Protective effects of the flavonoid mixture, silymarin, on fetal rat brain and liver

Vesicle delivery systems of functional substances for precision nutrition

Vesicular delivery systems are highly ordered assemblies consisting of one or more concentric bilayers formed by the self-assembly of amphiphilic building blocks in the presence of water. In the field of functional food, vesicular delivery systems have been widely explored for effective formulations to deliver functional substances. With the effort of scientific research, certain categories of vesicular delivery systems have successfully been translated from the laboratory to the global market of functional food. This chapter aims to present comprehensively the various vesicular delivery systems, including their design, preparation methods, encapsulation of functional substances, and application in nutritional interventions.

Silybins are stereospecific regulators of the 20S proteasome

A reduced proteasome activity tiles excessive amyloid growth during the progress of protein conformational diseases (PCDs). Hence, the development of safe and effective proteasome enhancers represents an attractive target for the therapeutic treatment of these chronic disorders. Here we analyze two natural diastereoisomers belonging to the family of flavonolignans, Sil A and Sil B, by evaluating their capacity to increase proteasome activity. Enzyme assays carried out on yeast 20S (y20S) proteasome and in parallel on a permanently "open gate" mutant (α3ΔN) evidenced that Sil B is a more efficient 20S activator than Sil A. Conversely, in the case of human 20S proteasome (h20S) a higher affinity and more efficient activation is observed for Sil A. Driven by experimental data, computational studies further demonstrated that the taxifolin group of both diastereoisomers plays a crucial role in their anchoring to the α5/α6 groove of the outer α-ring. However, due to the different stereochemistry at C-7" and C-8" of ring D, only Sil A was able to reproduce the interactions responsible for h20S proteasome activation induced by their cognate regulatory particles. The provided silybins/h20S interaction models allowed us to rationalize their different ability to activate the peptidase activities of h20S and y20S. Our results provide structural details concerning the important role played by stereospecific interactions in driving Sil A and Sil B binding to the 20S proteasome and may support future rational design of proteasome enhancers.

Comparison Between Hesperidin, Coumarin, and Deferoxamine Iron Chelation and Antioxidant Activity Against Excessive Iron in the Iron Overloaded Mice

OBJECTIVE

Iron accumulation in the brain leads to the development of Alzheimer's and Parkinson's diseases. Nowadays, iron chelation therapy is the best way to decrease the side effects of iron and amyloid plaques accumulation. Iron chelators are commonly used for the treatment of Alzheimer's disease. Previous studies have shown that natural products such as phenol and flavonoid compounds could chelate heavy metals. In the current study, we examined the iron chelation activity of hesperidin and coumarin on the brain tissue of iron-overloaded mice.

METHODS

48 NMRI male mice were divided into eight groups (n = 6). Six groups were treated with iron dextran (100 mg/kg/day) four times a week for 6 weeks. After stopping the injections for a month, five groups of iron-overloaded mice were treated with hesperidin, coumarin, and desferal four times a week subsequent for four subsequent weeks. Finally, the mice were anesthetized, and blood samples were collected from the ventricle of the heart for subsequent examination. The brain tissues were isolated and fixed in the 4% paraformaldehyde solution for Perl's staining.

RESULTS

The results show that hesperidin and coumarin could strongly chelate excessive iron from the serum and deposit iron from the brain tissue compared to desferal group. Catalase and super oxidase activity were decreased in the iron-overloaded group, but in the treated group by hesperidin and coumarin, the enzyme's activity was increased significantly.

CONCLUSION

Hesperidin and coumarin, as natural products, are powerful options to chelate iron ions and increase the activity of antioxidant enzymes.

Phytosomes as Innovative Delivery Systems for Phytochemicals: A Comprehensive Review of Literature

Nowadays, medicinal herbs and their phytochemicals have emerged as a great therapeutic option for many disorders. However, poor bioavailability and selectivity might limit their clinical application. Therefore, bioavailability is considered a notable challenge to improve bio-efficacy in transporting dietary phytochemicals. Different methods have been proposed for generating effective carrier systems to enhance the bioavailability of phytochemicals. Among them, nano-vesicles have been introduced as promising candidates for the delivery of insoluble phytochemicals. Due to the easy preparation of the bilayer vesicles and their adaptability, they have been widely used and approved by the scientific literature. The first part of the review is focused on introducing phytosome technology as well as its applications, with emphasis on principles of formulations and characterization. The second part provides a wide overview of biological activities of commercial and non-commercial phytosomes, divided by systems and related pathologies. These results confirm the greater effectiveness of phytosomes, both in terms of biological activity or reduced dosage, highlighting curcumin and silymarin as the most formulated compounds. Finally, we describe the promising clinical and experimental findings regarding the applications of phytosomes. The conclusion of this study encourages the researchers to transfer their knowledge from laboratories to market, for a further development of these products.

