Hepatoprotective Actions of Ascorbic Acid, Alpha Lipoic Acid and Silymarin or Their Combination Against Acetaminophen-Induced Hepatotoxicity in Rats.

Background and objectives: Ascorbic acid, alpha lipoic acid (ALA) and silymarin are well-known antioxidants that have hepatoprotective effects. This study aims to investigate the effects of these three compounds combined with attenuating drug-induced oxidative stress and cellular damage, taking acetaminophen (APAP)-induced toxicity in rats as a model both in vivo and in vitro. Materials and Methods: Freshly cultured primary rat hepatocytes were treated with ascorbic acid, ALA, silymarin and their combination, both with and without the addition of APAP to evaluate their in vitro impact on cell proliferation and mitochondrial activity. In vivo study was performed on rats supplemented with the test compounds or their combination for one week followed by two toxic doses of APAP. Results: Selected liver function tests and oxidative stress markers including superoxide dismutase (SOD), malondialdehyde (MDA) and oxidized glutathione (GSSG) were detected. The in vivo results showed that all three pretreatment compounds and their combination prevented elevation of SOD and GSSG serum levels indicating a diminished burden of oxidative stress. Moreover, ascorbic acid, ALA and silymarin in combination reduced serum levels of liver enzymes; however, silymarin markedly maintained levels of all parameters to normal ranges. Silymarin either alone or combined with ascorbic acid and ALA protected cultured rat hepatocytes and increased cellular metabolic activity. The subjected agents were capable of significantly inhibiting the presence of oxidative stress induced by APAP toxicity and the best result for protection was seen with the use of silymarin. Conclusions: The measured liver function tests may suggest an augmented hepatoprotection of the combination preparation than when compared individually.

Influence of molecular weight and degree of deacetylation of low molecular weight chitosan on the bioactivity of oral insulin preparations.

The objective of the present study was to prepare and characterize low molecular weight chitosan (LMWC) with different molecular weight and degrees of deacetylation (DDA) and to optimize their use in oral insulin nano delivery systems. Water in oil nanosized systems containing LMWC-insulin polyelectrolyte complexes were constructed and their ability to reduce blood glucose was assessed in vivo on diabetic rats. Upon acid depolymerization and testing by viscosity method, three molecular weights of LMWC namely, 1.3, 13 and 18 kDa were obtained. As for the DDA, three LMWCs of 55%, 80% and 100% DDA were prepared and characterized by spectroscopic methods for each molecular weight. The obtained LMWCs showed different morphological and in silico patterns. Following complexation of LMWCs with insulin, different aggregation sizes were obtained. Moreover, the in vivo tested formulations showed different activities of blood glucose reduction. The highest glucose reduction was achieved with 1.3 kDa LMWC of 55% DDA. The current study emphasizes the importance of optimizing the molecular weight along with the DDA of the incorporated LMWC in oral insulin delivery preparations in order to ensure the highest performance of such delivery systems.

Dopamine selectively modulates lipopolysaccharide-induced TNF-alpha, IFN-gamma and IL-10 within mice tissues.

OBJECTIVES: Dopamine (DA) administration in sepsis is used to modulate the hypotensive condition and to normalize the blood vessels perfusion. However, whether this administration of DA has an effect on the release of cytokines in vivo deserves investigation. METHODS AND RESULTS: Pre-exposure of DA (1 µg/ml) to whole blood enhanced IL-10 (30%) production level following LPS stimulation. This IL-10 enhancement became statistically significant (p<0.001) upon the addition of D2-DA receptor (DAR) antagonists, Clozapine or Haloperidol. Furthermore, systemic administration of DA (0.5-50 mg/kg) in mice suppressed significantly LPS-induced TNF-α levels in blood, liver, spleen, brain, and lungs; IL-10 levels in blood, brain and liver; and IFN-γ levels in blood, liver, brain, and lungs. On the other hand, DA enhanced significantly LPS-induced IL-10 production in the lungs and spleen, and IFN-γ levels in the spleen. Administration of Clozapine (54 mg/kg) or Haloperidol (62 mg/kg) with LPS (1 µg) and DA (5 mg/kg) reversed DA suppressive effects on LPS-induced cytokines in blood, IFN-γ in brain and lungs, and enhanced significantly LPS-induced IL-10 production in blood, spleen, liver, and lungs. CONCLUSIONS: These results indicate that DA modulatory effect on LPS-induced blood cytokines-producing cells is mediated mainly by D2-DAR (D2/ D3/D4) through enhancing immune cells migration and extravasation into tissues. Furthermore, DA selectivity on cytokines modulation is tissue specific, mediated by the type of DAR expressed and on the immune cells lodged in each tissue.

