Hepatoprotective effect of silymarin

Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated review

Milk thistle (Silybum marianum) is a medicinal plant from the Asteraceae family. Silymarin is the major constituent of milk thistle extract and is a mixture of some flavonolignans such as silybin, which is the most active component of silymarin. It is most commonly known for its hepatoprotective effect. Also, studies have shown other therapeutic effects such as anticancer, anti-Alzheimer, anti-Parkinson, and anti-diabetic, so its safety is very important. It has no major toxicity in animals. Silymarin was mutagen in Salmonella typhimurium strains in the presence of metabolic enzymes. Silybin, silydianin, and silychristin were not cytotoxic and genotoxic at concentration of 100 μM. Silymarin is safe in humans at therapeutic doses and is well tolerated even at a high dose of 700 mg three times a day for 24 weeks. Some gastrointestinal discomforts occurred like nausea and diarrhea. One clinical trial showed silymarin is safe in pregnancy, and there were no anomalies. Consequently, caution should be exercised during pregnancy, and more studies are needed especially in humans. Silymarin has low-drug interactions, and it does not have major effects on cytochromes P-450. Some studies demonstrated that the use of silymarin must be with caution when co-administered with narrow therapeutic window drugs.

A significant therapeutic effect of silymarin administered alone, or in combination with chemotherapy, in experimental pulmonary tuberculosis caused by drug-sensitive or drug-resistant strains: In vitro and in vivo studies

For many years, tuberculosis (TB) has been a major public health problem worldwide. Advances for treatment and eradication have been very limited. Silymarin (Sm) is a natural product with antioxidant and hepatoprotective activities that has been proposed as a complementary medicine to reduce the liver injury produced by the conventional anti-TB chemotherapy. Sm also has immunoregulatory and microbicide properties. In this study, we determined the effect of Sm on the growth control of mycobacteria. In vitro studies showed that Sm and Silibinin (the principal active compound of Sm) have microbicidal activity against drug-sensitive and multidrug-resistant (MDR) mycobacteria, induce the production of protective cytokines from infected macrophages, and improve the growth control of mycobacteria (p ≤ 0.0001). Studies in vivo using a model of progressive pulmonary TB in BALB/c mice infected with drug-sensitive or MDR mycobacteria have shown that Sm induces significant expression of Th-1 cytokines such as IFN-γ and IL-12 as well as TNFα, which produce significant therapeutic activity when administered alone and apparently have a synergistic effect with chemotherapy. These results suggest that Sm has a bactericidal effect and can contribute to the control and establishment of a TH1 protective immune response against mycobacterial infection. Thus, it seems that this flavonoid has a promising potential as adjuvant therapy in the treatment of TB.

Role of Natural Phenolics in Hepatoprotection: A Mechanistic Review and Analysis of Regulatory Network of Associated Genes

The liver is not only involved in metabolism and detoxification, but also participate in innate immune function and thus exposed to frequent target Thus, they are the frequent target of physical injury. Interestingly, liver has the unique ability to regenerate and completely recoup from most acute, non-iterative situation. However, multiple conditions, including viral hepatitis, non-alcoholic fatty liver disease, long term alcohol abuse and chronic use of medications can cause persistent injury in which regenerative capacity eventually becomes dysfunctional resulting in hepatic scaring and cirrhosis. Despite the recent therapeutic advances and significant development of modern medicine, hepatic diseases remain a health problem worldwide. Thus, the search for the new therapeutic agents to treat liver disease is still in demand. Many synthetic drugs have been demonstrated to be strong radical scavengers, but they are also carcinogenic and cause liver damage. Present day various hepatic problems are encountered with number of synthetic and plant based drugs. Nexavar (sorafenib) is a chemotherapeutic medication used to treat advanced renal cell carcinoma associated with several side effects. There are a few effective varieties of herbal preparation like Liv-52, silymarin and Stronger neomin phages (SNMC) against hepatic complications. Plants are the huge repository of bioactive secondary metabolites viz; phenol, flavonoid, alkaloid etc. In this review we will try to present exclusive study on phenolics with its mode of action mitigating liver associated complications. And also its future prospects as new drug lead.

Silibinin encapsulation in polymersome: A promising anticancer nanoparticle for inducing apoptosis and decreasing the expression level of miR-125b/miR-182 in human breast cancer cells

Silibinin, a polyphenolic flavonolignan, is well-known as a safe therapeutic drug without any side effects in the treatment of many malignancies especially cancerous cells. In this study, to overcome problems such as low solubility of silibinin and to enhance its delivery to cancerous cells, we encapsulated silibinin in polymersome nanoparticles. Physicochemical measurements such as dynamic light scattering, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy confirmed the proper encapsulation of silibinin in nanoparticles. Furthermore, antiproliferative and apoptotic activities of silibinin encapsulated in polymersome nanoparticles (SPNs) on MDA-MB-231 breast cancer cell line were validated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Annexin V/Propidium Iodide measurement, and cell cycle analysis. In addition, quantitative reverse transcription polymerase chain reaction analysis confirmed that SPNs can repress oncogenic microRNAs (miRNAs) such as miR-125b and miR-182, as well as antiapoptotic genes such as Bcl2. SPNs can also induce overexpression of proapoptotic target genes such as P53, CASP9, and BAX directly and/or indirectly (through regulation of miRNAs). Our results suggested that polymersomes can be used as stable carriers in nano-dimensions and SPNs can be considered as a promising pharmacological agent for cancer therapy.

Methyl 3,4-dihydroxybenzoate protects against d-galN/LPS-induced acute liver injury by inhibiting inflammation and apoptosis in mice

Objectives

Aimed to investigate the effect and mechanism of methyl 3,4-dihydroxybenzoate (MDHB) on d-galactosamine/lipopolysaccharide (d-galN/LPS)-induced acute liver failure (ALF).

Methods

Confirmed the hepatoprotective effect and hepatotoxicity of MDHB by histopathological examination (HE) and examination of alanine aminotransferase (ALT) and aspartate aminotransferase (AST); the expression of serum tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) was detected by ELISA; transcription levels of TNF-α, IL-1β, IL-6 and Toll-like receptor 4 (TLR4) were detected by qRT-PCR; and phosphorylation levels of p38 and p65 were analysed by Western blot.

Results

Histopathological examination and examination of ALT and AST confirmed that MDHB is a low toxicity drug that can resist d-galN/LPS-induced ALF; MDHB can effectively reduce high transcription and expression of TNF-α, IL-1β, IL-6 and TLR4 in d-galN/LPS-induced ALF; and Western blot showed that MDHB could down-regulate the expression of bax, up-regulate the expression of bcl-xl and bcl-2, and inhibit the phosphorylation of p38 and p65.

Conclusions

Methyl 3,4-dihydroxybenzoate can effectively resist d-galN/LPS-induced acute liver failure, which is related to the inhibition of inflammation and apoptosis.

