Effects of Silymarin on Diabetes Mellitus Complications: A Review.

Diabetes mellitus is a common metabolic disorder that is caused by a deficit in the production of (type 1) or response to (type 2) insulin. Diabetes mellitus is characterized by a state of chronic hyperglycemia and such symptoms as weight loss, thirst, polyuria, and blurred vision. These disturbances represent one of the major causes of morbidity and mortality nowadays, despite available treatments, such as insulin, insulin secretagogues, insulin sensitizers, and oral hypoglycemic agents. However, many efforts have been made to discover new drugs for diabetes treatment, including medicinal plant extracts. Silymarin is a powder extract of the seeds from Silybum marianum, a plant from the Asteraceae family. The major active ingredients include four isomers: silybin, isosilybin, silychristin, and silydianin. Silymarin is indicated for the treatment of hepatic disorders, such as cirrhosis, chronic hepatitis, and gallstones. Moreover, several studies of other pathologies, including diabetes, sepsis, osteoporosis, arthritis, hypercholesterolemia, cancer, viral infections, and Alzheimer's and Parkinson's diseases, have tested the effects of silymarin and reported promising results. This article reviews data from clinical, in vivo, and in vitro studies on the use of silymarin, with a focus on the complications of diabetes, including nephropathy, neuropathy, healing delays, oxidative stress, hepatotoxicity, and cardiomyopathy. Copyright © 2017 John Wiley & Sons, Ltd.

Effects of statins on liver cell function and inflammation in septic rats.

BACKGROUND: Several studies suggest that the presence of statins may be beneficial during sepsis, but this idea is controversial. The aim of this study was to investigate the effects of long-term statin treatment in the livers of septic animals, focusing on its antioxidant, antiinflammatory, and metabolic properties. MATERIALS AND METHODS: Male Wistar rats were treated orally with simvastatin, atorvastatin, or vehicle once a d. After 30 d, sepsis was induced by cecal ligation and puncture (CLP) in Control, Simvastatin-treated, and Atorvastatin-treated groups, while the Sham group underwent only laparotomy. The Basal Simvastatin and Basal Atorvastatin groups received only their respective drugs without surgery. Twenty-four h after CLP or laparotomy, samples were collected from anesthetized rats for evaluation of hepatic oxidative stress, liver histology, hepatic mitochondria enzyme activity, leukocyte counts in blood and peritoneal cavity, gene expression of hepatic superoxide dismutase and TNF-2, and plasma biochemistry. RESULTS: Most parameters that we tested exhibited expected changes upon sepsis induction. However, statin treatment only improved liver mitochondrial enzymatic activity. In other parameters, simvastatin and atorvastatin failed to protect the liver against injuries incurred upon the CLP-induced polymicrobial sepsis model. CONCLUSIONS: Pretreatment with simvastatin or atorvastatin alone before sepsis induction improved mitochondrial activity in the liver; however, this result was not reproduced in other biomarkers of liver function and leukocyte migration during sepsis. Future studies should be performed to evaluate whether statins can be combined with other drugs to increase the efficacy of sepsis therapy.

Effects of silymarin on angiogenesis and oxidative stress in streptozotocin-induced diabetes in mice.

The present study evaluated the effects of acute treatment with silymarin, an extract that is obtained from Silybum marianum, on angiogenesis, oxidative stress, and inflammation in normoglycemic and diabetic mice. Diabetes was induced by streptozotocin (80 mg/kg, intraperitoneal) in male Swiss mice, 6 weeks of age. A polyether-polyurethane sponge was surgically implanted in the back of the mice as a model of healing in both diabetic and normoglycemic animals that were treated with oral silymarin or water for 10 days. The pancreas, liver, kidneys, blood, and sponges were collected and analyzed. Diabetes led to impairments of antioxidant defenses, reflected by a reduction of pancreatic superoxide dismutase and hepatic and renal catalase and an increase in pancreatic lipoperoxidation. An inflammatory process was observed in diabetic mice, reflected by an increase in pancreatic tumor necrosis factor α (TNF-α) and the infiltration of inflammatory cells in islets. The number of vessels was lower in the implanted sponges in diabetic mice. Silymarin treatment attenuated this damage, restoring antioxidant enzymes and reducing pancreatic TNF-α and inflammatory infiltration. However, silymarin treatment did not restore angiogenesis or glycemia. In conclusion, treatment with silymarin red uced oxidative stress and inflammation that were induced in the model of streptozotocin-induced diabetes in several organs, without apparent toxicity. Silymarin may be a promising drug for controlling diabetic complications.

Sesquiterpene lactones of Moquiniastrum polymorphum subsp. floccosum have antineoplastic effects in Walker-256 tumor-bearing rats.

