Garlic oil and DDB, comprised in a pharmaceutical composition for the treatment of patients with viral hepatitis, prevents acute liver injuries potentiated by glutathione deficiency in rats

Are silymarin and N-acetylcysteine able to prevent liver damage mediated by multiple factors? Findings against ethanol plus LPS-induced liver injury in mice

This study investigated the effect of N-acetylcysteine (NAC) and silymarin (SIL) in the liver of mice exposed to ethanol and lipopolysaccharides (LPS). Mice were divided into four groups (n = 6): naive, vehicle, NAC (200 mg/kg), and SIL (200 mg/kg). Treatments were given orally (po) once daily for 10 days. Liver injury was induced by administration of ethanol (30%, po) for 10 days, once daily, followed by a single administration of LPS (2 mg/kg, ip) 24 h before euthanasia. After the treatment period, animals were euthanized, and liver and blood samples were collected. NAC, but not SIL, prevented the increase in oxalacetic glutamic transaminase (OGT) and pyruvic glutamic transaminase (PGT) serum levels. NAC and SIL did not restore levels of reduced glutathione or hepatic malonaldehyde. The treatments with NAC or SIL showed no difference in the activity of glutathione S-transferase, superoxide dismutase, and catalase compared to vehicle group. Myeloperoxidase and N-acetylglucosaminidase activities are increased, as well as the IL-6 and IL-10 levels in the liver. The treatment with NAC, but not SIL, reduced the N-acetylglucosamines activity and the IL-6 and IL-10 amount in the liver. Histological findings revealed microsteatosis in the vehicle group, which was not prevented by SIL but was partially reduced in animals receiving NAC. Unlike other liver injury models, NAC (200 mg/kg) or SIL (200 mg/kg) did not positively affect antioxidant patterns in liver tissue of animals exposed to ethanol plus LPS, but NAC treatment displays anti-inflammatory properties in this model.

Toxicity of Nanoscaled Zero-Valent Iron Particles on Tilapia, Oreochromis mossambicus

This research effort aims to evaluate the hazardous potential of the redox state (OH^-) of zero-valent iron nanoparticles (nZVI) and its histopathological and oxidative stress toward Mozambique tilapia, Oreochromis mossambicus. X-ray powder diffraction (XRD) validated the nZVI nanoparticles' chemical composition, while transmission electron microscopy (TEM) revealed that their physical form is round and oval. The exposure to 10 g/mL of nZVI induced the activation of the cellular superoxide dismutase (SOD) activity. Dose-dependent testing of O. mossambicus had a reduction in SOD and an increase in malondialdehyde (MDA) levels, suggesting that nZVI caused oxidative damage. At a concentration of 100 g/mL, the catalase (CAT) and peroxidase (POD) activities of diverse tissues exhibited a gradual decrease after 2 days of exposure and a fast increase until day 6. The scavenging of reactive oxygen species (ROS) in the epidermis, liver, and gills of O. mossambicus deteriorated and accumulated gradually. MDA levels in the skin, gill, and liver tissues were substantially higher after 8 days of exposure to 100 and 200 g/mL nZVI compared to those of the control group and those exposed to 10 and 50 g/mL nZVI for 2 days. Extreme histological and morphological abnormalities were seen in the skin, gill, and liver tissues of experimental animals, demonstrating that the damage resulted from direct contact with nZVI in water. A one-way ANOVA followed by Dunnett's post-test was performed to investigate significant differences.

Garlic oil alleviates high triglyceride levels in alcohol-exposed rats by inhibiting liver oxidative stress and regulating the intestinal barrier and intestinal flora

Garlic oil (GO) is a kind of natural extract extracted from garlic, which has strong antioxidant activity. This study elucidates the protective mechanism of GO against alcohol-induced high triglyceride levels. Sixty male Sprague Dawley rats were assigned to five groups, including a control group (CON), a model group (MOD) treated with alcohol 56% v/v at 8 ml kg-1 day-1 for 2 weeks then 10 ml kg-1 day-1 for 8 weeks, a low-dose GO group (GO-L) given GO at 20 mg kg-1 day-1, a high-dose GO group (GO-H) given GO at 40 mg kg-1 day-1, and a positive group (POS) given diammonium glycyrrhizinate at 200 mg kg-1 day-1. The results showed that GO could significantly reduce the serum and liver triglyceride levels caused by alcohol exposure (p < .05). The GO-H group significantly reduced MDA level, increased SOD and GSH-Px levels in serum, liver, and colon (p < .05), significantly increased the levels of Sirt1 and PGC-1α proteins and reduced FoxO1 protein level in liver (p < .05), and significantly increased the levels of ZO-1 and Claudin1 proteins in the colon compared to the MOD group (p < .05). The 16S rRNA sequencing showed that the intestinal flora of the GO-H group was significantly changed compared with the MOD group. In summary, GO has the potential to improve high triglyceride levels in serum and liver induced by alcohol exposure, which may be related to the inhibition of oxidative stress regulation of Sirt1 and its downstream proteins, and to the restoration of the intestinal barrier and intestinal flora.

