The use of silymarin in the treatment of liver diseases

Metabolic, antioxidant, nutraceutical, probiotic, and herbal therapies relating to the management of hepatobiliary disorders

Many nutraceuticals, conditionally essential nutrients, and botanical extracts have been proposed as useful in the management of liver disease. The most studied of these are addressed in terms of proposed mechanisms of action, benefits, hazards, and safe dosing recommendations allowed by current information. While this is an area of soft science, it is important to keep an open and tolerant mind, considering that many major treatment discoveries were in fact serendipitous accidents.

Effects of Silymarin, a Natural Hepatoprotector, in Periparturient Dairy Cows

Silymarin, a natural acknowledged hepatoprotector used in humans to treat liver diseases, has been tested in dairy cows during peripartum, a period during which animals are subject to subclinical fatty liver. Ten grams of silymarin (76% pure extract consisting in flavonolignans, taxifolin, and other trace compounds) per day, was administered as a water suspension by an oral drench to 15 cows from d 10 before expected calving to 15 d after calving. Milk production was measured, and colostrum, milk, and blood samples were analyzed during the experimental period. Treated animals showed the peak of milk production at 55 +/- 1.85 d after calving, 1 wk before the control group (62 +/- 3.27 d); the average peak production was 41.6 +/- 1.05 kg for the treated group vs. 39.1 +/- 1.44 kg for the control; the treated animals maintained a greater milk production than control cows throughout lactation (9922.1 +/- 215.7 vs. 9597.8 +/- 225.4 kg). Milk composition was unaffected by treatment. No silymarin residues were detected in colostrum and all milk samples. After calving, body condition score (BCS) decrease was greater for control compared with treated cows. Glucose, urea, triglycerides (TG), total cholesterol, beta-hydroxibutyrate (BHBA), and gamma-glutamyl transferase (GGT) in plasma were unaffected by treatment. Plasma nonesterified fatty acids (NEFA) on d-7 were higher in treated cows compared with the control group (741 vs. 181 micromol/L). From this evidence, it is possible to conclude that silymarin beneficially affected lactation performances and body condition of treated animals. Blood and milk parameters do not indicate any adverse effects of feeding this natural compound.

Silibinin inhibits the invasion of human lung cancer cells via decreased productions of urokinase-plasminogen activator and matrix metalloproteinase-2

Cancer metastasis, involving multiple processes and various cytophysiological changes, is a primary cause of cancer death and may complicate the clinical management, even lead to death. Silibinin is a flavonoid antioxidant and wildly used for its antihepatotoxic properties and recent studies have revealed pleiotropic anticancer and antiproliferative capabilities of silibinin. In this study, we first observed that silibinin exerted a dose- and time-dependent inhibitory effect on the invasion and motility, but hardly on the adhesion, of highly metastatic A549 cells in the absence of cytotoxicity. To look at the precise involvement of silibinin in cancer metastasis, A549 cells were treated with silibinin at various concentrations, up to 100 microM, for a defined period and then subjected to gelatin zymography, casein zymography and Western blot to investigate the impacts of silibinin on metalloproteinase-2 (MMP-2), urokinase plasminogen activator (u-PA), and tissue inhibitor of metalloproteinase-2 (TIMP-2), respectively. The results showed that a silibinin treatment may decrease the expressions of MMP-2 and u-PA in a concentration- and time-dependent manner and enhance the expression of TIMP-2. Further analysis with semi-quantitative RT-PCR showed that silibinin may regulate the expressions of MMP-2 and u-PA on the transcriptional level while on the translational or post-translational level for TIMP-2.

Silymarin, a possible hepatoprotector in dairy cows: biochemical and histological observations

Silymarin, a standardized extract from Silybum marianum seed, is a natural hepatoprotector used for the treatment of liver diseases in man. The aim of this study was to investigate its safety and efficacy in periparturient dairy cows. Ten treated and 10 control pregnant dairy cows were paired by parity, body condition score (BCS), health condition and previous milk production. Treatment consisted of daily 10 g per animal of silymarin extract administered as oral drenches, from 10 days prior to the calving date to 15 days after calving. Blood samples and liver biopsies were taken from each animal at 7 and 30 days after calving. Hepatic functions were evaluated by assay of plasma beta-hydroxybutyrate (BHBA), total cholesterol, high-density lipoproteins, low-density lipoproteins, triglyceride and total bilirubin. The histological aspect of the liver was assessed in biopsies. Clinical chemistry values were similar for both groups and effects at different times (day 7 versus day 30; P < 0.05) were attributed to physiological variations in periparturient cows. Histology showed fat accumulation in the liver of both groups, as it is expected in periparturient dairy cows. In treated cows, fat-rich hepatocytes were observed near the central vein. These observations suggest that, at the used dosage, S. marianum extract has no adverse effect on the liver of lactating cows, and presents no objective evidence for a hepatoprotective effect in this species.

