Protective effect of a mixture of Aloe vera and Silybum marianum against carbon tetrachloride-induced acute hepatotoxicity and liver fibrosis

Aloe vera-An Extensive Review Focused on Recent Studies

Since ancient times, Aloe vera L. (AV) has attracted scientific interest because of its multiple cosmetic and medicinal properties, attributable to compounds present in leaves and other parts of the plant. The collected literature data show that AV and its products have a beneficial influence on human health, both by topical and oral use, as juice or an extract. Several scientific studies demonstrated the numerous biological activities of AV, including, for instance, antiviral, antimicrobial, antitumor, and antifungal. Moreover, its important antidepressant activity in relation to several diseases, including skin disorders (psoriasis, acne, and so on) and prediabetes, is a growing field of research. This comprehensive review intends to present the most significant and recent studies regarding the plethora of AV's biological activities and an in-depth analysis exploring the component/s responsible for them. Moreover, its morphology and chemical composition are described, along with some studies regarding the single components of AV available in commerce. Finally, valorization studies and a discussion about the metabolism and toxicological aspects of this "Wonder Plant" are reported.

Medicinal Plant-derived Phytochemicals in Detoxification

The average worldwide human life expectancy is 70 years, with a significantly higher value in Western societies. Many modern diseases are not associated with premature mortality but with a decreased quality of life in aged patients and an excessive accumulation of various toxic compounds in the human body during life. Today, scientists are especially interested in finding compounds that can help increase a healthy lifespan by detoxifying the body. Phytotherapy with specific approaches is used in alternative medicine to remove toxins from the body. Worldwide, research is conducted to identify medicinal plant-derived molecules that, with few or no side effects, may protect the liver and other organs. This review provides updated information about the detoxification process, the traditional and modern use of the most effective medicinal plants, their active metabolites as detoxifying agents, and the mechanisms and pathways involved in the detoxification process. Among medicinal plants with substantial detoxifying properties, a major part belongs to the Asteraceae family (Silybum marianum, Cynara scolymus, Arctium lappa, Helichrysum species, Inula helenium, and Taraxacum officinale). The most widely used hepatoprotective phytocomponent is silymarin, a standardized extract from the Silybum marianum seeds containing a mixture of flavonolignans. Many polysaccharides, polyphenols, and terpenoids have a detoxifying effect. Overall, scientific data on medicinal plants used in phytotherapeutic practice worldwide provides an understanding and awareness of their efficacy in detoxification.

Lonicera flos and Cnicus japonicus extracts improved egg quality partly by modulating antioxidant status, inflammatory-related cytokines and shell matrix protein expression of oviduct in laying hens

This study was conducted to investigate the effects of Lonicera flos and Cnicus japonicus extracts (LCE) on the laying performance, egg quality, morphology, antioxidant status, inflammatory-related cytokines, and shell matrix protein expression of oviduct in laying hens. A total of 1,728 Roman Pink laying hens aged 73-wk-old were randomly assigned into 4 groups (18 replicates/group, 24 layers/replicate) fed basal diets supplemented with 0, 300, 500, and 1,000 mg of LCE per kg of diet, respectively. The trial lasted for 11 wk, including 2-wk adjustment period and 9-wk testing period. The results indicated that laying hens fed diets supplemented with LCE linearly increased egg weight, yolk color and shell thickness at wk 78 and albumen height, Haugh unit and shell thickness at wk 83 (P < 0.05). At wk 78, LCE groups linearly affected the hydrogen peroxide content in magnum (P < 0.05) and 300 mg/kg LCE groups had the highest catalase activity in isthmus (P < 0.05). At wk 83, LCE groups linearly reduced (P < 0.05) hydrogen peroxide content in the magnum and isthmus and malondialdehyde content in the uterus whereas increased catalase activity in isthmus (P < 0.05). Furthermore, LCE levels quadratically affected glutathione peroxidase activity in isthmus at wk 83 (P < 0.05). At wk 78, the mRNA expressions of inducible nitric oxide synthase and interferon-γ in isthmus and ovalbumin and ovocleidin-116 in uterus had linear effects in response to LCE levels (P < 0.05) and 1,000 mg/kg LCE group had the lowest mRNA expression of interleukin-6 in magnum (P < 0.05). At wk 83, LCE supplementation linearly decreased the mRNA expression of interleukin-1β, interferon-γ and tumor necrosis factor-α in magnum and tumor necrosis factor-α and inducible nitric oxide synthase in uterus (P < 0.05). It is concluded that LCE improved egg quality partly by modulating antioxidant status, inflammatory-related cytokines and shell matrix protein expression of oviduct in laying hens.