Intestinal Permeability Study of Clinically Relevant Formulations of Silibinin in Caco-2 Cell Monolayers

An ever-growing number of preclinical studies have investigated the tumoricidal activity of the milk thistle flavonolignan silibinin. The clinical value of silibinin as a bona fide anti-cancer therapy, however, remains uncertain with respect to its bioavailability and blood⁻brain barrier (BBB) permeability. To shed some light on the absorption and bioavailability of silibinin, we utilized the Caco-2 cell monolayer model of human intestinal absorption to evaluate the permeation properties of three different formulations of silibinin: silibinin-meglumine, a water-soluble form of silibinin complexed with the amino-sugar meglumine; silibinin-phosphatidylcholine, the phytolipid delivery system Siliphos; and Eurosil85/Euromed, a milk thistle extract that is the active component of the nutraceutical Legasil with enhanced bioavailability. Our approach predicted differential mechanisms of transport and blood⁻brain barrier permeabilities between the silibinin formulations tested. Our assessment might provide valuable information about an idoneous silibinin formulation capable of reaching target cancer tissues and accounting for the observed clinical effects of silibinin, including a recently reported meaningful central nervous system activity against brain metastases.

Hepatoprotective Effects of Silymarin on Liver Injury via Irisin Upregulation and Oxidative Stress Reduction in Rats with Type 2 Diabetes

BACKGROUND

Diabetes is one of the most prevalent metabolic diseases. Irisin (FNDC5 protein) is involved in the new strategy of combating type 2 diabetes. In the liver, the antidiabetic mechanism of silymarin at the molecular level is unknown. This study investigated the effects of silymarin on irisin and the related gene expression and oxidative stress status in the liver of type 2 diabetic rats.

METHODS

Thirty-six rats were divided into 6 groups (n=6 each) by simple randomization: control, control+silymarin (60 mg/kg daily in normal saline orally for 60 days), control+silymarin (120 mg/kg daily in normal saline orally for 60 days), diabetic, diabetic+silymarin (60 mg/kg daily for 60 days), and diabetic+silymarin (120 mg/kg daily for 60 days). Biochemical parameters were measured by spectrophotometric and immunoassay methods, and quantitative polymerase chain reaction was used to evaluate gene expression. The data were analyzed by one-way ANOVA, followed by the Tukey test, using SPSS software, version 16.0. The results were considered statistically significant at a P value less than 0.05.

RESULTS

In the diabetic rats treated with silymarin (60 and 120 mg/kg), by comparison with the diabetic group, body weight (P=0.04 and P=0.02), insulin (P<0.001), expression of PGC-1α (P=0.04 and P=0.02), expression of FNDC5 (P=0.03 and P=0.01), and concentration of irisin in the liver (P=0.02 and P=0.01) and serum (P<0.001) were significantly increased, whereas the levels of glucose (P<0.001), HOMA-IR (P=0.03 and P=0.01), and liver injury markers (P<0.001) were significantly reduced. Oxidative stress status and histopathological changes were improved in the treated groups.

CONCLUSION

These results suggest that silymarin because of its ability to upregulate irisin and antioxidant effects can be considered an antidiabetic agent.

Herbal preparations use in prevention and treatment of gastrointestinal and hepatic disorders-Data from Vojvodina, Serbia

OBJECTIVE

Gastrointestinal (GI) disorders are estimated to be frequent among general population. Various types of traditional and complementary therapies, primarily phytotherapy, can be used for prevention and treatment of many diseases and conditions, including GI complaints. Thus, the aim of this study was to investigate the patterns of use of medicinal herbs in treatment and prevention of GI disorders, together with their efficacy and safety.

METHODS

A prospective, repeated cross-sectional, descriptive study was conducted in the form of a specifically created questionnaire, filled in by consumers and/or patients in pharmacies on the territory of Autonomous Province of Vojvodina, Republic of Serbia. All data were statistically analyzed in Microsoft Excel 2007.

RESULTS

In the total number of 1137 patients, 10.4% declared themselves as consumers of phytopreparations for GI disorders. The most common diseases were constipation (44%) and dyspepsia (23%). The most frequently used preparations contained laxatives (with both anthraquinones and dietary fibers), artichoke and silymarin. Iberogast® was also frequently used. Pharmacists were the main source of recommendation for the most adequate herbal remedies. At the same time, phytopreparations were well tolerated, with no major side effects, and were evidently or presumably effective.

CONCLUSIONS

Some mild and moderate GI disorders seem to be treated frequently with phytopreparatons. Various herbal remedies are well accepted by patients, and the phytopreparations seem to have favorable ratio of safety and efficacy. Further integration into conventional medicine will improve the quality of the products used and provide a rational plan of use of medicinal plants.

Superior silybin bioavailability of silybin-phosphatidylcholine complex in oily-medium soft-gel capsules versus conventional silymarin tablets in healthy volunteers

BACKGROUND

Fibrosis is a response to chronic liver disease that results in excessive accumulation of extracellular matrix proteins and formation of scar tissue. Fibrosis represents a clinical challenge of worldwide significance. Several studies have demonstrated that many natural products and herbal medicines have activity against liver fibrosis, and extracts of milk thistle such as silymarin and silybin are the natural compounds most commonly prescribed for liver diseases. Therefore, we sought to assess and compare the pharmacokinetic properties and bioavailability of silybin-phosphatidylcholine complex in oily-medium soft-gel capsules and conventional silymarin tablets in healthy Mexican volunteers.

METHODS

We enrolled 23 healthy volunteers to participate in a prospective, balanced, blind, single-dose, two-way crossover study with a one-week washout period. Fasting participants received either 45 mg silybin-phosphatidylcholine complex or 70 mg silymarin to assess which formulation provided better bioavailability of silybin. Plasma was obtained and analysed for silybin concentration using a validated ultra-performance liquid chromatography-tandem mass spectroscopy method. Pharmacokinetic parameters were obtained by non-compartmental analysis and values were compared by analysis of variance for a crossover design. Ratios of maximum plasma drug concentration and area under the curve (AUC) were obtained and 90% confidence intervals were calculated.

RESULTS

The 23 healthy subjects (11 women, 12 men) who participated in the study were aged 22-31 years old (average: 28), average weight 64.8 kg, height 1.65 m and body mass index 23.5 kg/m2. Plasma levels of silybin were higher after the administration of silybin-phosphatidylcholine complex capsules compared with that after conventional silymarin tablets (P <  0.0001).

CONCLUSIONS

The silybin-phosphatidylcholine complex in oily-medium soft-gel capsules seems to provide superior bioavailability. However, clinical studies must be performed to demonstrate its clinical relevance in the treatment of liver diseases.

TRIAL REGISTRATION

NCT03440164 ; registered on November 11, 2016.

Glycyrrhizic acid and silymarin alleviate the neurotoxic effects of aluminum in rats challenged with fructose-induced insulin resistance: possible role of toll-like receptor 4 pathway

Aluminum is implicated in the etiology of different neurodegenerative diseases, diabetes and cancer. The current study was conducted to evaluate the protective effects of glycyrrhizic acid (GAM) and silymarin (SLY) on AlCl₃-induced neurotoxicity in insulin resistant rats. Insulin resistance (IR) was induced by fructose (10%) in drinking water for 18 weeks. Rats received AlCl₃ (34 mg/kg/day) with or without fructose, GAM (40 mg/kg/day), or SLY (100 mg/kg/day). The administration of GAM or SLY suppressed AlCl₃-induced memory deficit, oxidative stress, and neuroinflammation in brain tissue of IR rats. Both agents inhibited AlCl₃-induced activation of TLR4 signaling pathway including the downstream activation of NF-κB. The results show that IR can partly exacerbate AlCl₃-induced neurotoxicity, particularly memory deficit and neuroinflammation. In addition, GAM and SLY showed promising neuroprotective effect against AlCl₃-induced brain damage in IR rats. The neuroprotection induced by these natural products might be mediated through their antioxidant and anti-inflammatory effects. The latter effect seems to be mediated via inhibition of TLR4 signaling pathway providing new insights on the mechanisms implicated in AlCl₃-induced neurotoxicity and the neuroprotection afforded by GAM and SLY.