Current concepts in the treatment of canine chronic hepatitis

Chronic hepatitis is a common disorder in dogs seen by general practitioners. Several new drugs have been marketed for treating this disease. Unfortunately, there are few controlled studies that examine the efficacy of these medications for the treatment of canine chronic hepatitis. A rational therapeutic approach can be implemented based on histopathologic findings of a liver biopsy. A liver biopsy is essential for establishing a definitive diagnosis and guiding the optimal therapy. The biopsy allows characterizing the inflammatory process, quantitating hepatic copper concentrations, and determining if fibrosis is present. Copper associated hepatopathy is treated with zinc and copper chelators. Idiopathic chronic hepatitis is thought to be immune mediated. The treatment of idiopathic chronic hepatitis consists of controlling inflammation (prednisone, azathioprine), reversing fibrosis (colchicine), and protecting against oxidant damage (vitamin E, ursodeoxycholic acid, S-adenosylmethionine). The prognosis for chronic hepatitis is quite variable. Dogs with end-stage disease have a poor prognosis, while dogs diagnosed earlier can have a mean survival of years. Early diagnosis and intervention are key to the successful treatment of dogs with chronic hepatitis.

Chemoprotective effect of plant phenolics against anthracycline-induced toxicity on rat cardiomyocytes. Part I. Silymarin and its flavonolignans

Silymarin, an extract of fl avonolignans from the dried fruits of milk thistle (Silybum marianum L. Gaertneri) and its constituents silibinin, dehydrosilibinin, silychristin and silydianin were tested for protective effects on rat cardiomyocytes exposed to doxorubicin. Silymarin and individual fl avonolignans did not exert cytotoxicity in the range 25-100 micro m (incubation 9 h). Dehydrosilibinin was tested only at 25 micro m concentration due to its low solubility. All substances increased the cell ATP level. Silymarin and fl avonolignans displayed a dose-dependent cytoprotection against doxorubicin (100 micro m, incubation 8 h). The protective effects of silymarin, silibinin, dehydrosilibinin and silychristin were comparable to that of dexrasoxane, while silydianin exerted the best protective effect. The ability of silymarin complex and its components to protect cardiomyocytes against doxorubicin-induced oxidative stress is due mainly to their cell membrane stabilization effect, radical scavenging and iron chelating potency.

Pharmacognosy: phytomedicines and their mechanisms

The more a critical look at the medicinal properties of plants is undertaken, the more it will be realized that nature does not make it easy to find all there is to know about them and the complexities of their interactions. An illustration of this can be found in one of the earlier scientific studies on phytomedicines, the Nobel laureate Albert Szent-Györgyi and his colleagues [170] found that flavanone extracts from the Capsicum spp contain an ascorbate-protective factor. It has now been repeatedly shown that the electron-donating properties of the phytochemical flavonoids, providing both nutritive and chemotherapeutic benefits, are the basis of their antioxidant action [171-175]. Studies by zoologists have demonstrated that animals, by selectively choosing specific plants, soils, and clays, maintain their health and treat themselves in times of ill health. The term zoopharmacognosy, now well researched, has been coined to describe the study of this recognized phenomenon. Long ago, Isaac Newton stated that for every action, there is an equal and opposite reaction. The same may be seen in plants and plant material. The same may be said of life in general. At the most basic concept, we are talking of electrons and their activities.

Application of liquid chromatography-electrospray ionization-ion trap mass spectrometry to investigate the metabolism of silibinin in human liver microsomes

Silibinin is the main isomer of a group of flavanoids extracted from the seeds of the milk thistle weed, a common herb that is widely used to maintain liver health and for the treatment of liver disorders. Silibinin when incubated with human liver microsomes produced one major metabolite and at least two minor metabolites. Tandem mass spectrometry (MS) was used to identify the metabolite structures partially. MS studies confirmed that the major metabolite is demethylated silibinin and the two minor metabolites are mono-hydroxy and di-hydroxy silibinin. The K(m) value for the demethylation shows that silibinin has a strong affinity for the cytochrome P450 enzymes.

Recovery from severe hepatitis caused by mushroom poisoning without liver transplantation

BACKGROUND & AIMS

Toxic mushroom poisoning leads to a variety of clinical outcomes ranging from self-limited gastrointestinal symptoms to fulminant hepatic failure requiring orthotopic liver transplantation. We reviewed the outcomes of patients with severe acute hepatitis secondary to mushroom poisoning, treated with contemporary modalities.

METHODS

We retrospectively reviewed patients admitted to our institution over a 5-year period with elevated transaminase levels (>1000 IU/L) attributed to recent mushroom ingestion. The patients' clinical course, laboratory data, and treatment regimen were recorded and analyzed.