Trehalose Conjugates of Silybin as Prodrugs for Targeting Toxic Aβ Aggregates

Alzheimer's disease (AD) is linked to the abnormal accumulation of amyloid β peptide (Aβ) aggregates in the brain. Silybin B, a natural compound extracted from milk thistle (Silybum marianum), has been shown to significantly inhibit Aβ aggregation in vitro and to exert neuroprotective properties in vivo. However, further explorations of silybin B's clinical potential are currently limited by three main factors: (a) poor solubility, (b) instability in blood serum, and (c) only partial knowledge of silybin's mechanism of action. Here, we address these three limitations. We demonstrate that conjugation of a trehalose moiety to silybin significantly increases both water solubility and stability in blood serum without significantly compromising its antiaggregation properties. Furthermore, using a combination of biophysical techniques with different spatial resolution, that is, TEM, ThT fluorescence, CD, and NMR spectroscopy, we profile the interactions of the trehalose conjugate with both Aβ monomers and oligomers and evidence that silybin may shield the "toxic" surfaces formed by the N-terminal and central hydrophobic regions of Aβ. Finally, comparative analysis with silybin A, a less active diastereoisomer of silybin B, revealed how even subtle differences in chemical structure may entail different effects on amyloid inhibition. The resulting insight on the mechanism of action of silybins as aggregation inhibitors is anticipated to facilitate the future investigation of silybin's therapeutic potential.

Silymarin protects the structure of kidney in the neonatal rats exposed to maternal cadmium toxicity: A stereological study

The present study aimed to investigate the protective effect of silymarin on maternal cadmium toxicity complications in the kidney of neonatal rats. Forty adults Wistar female rats were selected and placed with male rats for copulation. The pregnant animals were randomly divided into five groups (n = 8) including control, sham, silymarin, cadmium, and silymarin + cadmium. The animals received 400 mg L^-1 cadmium and 100 mg kg^-1 silymarin (sub-cutaneously, three days per week, three weeks). Two-day neonates were dissected and their right kidneys were fixed in 10.00% buffered formalin solution and processed by standard paraffin embedding. Tissue sections were stained by hematoxylin and eosin and analyzed histologically and stereologically. The data were statistically analyzed by SPSS using a one-way ANOVA test and Tukey's post-hoc. The results showed that silymarin significantly increased the neonatal rats' weight compared to the control group. Cadmium significantly decreased the weight of neonatal rats' kidneys. The results of histological studies indicated that cadmium caused subacute glomerulosclerosis, severe damage to urinary tubules such as tubular necrosis, and severe hyperemia in the medulla, but silymarin could preserve these complications. Stereological results revealed that cadmium decreased the total volume of kidney, medulla, and proximal and distal tubules and increased interstitial tissue and indicated the protective effects of silymarin on maternal cadmium toxicity complications in the kidney tissue of neonatal rats. It can be concluded that the administration of silymarin during pregnancy may be used as a useful and effective way of protecting the maternal cadmium toxicity complications in the kidney tissue of neonatal rats.

Inhibition of Aβ Amyloid Growth and Toxicity by Silybins: The Crucial Role of Stereochemistry

The self-assembling of the amyloid β (Aβ) peptide into neurotoxic aggregates is considered a central event in the pathogenesis of Alzheimer's disease (AD). Based on the "amyloid hypothesis", many efforts have been devoted to designing molecules able to halt disease progression by inhibiting Aβ self-assembly. Here, we combine biophysical (ThT assays, TEM and AFM imaging), biochemical (WB and ESI-MS), and computational (all-atom molecular dynamics) techniques to investigate the capacity of four optically pure components of the natural product silymarin (silybin A, silybin B, 2,3-dehydrosilybin A, 2,3-dehydrosilybin B) to inhibit Aβ aggregation. Despite TEM analysis demonstrated that all the four investigated flavonoids prevent the formation of mature fibrils, ThT assays, WB and AFM investigations showed that only silybin B was able to halt the growth of small-sized protofibrils thus promoting the formation of large, amorphous aggregates. Molecular dynamics (MD) simulations indicated that silybin B interacts mainly with the C-terminal hydrophobic segment ³⁵MVGGVV⁴⁰ of Aβ40. Consequently to silybin B binding, the peptide conformation remains predominantly unstructured along all the simulations. By contrast, silybin A interacts preferentially with the segments ¹⁷LVFF²⁰ and ²⁷NKGAII³² of Aβ40 which shows a high tendency to form bend, turn, and β-sheet conformation in and around these two domains. Both 2,3-dehydrosilybin enantiomers bind preferentially the segment ¹⁷LVFF²⁰ but lead to the formation of different small-sized, ThT-positive Aβ aggregates. Finally, in vivo studies in a transgenic Caenorhabditis elegans strain expressing human Aβ indicated that silybin B is the most effective of the four compounds in counteracting Aβ proteotoxicity. This study underscores the pivotal role of stereochemistry in determining the neuroprotective potential of silybins and points to silybin B as a promising lead compound for further development in anti-AD therapeutics.

The Impact of Silymarin on Improvement of Hepatic Abnormalities in Patients with Severe Preeclampsia: A Randomized Clinical Trial

Background

Preeclampsia is a pregnancy-specific disorder, associated with increased blood pressure and proteinuria, and in extreme cases it can also cause liver and kidney problems.

Objective

To determine the impact of silymarin on the improvement of severe preeclampsia.