Therapeutic mechanisms and beneficial effects of non-antidiabetic drugs in chronic liver diseases

The global burden of chronic liver disease (CLD) is substantial. Due to the limited indication of and accessibility to antiviral therapy in viral hepatitis and lack of effective pharmacological treatment in nonalcoholic fatty liver disease, the beneficial effects of antidiabetics and non-antidiabetics in clinical practice have been continuously investigated in patients with CLD. In this narrative review, we focused on non-antidiabetic drugs, including ursodeoxycholic acid, silymarin, dimethyl4,4'-dimethoxy-5,6,5',6'-dimethylenedixoybiphenyl-2,2'-dicarboxylate, L-ornithine L-aspartate, branched chain amino acids, statin, probiotics, vitamin E, and aspirin, and summarized their beneficial effects in CLD. Based on the antioxidant, anti-inflammatory properties, and regulatory functions in glucose or lipid metabolism, several non-antidiabetic drugs have shown beneficial effects in improving liver histology, aminotransferase level, and metabolic parameters and reducing risks of hepatocellular carcinoma and mortality, without significant safety concerns, in patients with CLD. Although the effect as the centerpiece management in patients with CLD is not robust, the use of these non-antidiabetic drugs might be potentially beneficial as an adjuvant or combined treatment strategy.

Chemical constituents and medicinal properties of Allium species

Allium species, belonging to Alliaceae family, are among the oldest cultivated vegetables used as food. Garlic, onions, leeks and chives, which belong to this family, have been reported to have medicinal properties. The Allium species constituents have been shown to have antibacterial and antioxidant activities, and, in addition, other biological properties. These activities are related to their rich organosulfur compounds. These organosulfur compounds are believed to prevent the development of cancer, cardiovascular, neurological, diabetes, liver diseases as well as allergy and arthritis. There have also been reports on toxicities of these compounds. The major active compounds of Allium species includes, diallyl disulfide, diallyl trisulfide, diallyl sulfide, dipropyl disulfide, dipropyl trisulfide, 1-propenylpropyl disulfide, allyl methyl disulfide and dimethyl disulfide. The aim of this review is to focus on a variety of experimental and clinical reports on the effectiveness, toxicities and possible mechanisms of actions of the active compounds of garlic, onions, leek and chives.

Antiviral potential of garlic (Allium sativum) and its organosulfur compounds: A systematic update of pre-clinical and clinical data

BACKGROUND

Garlic (Allium sativum L.) is a common herb consumed worldwide as functional food and traditional remedy for the prevention of infectious diseases since ancient time. Garlic and its active organosulfur compounds (OSCs) have been reported to alleviate a number of viral infections in pre-clinical and clinical investigations. However, so far no systematic review on its antiviral effects and the underlying molecular mechanisms exists.

SCOPE AND APPROACH

The aim of this review is to systematically summarize pre-clinical and clinical investigations on antiviral effects of garlic and its OSCs as well as to further analyse recent findings on the mechanisms that underpin these antiviral actions. PubMed, Cochrane library, Google Scholar and Science Direct databases were searched and articles up to June 2020 were included in this review.

KEY FINDINGS AND CONCLUSIONS

Pre-clinical data demonstrated that garlic and its OSCs have potential antiviral activity against different human, animal and plant pathogenic viruses through blocking viral entry into host cells, inhibiting viral RNA polymerase, reverse transcriptase, DNA synthesis and immediate-early gene 1(IEG1) transcription, as well as through downregulating the extracellular-signal-regulated kinase (ERK)/mitogen activated protein kinase (MAPK) signaling pathway. The alleviation of viral infection was also shown to link with immunomodulatory effects of garlic and its OSCs. Clinical studies further demonstrated a prophylactic effect of garlic in the prevention of widespread viral infections in humans through enhancing the immune response. This review highlights that garlic possesses significant antiviral activity and can be used prophylactically in the prevention of viral infections.

Hepatoprotective and Renoprotective Properties of Lovastatin-Loaded Ginger and Garlic Oil Nanoemulsomes: Insights into Serum Biological Parameters

Background and Objectives: Dyslipidemia is gaining much attention among healthcare professionals because of its high association with the malfunctioning of a number of normal physiological and metabolic processes in the body. Obesity is directly interconnected with dyslipidemia and is said to be a denouement of hyperlipidemia and, if left untreated, may lead to intense damage to organs that are directly involved in fat metabolism. The objective of this study was to investigate the synergistic antiobesity and anti-hyperlipidemic activities along with hepato- and renoprotective potential of nanoemulsomes (NES) of lovastatin (LTN)-loaded ginger (GR) and garlic (GL) oils. Materials and Methods: LTN nanoemulsomes co-encapsulated with GR oil and GL oil were prepared by a thin hydration technique. Eight-week-old male Wistar rats weighing 200-250 g were induced with hyperlipidemia via a high-fat diet (HFD) comprising 40% beef tallow. Body weight, serum biochemical lipid parameters, and those for liver and kidney functions, serum TC, LDL-C, vLDL-C, HDL-C, TG, atherogenic index (AI), ALT, AFT, ALP, γ-GT, total protein (TP), serum albumin and globulin ratio (A/G), serum creatinine, blood urea nitrogen (BUN) and blood urea, and histopathology of hematoxylin and eosin (H&E) stained liver and kidney sections of all aforementioned groups were examined in the treated animals. Results: Nanoemulsomes of LTN-loaded GR and GL oils provided synergistic effects with LTN, exerted better ameliorative actions in reducing serum TC, LDL-C, vLDL-C, triglycerides, and AI, and improved serum HDL-C levels. Serum ALT, AST, ALP, and γ-GT levels were in the normal range for nanoemulsome groups. H&E stained liver and kidney sections of these animals confirmed better hepatoprotective and renoprotective effects than LTN alone. Serum biochemical parameters for renal functions also claimed to be in the moderate range for nanoemulsome-treated groups. Conclusion: This study demonstrated that nanoemulsomes of LTN-loaded GR and GL oils synergistically provided better antihyperlipidemic, hepatoprotective, and renoprotective effects as compared to LTN alone.