Network Pharmacology and Molecular Docking Study on the Multi-Target Mechanisms of Aloe vera for Non-Alcoholic Steatohepatitis Treatment

Non-alcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease with limited treatment options. The widely distributed plant Aloe vera has shown protective effects against NASH in animals, yet the precise mechanism remains unknown. In this study, we investigated the potential mechanisms underlying the anti-NASH effects of Aloe vera using a network pharmacology and molecular docking approach. By searching online databases and analyzing the Gene Expression Omnibus dataset, we obtained 260 Aloe vera-NASH common targets. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that the common targets were strongly associated with the key pathological processes implicated in NASH, including lipid and glucose metabolism, inflammation, apoptosis, oxidative stress, and liver fibrosis. Four core proteins, AKT serine/threonine kinase 1 (AKT1), tumor necrosis factor alpha (TNFα), transcription factor c-Jun, and tumor suppressor protein p53, were identified from compound-target-pathway and protein-protein interaction networks. Molecular docking analysis verified that the active ingredients of Aloe vera were able to interact with the core proteins, especially AKT1 and TNFα. The results demonstrate the multi-compound, multi-target, and multi-pathway mechanisms of Aloe vera against NASH. Our study has shown the scientific basis for further experiments in terms of the mechanism to develop Aloe vera-based natural products as complementary treatments for NASH. Furthermore, it identifies novel drug candidates based on the structures of Aloe vera's active compounds.

Hepatoprotective Plants from Bangladesh: A Biophytochemical Review and Future Prospect

Liver diseases are quite prevalant in many densely populated countries, including Bangladesh. The liver and its hepatocytes are targeted by virus and microbes, as well as by chemical environmental toxicants, causing wide-spread disruption of metabolic fuctions of the human body, leading to death from end-stage liver diseases. The aim of this review is to systematically explore and record the potential of Bangladeshi ethnopharmacological plants to treat liver diseases with focus on their sources, constituents, and therapeutic uses, including mechanisms of actions (MoA). A literature survey was carried out using Pubmed, Google Scholar, ScienceDirect, and Scopus databases with articles reported until July, 2020. A total of 88 Bangladeshi hepatoprotective plants (BHPs) belonging to 47 families were listed in this review, including Euphorbiaceae, Cucurbitaceae, and Compositae families contained 20% of plants, while herbs were the most cited (51%) and leaves were the most consumed parts (23%) as surveyed. The effect of BHPs against different hepatotoxins was observed via upregulation of antioxidant systems and inhibition of lipid peroxidation which subsequently reduced the elevated liver biomarkers. Different active constituents, including phenolics, curcuminoids, cucurbitanes, terpenoids, fatty acids, carotenoids, and polysaccharides, have been reported from these plants. The hepatoameliorative effect of these constituents was mainly involved in the reduction of hepatic oxidative stress and inflammation through activation of Nrf2/HO-1 and inhibition of NF-κB signaling pathways. In summary, BHPs represent a valuable resource for hepatoprotective lead therapeutics which may offer new alternatives to treat liver diseases.

Hepatoprotective effect and possible mechanism of phytoestrogen calycosin on carbon tetrachloride-induced liver fibrosis in mice

The study was to explore the hepatoprotective effect and possible mechanism of calycosin on carbon tetrachloride (CCl4)-induced liver fibrosis in mice. Hepatic fibrosis was induced by intraperitoneal injection of CCl4 in C57BL/6 male mice. Serum alanine aminotransferase (ALT) and aspartate transaminase (AST) activity, superoxide dismutase (SOD) activity, and hydroxyproline (Hyp) and malondialdehyde (MDA) levels were determined by biochemical assays. Liver histopathology was assessed by H&E and Masson trichrome staining. The mRNA expressions of α-smooth muscle actin (α-SMA), collagen-I (Col-I), Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) were determined using qRT-PCR. The protein levels of α-SMA, Col-I, estrogen receptor α (ERα), estrogen receptor β (ERβ), tissue inhibitor of metalloproteinase-1 (TIMP-1), matrix metalloproteinase-1 (MMP-1), JAK2, phospho-JAK2 (p-JAK2), STAT3, and phospho-STAT3 (p-STAT3) were detected by Western blotting. The levels of α-SMA and ERβ were measured by immunohistochemistry. Calycosin significantly reduced liver index, MDA level, and ALT and AST activity and increased SOD activity. The α-SMA, Col-I, and Hyp of the calycosin group were significantly lower than those of the model group. Calycosin increased MMP-1 and inhibited TIMP-1 expression resulting in the improvement of MMP-1/TIMP-1 ratio. Importantly, calycosin improved ERβ protein expression, JAK2 and STAT3 mRNA expressions, p-JAK2/JAK2, and p-STAT3/STAT3 relative protein expressions. However, ERα, JAK2, and STAT3 protein expressions were relatively unchanged. Calycosin significantly inhibits liver fibrosis in mice, and its mechanism may involve the following: calycosin inhibits oxidative stress; calycosin inhibits collagen synthesis and balances MMP-1/TIMP-1 system; calycosin increases ERβ expression and activates JAK2-STAT3 pathway.