Methods

This randomized clinical trial was conducted at Hajar Hospital in Shahrekord, Iran, from April 2014 to September 2015. Sixty patients whose pregnancy had ended as a result of severe preeclampsia, were entered into the study. Patients were randomly divided into two groups of thirty study and control groups. In addition to current treatment for preeclampsia, case groups were administered 70 mg of silymarin, three and twenty four hours after the termination of pregnancy. The control group received placebo at the same time. The blood pressure and AST, ALT, ALP, LDH, uric acid, bilirubin and kidney tests were compared at the baseline and 12, 36 and 60 hours post-measurements in two groups by SPSS software, version 22, by the ANOVA test, and by the independent-samples t-test.

Results

AST and ALT liver enzyme levels decreased significantly 36 and 60 hours after the termination of pregnancy in the study group compared to the control group (p <0.01).

Conclusion

Silymarin is used to treat liver disorders, and has beneficial results. It seems that this drug can be used for accelerating improvement of liver disorders in severe preeclampsia. However, adjusting the dose of the drug for the treatment of liver disorders in severe preeclampsia requires further studies.

Clinical trial registration

The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the Irct ID: IRCT201509042388/N1.

Funding

Shahrekord University of Medical Sciences supported this research (project no. 2006).

The impact of Silymarin on improvement of platelet abnormalities in patients with severe preeclampsia

Background

Preeclampsia is a pregnancy-specific disorder that is associated with an increase in blood pressure and proteinuria; in severe cases, it can cause platelet abnormalities. Silymarin is the extract of Silybum marianum, which is recognized as a safe antioxidant drug.

Objective

To determine the impact of Silymarin on the improvement of severe preeclampsia in 60 patients with severe preeclampsia.

Methods

In this double-blind clinical trial study, This study included 60 patients whose pregnancies were terminated because of severe preeclampsia and who were referred to Hajar Hospital in Shahrekord, Iran, from April 2014 to September 2015. The patients were divided randomly into two groups, i.e., a group of 30 patients and a control group of 30 patients. In addition to the current treatments for preeclampsia, The members of the study group were administered 70 mg of Silymarin at three hours and 24 hours after the termination of their pregnancies. The control group received a placebo at the same times. Platelet count tests were compared at the baseline and at 12, 36, and 60 hours post-measurements in the two groups by SPSS software, version 22, by the ANOVA test, and by the independent-samples t-test.

Results

At the baseline, the two groups were not significantly different in terms of various criteria, such as age, BMI, and platelet counts. There were no significant differences between the two groups regarding the number of platelets at 12, 36, and 60 h after their pregnancies were ended (p > 0.01).

Conclusions

The results of this study indicated that, although oxidative factors are involved in the incidence of complications of preeclampsia, e.g., thrombocytopenia, merely using an oxidative agent does not alleviate this effect. This indicated that other factors likely are involved in the pathogenesis of this disease. Additional studies are needed to prove the beneficial effects of this drug in the treatment of preeclampsia.

Clinical trial registration

The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the Irct ID: IRCT201509042388/N1.

Funding

Shahrekord University of Medical Sciences supported this research (project no. 2006).

Protective effects of silibinin and its possible mechanism of action in mice exposed to chronic unpredictable mild stress

Silibinin, a natural flavonoid antioxidant isolated from extracts of the milk thistle herb, has recently been identified as having anti-hepatotoxic and anticancer properties. In this paper, we investigated the effects of silibinin on behavior and neuroplasticity in mice subjected to chronic unpredictable mild stress (CUMS). After 5 consecutive weeks of CUMS, the mice were treated with silibinin (100 mg/kg, 200 mg/kg and 400 mg/kg by oral gavage) for 3 consecutive weeks. The results showed that silibinin administration significantly alleviated the CUMS-induced depressive-like behavior, including the total number of squares crossed and the frequency of rearing in the open field test, the immobility time in the tail suspension test and the forced swimming test. Furthermore, silibinin treatment increased the levels of brain-derived neurotrophic factor (BDNF), serotonin (5-HT) and norepinephrine (NE) in the prefrontal cortex and hippocampus. Our study provides new insight into the protective effects of silibinin on the depressive status of CUMS mice, specifically by improving neuroplasticity and neurotransmission.

Neurotrophic and antioxidant effects of silymarin comparable to 4-methylcatechol in protection against gentamicin-induced ototoxicity in guinea pigs

BACKGROUND

Despite that gentamicin is a very effective aminoglycoside, its potential ototoxicity which is of irreversible nature makes a challenge and limitation for its use. This study was designed to investigate possible neurotrophic and antioxidant effects of silymarin comparable to 4-methylcatechol in protection against gentamicin-induced ototoxicity.

METHODS AND RESULTS

Twenty pigmented guinea pigs were divided into four equal groups, where group I served as normal control group. The other groups received gentamicin (120 mg/kg/day, ip) for 19 days where group II given vehicle of 1% CMC, group III and group IV were pre-treated 2h before gentamicin by 4-methylcatechol (10 μg/kg, ip) and silymarin (100mg/kg, oral gavage), respectively. The main findings indicated that silymarin exhibited restoration of nerve growth factor (NGF) levels and increased tropomyosin-related kinase receptors-A (Trk-A) m-RNA expression in cochlear tissue and preservation of hair cells of organ of Corti by scanning electron microscopy (SEM) with significant decrease in auditory brainstem response (ABR) threshold compared to 4-methylcatechol. Only silymarin caused significant amelioration in oxidative stress state by reducing malondialdehyde (MDA) levels and increasing catalase activity.

