The potential of silymarin for the treatment of hepatic disorders

Alleviation of microcystin-leucine arginine -induced hepatotoxicity: An updated overview

OBJECTIVES

Contamination of surface waters is a major health threat for all living creatures. Some types of blue-green algae that naturally occur in fresh water, are able to produce various toxins, like Microcystins (MCs). Microcystin-leucine arginine (MC-LR) produced by Microcystis aeruginosa is the most toxic and abundant isoforms of MCs, and it causes hepatotoxicity. The present article reviews preclinical experiments examined different treatments, including herbal derivatives, dietary supplements and drugs against MC-LR hepatotoxicity.

METHODS

We searched scientific databases Web of Science, Embase, Medline (PubMed), Scopus, and Google Scholar using relevant keywords to find suitable studies until November 2023.

RESULTS

MC-LR through Organic anion transporting polypeptide superfamily transporters (OATPs) penetrates and accumulates in hepatocytes, and it inhibits protein phosphatases (PP1 and PP2A). Consequently, MC-LR disturbs many signaling pathways and induces oxidative stress thus damages cellular macromolecules. Some protective agents, especially plants rich in flavonoids, and natural supplements, as well as chemoprotectants were shown to diminish MC-LR hepatotoxicity.

CONCLUSION

The reviewed agents through blocking the OATP transporters (nontoxic nostocyclopeptide-M1, captopril, and naringin), then inhibition of MC-LR uptake (naringin, rifampin, cyclosporin-A, silymarin and captopril), and finally at restoration of PPAse activity (silybin, quercetin, morin, naringin, rifampin, captopril, azo dyes) exert hepatoprotective effect against MC-LR.

Action of Carduus marianus 6cH on Hepatopathy and Gallstone in Ambystoma mexicanum (Axolotl): Case Report

BACKGROUND

 Carduus marianus is a Mediterranean plant used for treating liver diseases. One of its properties is that it inhibits fat peroxidation, which can contribute toward the prevention of metabolites that are harmful to the liver.

OBJECTIVE

 The aim of this study was to describe the treatment of fatty liver disease in an axolotl (Ambystoma mexicanum).

METHODS

 An approximately 6-year-old female specimen of A. mexicanum, of length 21 cm and weight 153 g, presented edema in the rostral region and inappetence. Ultrasound showed hepatopathy and a gallbladder stone. A globule of C. marianus 6cH was diluted in 30 mL distilled water and administered in spray form over the animal twice a day.

RESULTS

 Twenty days after the beginning of the treatment, improvement of the facial edema and return of appetite were observed. Ultrasound showed improvement in the appearance of the liver and reduction in the size of the gallstone. The Modified Naranjo Criteria for Homeopathy score was +9 in this case, thus suggesting a causal relationship between the use of homeopathic medicine and the clinical outcome.

CONCLUSION

 C. marianus 6cH appeared to be effective in treating fatty liver disease and gallstone in this specimen of A. mexicanum.

Effects of silymarin use on liver enzymes and metabolic factors in metabolic dysfunction-associated steatotic liver disease: a systematic review and meta-analysis

Background

Fatty liver disease comprises a wide range of related liver disorders affecting mainly people who drink no or minimal amounts of alcohol. Silymarin is a member of the Carduus marianum family that has been used for centuries to treat different diseases. There is little evidence supporting its efficacy in humans.

Objectives

To evaluate the effects of Silymarin in patients with non alcoholic fatty liver disease (NAFLD) or recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD).

Methods

We searched PubMed, SCOPUS, Web of Science, and Cochrane Library for relevant clinical trials assessing the use of silymarin in patients with NAFLD. A risk of bias assessment was performed using Cochrane's risk of bias tool. We included the following outcomes: alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transferase (GGT), total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL) (mg/dL), degree of fibrosis resolution, low-density lipoprotein (LDL), and HOMA-IR. We analyzed continuous data using mean difference (MD) and relative 95% confidence interval (CI).

Results

We included nine clinical trials. We found that silymarin significantly reduced the levels of ALT (MD= -17.12 [-28.81, -4.43]), (P < 0.004), AST (MD= -12.56 [-19.02, -6.10]), (P < 0.0001) and TG (MD = -22.60 [-23.83, -21.38]) (p < 0.00001). It also improved HDL (MD= 2.13 [1.60, 2.66]), (P < 0.01)). There was no significant difference regarding GGT (P=o.07), TC (P= 0.52), LDL (P= 0.06), HOMA-IR (P= 0.06) and BMI (p=0.1).One study reported significant improvement in the degree of fibrosis (P = 0.023).