Hepatoprotective effects of blue honeysuckle on CCl4-induced acute liver damaged mice

The objective of this study was to evaluate the hepatoprotective effects of blue honeysuckle (BH) on carbon tetrachloride (CCl4)-induced acute hepatic damage in mice. The experiment used a total of 60 ICR mice, which were divided into six groups. Except for the intact control groups, all groups received a single intraperitoneal injection of CCl4 after a 7 day pre-treatment period with distilled water, BH extracts, or silymarin. Twenty-four hours after the CCl4 injection, the following observations, representative of classical oxidative stress-mediated centrolobular necrotic acute liver injuries, were observed: decreased body weight; small nodule formation and enlargement on the gross inspections with related liver weight increase; elevation of serum AST and ALT, increases in hepatic lipid peroxidation and related depletion of endogenous antioxidants and antioxidative enzymes; centrolobular necrosis; increases in apoptotic markers, lipid peroxidation markers, and oxidative stress markers. However, liver damage was significantly inhibited by the pre-treatment with BH extracts. The present study demonstrated that oral administration of BH extracts prior to exposure to CCl4 conferred favorable hepatoprotective effects. These results demonstrated that BHe possessed suitable properties for use as a potent hepatoprotective medicinal food.

Evaluation of Silymarin for management of anti-tuberculosis drug induced liver injury: a randomized clinical trial

AIM

This study was performed to evaluate the potential efficacy of silymarin in the management of anti-tuberculosis medication's induced liver injury.

BACKGROUND

Hepatic toxicity is the most serious complication in treatment of tuberculosis.

METHODS

In a randomized double blind clinical trial (ACTRN12610000643077), 55 cases with hepatotoxicity caused by anti-tuberculosis drugs were divided into two groups. Informed consents were obtained. The intervention group received silymarin and the control group received placebo. Severity of liver injury, the duration necessary for normalization of liver function and hospital stay were compared between the two groups.

RESULTS

There was not any statistically significant difference in the rate of adverse effects between silymarin and placebo groups.

CONCLUSION

Although silymarin is considered a safe herbal medication, it was not effective to treat hepatic toxicity of anti-tuberculosis drugs.

Selenium-biofortified corn peptides: Attenuating concanavalin A-Induced liver injury and structure characterization

The relationship between hepatoprotective effects of selenium-biofortified corn (Zea mays Linn) peptides (SeCPs) and its antioxidant ability was evaluated and the structure of SeCPs was identified. SeCPs and corn peptides (CPs) both had good antioxidant ability, and the effect of SeCPs was significantly higher than CPs within a certain concentration range (P < 0.05). Additionally, animal experiments indicated that SeCPs (200 mg/kg) had a significantly protective effect against concanavalin A (Con A) induced hepatic lesions, as it significantly declined glutamic-pyruvic transaminase (AST), alanine transaminase (ALT) activities, tumor necrosis factor alpha (TNF-α), interferon (IFN)-γ contents in serum, and malondialdehyde (MDA) contents in liver (P < 0.05). Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in liver were also significantly increased by SeCPs (P < 0.05). The amino acid composition of SeCPs with Mw < 1 kDa was mainly glutamic acid (Glu, 31.18%), leucine (Leu, 21.06%) and alanine (Ala, 13.26%). According to the retention time, the amino acid sequences of 8 selenium-biofortified corn peptides and 29 selenium-free corn peptides were identified. Our results illustrated that the mechanisms of SeCPs against Con A induced hepatic injury in mice may be related to its antioxidant ability and reduction of lipid peroxidation, inhibiting the release of immune factors, such as TNF-α and IFN-γ.

Hepatoprotective Effect of Eriobotrya japonica Leaf Extract and Its Various Fractions against Carbon Tetra Chloride Induced Hepatotoxicity in Rats

Eriobotrya japonica is traditionally used as an antipyretic, digestive, and diuretic agent. Its flowers possess free radical-scavenging, antioxidative, and hepatoprotective effects. We investigated the hepatoprotective potential of E. japonica leaf extract and its various fractions against hepatotoxicity in rats. Liver injury was stimulated by the oral administration of carbon tetrachloride (CCl₄; 2.5 mL/kg b.wt.). Male albino rats (n = 55) were distributed arbitrarily into 11 groups: Group I, normal control group; Group II, CCl₄ (positive control group); Group III, CCl₄ + silymarin; Groups IV and V, CCl₄ + two doses of 250 and 500 mg/kg of the 80% methanolic extract of E. japonica leaves, respectively; Groups VI and VII, CCl₄ + 250 mg/kg and 500 mg/kg of the ethyl acetate fraction, respectively; Groups VIII and IX, CCl₄ + 250 and 500 mg/kg of the butanol fraction, respectively; and Groups X and XI, CCl₄ + 250 and 500 mg/kg of the aqueous fraction of E. Japonica leaves, respectively. CCl₄-treated rats that were given 250 or 500 mg/kg of the methanol extract of E. Japonica leaves, or its ethyl acetate, butanol, or aqueous fractions, had significantly lower levels of biochemical parameters such as alanine aminotransferase, aspartate transaminase, alkaline phosphate, total protein, gamma-glutamyl transferase, and bilirubin levels than those of the CCl₄ positive group. However, the extract and fractions did not significantly affect lipid profiles. Thus, we conclude that Eriobotrya leaf extract and its fractions have a hepatoprotective effect against CCl₄-induced hepatotoxicity in rats.

Anti-hepatofibrosis effect of Allium senescens in activated hepatic stellate cells and thioacetamide-induced fibrosis rat model

CONTEXT

Allium senescens Linn. (Liliaceae) (ASL) has been traditionally used in Korea and other Asian countries for improving digestive and liver functions.

OBJECTIVE

The anti-hepatofibrosis effect of ASL ethanol extract in cellular and experimental fibrosis rat model was investigated.

MATERIALS AND METHODS

In vitro cell viability, cell cycle and apoptosis in hepatic stellate cells (HSCs) were studied using MTT assay, flow cytometry and Annexin V-FITC/PI staining. Thioacetamide (TAA; 200 mg/kg, i.p.)-induced liver fibrosis model using Sprague Dawley rats (n = 10) was developed in vivo by injecting TAA twice per week for 13 weeks. ASL (25 and 100 mg/kg) and silymarin (50 mg/kg) were administered through oral gavage 2 times per week from 7th to 13th week. Specific fibrotic-related biomarkers such as aspartate transaminase (AST), alanine transaminase (ALT), glutathione and hydroxyproline levels in serum were analyzed by spectrophotometer using commercial kits. Morphological, histopathological and fibrotic-related gene expression such as TGF-β, Col1α1 and α-SMA in liver tissues was estimated by hematoxylin and eosin staining, Picrosirius red stain and quantitative real-time polymerase chain reaction, respectively.