Anti-inflammatory effects of aloe vera on soy meal-induced intestinal inflammation in zebrafish

Soybean meal is one of the most promising alternatives to replace fishmeal in the aquaculture industry. However, its ingestion triggers an intestinal inflammatory process that compromises fish health and nutrition. Therefore, finding strategies that reduce the deleterious effects of a soy protein-based diet are relevant. In this work we analyzed the effects of an aloe vera (Aloe barbadensis miller, AV) extract on intestinal inflammation and innate immunity of zebrafish by adding it to the water and by supplementing it in a soybean meal-based diet. To search for potential immunomodulatory effects of AV, we tested its effectiveness in two inflammation assays and compared fish fed with either fishmeal or soybean meal-based feed supplemented with AV. Our results show a strong anti-inflammatory effect of AV. Furthermore, while soy-based meal strongly induces the expression of inflammation markers, supplementation with AV reverted this effect. Finally, we show that fish fed with a soy meal diet are highly susceptible to bacterial infection, but that this condition is significantly reduced when the soy meal is supplemented with AV. Our results suggest that AV is a good candidate to be incorporated as an additive in farmed fish diets to facilitate the replacement of fishmeal by soybean meal, maintaining intestinal health.

Antidiabetic and Antihyperlipidemic Activities of the Leaf Latex Extract of Aloe megalacantha Baker (Aloaceae) in Streptozotocin-Induced Diabetic Model

BACKGROUND

Diabetes mellitus has become a major public health and economic problem across the globe. The inadequacies, as well as serious adverse effects associated with conventional medicines, led to a determined search for alternative natural therapeutic agents. The leaf latex extract of Aloe megalacantha has been used for the management of diabetes mellitus in Ethiopian folk medicine. This study aimed to evaluate the antidiabetic and antihyperlipidemic effects of the leaf latex extract of A. megalacantha in streptozotocin- (STZ-) induced diabetic model.

METHODS

The experimental diabetes was induced in Swiss albino mice by the administration of a single dose of STZ (150 mg/kg), intraperitoneally. The leaf latex extract of A. megalacantha at three different doses (100, 200, and 400 mg/kg) was administered for a period of 14 days. Fasting blood glucose levels (BGLs) were measured by glucose-oxidase and peroxidase reactive strips. After fourteen days, mice from all groups fasted and the blood was collected through puncturing the retroorbit of the eyes under mild anesthetic condition. The collected blood sample was used to determine serum biochemical parameters such as total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), and high-density lipoprotein (HDL) cholesterol. The statistical analysis of results was carried out using one-way analysis (ANOVA) followed by post hoc multiple comparison tests.

RESULTS

Oral administration of A. megalacantha leaf latex extract at doses of 100, 200, and 400 mg/kg daily for 14 days results in a significant (p < 0.05) decrease in fasting BGL as compared to negative control STZ-induced diabetic mice. The leaf latex has significantly reduced the level of TC, TG, and LDL, VLDL cholesterol while a significant (p < 0.05) HDL cholesterol increment was observed.

CONCLUSIONS

The findings of the present investigation indicated that the leaf latex of A. megalacantha possessed significant antihyperglycemic and antihyperlipidemic potential which may prove the claimed use of the plant in amelioration of diabetes and associated complications in Ethiopian folk medicine.

The protective effect of Zataria multiflora Boiss essential oil on CCl4 induced liver fibrosis in rats

Activation of hepatic stellate cells by free radicals is an initial step in the development of liver fibrosis. Zataria multiflora Boiss (ZM) essential oil as a natural product has antioxidant activity and maybe a suitable candidate for treatment or prevention of the disease. Thus, this study aims to evaluate the protective effect of ZM oil in CCl₄ induced liver fibrosis. Male rats were divided into 5 groups, group C: control rats; CO: vehicle control group; CE: rats that received essential oil (500 µl/kg); F: fibrosis group, rat were intraperitoneally injected with CCl₄ (1 mL/kg); FE: fibrosis rats that received both CCl₄ and ZM essential oil as mentioned above. At the end of the 11th week, serum samples and liver tissues were collected for the evaluation of fibrosis markers, liver enzymes, oxidative stress parameters and histopathological studies. The results showed a significant increase in the activity of serum AST, ALT, total bilirubin, TGF-β1, hyaluronan, and hydroxyproline levels in serum and liver tissues in F group. Also, an abnormality in lipid profile and the existence of oxidative stress was found in serum and liver tissues in F group compared to the control groups. Our study showed that ZM essential oil could ameliorate mentioned parameters. Histopathological examinations confirmed the results of biochemical evaluations.