RESULTS

Eight patients who presented with severe hepatitis after mushroom ingestion qualified for analysis. The mean peak serum levels were: aspartate transaminase 5488 IU/L, alanine transaminase 7618 IU/L, and total bilirubin 10.5 mg/dL. The mean peak prothrombin time was 31 seconds. One patient developed acute renal failure requiring hemodialysis. Three patients developed encephalopathy ranging from grade I to III. All 8 patients survived without significant morbidity or need for liver transplantation. Subgroup analysis revealed that older patients spent more days in the intensive care unit and subsequently had longer hospital stays. The older group also had a trend toward more severe laboratory abnormalities.

CONCLUSIONS

Patients with severe hepatitis from mushroom poisoning are thought to have a poor prognosis and frequently need liver transplantation for survival. We suggest that with early and aggressive multidisciplinary care, such patients have improved outcomes and may avoid liver transplantation.

Silibinin protects mice from T cell-dependent liver injury

BACKGROUND/AIMS

Silibinin is the major pharmacologically active compound of the Silybum marianum fruit extract silymarin. Its well-known hepatoprotective activities are mostly explained by antioxidative properties, inhibition of phosphatidylcholine synthesis or stimulation of hepatic RNA and protein synthesis. Here, we characterized the hepatoprotective potential of silibinin as an immune-response modifier in T cell-dependent hepatitis in vivo.

METHODS

Silibinin was tested in the mouse model of concanavalin A (ConA)-induced, T cell-dependent hepatitis. Liver injury was assessed by quantification of plasma transaminase activities and intrahepatic DNA fragmentation. Plasma cytokine concentrations were determined by enzyme-linked immunosorbent assay (ELISA), intrahepatic cytokine and inducible NO synthase (iNOS) mRNA levels by reverse transcriptase polymerase chain reaction, intrahepatic iNOS expression by immunofluorescent staining, and intrahepatic nuclear factor kappa B (NF-kappaB) activation by electrophoretic mobility shift assay.

RESULTS

Silibinin significantly inhibited ConA-induced liver disease. Silibinin proved to be an immune-response modifier in vivo, inhibiting intrahepatic expression of tumor necrosis factor, interferon-gamma, interleukin (IL)-4, IL-2, and iNOS, and augmenting synthesis of IL-10. In addition, silibinin inhibited intrahepatic activation of NF-kappaB.

CONCLUSIONS

Silibinin, suppressing T cell-dependent liver injury as an immune-response modifier, might be a valuable drug in therapeutic situations in which intrahepatic immunosuppression is required.

L-cysteine administration prevents liver fibrosis by suppressing hepatic stellate cell proliferation and activation

Recent studies showed that the function of some amino acids is not only nutritional but also pharmacological. However, the effects of amino acids on liver fibrosis and hepatic stellate cell (HSC) remain unclear. In this research, as a result of screening of amino acids using liver fibrosis induced by DMN administration, L-cysteine was selected as a suppressor of liver fibrosis. Furthermore, the number of activated HSCs, which increased in the fibrotic liver after DMN administration, was decreased in L-cysteine-fed rats. Treatment of freshly isolated HSCs with L-cysteine resulted in inhibition of the increase in smooth muscle alpha-actin (alphaSMA) expression by HSCs and BrdU incorporation into the activated HSCs. These findings suggest that L-cysteine is effective against liver fibrosis. The mechanism of inhibition of fibrosis in the liver is surmized to be direct inhibition of activated HSC proliferation and HSC transformation by L-cysteine.

Cutaneous photodamage, oxidative stress, and topical antioxidant protection

New methods to protect skin from photodamage from sun exposure are necessary if we are to conquer skin cancer and photoaging. Sunscreens are useful, but their protection is not ideal because of inadequate use, incomplete spectral protection, and toxicity. Skin naturally uses antioxidants (AOs) to protect itself from photodamage. This scientific review summarizes what is known about how photodamage occurs; why sunscreens--the current gold standard of photoprotection--are inadequate; and how topical AOs help protect against skin cancer and photoaging changes. This review is intended to be a reference source, including pertinent comprehensive reviews whenever available. Although not all AOs are included, an attempt has been made to select those AOs for which sufficient information is available to document their potential topical uses and benefits. Reviewed are the following physiologic and plant AOs: vitamin C, vitamin E, selenium, zinc, silymarin, soy isoflavones, and tea polyphenols. Their topical use may favorably supplement sunscreen protection and provide additional anticarcinogenic protection. (J Am Acad Dermatol 2003;48:1-19.)