RESULTS

ASL (0.1 mg/mL) and silymarin (0.05 mg/mL) treatment induced apoptosis (4.06% and 8.67%) in activated HSC-T6 cells, compared with control group (3.7%). The altered morphology in activated primary HSCs was also restored by ASL (0.1 mg/mL) treatment. Further, ASL (100 and 25 mg/kg) ameliorated the TAA-induced altered fibrotic-related biomarkers, histopathological changes and fibrotic-related gene expression significantly (p < 0.05 ∼ p < 0.001).

CONCLUSIONS

ASL can potentially be developed as a therapeutic agent in the treatment of hepatic fibrosis.

Therapeutic Potential of Plants and Plant Derived Phytochemicals against Acetaminophen-Induced Liver Injury

Acetaminophen (APAP), which is also known as paracetamol or N-acetyl-p-aminophenol is a safe and potent drug for fever, pain and inflammation when used at its normal therapeutic doses. It is available as over-the-counter drug and used by all the age groups. The overdose results in acute liver failure that often requires liver transplantation. Current clinical therapy for APAP-induced liver toxicity is the administration of N-acetyl-cysteine (NAC), a sulphydryl compound an approved drug which acts by replenishing cellular glutathione (GSH) stores in the liver. Over the past five decades, several studies indicate that the safety and efficacy of herbal extracts or plant derived compounds that are used either as monotherapy or as an adjunct therapy along with conventional medicines for hepatotoxicity have shown favorable responses. Phytochemicals mitigate necrotic cell death and protect against APAP-induced liver toxicityby restoring cellular antioxidant defense system, limiting oxidative stress and subsequently protecting mitochondrial dysfunction and inflammation. Recent experimental evidences indicat that these phytochemicals also regulate differential gene expression to modulate various cellular pathways that are implicated in cellular protection. Therefore, in this review, we highlight the role of the phytochemicals, which are shown to be efficacious in clinically relevant APAP-induced hepatotoxicity experimental models. In this review, we have made comprehensive attempt to delineate the molecular mechanism and the cellular targets that are modulated by the phytochemicals to mediate the cytoprotective effect against APAP-induced hepatotoxicity. In this review, we have also defined the challenges and scope of phytochemicals to be developed as drugs to target APAP-induced hepatotoxicity.

Baicalein Enhances the Oral Bioavailability and Hepatoprotective Effects of Silybin Through the Inhibition of Efflux Transporters BCRP and MRP2

Although hepatoprotective properties of silybin are well documented, the clinical therapeutic efficacy is limited by its low bioavailability due to absorption rates, extensive phase II metabolism, and biliary excretion. As our previous study indicated that metabolic enzymes may have limited effects on the pharmacokinetic (PK) behavior of silymarin, here, we intended to increase the oral bioavailability and bio-efficacy of silybin through the inhibition of active efflux. In Caco-2 and transfected MDCKII cell models, flavone baicalein significantly inhibited the efflux of silybin as a BCRP and MRP2 inhibitor. In addition, baicalein reduced the biliary excretion index (BEI) and biliary clearance of silybin conjugates in the sandwich-cultured rat hepatocyte (SCH) model, indicating the inhibition of baicalein in biliary excretion of conjugated silybin metabolites. PK study demonstrated that baicalein significantly increased the area under the curve (AUC) and C_max of silybin and its conjugates, suggesting enhanced absorption in vivo. Moreover, coadministration of silybin with baicalein boosted the liver protective, antioxidant, and anti-inflammatory effects of silybin in the carbon tetrachloride (CCl₄)-induced liver injury model in comparison with silybin given alone. In summary, efflux transporters play a critical role in the low bioavailability of silybin, while inhibition of breast cancer resistance protein (BCRP) and multi-drug resistance protein 2 (MRP2) by baicalein can significantly increase the absorption and bio-efficacy of silybin, which provides a new combination therapeutic approach for the treatment of chronic liver diseases.

Chitosan-functionalized lipid-polymer hybrid nanoparticles for oral delivery of silymarin and enhanced lipid-lowering effect in NAFLD

Background

Non-alcoholic fatty liver disease (NAFLD) is a chronic disease that causes excessive hepatic lipid accumulation. Reducing hepatic lipid deposition is a key issue in treatment and inhibition of NAFLD evolution. Silymarin is a potent hepatoprotective agent; however, it has low oral bioavailability due to its poor aqueous solubility and low membrane permeability. Unfortunately, few studies have addressed the development of convenient oral nanocarriers that can efficiently deliver silymarin to the liver and enhance its lipid-lowering effect. We designed silymarin-loaded lipid polymer hybrid nanoparticles containing chitosan (CS-LPNs) to improve silymarin bioavailability and evaluated their lipid-lowering effect in adiponutrin/patatin-like phospholipase-3 I148M transgenic mice, an NAFLD model.

Results

Compared to chitosan-free nanoparticles, CS-LPNs showed 1.92-fold higher uptake by fatty liver cells. Additionally, CS-LPNs significantly reduced TG levels in fatty liver cells in an in vitro lipid deposition assay, suggesting their potential lipid-lowering effects. The oral bioavailability of silymarin from CS-LPNs was 14.38-fold higher than that from suspensions in rats. Moreover, compared with chitosan-free nanoparticles, CS-LPNs effectively reduced blood lipid levels (TG), improved liver function (AST and ALT), and reduced lipid accumulation in the livers of mice in vivo. Reduced macrovesicular steatosis in pathological tissue after CS-LPN treatment indicated their protective effect against liver steatosis in NAFLD.

Conclusions

CS-LPNs enhanced oral delivery of silymarin and exhibited a desirable lipid-lowering effect in a mouse model. These findings suggest that CS-LPNs may be a promising oral nanocarrier for NAFLD therapeutics.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0391-9) contains supplementary material, which is available to authorized users.

Silymarin nanoformulation as potential anticancer agent in experimental Ehrlich ascites carcinoma-bearing animals

Aim: This study aimed to evaluate, for the first time the potential use of a safe biocompatible nanoformulation of silymarin (SM) as antitumor agent and to provide its mechanism of action compared with native SM. Materials & methods: SM was loaded into pluronic nanomicelles and Ehrlich ascites carcinoma-tumor-bearing mice were used as experimental model. Biochemical parameters including SOD, CAT and GSH, lipid peroxidation biomarkers (MDA), histopathological, ultrastructural and immunohistochemical studies were applied on the Ehrlich ascites carcinoma cells. Furthermore, the cell cycle as well as caspase-3 were examined. Results & conclusion: Nanoformulated SM (SMnp) destroyed tumors via increasing SOD, CAT and GSH concomitant with decreasing MDA. Moreover, SMnp-induced apoptosis through decreasing Ki-67 and Bcl2 expression, along with the activation of caspase-3, leads to inhibition of proliferation and the arrest of ceel cycle progression at the G1/S phase. Electron microscopy studies presented the superiority of SMnp over native SM in causing mitochondrial and nuclear degeneration in cancer cells.