CONCLUSIONS

Silymarin exerts superiority over 4-methylcatechol when recommended as protective agent against gentamicin ototoxicity based on its efficient neurotrophic and antioxidant activities.

Silymarin effect on amyloid-β plaque accumulation and gene expression of APP in an Alzheimer's disease rat model

Background

The deposition of amyloid peptides is associated with Alzheimer’s disease (AD). These amyloid peptides are derived from the amyloid protein precursor (APP). Silymarin, a standardized extract of milk thistle, which is currently used in liver diseases, may be effective in the inhibition of amyloid formation. However, its effect has not been assessed on APP expression.

Results

In this study, first, the effect of silymarin was examined on the passive avoidance learning in a rat model of AD. This model was induced by the intracerebroventricular injection of Aβ peptide (Aβ_1–42) in Wistar rats. Rats were treated with 70 and 140 mg/kgof the extract, once a day, for 4 weeks. Memory function that was evaluated in a shuttle-cage test, showed improvement upon administration of this extract. Brain amyloid plaques had also decreased upon administration of the extract. Furthermore, APP gene expression was compared in treated and untreated groups. The result showed that silymarin was able to suppress APP expression.

Conclusion

Our results are in accordance with the in vitro tests concerning the positive antiamyloidogenic property of the main component of silymarin, namely silibinin. We suggest that the beneficial effect of sylimarin in the AD model is related to its capacity to disaggregate amyloid plaques and to suppress APP expression. Considering the limited side effects of silymarin, this compound could be of use in AD therapy.

Anthocyanins protect against ethanol-induced neuronal apoptosis via GABAB1 receptors intracellular signaling in prenatal rat hippocampal neurons

Here, we investigated the possible involvement of gamma-aminobutyric acid B1 receptor (GABAB1R) in mediating the protective effects of black soybean anthocyanins against ethanol-induced apoptosis in prenatal hippocampal neurons because GABARs are known to play an important role in the development of central nervous system. Treatments were performed on primary cultures of prenatal rat hippocampal neurons transfected with or without GABAB1R small interfering RNA (siRNA). The results showed that, when ethanol treatment was followed by anthocyanins treatment, cellular levels of proapoptotic proteins such as Bax, activated caspase-3, and cleaved poly (ADP-ribose) polymerase 1 (PARP-1) were decreased, and the cellular level of the antiapoptotic protein Bcl-2 was increased compared to treatment with ethanol alone. Furthermore, the effects of ethanol on cellular levels of GABAB1R and its downstream signaling molecules such as protein kinase A, calcium/calmodulin-dependent protein kinase II (CaMKII), and phosphorylated cAMP response element binding protein were diminished or reversed by anthocyanins treatment. The ability of anthocyanins to reverse the effects of ethanol on cellular levels of Bax, Bcl-2, active caspase-3, cleaved PARP-1, GABAB1R, and CaMKII were abrogated in cells transfected with GABAB1R siRNA. In a GABAB1R-dependent manner, anthocyanins also inhibited the ability of ethanol to elevate intracellular free Ca(2+) level and increase the proportion of cells with low mitochondrial membrane potential in the population. Cell apoptosis assay and morphological studies also confirmed the neuroprotective effect of anthocyanins against ethanol via GABAB1R. Our data suggest that GABAB1R plays an important role in the neuroprotective effects of anthocyanins against ethanol.

Hepatoprotective effect of poly herbal formulation against various hepatotoxic agents in rats

Background:

Individually Andrographis paniculata Nees. (Acanthaceae), Phyllanthus niruri Linn.(Euphorbiaceae) and Phyllanthus emblica Linn. single plant extracts have been reported to have hepatoprotective activity. However, literature survey shows that no sufficient scientific data has been publish on pharmacological evaluation of these plants in combined form.

Method:

Hepatoprotective activity of the polyherbal hepatoprotaective formulation (PHF)-containing spray-dried aqueous extracts of Andrographis paniculata Nees. (Acanthaceae), Phyllanthus niruri Linn. (Euphorbiaceae) and Phyllanthus emblica Linn. (Euphorbiaceae), was screened against paracetamol, carbon tetrachloride (CCl₄), and ethanol-induced hepatic damage in rats. PHF was evaluated by measuring levels of serum marker enzymes like SGOT, SGPT, ALP, direct bilirubin (DB), and lactate dehydrogenase (LDH). The histological studies were also studied support the biochemical parameters. Silymarin was used as standard drug.

Results:

Administration of PHF (100 and 200 mg/kg p.o.) significantly inhibited paracetamol, CCl₄ and ethanol-induced elevation levels of SGPT, SGOT, ALP, DB and LDH. A comparative histopathological study of liver exhibited almost normal architecture as compared to toxicant group.

