Neuroprotective Effect Of Silymarin Research Articles

Neuroprotective effects of silymarin in 3-nitropropionic acid-induced neurotoxicity in male mice: improving behavioral deficits by attenuating oxidative stress and neuroinflammation.

3-Nitropropionic acid (3-NP) is strongly believed to be an irreversible inhibitor of mitochondrial complex II, leading to neural damage. This study aimed to investigate the neuroprotective effects of silymarin against 3-NP-induced neurotoxicity in male mice. Six-week-old mice received subacute doses of 3-NP intraperitoneally for 17days. Mice were given silymarin (70mg/kg/day, P.O.) for 2weeks before 3-NP administration or for 4weeks after 3-NP administration. At the end of the treatment schedule, animals were evaluated for behavioral alterations. Subsequently, neuronal damage in the hippocampus region of the brain tissues, oxidative stress-related parameters (lipid peroxidation, nitric oxide, superoxide dismutase, glutathione, and total antioxidant capacity), and pro-inflammatory cytokine (TNF-α, IL-17, and IL-1β) levels were evaluated. Our results indicated that 3-NP treatment significantly (p < 0.05) tended to reduce motor coordination, memory, and neuronal antioxidant status while increasing pro-inflammatory cytokine levels. However, silymarin in both treatment and pretreatment protocols markedly (p < 0.05) attenuated the behavioral deficits, oxidative stress status, and neuroinflammation. The results of the current study suggest that the neuroprotective effect of silymarin against 3-NP-induced neurotoxicity might be due to the mitigation of oxidative stress status and provide insight into the therapeutic potential of silymarin.

Thiamethoxam evoked neural oxido-inflammatory stress in male rats through modulation of Nrf2/NF-kB/iNOS signaling and inflammatory cytokines: Neuroprotective effect of Silymarin

Thiamethoxam (TMX), a neonicotinoid insecticide, is a widely used insecticide with neurotoxic potential. Silymarin (SM), a milk thistle-derived flavonoid, is known with its promising biological activities. This study explored the neuroprotective effects of SM against TMX-triggered cortical injury in male rats. Animals were divided into four groups and treated daily either with SM (150 mg/kg), TMX (78.15 mg/kg), or both at the aforementioned doses for 28 days. Our results revealed marked declines in cortical SOD and CAT activities with elevations in MDA, IL-1b and TNF-α levels in TMX-treated rats. Further, TMX induced down-regulation in the gene expressions of Sod, Cat, Gpx, and Nrf-2, with up-regulation in the gene expressions of IL-1b, IL-6, iNOS, TNF-α and NF-kB. Interestingly, pre-treatment with SM provided a notable neuroprotective action against TMX-mediated cortical damage that indicates its promising antioxidant and anti-inflammatory activities. This effect may be mediated by Nrf2/NF-kB/iNOS signalling and suppression of excess free radicals and production of inflammatory cytokines. In brief, SM could be a promising therapeutic agent against TMX-mediated neural complication via its antioxidant and anti-inflammatory properties. Practical applicationsThe using of neonicotinoids as thiamethoxam is recently increased and is associated with brain damage. TMX induced excessive oxidative and inflammatory damage. Therefore, new therapeutic approaches are needed to counteract its adverse effects on the nervous system. SM, a flavonoid, is extracted from the seeds and fruits of milk thistle. Due to its potent antioxidative activity, SM have been applied to mitigate the oxidative stress as well as inflammatory disorders. Herein, we examined the potential therapeutic role of SM against TMX-induced brain oxidative stress and inflammation in rats through evaluating oxidative markers, inflammatory response, and histopathological changes in the brain cortical tissue.

Neuroprotective effect of silymarin against 3-Nitropropionic acid-induced neurotoxicity in rats

(HD) Huntington's disease is a severe hereditary catastrophic neurological disease with an autosomal dominant heritable changes manifested by cognitive, behavioural, and motor progression deficits, resulting in death. Several mechanisms are involved in the pathogenesis of this complex and rare disease, including excitotoxicity, mitochondrial dysfunction, neurotransmitters imbalance, and oxidative stress. Silymarin was selected as an investigational drug, due to its numerous activities in current research, it possesses substantial antioxidant and neuroprotective functionalities. The present research attempts, i.p. injections of 3-NPA (10 ​mg/kg) were given for 21 days to trigger Huntington-like symptoms in rats. The percentage fluctuations in body weight, the footfall counts, and the time required to transverse the beam and motor functions were analyzed at multiple time points. Oxidative stress markers like MDA/LPO, GSH, protein, nitrite, catalase, and superoxide dismutase levels were examined in the striatum region. The current study results conclusively demonstrate that chronic 3-NPA administration significantly decreased the body weight and showed marked abnormalities in motor coordination, locomotion, and increased striatal generation of free radicals. Furthermore, treatment with silymarin (100 & 200 ​mg/kg/p.o.), mitigated 3-NPA triggered behavioural and biochemical alterations. Our study results could conclude that Silymarin may be advantageous and might develop an adjuvant treatment for the management of Huntington's disease.