Antioxidation, anti-inflammation and anti-apoptosis by paeonol in LPS/d-GalN-induced acute liver failure in mice

To evaluate the hepatoprotective effects and potential mechanisms of paeonol (Pae) against acute liver failure (ALF) induced by lipopolysaccharide (LPS)/d-galactosamine (d-GalN) in mice, we examined anti-oxidative, anti-inflammatory and anti-apoptotic activities of Pae. We found that Pae pretreatment markedly reduced the activities of alanine transaminase and aspartate transaminase as well as the histopathological changes induced by LPS/d-GalN. Catalase, glutathione and superoxide dismutase activities increased and reactive oxygen species activity decreased after Pae treatment compared with LPS/d-GalN treatment. Pretreatment with Pae also significantly inhibited the expression levels of iNOS, nitric oxide (NO), COX-2 and prostaglandin E₂ (PGE₂). In addition, Pae administration prevented the phosphorylated expression of IκB kinase, inhibitor kappa B in the nuclear factor-kappa B (NF-κB) signaling pathway, and suppressed the phosphorylated expression of extracellular signal-regulated kinase (ERK), c-jun-N-terminal kinase and p38 in the MAPK signaling pathway. Pretreatment with Pae also inhibited hepatocyte apoptosis by reducing the expression of caspases 3, 8, 9, and Bax, and increasing Bcl-2. In total, protective effects of Pae against LPS/d-GalN-induced ALF in mice are attributed to its antioxidative effect, inflammatory suppression in NF-κB and MARK signaling pathways, and inhibition of hepatocyte apoptosis inhibition. Therefore, Pae can be a potential therapeutic agent in attenuating LPS/d-GalN-induced ALF in the future.

Protection from diclofenac-induced liver injury by Yulangsan polysaccharide in a mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

Millettia pulchra Kurz var-laxior (Dunn) Z. Wei, a wild-growing plant of the family Fabaceae is known to possess multifarious medicinal properties. Yulangsan polysaccharide (YLSPS) is a chief ingredient of its root, which has been used in Chinese traditional medicine with a long history for remedy of acute or chronic hepatitis and jaundice.

AIM OF THE STUDY

To investigate the ability of the YLSPS to protect against diclofenac-induced hepatotoxicity in mice.

MATERIALS AND METHODS

Mice were orally treated with YLSPS daily 1h after the injection of diclofenac for 2 weeks. Dimethyl diphenyl bicarboxylate was used as a reference drug.

RESULTS

YLSPS effectively reduced the elevated levels of serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase and enhanced the reduction of superoxide dismutase, catalase, and glutathione peroxidase activities in the liver. Moreover, the content of malondialdehyde was reduced by treatment with YLSPS, and histological findings also confirmed the anti-hepatotoxic activity. In addition, YLSPS significantly inhibited proinflammatory mediators, such as tumor necrosis factor-alpha and interleukin 1 beta. YLSPS also enhanced mitochondrial antioxidants and inhibited cell death by preventing the down-regulation of Bcl-2 and the up-regulation and release of Bax along with caspase 9 and 3 activity; thus, these findings confirm the involvement of mitochondria in diclofenac-induced apoptosis.

CONCLUSION

The results indicate that protective effects of YLSPS against diclofenac-induced acute hepatic injury may rely on its effect on reducing oxidative stress, suppressing inflammatory responses, and improving drug-metabolizing enzyme activity in the liver.

Hepatoprotective effects of Yulangsan polysaccharide against nimesulide-induced liver injury in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Yulangsan polysaccharide (YLSPS) is often used in popular folk medicine in the Guangxi Zhuang Autonomous Region of China as a chief ingredient of Millettia pulchra, which is used as a hepatic protection, anti-aging and memory improving agent.

AIM OF THE STUDY

This study was designed to investigate the protective effects of polysaccharides from Millettia pulchra Kurz var.laxior (Dunn) (Yulangsan polysaecharide, YLSPS) against nimesulide-induced hepatotoxicities in mice.

MATERIALS AND METHODS

Liver injury was induced in mice by administering nimesulide. Simultaneously, YLSPS was administered 2h prior to the administration of nimesulide. Dimethyl diphenyl bicarboxylate (DDB) was used as a reference drug.

RESULTS

Compared with the nimesulide group, YLSPS significantly decreased the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and the content of bilirubin in the serum. The anti-oxidative effect of YLSPS was observed from the increase of the superoxide dismutase (SOD) and catalase and glutathione peroxidase (GSH-Px) activities in the liver, both of which were decreased by nimesulide. Moreover, the content of malondialdehyde (MDA) was reduced, and histological findings also confirmed the anti-hepatotoxic activity. In addition, YLSPS significantly inhibited proinflammatory mediators, such as tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6). Additionally, YLSPS also enhanced the mitochondrial antioxidant and inhibited dead cells by preventing the down-regulation of Bcl-2, up-regulation and release of Bax along with caspase 9 and 3 activity, confirming the involvement of mitochondria in the nimesulide-induced apoptosis.

CONCLUSION

The protective effect of YLSPS against nimesulide-induced hepatic injury may rely on its ability to reduce oxidative stress and prevent nimesulide-induced hepatotoxicity by inhibiting critical control points of apoptosis.