Performance and serum biochemical profile of Japanese quail supplemented with silymarin and contaminated with aflatoxin B1

The aim of this study was to evaluate the hepatoprotective effect of silymarin in diets contaminated or not with aflatoxin B1 (AFB1) on the productive performance and serum biochemical profile of Japanese quail (Coturnix coturnix japonica) in the laying phase. A total of 240 12-week-old Japanese quail was used in a completely randomized design in a 3 × 2 factorial scheme (additives x contaminated or not with AFB1 - 1,500 μg/kg), totaling 6 treatments and 5 replicates of 8 birds each. The additives used were silymarin (500 g/ton), adsorbent (1 kg/ton), and a control diet (without additive). Of the total aflatoxin content, 84.64% was AFB1; 4.28% was AFB2; 11.07% was AFG1; and AFG2 was not detected. The data were submitted to ANOVA, and means were compared by Tukey's test. There was no interaction (P > 0.05) between the additive and AFB1 on performance parameters. However, the inclusion of AF in diets reduced (P < 0.05) egg weight and feed intake, impairing feed conversion compared to the unchallenged groups. There was an increase (P < 0.05) in blood concentrations of aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), and creatine kinase (CK) in birds challenged with AFB1, regardless of the additive used, characterizing a possible alteration in hepatic metabolism. Serum total protein and globulin levels were reduced (P < 0.05) in birds challenged with toxins. The consumption of diets contaminated with 1,500 μg AFB1/kg altered hepatic function in quail, impairing productive performance and egg weight. The concentrations of silymarin and adsorbent evaluated in this study were not able to mitigate the negative effect of toxins on the metabolism and performance of laying quail.

Immunomodulatory effects of silymarin after subacute exposure to mice: A tiered approach immunotoxicity screening

Silymarin is a flavonoid complex extracted from the Silybum marianum plant with a wide range of pharmacological and biochemical effects. In the present study, the immunomodulatory effects of silymarin were investigated in BALB/c mice. Silymarin was administered daily by intraperitoneal injection at doses of 50, 100 and 150 mg/kg for 14 consecutive days. Following the exposure, host hematological parameters, spleen cellularity and histopathological examination, as well as delayed-type hypersensitivity (DTH) responses, hemagglutination titers (HA), splenocyte cytokine production and lymphocyte proliferation assay were studied in all of the test groups of animals. The results showed that the low dose of silymarin (50 mg/kg) could stimulate both cellular and humoral immune functions in the treated hosts. In addition, silymarin at 100 mg/kg appeared to impact on DTH responses and lymphoproliferation. Based on the finding here, it would seem that silymarin has efficient immunostimulant properties. As a recommendation, the application of silymarin along with acupuncture technique (herbal acupuncture) can be thought as a good plan to modulate and enhance the immune system for the management of several immunodeficiency disorders. However, further studies are required to demonstrate this hypothesis.

Silymarin prevents lipid accumulation in the liver of rats with type 2 diabetes via sirtuin1 and SREBP-1c

BACKGROUND

In this study, we have investigated whether silymarin intake influences lipid and glycogen content in conjunction with sirtuin1 (SIRT1) and sterol regulatory element-binding protein 1c (SREBP-1c) expressions in liver of type 2 diabetic rat.

METHODS

Thirty-six male Wistar rats were randomly divided into six groups: control groups (C) and diabetic groups (D); the control groups received 60 or 120 mg/kg silymarin (C+S60 or C+S120), and the diabetic groups received 60 or 120 mg/kg silymarin (D+S60 or D+S120) daily for 8 weeks. Serum biochemical parameters, as well as glycogen, lipid and oxidative stress biomarkers, in the liver tissue were measured by spectrophotometric methods. Additionally, SIRT1 and SREBP-1c messenger RNA (mRNA) expressions were evaluated by quantitative polymerase chain reaction.

RESULTS

Diabetes caused a significantly increased fasting blood sugar, homeostasis model assessment for insulin resistance, liver total cholesterol and triglyceride (TG) content, which were attenuated after the administration of silymarin. Dietary silymarin caused the improvement of lipid content in the liver of diabetic rats. Moreover, silymarin administration promoted SIRT1, suppressed SREBP-1c mRNA expression, reduced liver nitric oxide and protein carbonyl content, and increased liver glycogen, catalase and glutathione peroxidase activity. Furthermore, histopathological changes were improved in the treated groups.

CONCLUSIONS

Silymarin administration considerably restored hepatic changes induced by streptozotocin and nicotinamide. The upregulation of SIRT1 mRNA expression by silymarin may be associated with decreased lipid, increased glycogen content and downregulation of the SREBP-1c gene in the liver.

Effects of DA-5513 on alcohol metabolism and alcoholic fatty liver in rats

Hangover is characterized by a number of unpleasant physical and mental symptoms that occur after heavy alcohol drinking. In addition, consistently excessive alcohol intake is considered as a major reason causes liver disease. The present study investigated the in vivo effects of DA-5513 (Morning care® Kang Hwang) on biological parameters relevant to hangover relief and alcoholic fatty liver. Blood alcohol and acetaldehyde concentrations were determined in rats administered a single dose of alcohol and treated with DA-5513 or commercially available hangover relief beverages (Yeomyung® and Ukon®). The effects of DA-5513 on alcoholic fatty liver were also determined in rats fed alcohol-containing Lieber-DeCarli diets for 4 weeks. Serum liver function markers (aspartate and alanine aminotransferase activities) and serum/liver lipid levels were assessed. Blood alcohol and acetaldehyde concentrations were lower in the groups treated with DA-5513 or Yeomyung®, as compared with control rats. However, Ukon® did not produce any significant effects on these parameters. Treatment with DA-5513 significantly reduced serum aspartate and alanine aminotransferase activities and markedly reduced serum cholesterol and triglyceride levels, as compared with control rats. Histological observations using Oil Red O staining found that DA-5513 delayed the development of alcoholic fatty liver by reversing hepatic fat accumulation. These findings suggest that DA-5513 could have a beneficial effect on alcohol-induced hangovers and has the potential to ameliorate alcoholic fatty liver.

Escalation of liver malfunctioning: A step toward Herbal Awareness

ETHNOPHARMACOLOGICAL RELEVANCE

About 2-5% of the world's population is suffering from liver toxicity including Pakistan with the second highest rate of hepatitis prevalence. Liver is a vital body organ which not only performs metabolic activities but also aids in detoxification, storage and digestion of food. Now a day's malnutrition, alcohol consumption and drug addiction are major causes of liver diseases throughout the world. In fact, there is no possible outcome to compensate liver malfunction for long term, and transplantation of liver is the only option left after the irretrievable injury of hepatic function. Subsequently, natural based therapeutic approaches are in the process of scrupulous testing as strong hepatoprotective mediator. In this regard plants are well thought hepatoprotective agents having multiple active components. In this review, based on species' pharmacology and safety we have compiled some plants which show strong hepatoprotective activity, main phytoconstituents with biological activities and few commercially used herbal formulations.