Conclusion

Silymarin treatment significantly reduces biochemical and transaminase levels in patients with MASLD.

Amanitin intoxication: effects of therapies on clinical outcomes - a review of 40 years of reported cases

BACKGROUND AND AIMS

Amanita phalloides poisoning causes severe liver damage which may be potentially fatal. Several treatments are available, but their effectiveness has not been systematically evaluated. We performed a systematic review to investigate the effect of the most commonly used therapies: N-acetylcysteine (NAC), benzylpenicillin (PEN), and silibinin (SIL) on patient outcomes. In addition, other factors contributing to patient outcomes are identified.

METHODS

We searched MEDLINE and Embase for case series and case reports that described patient outcomes after poisoning with amanitin-containing Amanita mushrooms. We extracted clinical characteristics, treatment details, and outcomes. We used the liver item from the Poisoning Severity Score (PSS) to categorize intoxication severity.

RESULTS

We included 131 publications describing a total of 877 unique cases. The overall survival rate of all patients was 84%. Patients receiving only supportive care had a survival rate of 59%. The use of SIL or PEN was associated with a 90% (OR 6.40 [3.14-13.04]) and 89% (OR 5.24 [2.87-9.56]) survival rate, respectively. NAC/SIL combination therapy was associated with 85% survival rate (OR 3.85 [2.04, 7.25]). NAC/PEN/SIL treatment group had a survival rate of 76% (OR 2.11 [1.25, 3.57]). Due to the limited number of cases, the use of NAC alone could not be evaluated. Additional analyses in 'proven cases' (amanitin detected), 'probable cases' (mushroom identified by mycologist), and 'possible cases' (neither amanitin detected nor mushroom identified) showed comparable results, but the results did not reach statistical significance. Transplantation-free survivors had significantly lower peak values of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total serum bilirubin (TSB), and international normalized ratio (INR) compared to liver transplantation survivors and patients with fatal outcomes. Higher peak PSS was associated with increased mortality.

CONCLUSION

Based on data available, no statistical differences could be observed for the effects of NAC, PEN or SIL in proven poisonings with amanitin-containing mushrooms. However, monotherapy with SIL or PEN and combination therapy with NAC/SIL appear to be associated with higher survival rates compared to supportive care alone. AST, ALT, TSB, and INR values are possible predictors of potentially fatal outcomes.

Molecular mechanisms involved in the effects of morin in experimental hepatic encephalopathy

This study aimed to investigate the possible usefulness of morin flavonoid in comparison to silymarin as a hepatic/neuronal-supportive agent with similar effects and higher bioavailability in a rat model of hepatic encephalopathy (HE). Morin effects on rat liver and brain were evaluated post-induction of HE by thioacetamide (TAA; 200 mg/kg/day for 3 successive days). Then, the serum activities of aspartate transaminase (AST) and alanine transaminase (ALT) together with ammonia concentration were estimated to assess the liver function. Also, the degree of brain effects was evaluated via the assessment of brain contents of reduced glutathione (GSH), malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), and interleukin (IL-1β) together with glutathione peroxidase (GPx) activity. In addition, the apoptotic and inflammatory changes in brain and liver tissues were also assessed via immunohistochemical examination. Our findings revealed a promising effect of morin against HE complications; as it corrected the liver functions, attenuated the brain/liver tissue injuries, and reduced the apoptotic and inflammatory insults of HE on both organs. These effects are comparable to those of silymarin. Morin could be introduced as a promising hepato- and neuro-therapeutic adjuvant in HE-associated neuronal complications especially in cases like silymarin intolerance.