Prevalence and current therapy in chronic liver disorders

BACKGROUND

Herbal medicine plays an important role in health, particularly in remote parts of developing areas with few health facilities. According to WHO estimates, about three-quarters of the world's population currently use herbs or traditional medicines to treat various ailments, including liver diseases. Several studies have found that the use of medicinal plants was effective in the treatment of infectious and non-infectious diseases. Hepatitis and liver cirrhosis associated with many clinical manifestations can be treated with allopathic medicines, but reports of a number of side effects including immunosuppression, bone marrow suppression, and renal complications have motivated researchers to explore more natural herbal medicines with low or no side effects and with high efficacy in treating hepatic diseases.

METHODS

Databases including PubMed, Medline, and Google Scholar were searched for findings on the hepatoprotective effects of plants.

RESULTS

Various medicinal plants are used for the treatment of liver disorders. The range of alternative therapies is huge, and they are used worldwide, either as part of primary health care or in combination with conventional medicine. Hepatoprotective plants contain a variety of chemical constituents including flavonoids, alkaloids, glycosides, carotenoids, coumarins, phenols, essential oil, organic acids, monoterpenes, xanthenes, lignans, and lipids.

CONCLUSION

This review shows that numerous plants are found to contain hepatoprotective compounds. However, further studies are needed to determine their association with existing regimes of antiviral medicines and to develop evidence-based alternative medicine to cure different kinds of liver disease in humans.

The hepatoprotective effect of Aloe vera on ischemia-reperfusion injury in rats

OBJECTIVE:

Aloe vera is known for its antioxidant properties. In this experimental study, we aimed to investigate the efficacy of Aloe vera in ischemia-reperfusion (I/R) liver injury in rats.

METHODS:

Male Wistar Albino rats were divided into three groups, where the sham group (n=7) underwent no medication or surgical procedures, the I/R group (n=7) was the control group that received 45 minutes of applied abdominal aorta ischemia and rats were sacrificed 24 hours after reperfusion, and the I/R+AV group (n=7) was the treatment group that was given Aloe vera (30 mg/kg) every day followed by gastric lavage for a month before applying ischemia and performing sacrifice as in the previous group. Before sacrifice, all the liver tissues were removed. Tissues were examined for histopathological investigation, iNOS immunoreactivity and tissue biochemistry, malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities.

RESULTS:

The SOD, CAT, and GSH-Px levels of the I/R+AV group were not significantly different from the sham group (p>0.05) but were significantly higher when compared to the I/R group. MDA levels of liver tissues were significantly lower (p<0.05) in the I/R+AV group as compared to the I/R group. Disrupted hepatic cords, sinusoidal dilatation, hemorrhage, cytoplasmic vacuolization of hepatocytes, and intensive iNOS immunoreactivity were detected in the I/R group. Decreased histopathological change score and iNOS immunoreactivity score were noticed in the I/R+AV group as compared to the I/R group.

CONCLUSION:

It was found that Aloe vera showed a hepatoprotective effect against I/R injury. Further research is required to determine the effective dose, administration method, and effects of Aloe vera for liver transplantation.

Herbal remedies for liver fibrosis: A review on the mode of action of fifty herbs

Liver fibrosis is a dynamic pathological condition which can be slowed down in its initial phases. Without proper clinical management of fibrosis, progressive liver damage may lead to cirrhosis and ultimately to liver failure or primary liver cancer, which are irreversible conditions. Therefore, in order to cure fibrotic damage to liver, its early stages should be the centre of attention. In this context, some supplements and ‘complementary and alternative medicine (CAM)’ deserve specific mention, because of their already recognized natural way of healing and long lasting curative effects. Moreover, CAM display negligible side effects and hence it is gaining worldwide importance in clinical practices. In particular, herbal medicines are now replacing synthetic pharmaceuticals and looked upon as the sources of novel bioactive substances. To develop satisfactory herbal combinations for treating liver fibrosis, phytoproducts need to be systematically evaluated for their potency as anti-fibrotic, anti-hepatotoxic and antioxidant agents. More importantly, the identified herb/agent should have the remarkable tendency to stimulate hepatocytes regeneration. The present review is a systematic account of at least fifty medicinal herbs and their products which in experimental models have demonstrated antifibrotic activity and thus, most likely candidates to offer therapeutic protection to liver. Nevertheless, much additional work is still needed to explore molecular pathways to discover potential applications of these medicines so as to open up new vistas in biomedical research.