[Comparison on the efficacy and safety of biphenyl dimethyl dicarboxylate and ursodeoxycholic acid in patients with abnormal alanine aminotransferase: multicenter, double-blinded, randomized, active-controlled clinical trial]

BACKGROUND/AIMS

Chronic hepatocellular damage is closely associated with hepatic fibrosis and fatal complication in most liver diseases. The aim of this study is to compare the efficacy and safety of biphenyl dimethyl dicarboxylate (DDB) and ursodeoxycholic acid (UDCA) in patients with abnormal ALT.

METHODS

One-hundred thirty-five patients with elevated ALT were randomized to receive either 750 mg/day of DDB or 300 mg/day of UDCA for 24 weeks in 4 referral hospitals. Ninety-three (69%) patients had non-alcoholic steatohepatitits, 27 (20%) had alcoholic hepatitis, and 15 (11%) had chronic hepatitis. The primary end point was the rate of ALT normalization at week 24. The secondary endpoints were changes in AST, liver stiffness, and the incidence of adverse events.

RESULTS

A total of 101 patients completed 24 weeks of therapy. ALT normalization at week 24 was observed in 44 (80.0%) patients in DDB group and 16 (34.8%) in UDCA group (p<0.001). Higher mean reduction of ALT levels from baseline to 24 weeks was seen in DDB group compared with UDCA group (-70.0% vs. -35.9%, p<0.001). Normalization of AST level (p=0.53) and change in the liver stiffness (p=0.703) were not significantly different between the two groups. Severe adverse drug reaction occurred in 1 patient in DDB group but the subject continued therapy during the study period.

CONCLUSIONS

DDB was not inferior to UDCA for normalizing ALT level. Furthermore it was safe and well tolerated by patients with abnormal ALT.

Effect of sub-acute exposure to nickel nanoparticles on oxidative stress and histopathological changes in Mozambique tilapia, Oreochromis mossambicus

The aim of the present study was to assess the oxidative stress, antioxidant response and histopathological changes of nickel nanoparticles (Ni NPs) exposure (14 days) in Mozambique tilapia, Oreochromis mossambicus. Ni NPs were synthesized by metal salt reduction method and characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The XRD peaks at 44°, 51° and 76° were indexed to the (111), (200) and (220) Bragg's reflections of cubic structure of Nickel, respectively. The crystallite sizes were calculated using Scherrer's formula applied to the major intense peaks and found to be the size of 56nm. TEM images showed that the synthesized Ni NPs are spherical in shape. Biochemical analysis indicated that the superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity was significantly affected by Ni NPs treated O. mossambicus. Reduced antioxidant enzymes and the contents of antioxidants were lowered in the liver and gills of fishes treated with Ni NPs. After 14 days of exposure, a significant accumulation of Ni in the Ni NPs in experimental group was observed in the gill and skin tissues, with the highest levels found in the liver. Ni NPs exposed fish showed nuclear hypertrophy (NH), nuclear degeneration (ND), necrosis (NC) and irregular-shaped nuclei were observed in liver tissue. The hyperplasia of the gill epithelium (GE), lamellar fusion of secondary lamellae (LF), dilated marginal channel (MC), epithelial lifting (EL) and epithelial rupture were observed in gill tissue. Degeneration in muscle bundles (DM), focal area of necrosis (NC) vacuolar degeneration in muscle bundles (VD), edema between muscle bundles (ED) and splitting of muscle fibers were noticed in skin tissue. Further ecotoxicological evaluation will be made concerning the risk of Ni NPs on aquatic environment.

Hepatoprotective effects of Yulangsan polysaccharide against isoniazid and rifampicin-induced liver injury in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Yulangsan polysaccharide (YLSPS) is often used in popular folk medicine in the Guangxi Zhuang Autonomous Region of China as a chief ingredient of Millettia pulchra, which is used as an hepatic protection, anti-aging and memory improving agent. In this study, the hepatoprotective effects of YLSPS against isoniazid (INH) or rifampicin and isoniazid (RFP+INH)-induced liver injury were investigated in mice.

MATERIALS AND METHODS

The liver injury was induced by intragastric administration of INH or RFP+INH daily for 10 days. During the experiment, the model group received INH or RFP+INH only, and the normal control group received an equal volume of saline. Treatment groups received not only INH or RFP+INH but also the corresponding drugs, DDB (200mg/kg/day) or YLSPS (100, 200, and 400mg/kg/day) 2h after the administration of INH or RFP+INH.

RESULTS

Analysis experiments showed that YLSPS significantly alleviated liver injury as indicated by the decreased levels of ALT and AST and the increased levels of SOD, GSH and GSH-Px. Moreover, YLSPS could effectively reduce the pathological tissue damage. The research on the mechanisms underlying the hepatoprotective effect showed that YLSPS was able to reduce lipid peroxidation and activate the anti-oxidative defense system.

CONCLUSION

Our results show that YLSPS is effective in attenuating hepatic injury in the INH or RFP+INH-induced mouse model, and could be developed as a new drug for treatment of liver injury.

Potential therapeutic effects of functionally active compounds isolated from garlic

The medicinal properties of functionally active organosulfur compounds such as allin, diallyl disulfide, S-allylmercaptocysteine, and S-trityl-L-cysteine isolated from garlic have received great attention from a large number of investigators who have studied their pharmacological effects for the treatment of various diseases. These organosulfur compounds are able to prevent for development of cancer, cardiovascular, neurological, and liver diseases as well as allergy and arthritis. There have been also many reports on toxicities and pharmacokinetics of these compounds. The aim of this study is to review a variety of experimental and clinical reports, and describe the effectiveness, toxicities and pharmacokinetics, and possible mechanisms of pharmaceutical actions of functionally active compounds isolated from garlic.