In vitro Dissolution Testing and Pharmacokinetic Studies of Silymarin Solid Dispersion After Oral Administration to Healthy Pigs

We evaluated the pharmacokinetics of silymarin solid dispersion in pigs to determine whether silybin bioavailability would be increased over that of a silymarin premix. In vitro dissolution testing was conducted using dissolution apparatus 1 (baskets) at 100 rpm at 37 ± 0.5°C in pH 1.2 HCl, pH 6.8 phosphate, and pH 4.3 acetate buffers containing 0.5% Tween-80. In vivo pharmacokinetics were studied using 16 healthy pigs (Yorkshire × Landrace) that were randomly assigned to two groups. Silymarin as solid dispersion and premix dosage forms were administered directly by stomach tubes at 50 mg kg⁻¹ silybin. In vitro dissolution of silybin for the premix was 35.02, 35.90, and 38.70% in these buffers, respectively. In contrast, silybin dissolution in solid dispersions was increased to 82.92, 87.48, and 99.70%, respectively. Silymarin solid dispersion administered at a single dose resulted in a peak concentration (C_max) of 1,190.02 ± 246.97 ng ml⁻¹ with the area under the curve (AUC_0−∞) at 1,299.19 ± 67.61 ng ml⁻¹ h. These parameters for the premix groups were 411.35 ± 84.92 ng ml⁻¹ and 586.82 ± 180.99 ng ml⁻¹ h, respectively. The C_max and AUC_0−∞ values for the solid dispersion were about twice that of the premix and were consistent with the in vitro dissolution data.

A Comparative Study of the Hepatoprotective Effect of Centella asiatica Extract (CA-HE50) on Lipopolysaccharide/d-galactosamine-Induced Acute Liver Injury in C57BL/6 Mice

Acute liver failure (ALF) refers to the sudden loss of liver function and is accompanied by several complications. In a previous study, we revealed the protective effect of Centella asiatica 50% ethanol extract (CA-HE50) on acetaminophen-induced liver injury. In the present study, we investigate the hepatoprotective effect of CA-HE50 in a lipopolysaccharide/galactosamine (LPS-D-Gal)-induced ALF animal model and compare it to existing therapeutic silymarin, Lentinus edodes mycelia (LEM) extracts, ursodeoxycholic acid (UDCA) and dimethyl diphenyl bicarboxylate (DDB). Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were decreased in the CA-HE50, silymarin, LEM, UDCA and DDB groups compared to the vehicle control group. In particular, AST and ALT levels of the 200 mg/kg CA-HE50 group were significantly decreased compared to positive control groups. Lactate dehydrogenase (LDH) levels were significantly decreased in the CA-HE50, silymarin, LEM, UDCA and DDB groups compared to the vehicle control group and LDH levels of the 200 mg/kg CA-HE50 group were similar to those of the positive control groups. Superoxide dismutase (SOD) activity was significantly increased in the 100 mg/kg CA-HE50, LEM and UDCA groups compared to the vehicle control group and, in particular, the 100 mg/kg CA-HE50 group increased significantly compared to positive control groups. In addition, the histopathological lesion score was significantly decreased in the CA-HE50 and positive control groups compared with the vehicle control group and the histopathological lesion score of the 200 mg/kg CA-HE50 group was similar to that of the positive control groups. These results show that CA-HE50 has antioxidant and hepatoprotective effects at a level similar to that of silymarin, LEM, UDCA and DDB, which are known to have hepatoprotective effects; further, CA-HE50 has potential as a prophylactic and therapeutic agent in ALF.

Risk Factors and Prevention of Viral Hepatitis-Related Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common cancer in the world, and its incidence is increasing yearly. Hepatitis B virus (HBV) infection and hepatitis C virus (HCV) infection are important causes of HCC. Liver cirrhosis, age, sex, smoking and drinking, and metabolic risk factors will increase the risk of cancer in HBV/HCV patients. And viral load, APRI, FIB-4, and liver stiffness can all predict the risk of HCC in patients with viral infection. In addition, effective prevention strategies are essential in reducing the risk of HCC. The prevention of HCC involves mainly tertiary prevention strategies, while the primary prevention is based on standardized vaccine injections to prevent the occurrence of HBV/HCV. Eliminating the route of transmission and vaccination will lead to a decrease in the incidence of HCC. Secondary prevention involves effective antiviral treatment of HBV/HCV to prevent the disease from progressing to HCC, and tertiary prevention is actively treating HCC to prevent its recurrence.