MATERIALS AND METHODS

Ethnopharmacological information was gathered by an extensive literature survey like WHO monographs on selected herbal medicinal plants (Vol 1-Vol 4); Principles and Practice of Phytotherapy, Mills S and Bone K, Churchill Livingstone, London, UK; Herbal Drugs and Phytopharmaceuticals, Wichtl M Medpharm Press, Stuttgart 3rd edn; Pharmacology and Applications of Chinese Materia Medica Vols 1 and 2, Chang H-M and But P P-H World Scientific, Singapore; British Herbal Compendium Vol. 2, Bradley P British Herbal Medicine Association, Bournemouth, UK; ESCOP Monographs 2nd edn. Thieme, Stuttgart, Germany; as well as by using electronic databases such as Pubchem, Chemspider, http://www.herbal-ahp.org; http://www.ahpa.org; http://whqlibdoc.who.int/publications/2003/9241546271.pdf; http://www.escop.com, Pubmed, HubMed and Scopus.

RESULTS

Data for more about 29 plants have been accomplished for their bioactive constituent(s), biological activities and medicinal uses. Some of the plants have been identified as strong hepato-modulator. Such knowledge about traditional medicinal plants can be globally applied for safe and evidence based use in pharmacological applications.

CONCLUSION

With the rise in liver risks a meek struggle has been made to draw attention toward herbal therapy. Hepatoprotective constituents of said plants are expressed with chemical structures. However, for certain plants active constituents are not still isolated/purified but overall plant extract was found effective in providing protection against hepatic injury. As a future perspective, there is need to purify plant active constituents for ethnomedical rationale.

Effects of Silymarin-Loaded Nanoparticles on HT-29 Human Colon Cancer Cells

Background and objective: Previous studies have demonstrated the anti-cancer effects of silymarin (SLM). However, the low bioavailability of SLM has restricted its use. This study investigated the toxic effect of nanostructured SLM encapsulated in micelles (Nano-SLM) on the growth of the HT-29 human colon cancer cell line. Materials and methods: HT-29 cells were treated with 25 μM/mL of SLM or Nano-SLM for 48 h. MTT and colony formation assays were used to assess the cytotoxicity and proliferation of HT-29 cells, respectively. The cells were stained with annexin V/PI for assessment of apoptosis. Results: MTT assays revealed that Nano-SLM treatment was able to exert a more pronounced toxic effect on the HT-29 cells as compared to free SLM treatment (p < 0.01). In the Nano-SLM-treated cells, colony numbers were significantly reduced in comparison to the free SLM-treated cells (p < 0.01). Apoptotic and necrotic indexes of Nano-SLM-treated HT-29 cells were also significantly increased in comparison to those of the free SLM-treated cells (p < 0.01). The viability, proliferation and apoptosis of healthy cells (NIH-3T3 cells) were not changed in response to Nano-SLM or SLM. Conclusions: Our results indicate that Nano-SLM enhances the anti-cancer effects of SLM against human colon cancer cells.

Potential role of potassium and chloride channels in regulation of silymarin-induced apoptosis in Candida albicans

Silymarin, which is derived from the seeds of Silybum marianum, has been widely used to prevent and treat liver diseases. In our previous study, we reported that at concentrations above the minimal inhibitory concentration (MIC), silymarin exhibited antifungal activity against Candida albicans by targeting its plasma membrane. However, the antifungal mechanism at concentration below the MIC remains unknown. Therefore, we aimed to determine the underlying mechanism of antifungal effects of silymarin at concentration below the MIC. To evaluate the inhibitory effects on the ion channels, C. albicans cells were separately pretreated with potassium and chloride channel blockers. The antifungal activity of silymarin at sub-MIC was affected by the ion channel blockers. Potassium channel blockade inhibited the antifungal effects, whereas chloride channel blockade slightly enhanced these effects. Subsequently, we found that silymarin induced disturbances in calcium homeostasis via the cytosolic and mitochondrial accumulation of calcium. Furthermore, apoptotic responses, such as phosphatidylserine exposure, loss of mitochondrial membrane potential (MMP), DNA damage, and caspase activation were induced in response to silymarin treatment. The increases in intracellular calcium level and pro-apoptotic changes were prevented when potassium ion channels were blocked. In contrast, these changes were enhanced upon chloride channels blockade; however, this did not affect the intracellular calcium levels and MMP loss. Thus, we showed that silymarin treatment at concentration below the MIC induced apoptosis in C. albicans; additionally, ion channels contributed these effects. © 2018 IUBMB Life, 70(3):197-206, 2018.

In vitro inhibitory effects of major bioactive constituents of Andrographis paniculata, Curcuma longa and Silybum marianum on human liver microsomal morphine glucuronidation: A prediction of potential herb-drug interactions arising from andrographolide, curcumin and silybin inhibition in humans

This study aimed to investigate the liver microsomal inhibitory effects of silybin, silychristin, andrographolide, and curcumin by using morphine as an in vitro UGT2B7 probe substrate, and predict the magnitude of the herb-drug interaction arising from these herbal constituents' inhibition in vivo. Studies were performed in the incubation with and without bovine serum albumin (BSA). Andrographolide and curcumin showed a marked inhibition on morphine 3- and 6-glucuronidation with IC50 of 50&87 and 96&111 μM, respectively. In the presence of 2%BSA, andrographolide also showed a strong inhibition on morphine 3- and 6-glucuronidation (IC50 4.4&21.6 μM) whereas curcumin showed moderate inhibition (IC50 338&333 μM). In the absence and presence of 2%BSA, morphine 3- and 6-glucuronidation was moderately inhibited by silybin (IC50 583&862 and 1252&1421 μM, respectively), however was weakly inhibited by silychristin (IC50 3527&3504 and 1124&1530 μM, respectively). The Ki of andrographolide, curcumin and silybin on morphine 3- and 6-glucuronidation were 7.1&9.5, 72.7&65.2, and 224.5&159.7 μM, respectively, while the respective values generated from the system containing 2%BSA were 2.4&3.1, 96.4&108.8, and 366.3&394.5 μM. Using the in vitro and in vivo extrapolation approach, andrographolide was herbal component that may have had a potential interaction in vivo when it was co-administered with morphine.

Intraperitoneal Administration of Silymarin Protects End Organs from Multivisceral Ischemia/Reperfusion Injury in a Rat Model

Objective

To determine whether intraperitoneal silymarin administration has favorable effects on the heart, lungs, kidney, and liver and on oxidative stress in a rat model of supraceliac aorta ischemia/reperfusion injury.

Methods

Thirty male Wistar albino rats were divided equally into three groups: sham, control, and silymarin. The control and silymarin groups underwent supraceliac aortic occlusion for 45 min, followed by a 60 min period of reperfusion under terminal anesthesia. In the silymarin group, silymarin was administered intraperitoneally during ischemia at a dose of 200 mg/kg. Rats were euthanized using terminal anesthesia, and blood was collected from the inferior vena cava for total antioxidant capacity, total oxidative status, and oxidative stress index measurement. Lungs, heart, liver and kidney tissues were histologically examined.

Results

Ischemia/reperfusion injury significantly increased histopathological damage as well as the total oxidative status and oxidative stress index levels in the blood samples. The silymarin group incurred significantly lesser damage to the lungs, liver and kidneys than the control group, while no differences were observed in the myocardium. Furthermore, the silymarin group had significantly lower total oxidative status and oxidative stress index levels than the control group.

