resistance, neurodegeneration, and α-synuclein aggregation assays. The C. elegans ortholog of Atg8/LC3, LGG-1 that is involved in the autophagy pathway was also evaluated by quantitative RT-PCR and transgenic strain experiments.

RESULTS

β-Amyrin exerted excellent antioxidant activity and reduced intracellular oxygen species in C. elegans. Using the transgenic strain BZ555, β-amyrin showed a protective effect on dopaminergic neurons reducing cell damage induced by 6-hydroxydopamine (6-OHDA). In addition, β-amyrin significantly reduced the α-synuclein aggregation in the transgenic strain NL5901. Moreover, β-amyrin up-regulated LGG-1 mRNA expression and increased the number of localized LGG-1 puncta in the transgenic strain DA2123.

CONCLUSION

The results from this study suggest that the anti-Parkinsonian effects of β-amyrin might be regulated via LGG-1 involved autophagy pathway in C. elegans. Therefore, β-amyrin may be useful for therapeutic applications or supplements to treat or slow the progression of PD.

Shatavarin IV elicits lifespan extension and alleviates Parkinsonism in Caenorhabditis elegans

Shatavarin IV (SIV), a steroidal saponin, is a major bioactive phytomolecule present in roots of Asparagus racemosus (Liliaceae) known for its anticancer activity. Age-associated neurodegenerative Parkinson's disease (PD) is characterised by alpha-synuclein aggregation in dopaminergic neuron resulting in neurodegeneration. The invention of bioactive molecules that delay aging and age-associated disorders endorses development of natural phytomolecule as a therapeutic agent for curing age-related diseases. Therefore, the present study for the first time explores the potential of SIV against aging and Parkinsonism utilising Caenorhabditis elegans model system. SIV significantly attenuated oxidative stress in terms of intracellular reactive oxygen species (ROS) as well as oxidative damage including protein carbonylation and also promotes longevity. SIV also significantly increased the mRNA expression of stress responsive genes namely sod-1, sod-2, sod-3, gst-4, gst-7 and ctl-2 suggesting its anti-oxidant property that might be contributed in the modulation of oxidative stress and promoting lifespan. Additionally, SIV improved PD symptoms by reducing the alpha-synuclein aggregation, lipid accumulation and enhancing dopamine level. Altogether, present findings indicate that SIV possibly utilising ubiquitin-mediated proteasomal system and attenuating oxidative stress by up-regulating PD-associated genes pdr-1, ubc-12 and pink-1. Therefore, this study is a forward step in exploring the anti-aging and anti-Parkinsonism potential of bioactive compound SIV in C. elegans.