Carveol a Naturally-Derived Potent and Emerging Nrf2 Activator Protects Against Acetaminophen-Induced Hepatotoxicity

Acetaminophen (N-acetyl p-aminophenol or APAP) is used worldwide for its antipyretic and anti-inflammatory potential. However, APAP overdose sometimes causes severe liver damage. In this study, we elucidated the protective effects of carveol in liver injury, using molecular and in silico approaches. Male BALB/c mice were divided into two experimental cohorts, to identify the best dose and to further assess the role of carveol in the nuclear factor E2-related factor; nuclear factor erythroid 2; p45-related factor 2 (Nrf2) pathway. The results demonstrated that carveol significantly modulated the detrimental effects of APAP by boosting endogenous antioxidant mechanisms, such as nuclear translocation of Nrf2 gene, a master regulator of the downstream antioxidant machinery. Furthermore, an inhibitor of Nrf2, called all-trans retinoic acid (ATRA), was used, which exaggerated APAP toxicity, in addition to abrogating the protective effects of carveol; this effect was accompanied by overexpression of inflammatory mediators and liver = 2ltoxicity biomarkers. To further support our notion, we performed virtual docking of carveol with Nrf2-keap1 target, and the resultant drug-protein interactions validated the in vivo findings. Together, our findings suggest that carveol could activate the endogenous master antioxidant Nrf2, which further regulates the expression of downstream antioxidants, eventually ameliorating the APAP-induced inflammation and oxidative stress.

Transcriptome profiling reveals Silibinin dose-dependent response network in non-small lung cancer cells

Silibinin (SIL), a natural flavonolignan from the milk thistle (Silybum marianum), is known to exhibit remarkable hepatoprotective, antineoplastic and EMT inhibiting effects in different cancer cells by targeting multiple molecular targets and pathways. However, the predominant majority of previous studies investigated effects of this phytocompound in a one particular cell line. Here, we carry out a systematic analysis of dose-dependent viability response to SIL in five non-small cell lung cancer (NSCLC) lines that gradually differ with respect to their intrinsic EMT stage. By correlating gene expression profiles of NSCLC cell lines with the pattern of their SIL IC50 response, a group of cell cycle, survival and stress responsive genes, including some prominent targets of STAT3 (BIRC5, FOXM1, BRCA1), was identified. The relevancy of these computationally selected genes to SIL viability response of NSCLC cells was confirmed by the transient knockdown test. In contrast to other EMT-inhibiting compounds, no correlation between the SIL IC50 and the intrinsic EMT stage of NSCLC cells was observed. Our experimental results show that SIL viability response of differently constituted NSCLC cells is linked to a subnetwork of tightly interconnected genes whose transcriptomic pattern can be used as a benchmark for assessment of individual SIL sensitivity instead of the conventional EMT signature. Insights gained in this study pave the way for optimization of customized adjuvant therapy of malignancies using Silibinin.

Apigenin alleviated acetaminophen-induced hepatotoxicity in low protein-fed rats: Targeting oxidative stress, STAT3, and apoptosis signals

Apigenin (API) is a natural flavonoid abundant in fruits and vegetables. The present study was undertaken to evaluate the effect of protein malnutrition (PMN) on acetaminophen (APAP)-induced hepatotoxicity, together with the protective effects of API, in male Wistar albino rats. In total, 64 male rats were divided into eight groups. Silymarin (SIL) (100 mg/kg, PO) as a reference standard and API (50 mg/kg, PO) were given to normal and APAP-induced hepatic injury in low protein-fed rats. The present results revealed that PMN significantly potentiated APAP-induced hepatotoxicity. Interestingly, the administration of SIL and API alleviated the induced damage, as revealed by reduced serum alanine aminotransferase and aspartate aminotransferase activities along with a significant improvement of the histopathological damage. API suppressed inflammatory response by reducing the interleukin-1β level and signal transducer and activator of transcription 3 expressions along with attenuating oxidative stress as shown by a significant reduction in liver contents of malondialdehyde and nitrite/nitrate as well as restoration of hepatic content of reduced glutathione and superoxide dismutase activity. API also counteracted apoptosis through downregulation of caspase-3 expression level. In conclusion, PMN greatly potentiated the hepatotoxic effects of APAP, and API produced a multimechanistic hepatoprotective activity that can be attributed to its antioxidant, anti-inflammatory, and antiapoptotic effects.