Conclusion

Intraperitoneal administration of silymarin reduces oxidative stress and protects the liver, kidney, and lungs from acute supraceliac abdominal aorta ischemia/reperfusion injury in the rat model.

A composition of medicinal plants with an enhanced ability to suppress microsomal lipid peroxidation and a protective activity against carbon tetrachloride-induced hepatotoxicity

Treatment of liver injury induced by various toxicants represents a serious clinical challenge. Here, we utilized the ability of natural agents to inhibit microsomal lipid peroxidation (LPO) as the in-vitro screening paradigm for selecting efficacious tissue-protective combinations of cooperatively acting medicinal plants. Based on screening of 70 water-ethanol extracts obtained from different parts of 65 plants we prepared a highly active phytocomposition (PC-1) containing oregano (Origanum vulgare), wild thyme (Thymus serpyllum) and coltsfoot (Tussilago farfara) aerial parts, valerian (Valeriana officinalis) leaves and little-leaf linden (Tilia cordata) flowers. PC-1 extract exhibited the strongest anti-PLO and antihemolytic effects in vitro compared to those of the individual plants and other compositions tested. Using luciferase reporter assay and Western blotting in HepG2 human hepatocellular carcinoma cells, we found that PC-1 extract activated the Nrf2/antioxidant response element signaling pathway more effectively than the extracts of other phytocompositions. Importantly, oral administration of PC-1 extract (100-200 mg/kg) markedly ameliorated liver injury in rats acutely or chronically intoxicated by carbon tetrachloride. This was evidenced by improved liver histology, blood chemistry parameters, and microsomal LPO status and superoxide dismutase activity. In addition, treatment with PC-1 extract salvaged the osmotic resistance of erythrocytes in carbon tetrachloride-intoxicated rats. Collectively, these data support the strategy of in-vitro plant selection for developing efficacious tissue-protective phytocompositions.

Flavonoids as detoxifying and pro-survival agents: What's new?

The role of flavonoids in the survival machinery of cells has come in the spotlight due to the recent evidence of their effect on the relationship mitochondria-ER stress-proteasome, including the intracellular mechanisms of autophagy and apoptosis. Numerous experimental animal investigations and even human clinical studies have highlighted the major role of these natural compounds in the economy of life and their deep relationship with autotrophic organisms in the evolutionary space. Their role as anti-oxidant and oxidative stress preventive molecules has to date been investigated extensively in the literature. Despite this great amount of promising evidence, many concerns, however, remain, most of which dealing with biochemistry, bioavailability, pharmacokinetics, and interaction of flavonoids with gut microbiome, issues that make difficult any good attempt to introduce these molecules in the human healthcare systems as possible, encouraging therapeutic substances. This review tries to address and elucidate these items.

Silymarin impacts on immune system as an immunomodulator: One key for many locks

Silymarin is a flavonoid complex extracted from the Silybum marianum plant. It acts as a strong antioxidant and free radical scavenger by different mechanisms. But in addition to antioxidant effects, silymarin/silybin reveals immunomodulatory affects with both immunostimulatory and immunosuppression activities. Different studies have shown that silymarin has the anti-inflammatory effect through the suppression of NF-κB signaling pathway and TNF-α activation. It also has different immunomodulatory activities in a dose and time-dependent manner. As an immunomodulator agent, silymarin inhibits T-lymphocyte function at low doses while stimulates inflammatory processes at high doses. Studies have shown that silymarin has attenuated autoimmune, allergic, preeclampsia, cancer, and immune-mediated liver diseases and also has suppressed oxidative and nitrosative immunotoxicity. Silymarin also has indicated dual effects on proliferation and apoptosis of different cells. In conclusion, based on the current review, silymarin has a broad spectrum of immunomodulatory functions under different conditions. Recognizing the exact mechanisms of silymarin on cellular and molecular pathways would be very valuable for treatment of immune-mediated diseases. Also further studies are needed to assess the utility of silymarin in protection against autoimmune, cancer, allergic and other diseases in human subjects.

Allium tuberosum: Antidiabetic and hepatoprotective activities

Allium tuberosum (AT) is traditionally used for treating nocturnal emissions, abdominal pain, diarrhea, sexual dysfunction and asthma. This study aimed at investigating the antidiabetic and hepatoprotective activities of the butyl alcohol fraction from the methanolic extract of A. tuberosum. For the antidiabetic activity, rats were induced with diabetes by intraperitoneal injection of 150mg/kg alloxan and treated for 30days with AT extract (100, 200 and 400mg/kg). Animals were sacrificed after the study and the fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), HDL, malondialdehyde (MDA) catalase, superoxide dismutase and glutathione levels were determined. The hepatoprotective assay, mice were pretreated for seven days with AT (100, 200 and 400mg/kg) and silymarin (100mg/kg or). Thereafter 10ml/kg of 2% v/v CCl₄ was administered intraperitoneally on the 7th day to induce acute liver injury. Blood and liver samples were obtained and serum enzymes ALT, AST, ALP, SOD, GSH, CAT, MDA and pro-inflammatory mediators were assessed. AT significantly decrease FBG, serum TG, TC, MDA levels and significant increased HDL, SOD, GSH and CAT activities in the diabetic rats. In addition, AT significantly inhibited MDA, IL-1b, IL-6 and TNF-α levels and prevented the depletion of the antioxidant enzymes GSH, SOD and CAT activities in CCl₄ induced liver damage. Furthermore, AT markedly reduced AST, ALT and ALP levels in the CCl₄ treated mice groups. In conclusion, the antidiabetic and hepatoprotective effect of AT may be associated with its antioxidant and its ability to inhibit the pro-inflammatory mediators.

Nrf2 modulates cell proliferation and antioxidants defenses during liver regeneration induced by partial hepatectomy

The objective was to determine the regulatory dynamic of Nrf2 during liver regeneration and the administration of EtOH and/or the G. schiedeanum extract. Male Wistar rats weighing 200-230 g were subjected to a 70% partial hepatectomy; they were then divided into three groups (groups 1-3). During the experiment, animals in Group 1 drank only water. The other two groups (2-3) received an intragastric dose of ethanol (1.5 g/kg BW, solution at 40% in isotonic saline solution). Additionally, rats in group 3 received a geranium extract daily at a dose of 300 mg/kg BW i.g. EtOh and/or Geranium schiedeanum was administered to rats with regenerating livers for 7 days. At the end of treatment, the activity was determined of the antioxidant enzymes, DNA concentration, TBARS, and TAC, in addition to the expression of Nrf-2, Cyclin D1, and Nqo1. EtOH increased ROS and Nrf-2, which activated the antioxidant defenses and delayed liver proliferation. On the other hand, Geranium schiedeanum exerted an antioxidant effect, diminishing ROS, but Nrf-2 expression increased, favoring liver proliferation through the increase of DNA concentration and the overexpression of Cyclin D1, however it did not activate the antioxidant defenses. In sum, it can be concluded that Nrf-2 possesses a regulatory dynamic that is evident in the presence of a toxic agent (EtOH) and/or a phytochemical agent with antioxidant capacity (Geranium schiedeanum) during liver regeneration.