Conclusion:

Results suggests that the hepatoprotective effects of PHF might be useful for liver protection due to combined action of all plant extracts along with their phytoconstituents.

Silymarin protects neurons from oxidative stress associated damages in focal cerebral ischemia: a behavioral, biochemical and immunohistological study in Wistar rats

Cerebral stroke is the third largest cause of death and the severe leading cause of disability, thus have astronomical financial and social burden worldwide. Accumulated evidence suggests that ROS can be scavenged through utilizing natural antioxidant compounds present in foods and medicinal plants. In this study, we examined whether silymarin, an antioxidant, present in the milk of thistle can prevent or slowdown neuronal injury in focal cerebral ischemia. Male Wistar rats were pre-treated with silymarin (200mg/kg body weight, dissolved in 0.3 % sodium carboxymethyl cellulose, once orally) for 15 days. On day 16, they underwent a transient 2h suture-occlusion of the middle cerebral artery followed by 22 h of reperfusion. Rats were tested for neurobehavioral activity after 22 h reperfusion. Silymarin was found to be successful in upregulating the antioxidant status and lowering the apoptotic responses, and functional recovery returned close to the baseline. This study revealed that silymarin, a naturally occurring flavone from the milk thistle (Silybum marianum), may be helpful in slowing down the progression of neurodegeneration in focal cerebral ischemia. These results suggest that the neuroprotective potential of silymarin is mediated through its anti-oxidative and anti-apoptotic properties.

The role of oxidative stress in fetal alcohol spectrum disorders

The ingestion of alcohol/ethanol during pregnancy can result in abnormal fetal development in both humans and a variety of experimental animal models. Depending on the pattern of consumption, the dose, and the period of exposure to ethanol, a myriad of structural and functional deficits can be observed. These teratogenic effects are thought to result from the ethanol-induced dysregulation of a variety of intracellular pathways ultimately culminating in toxicity and cell death. For instance, ethanol exposure can lead to the generation of reactive oxygen species (ROS) and produce an imbalance in the intracellular redox state, leading to an overall increase in oxidative stress. In the present review we will provide an up-to-date summary on the effects of prenatal/neonatal ethanol exposure on the levels of oxidative stress in the central nervous system (CNS) of experimental models of fetal alcohol spectrum disorders (FASD). We will also review the evidence for the use of antioxidants as potential therapeutic strategies for the treatment of some of the neuropathological deficits characteristic of both rodent models of FASD and children afflicted with these disorders. We conclude that an imbalance in the intracellular redox state contributes to the deficits seen in FASD and suggest that antioxidants are potential candidates for the development of novel therapeutic strategies for the treatment of these developmental disorders.

Anthocyanins: are they beneficial in treating ethanol neurotoxicity?

Heavy alcohol exposure produces profound damage to the developing central nervous system (CNS) as well as the adult brain. Children with fetal alcohol spectrum disorders (FASD) have a variety of cognitive, behavioral, and neurological impairments. FASD currently represents the leading cause of mental retardation. Excessive alcohol consumption is associated with Wernicke-Korsakoff syndrome (WKS) and neurodegeneration in the adult brain. Although the cellular/molecular mechanism underlying ethanol's neurotoxicity has not been fully understood, it is generally believed that oxidative stress plays an important role. Identification of neuroprotective agents that can ameliorate ethanol neurotoxicity is an important step for developing preventive/therapeutic strategies. Targeting ethanol-induced oxidative stress using natural antioxidants is an attractive approach. Anthocyanins, a large subgroup of flavonoids present in many vegetables and fruits, are safe and potent antioxidants. They exhibit diverse potential health benefits including cardioprotection, anti-atherosclerotic activity, anti-cancer, anti-diabetic, and anti-inflammation properties. Anthocyanins can cross the blood-brain barrier and distribute in the CNS. Recent studies indicate that anthocyanins represent novel neuroprotective agents and may be beneficial in ameliorating ethanol neurotoxicity. In this review, we discuss the evidence and potential of anthocyanins in alleviating ethanol-induced damage to the CNS. Furthermore, we discuss possible underlying mechanisms as well as future research approaches necessary to establish the therapeutic role of anthocyanins.

Supramolecular phospholipids-polyphenolics interactions: the PHYTOSOME strategy to improve the bioavailability of phytochemicals

The poor and/or erratic oral bioavailability of polyphenolics can be improved using the PHYTOSOME delivery system, a strategy that enhances the rate and the extent of solubilization into aqueous intestinal fluids and the capacity to cross biomembranes. Phospholipids show affinity for polyphenolics, and form supramolecular adducts having a definite stoichiometry. This article reviews the preparation and characterization of PHYTOSOME complexes and their activity in various medicinal (cardiovascular, anti-inflammatory, hepatoprotective, anticancer) and cosmetic (skin aging) realms of application.