Improved resistance to Eimeria acervulina infection in chickens due to dietary supplementation with garlic metabolites

The effects of a compound including the secondary metabolites of garlic, propyl thiosulphinate (PTS) and propyl thiosulphinate oxide (PTSO), on the in vitro and in vivo parameters of chicken gut immunity during experimental Eimeria acervulina infection were evaluated. In in vitro assays, the compound comprised of PTSO (67 %) and PTS (33 %) dose-dependently killed invasive E. acervulina sporozoites and stimulated higher spleen cell proliferation. Broiler chickens continuously fed from hatch with PTSO/PTS compound-supplemented diet and orally challenged with live E. acervulina oocysts had increased body weight gain, decreased faecal oocyst excretion and greater E. acervulina profilin antibody responses, compared with chickens fed a non-supplemented diet. Differential gene expression by microarray hybridisation identified 1227 transcripts whose levels were significantly altered in the intestinal lymphocytes of PTSO/PTS-fed birds compared with non-supplemented controls (552 up-regulated, 675 down-regulated). Biological pathway analysis identified the altered transcripts as belonging to the categories 'Disease and Disorder' and 'Physiological System Development and Function'. In the former category, the most significant function identified was 'Inflammatory Response', while the most significant function in the latter category was 'Cardiovascular System Development and Function'. This new information documents the immunologic and genomic changes that occur in chickens following PTSO/PTS dietary supplementation, which are relevant to protective immunity during avian coccidiosis.

Histopathological studies and oxidative stress of synthesized silver nanoparticles in Mozambique tilapia (Oreochromis mossambicus)

To evaluate the potential environmental effects of engineered nano metals, it is important to determine the adverse effects of various nanomaterials on aquatic species. Adult tilapia (Oreochromis mossambicus) were maintained in 10 L glass aquaria, and exposed to a graded series of synthesized silver nanoparticles (AgNPs) at 25, 50 and 75 mg/L for eight days. The LC50 value was 12.6 mg/L. Reduced activities of antioxidant enzymes and the contents of antioxidants were lowered in the gills and liver of fishes treated with AgNPs, which resulted in heavy accumulation of free radicals. Histopathological results imply that the balance between the oxidative and antioxidant system in the fish was broken down during Ag-NPs exposure. The principal concern related with the release of nanomaterials and their smaller particle may change the materials transport and potential toxicity to aquatic organisms compared to larger particles.

Garlic in health and disease

The present article reviews the historical and popular uses of garlic, its antioxidant, haematological, antimicrobial, hepatoprotective and antineoplastic properties and its potential toxicity (from sulfoxide). Garlic has been suggested to affect several cardiovascular risk factors. It has also been shown that garlic and its organic allyl sulfur components are effective inhibitors of the cancer process. Since garlic and its constituents can suppress carcinogen formation, bioactivation and tumour proliferation, it is imperative that biomarkers be established to identify which individuals might benefit most. Garlic powder, aged garlic and garlic oil have demonstrated antiplatelet and anticoagulant effects by interfering with cyclo-oxygenase-mediated thromboxane synthesis. Garlic has also been found to have synergistic effects against Helicobacter pylori with a proton pump inhibitor. The active compound allicin may affect atherosclerosis not only by acting as an antioxidant, but also by other mechanisms, such as lipoprotein modification and inhibition of LDL uptake and degradation by macrophages. Freshly prepared garlic homogenate protects against isoniazid+rifampicin-induced liver injury in experimental animal models. Several mechanisms are likely to account for this protection.

Inhibitory effect of silibinin on tumour necrosis factor-alpha and hydrogen peroxide production by human monocytes

Silibinin is a chemically defined flavonoid and the main active component of silymarin, a polyphenolic complex from Silybum marianum, which has anti-inflammatory, hepatoprotective and anticarcinogenic properties. Monocytes obtained from healthy individuals were incubated with silibinin to evaluate cell viability, hydrogen peroxide (H(2)O(2)) release and tumour necrosis factor-alpha (TNF-α) production by these cells. The duration of treatment and different silibinin concentrations had no significant effect on cell viability. Monocytes showed a dose-dependent inhibitory effect on H(2)O(2) release by phorbol myristate acetate-stimulated monocytes in silibinin concentrations ranging from 6.25 to 50 µg mL(-1). Significant inhibition of TNF-α production by lipopolysaccharide-stimulated monocytes was observed at concentrations of 12.5, 50 and 100 µg mL(-1) of silibinin. These results suggest that silibinin exerts antioxidant and anti-inflammatory properties on human monocytes through an inhibitory effect on H(2)O(2) release and on TNF-α production, respectively.

The protective effects of garlic extract against acetaminophen-induced oxidative stress and glutathione depletion

Acetaminophen, the most commonly sold over-the-counter antipyretic analgesic, is capable of causing severe and sometimes fatal hepatic damage in humans and experimental animals. The incidence of liver injury due to acetaminophen overdose, either with suicidal intent or by accident, is increasing. Garlic is among those medicinal plants famous for its different health protective effects. In this study, the protective effects of garlic extract on acute acetaminophen-induced liver injury were investigated using freshly isolated rat hepatocytes. The hepatocytes were isolated from Sprague-Dawley male rats by a two step collagenase model. Formation of Reactive Oxygen Species (ROS) and Glutathione (GSH) depletion were studied after addition of acetaminophen to cell suspensions. The effects of garlic extract on prevention of ROS formation as well as GSH depletion was investigated and compared with the effects of N-Acetyl Cysteine (NAC) as the standard treatment. Reactive oxygen species formation was assessed by a spectrofluorometry method and garlic extract was shown to be as effective as NAC in decreasing ROS formation induced by acetaminophen. Glutathione (GSH) levels of hepatocytes were determined using HPLC. Garlic extract was effective in preventing GSH depletion significantly (p < 0.05). It is concluded that garlic extract has an antioxidant effect and can protect hepatocytes from GSH depletion following NAPQI production.