Clinically Relevant OATP2B1 Inhibitors in Marketed Drug Space

OATP2B1 is an intestinal and hepatic drug uptake transporter. Intestinal OATP2B1 has been elucidated as the mechanism of unexpected clinical drug-drug interactions (DDIs), where drug exposure was unexpectedly decreased with unchanged half-life. Hepatic OATP2B1 may be an understudied clinical DDI mechanism. The aim of the present work was to understand the prevalence of clinically relevant intestinal and hepatic OATP2B1 inhibitors in marketed drug space. HEK293 cells stably overexpressing human OATP2B1 or vector control were generated and cultured for 72 h in a 96-well format. OATP2B1-mediated uptake of dibromofluorescein (DBF) was found to be optimal at 10 μM concentration and 30 min incubation time. A total of 294 drugs (top 300 marketed drugs, excluding biologics and restricted drugs, supplemented with ∼100 small-molecule drugs) were screened for OATP2B1 inhibition at 10 μM. Drugs demonstrating ≥50% inhibition in this screen were advanced for IC₅₀ determination, which was extrapolated to clinical intestinal and hepatic OATP2B1 inhibition as per 2017 FDA DDI guidance. Of the 294 drugs screened, 67 elicited ≥50% inhibition of OATP2B1-mediated DBF uptake at 10 μM screening concentration. For the 67 drugs flagged in the single-concentration inhibition screen, upon evaluation of a full concentration range, IC₅₀ values could be determined for 58 drugs. OATP2B1 IC₅₀ values established for these 58 drugs were extrapolated as potentially clinically relevant at the intestinal level for 38 orally administered drugs (I_gut/IC₅₀ ≥ 10), and 17 were flagged as potential clinical inhibitors of hepatic OATP2B1 uptake (1 + I_in,max,u/IC₅₀ ≥ 1.1). This analysis of 294 drugs demonstrated prevalence of clinically relevant intestinal and hepatic OATP2B1 inhibitors to be 13 and 6%, respectively. As OATP2B1-inhibitor drugs are not exceedingly rare, these results suggest that clinical OATP2B1 DDIs have been rarely observed because OATP2B1 is uncommonly the predominant determinant of drug disposition.

Antioxidant Activity of Graptopetalum paraguayense E. Walther Leaf Extract Counteracts Oxidative Stress Induced by Ethanol and Carbon Tetrachloride Co-Induced Hepatotoxicity in Rats

(1) Background: Graptopetalum paraguayense E. Walther is a traditional Chinese herbal medicine. In our previous study, 50% ethanolic G. paraguayense extracts (GE50) demonstrated good antioxidant activity. (2) Methods: To investigate the hepatoprotective effects of GE50 on ethanol and carbon tetrachloride (CCl₄) co-induced hepatic damage in rats, Sprague–Dawley rats were randomly divided into five groups (Control group; GE50 group, 0.25 g/100 g BW; EC group: Ethanol + CCl₄, 1.25 mL 50% ethanol and 0.1 mL 20% CCl₄/100 g BW; EC + GE50 group: Ethanol + CCl₄ + GE50; EC + silymarin group: ethanol + CCl₄ + silymarin, 20 mg/100 g BW) for six consecutive weeks. (3) Results: Compared with the control group, EC group significantly elevated the serum aspartate aminotransferase (AST), alanine aminitransferase (ALT), and lactate dehydrogenase (LDH). However, GE50 or silymarin treatment effectively reversed these changes. GE50 had a significant protective effect against ethanol + CCl₄ induced lipid peroxidation and increased the levels of glutathione (GSH), vitamin C, E, total antioxidant status (TAS), and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and glutathione S-transferases (GST). Furthermore, in EC focal group, slight fat droplet infiltration was observed in the livers, while in the GE50 or silymarin treatment groups, decreased fat droplet infiltration. HPLC phytochemical profile of GE50 revealed the presence of gallic acid, flavone, genistin, daidzin, and quercetin. (4) Conclusions: The hepatoprotective activity of GE50 is proposed to occur through the synergic effects of its chemical component, namely, gallic acid, flavone, genistin, daidzin, and quercetin. Hence, G. paraguayense can be used as a complementary and alternative therapy in the prevention of alcohol + CCl₄-induced liver injury.