Anti- and pro-mutagenic effects of silymarin in the Ames bacterial reverse mutation assay

Silymarin, a polyphenolic flavonoid isolated from milk thistle (Silybum marianum), is being used clinically in Europe and Asia for the treatment of liver diseases. Silymarin has a strong antioxidative action capable of scavenging both free radicals and reactive oxygen species responsible for cancer. Silymarin, a powerful hepatoprotective and antioxidant, was chosen in the present study and was tested for its antimutagenic activity using an in vitro test, the Ames bacterial reverse mutation assay. The results indicated that silymarin showed a significant mutagenicity in frame shift mutant strains (TA97a and TA98) with metabolic activation. This compound also showed stronger antimutagenic effect against 2-aminofluorene and 4-nitroquinoline N-oxide induced mutation. When pre-, co- and post-treatment of silymarin was carried out, it showed stronger antimutagenic activity in the post-treatment with 2-aminofluorene and 4-nitroquinoline N-oxide in TA97a and TA98 strains.

Silibinin attenuates amyloid beta(25-35) peptide-induced memory impairments: implication of inducible nitric-oxide synthase and tumor necrosis factor-alpha in mice

In Alzheimer's disease (AD), the deposition of amyloid peptides is invariably associated with oxidative stress and inflammatory responses. Silibinin (silybin), a flavonoid derived from the herb milk thistle, has potent anti-inflammatory and antioxidant activities. However, it remains unclear whether silibinin improves amyloid beta (Abeta) peptide-induced neurotoxicity. In this study, we examined the effect of silibinin on the fear-conditioning memory deficits, inflammatory response, and oxidative stress induced by the intracerebroventricular injection of Abeta peptide(25-35) (Abeta(25-35)) in mice. Mice were treated with silibinin (2, 20, and 200 mg/kg p.o., once a day for 8 days) from the day of the Abeta(25-35) injection (day 0). Memory function was evaluated in cued and contextual fear-conditioning tests (day 6). Nitrotyrosine levels in the hippocampus and amygdala were examined (day 8). The mRNA expression of inducible nitric-oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-alpha) in the hippocampus and amygdala was measured 2 h after the Abeta(25-35) injection. We found that silibinin significantly attenuated memory deficits caused by Abeta(25-35) in the cued and contextual fear-conditioning test. Silibinin significantly inhibited the increase in nitrotyrosine levels in the hippocampus and amygdala induced by Abeta(25-35). Nitrotyrosine levels in these regions were negatively correlated with memory performance. Moreover, real-time RT-PCR revealed that silibinin inhibited the overexpression of iNOS and TNF-alpha mRNA in the hippocampus and amygdala induced by Abeta(25-35). These findings suggest that silibinin (i) attenuates memory impairment through amelioration of oxidative stress and inflammatory response induced by Abeta(25-35) and (ii) may be a potential candidate for an AD medication.

Silibinin prevents amyloid beta peptide-induced memory impairment and oxidative stress in mice

BACKGROUND AND PURPOSE

Accumulated evidence suggests that oxidative stress is involved in amyloid beta (Abeta)-induced cognitive dysfunction. Silibinin (silybin), a flavonoid derived from the herb milk thistle (Silybum marianum), has been shown to have antioxidative properties; however, it remains unclear whether silibinin improves Abeta-induced neurotoxicity. In the present study, we examined the effect of silibinin on the memory impairment and accumulation of oxidative stress induced by Abeta(25-35) in mice.

EXPERIMENTAL APPROACH

Aggregated Abeta(25-35) (3 nmol) was intracerebroventricularly administered to mice. Treatment with silibinin (2, 20 and 200 mg.kg(-1), once a day, p.o.) was started immediately after the injection of Abeta(25-35). Locomotor activity was evaluated 6 days after the Abeta(25-35) treatment, and cognitive function was evaluated in a Y-maze and novel object recognition tests 6-11 days after the Abeta(25-35) treatment. The levels of lipid peroxidation (malondialdehyde) and antioxidant (glutathione) in the hippocampus were measured 7 days after the Abeta(25-35) injection.

KEY RESULTS

Silibinin prevented the memory impairment induced by Abeta(25-35) in the Y-maze and novel object recognition tests. Repeated treatment with silibinin attenuated the Abeta(25-35)-induced accumulation of malondialdehyde and depletion of glutathione in the hippocampus.

CONCLUSIONS AND IMPLICATIONS

Silibinin prevents memory impairment and oxidative damage induced by Abeta(25-35) and may be a potential therapeutic agent for Alzheimer's disease.

Protective effect of silymarin on oxidative stress in rat brain

Brain is susceptible to oxidative stress and it is associated with age-related brain dysfunction. Previously, we have pointed out a dramatic decrease of glutathione levels in the rat brain after acetaminophen (APAP) oral administration overdose. Silymarin (SM) is a mixture of bioactive flavonolignans isolated from Silybum marianum (L.) Gaertn., employed usually in the treatment of alcoholic liver disease and as anti-hepatotoxic agent in humans. In this study, we have evaluated the effect of SM on enzymatic and non enzymatic antioxidant defensive systems in rat brain after APAP-induced damage. Male albino Wistar rats were treated with SM (200 mg/kg/die orally) for three days, or with APAP single oral administration (3 g/kg) or with SM (200 mg/kg/die orally) for 3 days and APAP single oral administration (3 g/kg) at third day. Successively the following parameters were measured: reduced and oxidized glutathione (GSH and GSSG), ascorbic acid (AA), enzymatic activity variations of superoxide dismutase (SOD) and malondialdehyde levels (MDA). Our results showed a significant decrease of GSH levels, AA levels and SOD activity and an increase of MDA and GSSG levels after APAP administration. After SM administration GSH and AA significantly increase and SOD activity was significantly enhanced. In the SM+APAP group, GSH values significantly increase and the others parameters remained unchanged respect to control values. These results suggest that SM may to protect the SNC by oxidative damage for its ability to prevent lipid peroxidation and replenishing the GSH levels.