Anti-inflammatory and arthritic effects of thiacremonone, a novel sulfur compound isolated from garlic via inhibition of NF-kappaB

INTRODUCTION

Sulfur compounds isolated from garlic exert anti-inflammatory properties. We recently isolated thiacremonone, a novel sulfur compound from garlic. Here, we investigated the anti-inflammatory and arthritis properties of thiacremonone through inhibition of NF-kappaB since NF-kappaB is known to be a target molecule of sulfur compounds and an implicated transcription factor regulating inflammatory response genes.

METHODS

The anti-inflammatory and arthritis effects of thiacremone in in vivo were investigated in 12-O-tetradecanoylphorbol-13-acetate-induced ear edema, carrageenan and mycobacterium butyricum-induced inflammatory and arthritis models. Lipopolysaccharide-induced nitric oxide (NO) production was determined by Griess method. The DNA binding activity of NF-kappaB was investigated by electrophoretic mobility shift assay. NF-kappaB and inducible nitric oxide synthetase (iNOS) transcriptional activity was determined by luciferase assay. Expression of iNOS and cyclooxygenase-2 (COX-2) was determined by western blot.

RESULTS

The results showed that topical application of thiacremonone (1 or 2 microg/ear) suppressed the 12-O-tetradecanoylphorbol-13-acetate-induced (1 microg/ear) ear edema. Thiacremonone (1-10 mg/kg) administered directly into the plantar surface of hind paw also suppressed the carrageenan (1.5 mg/paw) and mycobacterium butyricum (2 mg/paw)-induced inflammatory and arthritic responses as well as expression of iNOS and COX-2, in addition to NF-kappaB DNA-binding activity. In further in vitro study, thiacremonone (2.5-10 microg/ml) inhibited lipopolysaccharide (LPS, 1 microg/ml)-induced nitric oxide (NO) production, and NF-kappaB transcriptional and DNA binding activity in a dose dependent manner. The inhibition of NO by thiacremonone was consistent with the inhibitory effect on LPS-induced inducible nitric oxide synthase (iNOS) and COX-2 expression, as well as iNOS transcriptional activity. Moreover, thiacremonone inhibited LPS-induced p50 and p65 nuclear translocation, resulting in an inhibition of the DNA binding activity of the NF-kappaB. These inhibitory effects on NF-kappaB activity and NO generation were suppressed by reducing agents dithiothreitol (DTT) and glutathione, and were abrogated in p50 (C62S)-mutant cells, suggesting that the sulfhydryl group of NF-kappaB molecules may be a target of thiacremonone.

CONCLUSIONS

The present results suggested that thiacremonone exerted its anti-inflammatory and anti-arthritic properties through the inhibition of NF-kappaB activation via interaction with the sulfhydryl group of NF-kappaB molecules, and thus could be a useful agent for the treatment of inflammatory and arthritic diseases.

Effect of garlic (Allium sativum) on nickel II or chromium VI induced alterations of glucose homeostasis and hepatic antioxidant status under sub-chronic exposure conditions

Garlic (Allium sativum) has a profound effect in reducing plasma glucose and increasing serum insulin in diabetic rats. We studied the effect of a garlic extract on nickel- or chromium-induced alteration of plasma glucose and hepatic glycogen levels and anti-oxidant status in rats. Adult male albino rats (n=36) divided into six groups of six animals each were treated as follows: Group I, untreated controls; Group II, fresh aqueous homogenate of garlic; Group III, nickel sulfate; Group IV, nickel sulfate + garlic; Group V, potassium dichromate; Group VI, potassium dichromate + garlic. In Groups IV and VI, the simultaneous administration of garlic abrogated a significant nickel- or chromium-induced increase in plasma glucose and decrease in liver glycogen. Nickel and chromium alone also increased lipid peroxide (LPO) and decreased glutathione levels, as well as the activity of superoxide dismutase (SOD), catalase, and glutathione peroxidase. Simultaneous garlic administration significantly reduced the LPO level and remarkably improved SOD activity. Hence, we postulate that the administration of garlic can prevent nickel II- or chromium VI-induced alterations in blood glucose homeostasis while exerting a hepatoprotective effect on glycogen levels and antioxidant status in male albino rats.