Silybin Modulates Collagen Turnover in an In Vitro Model of NASH

Silybin has been proposed as a treatment for nonalcoholic steatohepatitis (NASH). In this study, we assessed the effect of Silybin in a well-established in vitro coculture model of early-stage NASH. LX2 and Huh7 cells were exposed to free fatty acid (FFA) and Silybin as mono- or coculture (SCC). Cell viability, LX2 activation, collagen deposition, metalloproteinase 2 and 9 (MMP2-9) activity, and ROS generation were determined at 24, 96, and 144 h. Exposure to FFA induced the activation of LX2 as shown by the increase in cell viability and upregulation of collagen biosynthesis. Interestingly, while cotreatment with Silybin did not affect collagen production in LX2, a significant reduction was observed in SCC. MMP2-9 activity was reduced in FFA-treated Huh7 and SCC and cotreatment with Silybin induced a dose-dependent increase, while no effect was observed in LX2. Silybin also showed antioxidant properties by reducing the FFA-induced production of ROS in all the cell systems. Based on these data, Silybin exerts its beneficial effects by reducing LX2 proliferation and ROS generation. Moreover, MMP2-9 modulation in hepatocytes represents the driving mechanism for the net reduction of collagen in this NASH in vitro model, highlighting the importance of hepatic cells interplay in NASH development and resolution.

Nephroprotective effect of silymarin against diclofenac induced renal damage and oxidative stress in male rats

Introduction: Diclofenac (DIC), a phenylacetic acid compound which belongs to nonsteroidal anti-inflammatory drugs (NSAIDs), is generally used for the treatment of various diseases such as rheumatoid arthritis, ankylosing spondylitis, acute muscle pain conditions and osteoarthritis. Overdose of DIC can lead to renal injuries in both experimental animal and human. Our research was done to assess the protective role of silymarin on renal damage induced by DIC in rats. Methods: Thirty-two Wistar rats were assigned to four groups (n=8/group). Group 1 was control group; animals in group 2 were administrated DIC; Groups 3 and 4 administrated DIC plus silymarin with doses of 100 mg/kg and 200 mg/kg, orally (p.o), respectively. Various biochemical, molecular, and histological parameters were evaluated in serum and tissue homogenate. Results: In the second group, the levels of kidney catalase (CAT), vitamin C and superoxide dismutase (SOD) remarkably reduced (P < 0.05) relative to the control group. Also, urea, creatinine (Cr), malondialdehyde (MDA), serum tumor necrosis factor-α (TNF-α) and gene expression of TNF-α in this group were noticeably elevated (P < 0.05) relative to the control group. Treatment with silymarin caused a remarkable elevation (P < 0.05) in vitamin C, SOD, CAT and a remarkable reduction (P < 0.05) in the content of MDA, urea, Cr, TNF-α gene expression and serum TNF-α in comparison with second group. Histological injuries were also ameliorated by silymarin administration. Conclusion: The results confirm that silymarin has an ameliorative role against renal damage and oxidative stress induced by DIC in male rats.

Piperine enhances the bioavailability of silybin via inhibition of efflux transporters BCRP and MRP2

BACKGROUND

Although silybin serves as a well-known hepatoprotective agent with prominent anti-inflammatory, anti-oxidant and anti-fibrotic activities, its low bioavailability limits its application in the treatment of chronic liver diseases. However, novel formulation products with increased solubility were not sufficient to achieve pharmacologically meaningful concentrations of silybin in the clinical studies even used at high dosage.

HYPOTHESIS/PURPOSE

We hypothesized that inhibiting efflux transporter(s) and/or glucuronidation by piperine might enhance the bioavailability and efficacy of silybin.

METHODS

Pharmacokinetics of silybin given alone or in-combination with piperine was determined by a validated LC-MS method. A CCl₄ induced rat model of liver injury was prepared and verified for comparing the effects of silybin and combination treatment. To investigate the underlying mechanism, the inhibition effects of piperine on transportation of silybin were performed in Caco-2 and transfected MDCKII cell lines as well as sandwich-cultured rat hepatocytes (SCH). Human liver microsomes incubation was used for exploring the modulation effects of piperine on the phase-2 metabolism of silybin.