LEARNING OBJECTIVE

At the completion of this learning activity, participants should have an understanding of current information about how the sun damages skin to produce skin cancer and photoaging changes, how the skin naturally protects itself from the sun, the shortcomings of sunscreens, and the added advantages of topical AOs for photoprotection.

Effects of polyphenolic fraction of silymarin on lipoprotein profile in rats fed cholesterol-rich diets

To study the influence of polymerised polyphenolics (PP), a fraction of silymarin (SM), on lipids and oxidant status, rats were fed high-cholesterol (1%), high-fat (10%) diets containing either lard fat (LFD) rich in saturated/monounsaturated fatty acids, or currant oil (COD) rich in polyunsaturated fatty acids. PP and SM were administered as dietary supplements (0.1-0.5-1.0%) for 3 weeks. PP (1%) decreased cholesterol (C) in VLDL (from 0.72+/-0.08 mmol l(-1) in LFD control to 0.35+/-0.07 mmol l(-1), P<0.01, and from 0.33+/-0.05 mmol l(-1) in COD control to 0.09+/-0.02 mmol l(-1), P<0.001), and increased HDL-C/VLDL-C ratio, however, without effect on the total plasma C and LDL-C. Liver C content (LFD 19.32+/-1.50 micromol g(-1), COD 18.64+/-2.13 micromol g(-1), N.S.) decreased after PP (1%) to 12.24+/-0.76 micromol g(-1), P<0.01, and 8.78+/-0.95 micromol g(-1), P<0.001, respectively. Triacylglycerols (TAG) in plasma and VLDL decreased after PP in the LFD group only, which displayed higher TAG levels than the COD group. Likewise, LFD caused a higher liver TAG content than did COD (31.16+/-3.00 micromol g(-1) versus 17.31+/-1.48 micromol g(-1), P<0.01), and PP (1%) decreased liver TAG only in rats fed LFD (19.55+/-2.43 micromol g(-1), P<0.02). Blood glutathione (GSH) increased after PP (1%) in the LFD group from 0.97+/-0.11 to 1.54+/-0.19 mmol l(-1) (P<0.05) and in the COD group from 0.58+/-0.15 to 1.23+/-0.10 mmol l(-1) (P<0.01), while liver GSH and plasma TBARS did not change. On principle, effects of PP were dose-dependent and parallel to SM. These results suggest that the polyphenolic fraction of SM positively modifies lipoprotein profile, counteracts the development of fatty liver and ameliorates an antioxidant status in circulation.

Understudied populations with hepatitis C

Managing patients with hepatitis C virus (HCV) infection consists primarily of antiviral treatment, currently with peginterferon and ribavirin. Unfortunately, treatment recommendations derive largely from trials that have focused on highly selected patient populations. As a consequence of the strict inclusion and exclusion criteria in these studies, more than half of all HCV-infected patients would be ineligible for enrollment. Even among the selected patients enrolled into studies, only 50% achieve a sustained virological response (SVR). Patients not eligible for current therapies include those with mild disease and normal alanine aminotransferase (ALT) levels, patients with advanced and decompensated liver disease, children, the elderly, patients with ongoing or recent alcohol and substance abuse, renal disease, human immunodeficiency virus (HIV) infection, severe psychiatric or neurologic illness, autoimmune disorders, solid organ transplant, and other significant comorbid conditions. Because these patients have been excluded from most clinical trials, little is known about the safety or efficacy of therapy in these populations. The expense and side effects of therapy are also an impediment to treatment of patients who are on public assistance, in prisons, and in institutions. Clearly, new efforts and new approaches are needed to expand the eligibility for antiviral therapy of hepatitis C and make treatment more available for understudied populations with this disease.

Understudied populations with hepatitis C

Managing patients with hepatitis C virus (HCV) infection consists primarily of antiviral treatment, currently with peginterferon and ribavirin. Unfortunately, treatment recommendations derive largely from trials that have focused on highly selected patient populations. As a consequence of the strict inclusion and exclusion criteria in these studies, more than half of all HCV-infected patients would be ineligible for enrollment. Even among the selected patients enrolled into studies, only 50% achieve a sustained virological response (SVR). Patients not eligible for current therapies include those with mild disease and normal alanine aminotransferase (ALT) levels, patients with advanced and decompensated liver disease, children, the elderly, patients with ongoing or recent alcohol and substance abuse, renal disease, human immunodeficiency virus (HIV) infection, severe psychiatric or neurologic illness, autoimmune disorders, solid organ transplant, and other significant comorbid conditions. Because these patients have been excluded from most clinical trials, little is known about the safety or efficacy of therapy in these populations. The expense and side effects of therapy are also an impediment to treatment of patients who are on public assistance, in prisons, and in institutions. Clearly, new efforts and new approaches are needed to expand the eligibility for antiviral therapy of hepatitis C and make treatment more available for understudied populations with this disease.