Aqueous garlic extract attenuates hepatitis and oxidative stress induced by galactosamine/lipoploysaccharide in rats

Injection of D-galactosamine and lipopolysaccharide (DGaIN/LPS) is useful as an experimental model of acute hepatic damage. Juvenile rats were used for investigation. The hepatoprotective activity of aqueous garlic (Allium sativum) extract (AGE) at a dose of 300 mg/kg body weight for 14 days, intraperitoneal (i.p.) prior to the induction of DGalN/LPS, was investigated against DGalN/LPS-induced hepatitis in rats. DGalN/LPS (300 mg/kg body weight/30 microg/kg body weight, i.p.), induced hepatic damage that was manifested by a significant increase in the activities of marker enzymes [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and gamma glutamyl transferase (gamma GT)], bilirubin, lipid peroxides (LPO), tumor necrosis factor (TNF-alpha) and myeloperoxidase (MPO) activity level in serum. Also, the lipid profile in serum and liver homogenate including total cholesterol, triglycerides, free fatty acids and phospholipids were significantly deteriorated. The antioxidant enzyme activities (superoxide dismutase, SOD; reduced glutathione, GSH; catalase, CAT and glutathione peroxidase, GPX) in liver homogenate were significantly decreased in the DGalN/LPS. Pretreatment of rats with AGE reversed these altered parameters near to normal control values. Results of this study revealed that AGE could afford a significant protection in the alleviation of DGalN/LPS-induced hepatic damage.

Diphenyl Dimethyl Bicarboxylate in the Treatment of Viral Hepatitis, Adjuvant or Curative?

Diphenyl dimethyl bicarboxylate (DDB) has been used in some countries as hepatoprotectant adjuvant in the treatment of liver diseases, such as chronic viral hepatitis, chemical or drug induced hepatic damage. Its early confirmed efficacy is to normalize elevated blood alanine aminotransferase (ALT) from different etiologies, however, it can rarely affect the rest hepatic enzymes. In addition, the lowering or normalization of ALT in most cases occurs during DDB treatment, withdrawal of DDB administration results in ALT re-elevated. Hence, for a long time, it has been only used as adjuvant of liver disease therapy. It is still controversial that whether DDB can be beneficial to liver histology. The normalization of ALT in hepatitis does not indicate therapeutic efficacy if without substantial liver histology improvement. In recent years, more studies showed that DDB might have new therapeutical potentials in liver diseases, it may have the effect of anti-viral, anti-malignancy. These new findings were mostly based on the in vitro or animal experiments, more basic studies and clinical trials are needed to ascertain these efficacies, prior to that stage, it is recommended to be cautious to apply DDB clinically for anti-virus and anti-malignancy purposes.

Nitric oxide as a target of complementary and alternative medicines to prevent and treat inflammation and cancer

Nitric oxide (NO) and associated reactive nitrogen species (RNS) are involved in many physiological functions. There has been an ongoing debate to whether RNS can inhibit or perpetuate chronic inflammation and associated carcinogenesis. Although the final outcome depends on the genetic make-up of its target, the surrounding microenvironment, the activity and localization of nitric oxide synthase (NOS) isoforms, and overall levels of NO/RNS, evidence is accumulating that in general, RNS drive inflammation and cancers associated with inflammation. To this end, many complementary and alternative medicines (CAMs) that work in chemoprevention associated with chronic inflammation, are inhibitors of excessive NO observed in inflammatory conditions. Here, we review recent literature outlining a role of NO/RNS in chronic inflammation and cancer, and point toward NO as one of several targets for the success of CAMs in treating chronic inflammation and cancer associated with this inflammation.

Wuweizisu C from Schisandra chinensis decreases membrane potential in C6 glioma cells

AIM

To study the effects of dibenzocyclooctadiene lignans isolated from Schisandra chinensis, such as wuweizisu C, gomisin N, gomisin A, and schisandrin, on the membrane potential in C6 glioma cells.

METHODS

The membrane potential was estimated by measuring the fluorescence change in DiBAC-loaded glioma cells.

RESULTS

Wuweizisu C decreased the membrane potential in a concentration-dependent manner. Gomisin N and gomisin A, however, showed differential modulation and no change was induced by schisandrin or dimethyl- 4,4'-dimethoxy-5,6,5',6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate, a synthetic drug derived from dibenzocyclooctadiene lignans. We found no involvement of G(i/o ) proteins, phospholipase C, and extracellular Na(+) on the wuweizisu C-induced decrease of the membrane potential. Wuweizisu C by itself did not change the intracellular Ca(2+)[Ca(2+)](i) concentration, but decreased the ATP-induced Ca(2+) increase in C6 glioma cells. The 4 lignans at all concentrations used in this study did not induce any effect on cell viability. Furthermore, we found a similar decrease of the membrane potential by wuweizisu C in PC12 neuronal cells.

CONCLUSION

Our results suggest that the decrease in the membrane potential and the modulation of [Ca(2+)](i) concentration by wuweizisu C could be important action mechanisms of wuweizisu C.

The anti-fatty liver effects of garlic oil on acute ethanol-exposed mice

The protective effects of single dose of garlic oil (GO) on acute ethanol-induced fatty liver were investigated. Mice were treated with ethanol (4.8 g/kg bw) to induce acute fatty liver. The liver index, the serum and hepatic triglyceride (TG) levels and the histological changes were examined to evaluate the protective effects. Hepatic malondialdehyde (MDA), glutathione (GSH) levels and superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST) activities were determined for the antioxidant capacity assay. Acute ethanol exposure resulted in the enlargement of the liver index and the increase of the serum and hepatic TG levels (P<0.01), which were dramatically attenuated by GO pretreatment in a dose-dependent manner (P<0.01). GO treatment (simultaneously with ethanol exposure) exhibited similar effects to those of pretreatment, while no obviously protective effects were displayed when it was used at 2h after ethanol intake. Histological changes were paralleled to these indices. Beside this, GO dramatically prolonged the drunken time and shortened the waking time, and these effects were superior to those of silymarin and tea polyphenol. In addition, GO dose-dependently suppressed the elevation of MDA levels, restored the GSH levels and enhanced the SOD, GR and GST activities. Compared with the ethanol group, the MDA levels decreased by 14.2% (P<0.05), 29.9% and 32.8% (P<0.01) in GO groups 50, 100 and 200 mg/kg, respectively. The GST activity increased by 9.97%, 19.94% (P<0.05) and 42.12% (P<0.01) of the ethanol group in GO groups 50, 100 and 200 mg/kg, respectively, while the GR activity increased by 28.57% (P<0.05), 37.97% (P<0.01), 50.45% (P<0.01) of the ethanol group in GO groups 50, 100 and 200 mg/kg, respectively. These data indicated that single dose of GO possessed ability to prevent acute ethanol-induced fatty liver, but may lose its capacity when used after ethanol exposure. The protective effects should be associated with its antioxidative activities.