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.

Neuroprotective effects of silymarin on ischemia-induced delayed neuronal cell death in rat hippocampus

We examined the effects of silymarin, which was extracted from Silybum marianum, on delayed neuronal cell death in the rat hippocampus. Rats were divided into four groups: sham-operated rats (sham group), rats which underwent ischemic surgery (control group), rats which were treated with silymarin before and after ischemic surgery (pre group), and rats which were treated with silymarin after ischemic surgery only (post group). We performed the ischemic surgery by occluding the bilateral carotid arteries for 20min and sacrificed the rats one week after the surgery. Silymarin was administered orally at 200mg/kg body weight. Smaller numbers of delayed cell deaths were noted in the rat CA1 region of the pre- and post-groups, and no significant difference was observed between these groups. There were few apoptotic cell deaths in all groups. Compared to the control group, significantly fewer cell deaths by autophagy were found in the pre- and post-group. We concluded that silymarin exerts a preservation effect on delayed neuronal cell death in the rat hippocampus and this effect has nothing to do with the timing of administering of silymarin.

Silymarin versus Silibinin: Differential Antioxidant and Neuroprotective Effects against H2O2-induced Oxidative Stress in PC12 Cells

The present study assessed comparatively the antioxidant activities of silymarin and its major active component silibinin and their neuroprotective effects against hydrogen peroxide (H2O2)-induced oxidative stress in rat pheochromocytoma PC12 cells. It was found that despite newly prepared silymarin and silibinin solution possessing comparable superoxide anion (O2*-)-scavenging activities, with time the activity of silymarin lowered slightly, but that of silibinin decreased dramatically. Both silymarin and silibinin suppressed H2O2-induced oxidative stress and apoptosis, and the neuroprotective effect of silymarin was overall relatively stronger than that of silibinin. The findings provided clues for future studies on therapeutic potentials of the whole silymarin or purified silibinin for neurodegenerative diseases.

Silymarin has antioxidant potential and changes the activity of Na+/K+-ATPase and monoamine oxidase in vitro

Silymarin is an extract of the milk thistle seeds Silybum marianum (L.) Gaerth used to treat liver disorders and recently reported as a putative neuroprotective agent against neurologic diseases including Parkinson’s disease. However, its action mechanism is not completely investigated. In the present study, we investigated in vitro the antioxidant effects of silymarin as well as on Na+/K+-ATPase and monoamine oxidase (MAO) activity in rat brain homogenate. HPLC fingerprinting of silymarin extract revealed the main component present is silibinin. Furthermore, silymarin showed a total antioxidant capacity and ability to scavenging the DPPH radical dependent of the concentration used. Silymarin decreased lipid peroxidation induced by both pro-oxidants tested, sodium nitroprusside (SNP) and iron (Fe2+), respectively. Silymarin also avoided the loss in activity of catalase and protein and non-protein thiol oxidation pre-incubated with SNP or Fe2+. With regard to MAO and Na+/K+-ATPase activity, silymarin inhibited MAO in a noncompetitive way with a higher potency to MAO-B and could activate Na+/K+-ATPase. Taken together, our in vitro data suggest that neuroprotective effects of silymarin may involve antioxidant and modulatory effects on MAO and Na+/K+-ATPase activity.

Neuroprotective effect of silymarin in a MPTP mouse model of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease secondary to the loss of dopaminergic neurons in the substantia nigra. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produces in mice and primates histopathological changes similar to PD in humans. A common feature of PD and MPTP models is neuronal death and dopamine depletion. Silymarin is a complex of flavonolignans derived from the seeds of the plant Silybum marianum and has mainly antioxidant, anti-inflammatory, cytoprotective and neuroprotective effects.In order to explore whether silymarin has a neuroprotective effects in a mouse model of PD we determined the concentration of striatal dopamine by HPLC, the number of apoptotic cells by in situ Tunel assay and the number of tyrosine hydroxylase positive neurons by immunohistochemistry in substantia nigra of vehicle-treated, silymarin-treated, MPTP-intoxicated and MPTP-silymarin treated C57BL/6J male mice. MPTP (30mg/kg) and silymarin doses (25, 50, 100, 200, 250, 300 or 400mg/kg) were administered intraperitoneally once daily for five consecutive days. Silymarin treatment showed a non-monotonic dose–response curve and only 50 and 100mg/kg doses preserved dopamine levels (62% and 69%, respectively) after MPTP intoxication. Additionally, 100mg/kg silymarin treatment significantly diminished the number of apoptotic cells and preserved dopaminergic neurons in the substantia nigra of MPTP-intoxicated mice. These results show the neuroprotective properties of 100mg/kg silymarin and may be of interest in the treatment of PD.