BACKGROUND AND AIM: This study aimed to evaluate the in vivo antitumor actions and toxicity of the dichloromethane fraction (F1B) of Moquiniastrum polymorphum subsp. floccosum (formerly Gochnatia polymorpha ssp. floccosa), composed of sesquiterpene lactones, against Walker-256 carcinosarcoma in rats. METHODS: Male Wistar rats received 100 mg kg(-1) F1B per day orally for 16 days after subcutaneous inoculation of Walker-256 cells in the pelvic limb. The tumor progression was monitored, and after treatment, tumor weight, oxidative stress, plasma biochemistry, inflammatory parameters, gene expression and histology of tumor and/or liver were evaluated. The toxicity of F1B was analyzed through the relative weight of organs. Additionally, an LD50 test was performed in mice. RESULTS: F1B treatment significantly reduced tumor volume and weight. There was no difference in oxidative stress in tumor tissue after treatment. F1B treatment modified hepatic glutathione and superoxide dismutase, and normalized plasma glucose, alkaline phosphatase, and amylase. F1B did not affect the activity of myeloperoxidase and N-acetylglucosaminidase or the nitric oxide levels in tumor tissue. However, F1B decreased the tumor necrosis factor (TNF)-α levels. Additionally, F1B increased apoptosis in the tumor, mediated by up-regulation of the p53 and Bax gene expression. No clinical signs of toxicity or death were observed in the rats treated with F1B. The LD50 calculated for mice was 1209 mg kg(-1). CONCLUSIONS: F1B, which is rich in sesquiterpene lactones, showed antitumor activity against Walker-256 carcinosarcoma. This effect may be, at least in part, related to the induction of apoptosis and inhibition of TNF-α signaling.

The FXR agonist 6ECDCA reduces hepatic steatosis and oxidative stress induced by ethanol and low-protein diet in mice.

BACKGROUND AND AIM: Excessive ethanol consumption can lead to development of hepatic steatosis. Since the FXR receptor regulates adipose cell function and liver lipid metabolism, the aim of this work was to examine the effects of the FXR agonist 6ECDCA on alcoholic liver steatosis development and on oxidative stress induced by ethanol consumption. METHODS: Swiss mice (n=24) received a low-protein diet (6%) and a liquid diet containing 10% ethanol or water for 6weeks. In the last 15days mice received oral treatment with 6ECDCA (3mgkg(-1)) or 1% tween (vehicle). The experimental groups (n=6) were: water+tween, water+6ECDCA, ethanol+tween and ethanol+6ECDCA. Moreover, as a diet control, we used a basal group (n=6), fed by a normal-proteic diet (23%) and water. After the treatment period, the animals were anesthetized for sample collection to perform plasma biochemistry assays, hepatic oxidative stress assays, hepatic cholesterol and triglycerides measurements, liver histology and hepatic gene expression. RESULTS: Ethanol associated with low-protein diet induced hepatic oxidative stress, increased plasma transaminases and induced hepatic lipid accumulation. Many of these parameters were reversed by the administration of 6ECDCA, including amelioration of lipid accumulation and lipoperoxidation, and reduction of reactive oxygen species. These effects were possibly mediated by regulation of Srebpf1 and FAS gene expression, both reduced by the FXR agonist. CONCLUSIONS: Our data demonstrated that 6ECDCA reverses the accumulation of lipids in the liver and decreases the oxidative stress induced by ethanol and low-protein diet. This FXR agonist is promising as a potential therapy for alcoholic liver steatosis.

Uncaria tomentosa exerts extensive anti-neoplastic effects against the Walker-256 tumour by modulating oxidative stress and not by alkaloid activity.

This study aimed to compare the anti-neoplastic effects of an Uncaria tomentosa (UT) brute hydroethanolic (BHE) extract with those of two fractions derived from it. These fractions are choroformic (CHCl3) and n-butanolic (BuOH), rich in pentacyclic oxindole alkaloids (POA) and antioxidant substances, respectively. The cancer model was the subcutaneous inoculation of Walker-256 tumour cells in the pelvic limb of male Wistar rat. Subsequently to the inoculation, gavage with BHE extract (50 mg.kg(-1)) or its fractions (as per the yield of the fractioning process) or vehicle (Control) was performed during 14 days. Baseline values, corresponding to individuals without tumour or treatment with UT, were also included. After treatment, tumour volume and mass, plasma biochemistry, oxidative stress in liver and tumour, TNF-α level in liver and tumour homogenates, and survival rates were analysed. Both the BHE extract and its BuOH fraction successfully reduced tumour weight and volume, and modulated anti-oxidant systems. The hepatic TNF-α level indicated a greater effect from the BHE extract as compared to its BuOH fraction. Importantly, both the BHE extract and its BuOH fraction increased the survival time of the tumour-bearing animals. Inversely, the CHCl3 fraction was ineffective. These data represent an in vivo demonstration of the importance of the modulation of oxidative stress as part of the anti-neoplastic activity of UT, as well as constitute evidence of the lack of activity of isolated POAs in the primary tumour of this tumour lineage. These effects are possibly resulting from a synergic combination of substances, most of them with antioxidant properties.

Characterization of an alcoholic hepatic steatosis model induced by ethanol and high-fat diet in rats

Alcoholic liver disease is characterized by a wide spectrum of liver damage, which increases when ethanol is associated with high-fat diets (HFD). This work aimed to establish a model of alcoholic hepatic steatosis (AHS) by using a combination of 10% ethanol and sunflower seeds as the source of HFD. Male rats received water or 10% ethanol and regular chow diet and/or HFD, which consisted of sunflower seeds. The food consumption, liquid intake and body weight of the rats were monitored for 30 days. After this period, blood was collected for biochemical evaluation, and liver samples were collected for histological, mitochondrial enzyme activity and oxidative stress analyses. Our results indicated that the combination of 10% ethanol and HFD induced micro- and macrosteatosis and hepatocyte tumefaction, decreased the levels of reduced glutathione and glutathione S-transferase activity and increased the level of lipoperoxidation and superoxide dismutase activity. The mitochondrial oxidation of NADH and succinate were partially inhibited. Complexes I and II were the main inhibition sites. Hepatic steatosis was successfully induced after 4 weeks of the diet, and the liver function was modified. The combination of 10% ethanol and sunflower seeds as an HFD produced an inexpensive model to study AHS in rats.