Epicatechin suppresses IL-6, IL-8 and enhances IL-10 production with NF-kappaB nuclear translocation in whole blood stimulated system.

OBJECTIVES: Cytokines induce the balance between inflammatory versus regulatory or antibody mediated reactions. So modulating the release of cytokines or inducing them by immunomodulating agents is an attractive mode for treating or help in treating several diseases such as autoimmune diseases. Eriobotrya japonica is a plant that is traditionally thought to have anti-inflammatory activities. Several compounds were isolated from the plant and showed distinctive biological effects. The purpose of this study was to determine the effects of epicatechin (EC) isolated from Eriobotrya Japonica on IL-6, IL-8, and IL-10 productions in whole blood stimulated with phytohemagglutinin (PHA)+lipopolysaccharide (LPS), and to examine if these cytokines are modulated through NFkappaB pathway. METHODS: Sixteen healthy males and females volunteered in the study. Blood samples were drawn, diluted, and cultured for 24 h with different concentrations of EC and then PHA+LPS was added for another 24 h. The supernatant, then, was harvested and assayed for cytokines. In addition, mixing studies of EC and hydrocortisone were performed to examine the cytoplasmic and nuclear fractions of NFkB levels in association with cytokine production levels. RESULTS: Increasing concentrations of EC (1-100 microg/ml) in PHA+LPS stimulated whole blood cells culture suppressed significantly (p<0.001) the production of IL-6 and IL-8. Moreover, increasing concentrations of EC modulated significantly the production of IL-10, as there was a significant increase in IL-10 level at 0.1, 1.0, and 10 microg/ml (p=0.058-0.004), while a significant decrease at a concentration of 100 microg/ml EC (p=0.037) was observed. In addition, an additive effect between EC and hydrocortisone (HC, 100 nmol/l) was seen in the production of IL-10, as there was a significant increase in IL-10 level (32%) compared with 27% for EC (10 microg/ml) and 19% HC. Furthermore, a significant decrease in cytoplasmic fractions of NFkappaB p65 level was found in samples containing EC 1, 10 microg/ml, but not in 100 microg/ml, when compared with control (p<0.03). These latter changes were accompanied with a 29%, 67%, and 98% increase, respectively, of NFkappaB p65 in nuclear fractions compared to 24% reduction of NFkappaB p65 level in HC culture (p<0.03). CONCLUSIONS: These results indicate that EC suppresses the production of pro-inflammatory cytokines, IL6 and IL-8, enhances the production of anti-inflammatory cytokine, IL-10, and stimulates NFkappaB p65 translocation to nucleus in PHA+LPS stimulated whole blood culture.

Antioxidative stress effects of vitamins C, E, and B12, and their combination can protect the liver against acetaminophen-induced hepatotoxicity in rats.

BACKGROUND: Several vitamins, including C, E, and B12, have been recognized as antioxidants and have shown hepatoprotective effects against the hepatotoxicity caused by acetaminophen (APAP) overdose. The current investigation aims to study the effect of these vitamins and their combination in protecting the liver from APAP hepatotoxicity in rats. MATERIALS AND METHODS: An in vitro model of freshly isolated rat hepatocytes was utilized for assessing hepatocyte mitochondrial activity conducted by cell proliferation assay (MTT). The isolated hepatocytes were treated with vitamin C, vitamin E, vitamin B12 and their combination, with and without further addition of toxic concentrations of APAP. In addition, an in vivo experiment was carried out on Sprague Dawley rats treated intraperitoneally for 8 days with emulsions of the vitamins or their combination prior to injecting them with APAP. RESULTS: In vitro results showed that vitamins C and B and the combination preparation significantly increased the percentage of hepatocyte mitochondrial activity, both with and without the addition of APAP (P<0.01). The mitochondrial activity in the isolated cultured hepatocytes was further enhanced with APAP addition. In vivo, the vitamins and their combination effectively reduced APAP-induced serum liver enzymes levels, namely ALT, AST, and ALP, and also attenuated oxidative stress and lipids peroxidation confirmed by the results of glutathione, superoxide dismutase, and maloondialdehyde. CONCLUSION: Pretreatment with vitamins C, E, B12, or their combination was found to be beneficial in preventing in vivo hepatic oxidative stress induced by APAP overdose. Vitamin C on its own showed superior protection against APAP-induced liver injury in rats compared to the other vitamins. The proliferation of APAP-intoxicated liver cells in vitro was highest when protected with the vitamins' combination.