Effect of sılymarın on oxıdatıve stress and lıver hıstopathology ın experımental obstructıve jaundıce model

PURPOSE:

To investigate the effect of silymarin on oxidative stress and hepatic injury induced by obstructive jaundice in an experimental model.

METHODS:

Thirty Wistar-Albino type female rats were divided into 3 groups each including 10 rats. Only laparotomy was performed in group 1. Bile duct ligation was performed in group 2. In group 3, bile duct ligation was performed and orogastic silymarin 300 mg/kg/day dose was given for seven days. At the end of seven days, rats were sacrificed. The blood and liver tissue samples were taken to be examined biochemically and histopathologically.

RESULTS:

The plasma and liver levels of malondialdehyde were significantly lower in silymarin group than in the bile duct ligated group. Although liver levels of GSH were significantly higher in silymarin group than in the bile duct ligated group, there was no significant difference between the plasma GSH levels of these groups. In silymarin group; the enlargement of hepatocytes, dilatation of canaliculi and the edema were regressed.

CONCLUSION:

Silymarin diminished the harmful effects of obstructive jaundice on liver.

Glycyrrhetic acid, but not glycyrrhizic acid, strengthened entecavir activity by promoting its subcellular distribution in the liver via efflux inhibition

Entecavir (ETV) is a superior nucleoside analogue used to treat hepatitis B virus (HBV) infection. Although its advantages over other agents include low viral resistance and the elicitation of a sharp decrease in HBV DNA, adverse effects such as hepatic steatosis, hepatic damage and lactic acidosis have also been reported. Glycyrrhizin has long been used as hepato-protective medicine. The clinical combination of ETV plus glycyrrhizin in China displays better therapeutic effects and lower rates of liver damage. However, there is little evidence explaining the probable synergistic mechanism that exists between these two drugs from a pharmacokinetics view. Here, alterations in the plasma pharmacokinetics, tissue distribution, subcellular distribution, and in vitro and in vivo antiviral activity of ETV after combination with glycyrrhizic acid (GL) were analysed to determine the synergistic mechanisms of these two drugs. Specific efflux transporter membrane vesicles were also used to elucidate their interactions. The primary active GL metabolite, glycyrrhetic acid (GA), did not affect the plasma pharmacokinetics of ETV but promoted its accumulation in hepatocytes, increasing its distribution in the cytoplasm and nucleus and augmenting the antiviral efficiency of ETV. These synergistic actions were primarily due to the inhibitory effect of GA on MRP4 and BCRP, which transport ETV out of hepatocytes. In conclusion, GA interacted with ETV at cellular and subcellular levels in the liver through MRP4 and BCRP inhibition, which enhanced the antiviral activity of ETV. Our results partially explain the synergistic mechanism of ETV and GL from a pharmacokinetics view, providing more data to support the use of these compounds together in clinical HBV treatment.

The effect of milk thistle (Silybum marianum) and its main flavonolignans on CYP2C8 enzyme activity in human liver microsomes

Milk thistle is a widely-consumed botanical used for an array of purported health benefits. The primary extract of milk thistle is termed silymarin, a complex mixture that contains a number of structurally-related flavonolignans, the flavonoid, taxifolin, and a number of other constituents. The major flavonolignans present in most extracts are silybin A, silybin B, isosilybin A and isosilybin B, silydianin, silychristin and isosilychristin. Silymarin itself has been reported to inhibit CYP2C8 activity in vitro, but the effect of the individual flavonolignans on this enzyme has not been studied. To investigate the effects of milk thistle extract and its main flavonolignans (silybin A, silybin B, isosilybin A and isosilybin B) on CYP2C8 activity at relevant concentrations, the effect of milk thistle extract and the flavonolignans on CYP2C8 enzyme activity was studied in vitro using human liver microsomes (HLM) incorporating an enzyme-selective substrate for CYP2C8, amodiaquine. Metabolite formation was analyzed using liquid chromatography-tandem mass spectrometry (LC/MS-MS). The concentration causing 50% inhibition of enzyme activity (IC50) was used to express the degree of inhibition. Isosilibinin, a mixture of the diastereoisomers isosilybin A and isosilybin B, was found to be the most potent inhibitor, followed by isosilybin B with IC50 values (mean ± SE) of 1.64 ± 0.66 μg/mL and 2.67 ± 1.18 μg/mL, respectively. The rank order of observed inhibitory potency after isosilibinin was silibinin > isosilybin A > silybin A > milk thistle extract > and silybin B. These in vitro results suggest a potentially significant inhibitory effect of isosilibinin and isosilybin B on CYP2C8 activity. However, the observed IC50 values are unlikely to be achieved in humans supplemented with orally administered milk thistle extracts due to the poor bioavailability of flavonolignans documented with most commercially available formulations.

New amides from seeds of Silybum marianum with potential antioxidant and antidiabetic activities

Two new amide compounds, mariamides A and B (1-2), were obtained together with fourteen known compounds from the seeds of milk thistle (Silybum marianum). Their structures were established on the basis of extensive 1D and 2D NMR analyses, as well as HR-ESI-MS data. Most of the compounds showed significant antioxidant activities than positive control in ABTS and FRAP assays. However, only amide compounds 1-4 showed moderate DPPH radical scavenging activity and compounds 7 and 16 showed the most potent activity against DPPH. Most of the compounds showed moderate to stronger α-glucosidase inhibitory activities. Nevertheless, only flavonoids showed strong PTP1B inhibitory activities. These results indicate a use of milk thistle seed extracts as promising antioxidant and antidiabetic agents.

Evaluation of HepaRG cells for the assessment of indirect drug-induced hepatotoxicity using INH as a model substance

HepaRG cells are widely used as an in vitro model to assess drug-induced hepatotoxicity. However, only few studies exist so far regarding their suitability to detect the effects of drugs requiring a preceding activation via the cytochrome P450 (CYP) system. A prototypic substance is the anti-tuberculosis agent INH, which is metabolized into N-acetylhydrazine, which then triggers hepatotoxicity. Therefore, the aim of the present study was to test if this effect can also be detected in HepaRG cells and if it can be counteracted by the known hepatoprotectant silibinin. For this purpose, differentiated HepaRG cells were treated with increasing concentrations of INH (0.1-100 mM) or 10 mM INH plus escalating concentrations of silibinin (1-100 µM). After 48 h of treatment, cell morphology and parameters indicating cell vitality, oxidative stress, and liver cell function were assessed. High concentrations of INH led to severe histopathological changes, reduced cell vitality and glutathione content, increased LDH and ASAT release into the medium, enhanced lipid peroxidation, and elevated cleaved caspase-3 expression. Additionally, glycogen depletion and reduced biotransformation capacity were seen at high INH concentrations, whereas at low concentrations an induction of biotransformation enzymes was noticed. Silibinin caused clear-cut protective effects, but with few parameters INH toxicity was even aggravated, most probably due to increased metabolization of INH into its toxic metabolite. In conclusion, HepaRG cells are excellently suited to evaluate the effects of substances requiring prior toxification via the CYP system, such as INH. They additionally enable the identification of complex substance interactions.