Protective role of dimethyl diphenyl bicarboxylate (DDB) against erythromycin induced hepatotoxicity in male rats

In this study, dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate (DDB) was examined to justify its role in the hepatoprotection against erythromycin toxicity in male rats. Oral daily administration of toxic dose of erythromycin stearate (EE, 100 mg/kg body weight) was given to male rats for fourteen days to induce hepatotoxicity. It was found at the end of the experiment (14 days) that the total body weight was markedly decreased in rat treated with erythromycin stearate (EE). Hepatomegaly and splenomegaly were recorded in rats treated with erythromycin stearate (EE). The red blood cells (RBCs) count, haemoglobin content (Hb) and haematocrit value (Hct) were significantly reduced in rats treated with EE. The hepatotoxicities were monitored by increased level of plasma enzymes (aspartate aminotransferase; AST and alanine aminotransferase; ALT), total bilirubin, direct bilirubin, cholesterol, total lipids and glucose. The data obtained showed that oral administration of DDB (100 mg/kg body weight) has significantly prevented the occurrence of EE-induced liver damage. The biochemical data were supplemented by histopathological examination of the liver of control and treated rats. DDB showed a better hepatoprotective effect compared with ursodesoxycholic acid or Silymarin (Sil), as a reference drug.

Liquiritigenin, an aglycone of liquiritin in Glycyrrhizae radix, prevents acute liver injuries in rats induced by acetaminophen with or without buthionine sulfoximine

Glycyrrhizae radix has been used as one of the oldest and most frequently employed botanicals in both western and oriental countries. Previously, we showed that liquiritigenin (LQ), an aglycone of liquiritin in G. radix, exerts cytoprotective effects against heavy metal-induced toxicity in vitro. This study investigated in vivo protective effects of LQ against acute liver injuries induced by acetaminophen (APAP) or APAP plus buthionine sulfoximine (BSO). Liver injuries were assessed by blood biochemistry and histopathology in rats administered with LQ purified from the acid hydrolyates of liquiritin singly (p.o. or i.v., 2-4 days) or in combination with dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylenedioxybiphenyl-2,2'-dicarboxylate (DDB), a synthetic derivative of Schisandrin C in Fructus shizandrae, and exposed to APAP or APAP + BSO. LQ treatments (oral) effectively decreased liver injuries induced by a single dose of APAP, as evidenced by decreases in hepatic necrosis and inflammation as well as plasma alanine aminotransferase and lactate dehydrogenase activities. LQ, when intravenously applied, enhanced hepatoprotective effect with a greater potency. APAP + BSO led to severe liver injuries, resulting in lethality. LQ pretreatments significantly reduced the potentiated liver necrosis, decreasing mortality. In spite of the improvement in blood biochemistry, DDB failed to protect the liver from injuries induced by APAP or APAP + BSO. Combined treatments of rats with LQ and DDB showed some additive protective effect. The present study demonstrates that LQ efficaciously protects the liver from acute injuries induced by APAP or from APAP-induced severe injuries during GSH deficiency, indicating that LQ is one of the principal cytoprotective components comprised in G. radix.

Effect of garlic on isoniazid and rifampicin-induced hepatic injury in rats

AIM: To evaluate the hepatoprotective effect of garlic on liver injury induced by isoniazid (INH) and rifampicin (RIF).

METHODS: Wistar rats weighing 150-200 g were treated orally with 50 mg/kg of INH and RIF daily each for 28 d. For hepatoprotective studies, 0.25 g/kg per day of freshly prepared garlic homogenate was administered orally half an hour before the INH+RIF doses. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and bilirubin were estimated on d 0, 14, 21, and 28 in all the rats. Histological analysis was carried out to assess the injury to the liver. Lipid peroxidation (LPO) as a marker of oxidative stress and non-protein thiols (glutathione) for antioxidant levels were measured in liver homogenate.

RESULTS: The treatment of rats with INH+RIF (50 mg/kg per day each) induced hepatotoxicity in all the treated animals as judged by elevated serum ALT, AST, and bilirubin levels, presence of focal hepatocytic necrosis (6/8) and portal triaditis (8/8). Garlic simultaneously administered at a dose of 0.25 g/kg per day prevented the induction of histopathological injuries in INH+RIF co-treated animals, except in 4 animals, which showed only moderate portal triaditis. The histological changes correlated with oxidative stress in INH+RIF treated animals. The group which received 0.25 g/kg per day garlic homogenate along with INH+RIF showed higher levels of glutathione (P < 0.05) and low levels of LPO (P < 0.05) as compared to INH+RIF treated group.

CONCLUSION: Freshly prepared garlic homogenate protects against INH+RIF-induced liver injury in experimental animal model.