Neuroprotective potential of silymarin against CNS disorders: insight into the pathways and molecular mechanisms of action.

Silymarin, a C25 containing flavonoid from the plant Silybum marianum, has been the gold standard drug to treat liver disorders associated with alcohol consumption, acute and chronic viral hepatitis, and toxin-induced hepatic failures since its discovery in 1960. Apart from the hepatoprotective nature, which is mainly due to its antioxidant and tissue regenerative properties, Silymarin has recently been reported to be a putative neuroprotective agent against many neurologic diseases including Alzheimer's and Parkinson's diseases, and cerebral ischemia. Although the underlying neuroprotective mechanism of Silymarin is believed to be due to its capacity to inhibit oxidative stress in the brain, it also confers additional advantages by influencing pathways such as β-amyloid aggregation, inflammatory mechanisms, cellular apoptotic machinery, and estrogenic receptor mediation. In this review, we have elucidated the possible neuroprotective effects of Silymarin and the underlying molecular events, and suggested future courses of action for its acceptance as a CNS drug for the treatment of neurodegenerative diseases.

Neuroprotective Effect of Silymarin by Modulation of Endogenous Biomarkers in Streptozotocin Induced Painful Diabetic Neuropathy

Aim of the present study is to investigate the effect of silymarin (SM), a potent antioxidant and anti-inflammatory compound on experimentally-induced Diabetic Neuropathy (DN) in male Wistar rats. Diabetes was induced by single streptozotocin (STZ) injection in rats. Pain-related behavior tests were performed including tail flick, paw-pressure analgesia and Rota-rod performance. Silymarin treatment was started after 21st day of diabetes induction and continued for 6 consecutive weeks. In serum fasting glucose, insulin, tumor necrosis factor-&alpha (TNF-α), interleukin-6 (IL-6) and interleukin-1&beta (IL-1&beta) levels were estimated and in sciatic nerve, thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), Superoxide Dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST), glutathione-reductase (GR) and glutathione peroxidase (GSH-Px) activities were measured. Diabetic rats developed neuropathy which was apparent from decreased tail-flick latency and paw-withdrawal latency.This was escorted by decreased motor coordination as assessed by performance on Rota-rod treadmill. Treatment with SM ameliorated the hyperalgesia, analgesia and improved motor coordination. STZ significantly increased TBARS and decreased GSH levels in sciatic nerve where silymarin treatment significantly protected those changes. Enzymatic activities such as SOD, CAT, GST, GSH-Px and GR were significantly inhibited in sciatic nerve of diabetic rats. The SM treatment significantly ameliorated decrease in antioxidant defense. Our results clearly demonstrate protective effect of SM is mediated through attenuation of oxidative stress and suggest therapeutic potential of SM in attenuation of diabetic neuropathy.

Neuroprotective effects of silymarin on sodium fluoride-induced oxidative stress

Silymarin is a well-known potent antioxidant agent. Numerous reports highlighted that antioxidant consumption can mitigate sodium fluoride induced neuronal damage. The present study aimed to examine the ameliorative potential of silymarin on sodium fluoride-induced oxidative stress using the rat brain as model. Silymarin (10 and 20mg/kg) and vitamin C (10mg/kg) were intraperitoneally administrated for seven days followed by one week of sodium fluoride (600ppm) treatment through drinking water. Antioxidant enzyme activities – superoxide dismutase and catalase – the levels of reduced glutathione and lipid peroxidation were evaluated in brain homogenates. The levels of lipid peroxidation were significantly increased in the sodium fluoride treated group (42.0±2.1nmolMDAeq/g tissue) compared to the control group (36.0±1.1nmolMDAeq/g tissue). Silymarin at 20mg/kg showed significant a reduction in the levels of lipid peroxidation (36.0±1.2nmolMDAeq/g tissue). Treatment of rats with sodium fluoride significantly reduced the activities of the antioxidant enzymes and the levels of reduced glutathione in brain homogenates. Pre-treatment with silymarin prevented the deleterious effects of sodium fluoride intoxication in a dose dependent response. In conclusion, sodium fluoride induced oxidative stress in rat brain which can be prevented with silymarin administration.