Semen quality, antioxidant status and reproductive performance of rabbits bucks fed milk thistle seeds and rosemary leaves

The study aimed to investigate the effects of milk thistle seeds (MTS) and rosemary leaves (RL) both at 5 and 10g/kg diet on reproductive performance, semen quality and blood metabolites of rabbit bucks. A total of 35 rabbit bucks were randomly distributed into five experimental groups (7 bucks/group). All the groups were fed the same basal diet. The 1st group (control) did not have MTS and RL in its basal diet. The 2nd and 3rd groups were supplemented with MTS at 5 and 10g/kg, respectively. The 4th and 5th groups were fed the basal diet supplemented with RL at 5 and 10g/kg, respectively. The sperm concentration (SC), total sperm output (TSO), live sperm (LS), total live sperm (TLS) and total motile sperm (TMS) were significantly greater in the bucks fed MTS at 10 and RL at 5g/kg diet than the control group. Bucks fed MTS at 10g/kg diet had higher fertility than the control. Also, RL 5g/kg group showed higher testosterone and fertility than the control, but the MTS 10g/kg group showed the highest value for both parameters. In conclusion, MTS and RL at 10 and 5g/kg, respectively, significantly improved the semen quality and the fertility and MTS also increased the economic efficiency of rabbit bucks.

Hepatoprotective effect of oral application of a silymarin extract in carbon tetrachloride-induced hepatotoxicity in rats

Background

Silymarin derived from the milk thistle plant “Silybum marianum” is composed of four major flavonolignans. Clinical as well as experimental studies indicate hepatoprotective effects of silymarin. However, the underlying mechanisms are only incompletely understood.

The aim of this study was to assess the effect of oral administration of a defined silymarin extract in the model of acute carbon tetrachloride (CCl4) induced liver injury.

Methods

A single dose of a silymarin extract (SE; 20 or 100 mg/kg body weight) was given to rats by oral gavage. Subsequently, rats were injected with a single dose of CCl4 (2 ml/kg body weight).

Results

After 24h, analysis of liver to body weight ratio, serum levels of transaminases and histological analysis revealed a marked liver damage which was inhibited by SE in a dose dependent manner. CCl4-induced expressions of pro-inflammatory and pro-fibrogenic genes were significantly reduced in SE treated rats. Molecular analysis revealed that SE reduced the expression of the pro-inflammatory chemokine MCP-1, the pro-fibrogenic cytokine TGF-beta as well as collagen I in isolated human hepatic stellate cells (HSC), which are the key effector cells of hepatic fibrosis.

Conclusion

Oral administration of the tested silymarin extract inhibited hepatocellular damage in a model of acute liver injury. Moreover, we newly found that the silymarin extract had direct effects on pro-inflammatory and pro-fibrogenic gene expression in HSCs in vitro. This indicates that direct effects on HSC also contribute to the in vivo hepatoprotective effects of silymarin, and further promote its potential as anti-fibrogenic agent also in chronic liver disease.

Herbal hepatotoxicity: current status, examples, and challenges

INTRODUCTION

Herbal medicines have commonly been considered safe by the general public due to their natural origin and long history of traditional uses. In contrast to this belief, many plants produce toxic substances as secondary metabolites that are sometimes not easily distinguishable from the pharmacological active compounds. Some herbal medicines have been associated with adverse effects and toxic effects, including hepatotoxicity, which have been reversed upon discontinuation of the herbal medicine by the patient.

AREAS COVERED

This review reflects on selected herbal medicines that are associated with hepatotoxic effects including a description of the phytochemicals that have been linked to liver injury where available. Although case studies are discussed where patients presented with hepatotoxicity due to use of herbal medicines, results from both in vitro and in vivo studies that have been undertaken to confirm liver injury are also included.

EXPERT OPINION

Increasing evidence of herbal hepatotoxicity has become available through case reports; however, several factors contribute to challenges associated with causality assessment and pre-emptive testing as well as diagnosis of herb-induced liver injury.

Protective effect and antioxidant role of sweetgum (Liquidambar orientalis) oil against carbon tetrachloride-induced hepatotoxicity and oxidative stress in rats

CONTEXT

Sweetgum oil (SO) obtained from the Liquidambar orientalis Mill (Hamamelidaceae) tree has been used in Turkish folk medicine for centuries as an antiulcerigenic. Some studies have reported the antibacterial and antioxidant activities of SO; however, its effect on hepatic and oxidative stress complications is still unexplored.

OBJECTIVE

This study investigates the hepatoprotective effect and the antioxidant role of SO against carbon tetrachloride (CCl4) toxicity.

MATERIALS AND METHODS

The experiment included control, CCl4, SO, and CCl4 + SO treatment groups. Control and SO group rats were fed a diet without CCl4. CCl4 and CCl4 + SO treatment groups received 0.5 mL/kg CCl4 diluted in olive oil (1:1 dilution) intraperitonally injection twice per week. The CCl4 + SO group also received 1000 mg/kg SO-supplemented feed for 50 d. Blood and tissue samples were used for the determination of hepatic damage serum biomarkers (HDSBs) levels, antioxidant defense system constituents (ADSCs), and malondialdehyde (MDA) contents. In addition, the liver was evaluated for histopathological changes.