Evidence of reduced oral bioavailability of paracetamol in rats following multiple ingestion of grapefruit juice.

The aim of the current investigation was to assess the ability GFJ to modulate the pharmacokinetic profile of paracetamol following single or repeated administrations of GFJ in Sprague-Dawley rats. Diclofenac and carbamazepine were both used as positive controls. Rats received single GFJ or single distilled water doses or pretreated with three doses of GFJ prior to test drug administration. Blood samples were collected, processed and analyzed using validated HPLC methods, and pharmacokinetic data were constructed for each group. Increase in the bioavailability of both diclofenac and carbamazepine following multiple GFJ ingestion was revealed. Conversely, the bioavailability of paracetamol was significantly reduced following multiple GFJ administration. The percentage of reduction in the C max and AUC of paracetamol were calculated as 31 and 51 %, respectively, compared to none-GFJ-treated control (P < 0.05). The T(max) was not essentially changed. In conclusion, frequent administration of GFJ was confirmed to modulate the pharmacokinetics of paracetamol in rats by reducing its bioavailability. Meanwhile, it may be advisable not to ingest large amounts of GFJ along with paracetamol to avoid a possible potential loss of the efficacy.

Effects of prickly pear dried leaves, artichoke leaves, turmeric and garlic extracts, and their combinations on preventing dyslipidemia in rats.

The successful use of herbal combinations in managing diseases or conditions over a single herb has lead us to evaluate the anti-dyslipidemic properties of the combination of the artichoke leaves extract, turmeric extract, prickly pear dried leaves (PPL) and garlic extract versus each one alone in two different hyperlipidemic animal models. A two-week treatment of each of the natural extracts, combination 1 (artichoke, turmeric and PPL) or combination 2 (artichoke, turmeric, PPL and garlic) prior to a single intraperitoneal injection of Pluronic F-127 resulted in decreasing significantly serum LDL levels by garlic and PPL extracts and serum LDL/HDL ratios by turmeric, PPL, combination 1 and 2. In a 10-day high fat diet model, only the combination 1 and 2 lowered serum cholesterol, LDL by 8-12%, decreased significantly triglycerides, LDL/HDL ratio; and increased significantly HDL (P < 0.0001). However, a long term treatment of each natural product for 7 weeks resulted in decreasing significantly serum LDL levels and LDL/HDL ratio (P < 0.05-0.0001). Furthermore, only artichoke and PPL inhibited significantly HMG-CoA reductase activity (P < 0.05). In conclusion, short term, as well as long term, treatment using the combination of artichoke, turmeric, PPL and garlic extract prevents dyslipidemia; partially through inhibiting HMG-CoA reductase.

Non-selective inhibition of cyclooxygenase enzymes by aminoacetylenic isoindoline 1,3-diones.

The reported pharmacological activities of acetylenic and phthalimide groups promoted our interest to synthesize a novel series of N-[4-(t-amino-yl)-but-2-yn-1-yl] isoindoline-1,3-diones as anti-inflammatory compounds. The aim of this research is to investigate the selectivity of two compounds, ZM4 and ZM5, on inhibiting cyclooxygenase (COX) in vitro and in silico as well as reducing carrageenan-induced edema in rats. Oral administration of 5-20 mg/kg ZM4 and ZM5 reduced significantly carrageenan-induced edema in dose-and time dependent manner. Furthermore, the IC50 values induced by ZM4 and ZM5 were in the range of 3.0-3.6 µM for COX1 and COX 2 but were higher than those induced by Diclofenac and Celecoxib, respectively. Docking of ZM4 and ZM5 in both COX enzymes, on the other hand, exhibited the conventional binding modes that are usually adopted by different non-steroidal anti-inflammatory drugs (NSAIDs). Furthermore, ZM4 and ZM5 bind to COX enzymes as strongly as Flurbiprofen and Celecoxib. In conclusion, aminoacetylenic isoindoline 1, 3-dione compounds have shown anti-inflammatory activity by inhibiting COX-1 and COX-2 enzymes. Interestingly, the best hits showed inhibition at low micromolar levels although they are not selective at this stage. Further research will be conducted to improve both selectivity and potency.