RESULTS

In the present study, we demonstrated for the first time that piperine as a bioenhancer increased the bioavailability of silybin (146%- 181%), contributing to a boosted therapeutic effect in CCl₄-induced acute liver-injury rat model. The underlying mechanisms involved that piperine enhanced the absorption of silybin by inhibiting the efflux transporters including MRP2 and BCRP but not MDR1 in Caco-2 and transfected MDCKII cell lines. Moreover, piperine could inhibit the biliary excretion of silybin and conjugated metabolites in sandwich-cultured rat hepatocytes. Notably, we found that piperine did not affect the phase-2 metabolism of silybin.

CONCLUSION

Efflux transporters play an important role in the pharmacokinetic behavior of flavolignans, and modulating these transporters by bioenhancer such as piperine could enhance the in vivo absorption of silybin, leading to more effective treatments.

Differential regulation of CD4+ T cell subsets by Silymarin in vitro and in ovalbumin immunized mice

CD4+ T cell subsets including regulatory T cells (Tregs), Th1 and Th17 are critical for control and development of inflammation and autoimmunity. We investigated the in vitro and in vivo effects of silymarin, a well-known herbal medicine on differentiation and function of Tregs and Th1 and Th17 responses. For in vitro study, mice splenocytes treated with 20-30 μg/ml silymarin were evaluated for gene expressions of specific transcription factors and cytokines of CD4+ T cell subsets using real-time PCR. Induction of Treg cell development in the presence of silymarin was performed on isolated naïve CD4+ T cells. Effect of silymarin-induced Tregs on T cell suppression was determined by CFSE labeling method. Results of this part showed that silymarin significantly decreased IFNγ, RORγt and IL-17 gene expressions and upregulated Foxp3, TGF-β and IL-10 mRNA. More silymarin-enhanced naïve CD4+ T cells differentiated to Tregs (67%) than the control (47%). Silymarin-induced Tregs reduced proliferation of naïve activated T cells (<50%). For in vivo study, mice were immunized with ovalbumin (Ova) on days 1 and 14. Silymarin (100 mg/Kg) was intraperitoneally administered two days before the first Ova challenge followed by on every day for two weeks. Splenocytes were then isolated for assessment of CD4+ T cell subsets and ex vivo analysis using flow cytometry. Treatment of Ova-immunized mice with silymarin increased Tregs (11.24 ± 1.2%, p < 0.01(but decreased Th1 (1.72 ± 0.4%, p < 0.001) and Th17 (1.07 ± 0.04%, p < 0.001) cells. Ex vivo Ova challenge of splenocytes from Ova-immunized mice treated with silymarin decreased proliferation of splenocytes, IFNγ (2.76% of control) and IL-17 (<8%) along with increased TGF-β (59.7%) expressions in CD4+T-bet+, CD4+RORγt+ and CD4+Foxp3+ T cells, respectively. In conclusion, silymarin promoted Treg differentiation and function and decreased Th1 and Th17 cells. Silymarin may differentially regulate CD4+ T cell responses which can provide potential benefits for its use as treatment of immune-related diseases. Graphical abstract ᅟ.

Molecular pathogenesis and clinical consequences of iron overload in liver cirrhosis

BACKGROUND

The liver, as the main iron storage compartment and the place of hepcidin synthesis, is the central organ involved in maintaining iron homeostasis in the body. Excessive accumulation of iron is an important risk factor in liver disease progression to cirrhosis and hepatocellular carcinoma. Here, we review the literature on the molecular pathogenesis of iron overload and its clinical consequences in chronic liver diseases.

DATA SOURCES

PubMed was searched for English-language articles on molecular genesis of primary and secondary iron overload, as well as on their association with liver disease progression. We have also included literature on adjuvant therapeutic interventions aiming to alleviate detrimental effects of excessive body iron load in liver cirrhosis.

RESULTS

Excess of free, unbound iron induces oxidative stress, increases cell sensitivity to other detrimental factors, and can directly affect cellular signaling pathways, resulting in accelerated liver disease progression. Diagnosis of liver cirrhosis is, in turn, often associated with the identification of a pathological accumulation of iron, even in the absence of genetic background of hereditary hemochromatosis. Iron depletion and adjuvant therapy with antioxidants are shown to cause significant improvement of liver functions in patients with iron overload. Phlebotomy can have beneficial effects on liver histology in patients with excessive iron accumulation combined with compensated liver cirrhosis of different etiology.

CONCLUSION

Excessive accumulation of body iron in liver cirrhosis is an important predictor of liver failure and available data suggest that it can be considered as target for adjuvant therapy in this condition.