RESULTS

According to the results, the HDSBs levels of the CCl4 group were significantly (p < 0.05) increased compared with the control, whereas the HDSB levels of the CCl4 + SO group resulted in marked decreases (p < 0.05) compared with the CCl4 group. In addition, the results showed that SO-supplemented diet restored the CCl4-induced MDA and ADS towards to control. Hepatoprotection of SO is further substantiated by the almost normal histologic findings in the CCl4 + SO group against degenerative changes in the CCl4 group.

DISCUSSION AND CONCLUSION

It was concluded that SO has a hepatoprotective effect and antioxidant capacity against CCl4 toxicity.

Isoliquiritigenin attenuates oxidative hepatic damage induced by carbon tetrachloride with or without buthionine sulfoximine

Glycyrrhizae radix (G. radix) has been demonstrated to have hepatoprotective properties. This study determined the therapeutic effects of isoliquiritigenin (isoLQ) in G. radix, against liver injury induced by CCl4 in rats. CCl4 (0.5 ml/kg/d, twice) or CCl4 plus buthionine sulfoximine exerted severe liver damage assessed by increased plasma levels of alanine aminotransferase and aspartate aminotransferase, in addition to hepatic degeneration and necrosis. These pathological changes were markedly protected by pretreatment with isoLQ (5, 20 mg/kg/d, p.o.) for 3 consecutive days. In addition, pretreatment with isoLQ inhibited CCl4-induced reduction of cytochrome P450 2E1 protein and mRNA expression as well as activity in the liver. Moreover, isoLQ pretreatment reversed the decrease in hepatic antioxidant capacity induced by CCl4 as well as suppressed expression of tumor necrosis factor-alpha and cyclooxigenase-2 in the liver. These results suggest that isoLQ has a protective effect against CCl4-induced liver damage through induction of antioxidant and anti-inflammatory activities.

Review of natural products with hepatoprotective effects

The liver is one of the most important organs in the body, performing a fundamental role in the regulation of diverse processes, among which the metabolism, secretion, storage, and detoxification of endogenous and exogenous substances are prominent. Due to these functions, hepatic diseases continue to be among the main threats to public health, and they remain problems throughout the world. Despite enormous advances in modern medicine, there are no completely effective drugs that stimulate hepatic function, that offer complete protection of the organ, or that help to regenerate hepatic cells. Thus, it is necessary to identify pharmaceutical alternatives for the treatment of liver diseases, with the aim of these alternatives being more effective and less toxic. The use of some plants and the consumption of different fruits have played basic roles in human health care, and diverse scientific investigations have indicated that, in those plants and fruits so identified, their beneficial effects can be attributed to the presence of chemical compounds that are called phytochemicals. The present review had as its objective the collecting of data based on research conducted into some fruits (grapefruit, cranberries, and grapes) and plants [cactus pear (nopal) and cactus pear fruit, chamomile, silymarin, and spirulina], which are consumed frequently by humans and which have demonstrated hepatoprotective capacity, as well as an analysis of a resin (propolis) and some phytochemicals extracted from fruits, plants, yeasts, and algae, which have been evaluated in different models of hepatotoxicity.

Hepatoprotective Effects of Silybum marianum (Silymarin) and Glycyrrhiza glabra (Glycyrrhizin) in Combination: A Possible Synergy

Oxidative stress, lipid peroxidation, and transaminase reactions are some of the mechanisms that can lead to liver dysfunction. A time-dependent study was designed to evaluate the ability of silymarin (SLN) and glycyrrhizin (GLN) in different dosage regimens to lessen oxidative stress in the rats with hepatic injury caused by the hepatotoxin carbon tetrachloride. Wistar male albino rats (n = 60) were randomly assigned to six groups. Group A served as a positive control while groups B, C, D, E, and F received a dose of CCl4 (50% solution of CCl4 in liquid paraffin, 2 mL/kg, intraperitoneally) twice a week to induce hepatic injury. Additionally, the animals received SLN and GLN in different doses for a period of six weeks. CCl4 was found to induce hepatic injury by significantly increasing serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and thiobarbituric acid reactive substances while decreasing total protein and the activities of reduced glutathione, superoxide dismutase, and catalase. Treatment with various doses of SLN and GLN significantly reduced ALT, AST, ALP, and TBARS levels and increased GSH, SOD, and CAT levels. Our findings indicated that SLN and GLN have hepatoprotective effects against oxidative stress of the liver.