A new silymarin preparation based on solid dispersion technique

Silymarin is a hepatoprotective agent that is poorly soluble in water. The present study describes a new preparation of solid dispersions in the form of "dripping pills" designed to enhance solubility. Dripping pills of silymarin were prepared at a 1:4 ratio by the traditional fusion method with the use of a mixture of silymarin and polyethylene glycol 6000 (PEG 6000). The prepared dripping pills were spherical and 3 to 4 mm in diameter, with an average weight of 30 mg per pill and with each pill containing 5 mg of silymarin. The dissolution rates of silymarin in dripping pill and of 3 other silymarin preparations, including Yiganling Film-Coating Tablet, Yiganling Sugar-Coating Tablet, and Legalon Capsule, were determined in pH 1.2 medium. The dissolution rate (T50) of the silymarin dripping pill was found to be significantly higher (by a factor of 7.5-11) than those of the other 3 preparations.

Effect of tetrahydrocurcumin on erythromycin estolate-induced lipid peroxidation in rats

Erythromycin estolate (EME), a potent macrolide antibiotic, generates free radicals, but their role in the development of liver toxicity is not yet well understood. The present study was carried out to investigate the effect of the antioxidant drug tetrahydrocurcumin (a metabolite of curcumin, the main component of turmeric) against EME-induced lipid peroxidation in rats. The oral administration of combined THC (80 mg/kg body weight) and EME (800 mg/kg body weight) for 15 days significantly decreased lipid peroxidation and enhanced cellular antioxidant defenses when compared with the group treated with EME alone. Supplemental histopathological examination of liver sections revealed that THC had a better antioxidant effect than Silymarin (200 mg/kg body weight), a reference drug. The results of this study indicate that THC affords significant protection against EME-induced lipid peroxidation.

Silybin and silymarin--new effects and applications

This article aims to review critically literature published mainly within this millennium on the new and emerging applications of silymarin, the polyphenolic fraction from the seeds of Silybum marianum and its main component silybin. Silymarin and silybin used so far mostly as hepatoprotectants were shown to have other interesting activities as e.g., anticancer and canceroprotective. These activities were demonstrated in a large variety of illnesses of different organs as e.g., prostate, lungs, CNS, kidneys, pancreas and others. Besides the cytoprotective activity of silybin mediated by its antioxidative and radical-scavenging properties also new activities based on the specific receptor interaction were discovered--e.g., inhibition and modulation of drug transporters, P-glycoproteins, estrogenic receptors, nuclear receptors and some others. New derivatives of silybin open new ways to its therapeutic applications. Pharmacology dealing with optically pure silybin diastereomers may suggest new mechanisms of its action.

The effects of ethanol and silymarin treatment during gestation on spatial working memory

BACKGROUND

Using a rat model we have found that the bioflavonoid silymarin (SY) ameliorates some of the negative consequences of in utero exposure to ethanol (EtOH). In the current study our aim was to determine if spatial working memory (SWM) was impaired in offspring whose mothers were maintained on a liquid diet containing EtOH during different gestational weeks. We also determined if SWM was altered with a concomitant administration of SY with EtOH during specific gestational weeks.

METHODS

We provided pregnant Fischer/344 rats with liquid diets containing 35% EtOH derived calories (EDC) during specific weeks of the gestational period. A silymarin/phospholipid compound containing 29.8% silybin co-administered with EtOH was also administered during specific weeks of the gestational period. We tested SWM of the offspring with a radial arm maze on postnatal day (PND) 60. After testing the rats were sacrificed and their brains perfused for later analysis.

RESULTS

We observed SWM deficits, as well as a significantly lower brain weight in female offspring born of mothers treated with EtOH during the third week of gestation in comparison to mothers treated during either the first or second weeks of gestation. Rats from any group receiving EtOH in co-administration with SY showed no significant deficits in SWM.

CONCLUSION

EtOH treatment during the last week of gestation had the greatest impact on SWM. The addition of SY to the EtOH liquid diet appeared to ameliorate the EtOH-induced learning deficits.

Hepatoprotective activity of Moringa oleifera on antitubercular drug-induced liver damage in rats

Moringa oleifera Lam (Moringaceae), commonly known as "Drumstick," is used in Indian folk medicine for the treatment of various illness. We have evaluated the hepatoprotective effect of an ethanolic extract of M. oleifera leaves on liver damage induced by antitubercular drugs such as isoniazid (INH), rifampicin (RMP), and pyrazinamide (PZA) in rats. Oral administration of the extract showed a significant protective action made evident by its effect on the levels of glutamic oxaloacetic transaminase (aspartate aminotransferase), glutamic pyruvic transaminase (alanine aminotransferase), alkaline phosphatase, and bilirubin in the serum; lipids, and lipid peroxidation levels in liver. This observation was supplemented by histopathological examination of liver sections. The results of this study showed that treatment with M. oleifera extracts or silymarin (as a reference) appears to enhance the recovery from hepatic damage induced by antitubercular drugs.