Lygodium flexuosum extract down regulates the expression of proinflammatory cytokines in CCl4-induced hepatotoxicity

OBJECTIVE

To examine the downregulation of proinflammatory cytokines in a time-dependent manner on carbon tetrachloride induced toxicity in experimental animals.

METHODS

CCl(4) (150 μL/100 g) was dissolved in corn oil (1:1 v/v %) and administered orally. Group I was treated as normal control and received corn oil on 8th day. Group II was toxic control and was given a single dose of CCl(4) on 8th days. Group III was treated with Lygodium flexuosum (L. flexuosum) n-hexane extract (200 mg/kg) for 8 days and on 8th day a single dose of CCl(4) was received. Group IV (negative control) received L. flexuosum n-hexane extract (200 mg/kg) alone for 8 days.

RESULTS

Treatment with n-hexane extract prior to the administration of CCl(4) significantly prevented an increase in serum AST, ALT, LDH activity and lipid peroxidation and prevented the depletion of glutathione (GSH). Rats treated with L. flexuosum had reduced mRNA levels of TGF-β1, TNF-α and IL-1β genes in liver of CCl(4) intoxicated rats when compared to CCl(4) control as evidenced by RT-PCR.

CONCLUSIONS

The data suggest that L. flexuosum, a widely available fern, significantly reduces CCl(4) induced acute hepatotoxicity by down-regulating the expression of pro-inflammatory cytokines in rats.

Antifibrotic effect of aloe vera in viral infection-induced hepatic periportal fibrosis

AIM: To investigate the anti-oxidative and anti-fibrotic effects of aloe vera in patients with liver fibrosis.

METHODS: Aloe vera high molecular weight fractions (AHM) were processed by patented hyper-dry system in combination of freeze-dry technique with microwave and far infrared-ray radiation. Fifteen healthy volunteers as the control group and 40 patients were included. The patients were randomly subdivided into two equal groups: the conventional group was treated with placebo (starch), and AHM group was treated with 0.15 gm/d AHM, both for 12 consecutive weeks. The patients were investigated before and after treatment. Serum activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), hyaluronic acid (HA), transforming growth factor-β (TGF-β) and matrixmetalloproteinase-2 (MMP-2) were determined. The reduced glutathione (GSH) and malondialdehyde (MDA) levels in liver were assayed and the expression of hepatic α-smooth muscle actin (α-SMA) was identified by immunohistochemistry.

RESULTS: At the start of the study, the hematoxylin and eosin staining revealed fibro-proliferated bile ductules, thick fibrous septa and dense inflammatory cellular infiltration in the patients before treatment. The use of AHM for 12 wk significantly ameliorated the fibrosis, inhibited the inflammation, and resulted in minimal infiltration and minimal fibrosis compared to the conventional group. The enzyme activities of the liver (ALT, AST and ALP) were attenuated after treatment in both groups, and the decrease in the AHM group was more significant as compared with the conventional group. Similar to the AST, the MDA levels were significantly higher before treatment, and were attenuated after treatment in both groups. In contrast, the hepatic glutathione content in the patients were decreased significantly in the AHM group compared to the controls. The serum levels of the fibrosis markers (HA, TGF-β and MMP-2) were also reduced significantly after treatment. The expression of α-SMA was modified in patients before and after treatment as compared with the normal controls. In the conventional group, there was only thin and incomplete parenchymal α-SMA positive septum joining the thickened centrilobular veins, while in the AHM group, few α-SMA positive cells were present in sinusoid and lobule after treatment.

CONCLUSION: Oral supplementation with AHM could be helpful in alleviating the fibrosis and inflammation of hepatic fibrosis patients.

Esculetin ameliorates carbon tetrachloride-mediated hepatic apoptosis in rats

Esculetin (ESC) is a coumarin that is present in several plants such as Fraxinus rhynchophylla and Artemisia capillaris. Our previous study found that FR ethanol extract (FR_EtOH) significantly ameliorated rats’ liver function. This study was intended to investigate the protective mechanism of ESC in hepatic apoptosis in rats induced by carbon tetrachloride. Rat hepatic apoptosis was induced by oral administration of CCl₄. All rats were administered orally with CCl₄ (20%, 0.5 mL/rat) twice a week for 8 weeks. Rats in the ESC groups were treated daily with ESC, and silymarin group were treated daily with silymarin. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) as well as the activities of the anti-oxidative enzymes glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase in the liver were measured. In addition, expression of liver apoptosis proteins and anti-apoptotic proteins were detected. ESC (100, 500 mg/kg) significantly reduced the elevated activities of serum ALT and AST caused by CCl₄ and significantly increased the activities of catalase, GPx and SOD. Furthermore, ESC (100, 500 mg/kg) significantly decreased the levels of the proapoptotic proteins (t-Bid, Bak and Bad) and significantly increased the levels of the anti-apoptotic proteins (Bcl-2 and Bcl-xL). ESC inhibited the release of cytochrome c from mitochondria. In addition, the levels of activated caspase-9 and activated caspase-3 were significantly decreased in rats treated with ESC than those in rats treated with CCl₄ alone. ESC significantly reduced CCl₄-induced hepatic apoptosis in rats.