Antioxidants and fetal protection against ethanol teratogenicity. I. Review of the experimental data and implications to humans

Ethanol is the most common human teratogen, and heavy drinking during pregnancy can result in serious adverse outcomes to the fetus. The cellular mechanisms by which ethanol induces damage in utero are not well understood, while induction of oxidative stress is believed to be one putative mechanism. Our objective is to review the data of antioxidant effects in experimental models of fetal alcohol syndrome. Prior to the description of the available experimental data, we will briefly review the mechanisms leading to ethanol-induced oxidative stress. Ethanol-induced oxidative damage to the fetus could be attenuated by a variety of antioxidants as was documented in whole animal and tissue culture studies. Experiments, retrieved from the literature search, are described and criticized. Although experimental data are still limited, the application of a treatment strategy that includes antioxidants is justified since antioxidant treatment in human pregnancy for pre-eclampsia was demonstrated to be safe and effective. The available experimental evidence and the safety of vitamins C and E in pregnancy suggest that experimental use of antioxidants in alcohol-consuming mothers should be seriously considered to reduce fetal alcohol damage.

Impact of in utero exposure to EtOH on corpus callosum development and paw preference in rats: protective effects of silymarin

BACKGROUND

Using a rat model we have found that the bioflavonoid silymarin (SY) ameliorates some of the negative consequences of in utero exposure to ethanol (EtOH). In the current study our aim was to determine if laterality preference and corpus callosum development were altered in rat offspring whose mothers were provided with a concomitant administration of SY with EtOH throughout gestation.

METHODS

We provided pregnant Fisher/344 rats with liquid diets containing 35% ethanol derived calories (EDC) throughout the gestational period. A silymarin/phospholipid compound containing 29.8% silybin was co administered with EtOH to a separate experimental group. We tested the offspring for laterality preference at age 12 weeks. After testing the rats were sacrificed and their brains perfused for later corpus callosum extraction.

RESULTS

We observed incomplete development of the splenium in the EtOH-only offspring. Callosal development was complete in all other treatment groups. Rats from the EtOH-only group displayed a left paw preference; whereas control rats were evenly divided between right and left paw preference. Inexplicably both SY groups were largely right paw preferring.

CONCLUSIONS

The addition of SY to the EtOH liquid diet did confer some ameliorative effects upon the developing fetal rat brain.

Dietary flavonoids as potential neuroprotectants

There is an increasing awareness of the role of certain nutritional components, including dietary flavonoids found in fruit, vegetables and beverages, in the maintenance of health and prevention of chronic diseases. In this regard, recent studies highlight an exciting role with respect to their potential neuroprotective actions, in particular towards deficits commonly observed with aging, such as reduced performance of cognitive, memory and learning tasks. These neurological functions, and possible mechanisms involved in controlling them, can be influenced by supplementation of single dietary flavonoids, or as part of a flavonoid-rich preparation. With this, a renewed emphasis is aimed at further understanding their modes and sites of action. Moreover a common theme among many in vitro studies examining mechanisms of neuroprotection is the failure to include biologically relevant metabolites of the flavonoids known to enter the circulation, and thus most likely to be bioavailable to cells and tissues. This oversight will ultimately influence the mechanisms of action proposed to explain the neuroprotection observed in animals and human studies. As such, emerging findings suggest a variety of potential mechanisms of action of flavonoids and their bioavailable metabolites in cytoprotection against oxidative stress, which may be independent of conventional antioxidant reducing activities. Such mechanisms might involve their interaction with cell signalling cascades, their influence on gene expression and the down regulation of pathways leading to cell death.

Fetoprotectivity of the flavanolignan compound siliphos against ethanol-induced toxicity

Of the three flavanolignans that are found in silymarin (Silybum marianum [L.] Gaertn.), silybin is thought to be the primary therapeutic constituent. To test the capacity of silybin to protect the rat fetus from toxic effects of maternally ingested EtOH we did the following: Adult female rats were assigned to one of four groups; EtOH, EtOH/silybin, pair-fed control, and chow fed control. Silybin was orally administered as Siliphos(R), which is one part silybin to two parts phosphatidylcholine. All groups except the chow-fed control were maintained on a liquid diet throughout pregnancy. On day 21 of pregnancy the rats were killed and the fetuses removed. Gamma glutamyl transpeptidase (GGTP) activity and glutathione (GSH) levels were determined for liver and brain tissue for both the fetuses and the dams. Maternal and fetal GGTP activity in the EtOH rats was significantly higher than that of pair-fed controls, whereas the GGTP activity observed in the Siliphos(R)/EtOH rats was not elevated. Fetal mortality rates in the EtOH rats significantly exceeded those of all three other groups.