Protective effect of probucol on liver injury induced by carbon tetrachloride in rats

AIM

To explore protective effect of probucol on liver injury induced by carbon tetrachloride (CCl4) in rats.

METHODS

We used CCl4 to induce a rat model of liver injury. Some of those rats were treated with an oral administration of probucol. Liver function, blood lipid, liver tissue malondialdehyde (MDA), superoxide dismutase (SOD), and degree of liver fibrosis were analyzed.

RESULTS

Probucol significantly decreased the elevation of serum aspartate transaminase, total bile acid, alkaline phosphatase and cholesterol, and improved liver histopathological changes (including fatty infiltration, inflammation cell infiltration, and fibrosis), decreased liver tissue MDA level, and increased liver tissue SOD level in liver injury rats.

CONCLUSIONS

For the first time, we demonstrated that probucol has protective effect against liver injury in animal experiment. The antioxidant action of probucol may play an important role in its hepatoprotective mechanism. Probucol also can reduce serum cholesterol. Thus, probucol may have the potential use in clinical liver diseases in which oxidative stress may be present, especially for the patients with hypercholesterolemia.

Hepatoprotective and antioxidant effects of gallic acid in paracetamol-induced liver damage in mice

OBJECTIVES

The aim of this research paper was to investigate the hepatoprotective and antioxidant effects of gallic acid in paracetamol-induced liver damage in mice.

METHODS

In the present study, the hepatoprotective and antioxidant effects of gallic acid were evaluated against paracetamol-induced hepatotoxicity in mice and compared with the silymarin, a standard hepatoprotective drug. The mice received a single dose of paracetamol (900 mg/kg body weight i.p.). Gallic acid (100 mg/kg body weight i.p.) and silymarin (25 mg/kg body weight i.p.) were administered 30 min after the injection of paracetamol. After 4 h, liver marker enzymes (aspartate transaminase, alanine transaminase and alkaline phosphatase) and inflammatory mediator tumour necrosis factor-alpha (TNF-alpha) were estimated in serum, while the lipid peroxidation and antioxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and glutathione) were determined in liver homogenate of the control and experimental mice.

KEY FINDINGS

Increased activities of liver marker enzymes and elevated TNF-alpha and lipid peroxidation levels were observed in mice exposed to paracetamol (P < 0.05), whereas the antioxidant status was found to be depleted (P < 0.05) when compared with the control group. However gallic acid treatment (100 mg/kg body weight i.p.) significantly reverses (P < 0.05) the above changes by its antioxidant action compared to the control group as observed in the paracetamol-challenged mice.

CONCLUSIONS

The results clearly demonstrate that gallic acid possesses promising hepatoprotective effects.

Enhancing effects of carbon tetrachloride on in vivo mutagenicity in the liver of mice fed 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx)

Chronic stimulus subsequent to cell injury plays an important role in cancer development, but the precise mechanisms remain unknown partly because appropriate animal models are lacking. In the present study, the effects of hepatotoxicant carbon tetrachloride (CCl(4)) on in vivo mutagenicity were investigated using gpt delta mice with or without p53. Female B6C3F(1) p53-proficient or -deficient gpt delta mice were given a diet containing 300 ppm of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) for 13 weeks, concurrently with intraperitoneal injection of 1 ml/kg CCl(4) solution once a week. Mutant frequencies of gpt and red/gam in p53-proficient mice fed MeIQx were both significantly elevated by CCl(4)co-treatment. Enhancing effects of CCl(4) treatment were also noted in p53-deficient mice. In the mutation spectra analysis of gpt mutant colonies, G:C to T:A transversions were predominantly observed regardless of CCl(4) injection, and clonal expansion of gpt colonies were increased in the co-treated group as compared with MeIQx alone group. The present data showing no significant changes in mRNA expression levels of CYP1A2 and GSTa4 between MeIQx-treated groups with and without CCl(4). In the Western blotting analysis, CYP1A2 protein levels were significantly decreased in the co-treated group as compared to MeIQx alone group, and GSTα protein levels were not changed among any groups. It is suggested that the mutant frequency by co-treatment with CCl(4) might result from some factors other than p53 or MeIQx metabolism/excretion. Thus, our data clearly demonstrate that this model could be a powerful tool for identifying the mechanisms underlying combinatorial effects on carcinogenesis.