Inhibitory action of Oren-gedoku-to extract on enzymatic lipid peroxidation in rat liver microsomes

We examined the inhibitory action of the extract of Oren-gedoku-to, a traditional herbal medicine known to act as an antioxidant, on enzymatic lipid peroxidation in rat liver microsomes. Simultaneous addition of a spray-dried preparation of Oren-gedoku-to extract (Tsumura TJ-15) inhibited enzymatic lipid peroxidation induced by reduced beta-nicotinamide adenine dinucleotide phosphate (NADPH) and ADP/Fe3+ complex in liver microsomes in a dose-dependent manner. When the inhibition by TJ-15 of enzymatic lipid peroxidation in liver microsomes was kinetically analyzed, this medicine showed a competitive inhibition against NADPH or ADP/Fe3+ complex. TJ-15 inhibited the NADPH-driven enzymatic reduction of ADP/Fe3+ complex or cytochrome c in liver microsomes competitively. TJ-15 enhanced NADPH consumption by liver microsomes with ADP/Fe3+ complex. Treatment with TJ-15 after the onset of enzymatic lipid peroxidation in liver microsomes inhibited the progression of lipid peroxidation in a dose-dependent manner. The present results indicate that Oren-gedoku-to extract inhibits enzymatic lipid peroxidation in rat liver microsomes in the initiation and propagation steps in a dose-dependent manner. These results also suggest that Oren-gedoku-to extract inhibits enzymatic lipid peroxidation in rat liver microsomes not only through its antioxidant action but also through reduction of the supply of electrons derived from NADPH to ADP/Fe3+ complex in liver microsomes both in a competitive manner and through stimulation of NADPH oxidation.     

木桔根甲醇提取物和其化学成分对小鼠在体和离体肝脏组织脂质过氧化的抑制作用的研究

本文报道木桔根甲醇提取物（MERA）及其化学成分对小鼠在体和离体肝脏组织或胞液（cytosol）脂质过氧化的抑制作用。MERA能够明显增加肝细胞中超氧化物歧化酶和谷胱甘肽过氧化物酶的活性，而对过氧化氢酶活性的影响无统计学意义。其主要成分之一4－甲氧基－1－甲基－2－喹诺酮（MMQ）有升高FeCl2-抗坏血酸（AA）－ADP中毒小鼠肝细胞中SOD活性的作用。从木桔根分离出的各类化合物对离体条件下FeCl2-抗坏血酸，CCl4-NADPH和ADP－NADPH等自由基发生系统诱导的大鼠肝细胞中脂质过氧化物质形成有程度不同的抑制作用。在受试化合物中，MMQ和其衍生物花椒喹诺酮(integriquinolone）对上述三种自由基发生系统引起的脂质过氧化有较强的抑制作用；在选定的浓度下，其作用与α－生育酚（维生素E）的效果类同。     

Garlic extract inhibits the enhanced peroxidation and production of lipids in carbon tetrachloride-induced liver injury

Carbon tetrachloride (CCl4) enhances lipid peroxidation, resulting in triglyceride accumulation in the liver. In this report, we studied the therapeutic, but not the preventive, effect of garlic extract on CCl4-intoxicated liver, in comparison to the effect of vitamin E. Garlic extract was given orally to mice in the dose of 10, 100 or 500 mg/kg at 6 hr after CCl4 administration. The increased conjugated-diene level was diminished significantly to 82% by the 100 mg/kg extract, and also thiobarbituric acid-reactivity was inhibited by all the doses of the extract. In addition to the above mentioned effects, the high doses of garlic extract lowered hepatic triglyceride and lipid contents. Highly significant and positive correlation was observed between hepatic triglyceride content and conjugated-diene level in the lipid fraction of the liver. Besides, vitamin E at the dose of 25 mg/kg inhibited only lipid peroxidation. We, therefore, conclude that not only is garlic extract effective on diminution of lipid peroxide and on alteration of peroxidative status to more reductive condition like the effect of vitamin E, but it also inhibits hepatic triglyceride accumulation in injured liver.     

Inhibitory effects of Maharishi-4 and Maharishi-5 on microsomal lipid peroxidation.

The effects of Maharishi-4 (M-4) and Maharishi-5 (M-5) on microsomal lipid peroxidation were examined in vitro. Rat liver microsomes were incubated with an NADPH-generating system or with sodium ascorbate and an ADP-iron complex to stimulate enzymatic or nonenzymatic lipid peroxidation respectively. Alcoholic or aqueous extracts of M-4 or M-5, when added to these incubation systems, inhibited hepatic microsomal lipid peroxidation in a concentration-dependent manner. The aqueous extract of M-4 was the most effective antiperoxidant in these systems. A 10% (w/v) aqueous extract of M-4 inhibited ascorbate or NADPH-induced lipid peroxidation by approximately 50% when added at volumes of 8 microliters and 3.5 microliters respectively to the incubation mixtures (total incubation volume, 2 ml). These findings suggest that M-4 and M-5, by virtue of their antiperoxidant properties, may be useful in the treatment of free radical-linked drug toxicities and disease states.     

In vitro evaluation of protective effects of ascorbic acid and water extract of Spirulina plantesis (blue green algae) on 5-fluorouracil-induced lipid peroxidation

Considering drug-induced lipid peroxidation as a possible mediator of drug-induced toxicity and exploiting the free radical scavenging action of antioxidants, the present study was designed to evaluate the protective effects of ascorbic acid (AA) and water extract of Spirulina plantesis (SP) to minimize 5-fluorouracil (5-FU)-induced lipid peroxidation. The study has been performed in vitro using goat liver as an experimental model. This evaluation was done by measuring the malondialdehyde (MDA), reduced glutathione (GSH), 4-hydroxy-2-nonenal (4-HNE) and nitric oxide (NO) content of the tissue as markers of lipid peroxidation. The results suggest that ascorbic acid and water extract of Spirulina plantesis could suppress the 5-FU-induced lipid peroxidation to a significant extent.     

In vitro inhibition of cytochrome P-450 reductases from pig liver microsomes by garlic extracts.

The activity of microsomal NADPH-cytochrome-P-450-reductase and NADH-cytochrome-b5-reductase are inhibited after the addition of an aqueous extract of a pharmaceutical preparation of garlic (Allium sativum, L.) to buffer-suspended microsomes. Incubation of garlic extract with isolated pig liver microsomes also decreases the activity of cytochrome P-450-dependent ethoxycoumarin deethylation. As measured by malondialdehyde release, the effects on the enzyme system are evidently not due to lipid peroxidation. No loss of cytochrome P-450 pigment is observed. Moreover, it could be shown that addition of garlic extract displays no protective effect on microsomal lipids when oxidation occurs spontaneously or is enforced by short-wave UV-irradiation. The above findings were reproduced after applying a HPLC-purified preparation of alliin to the incubation mixtures, suggesting that alliin is the active principle for the inhibitory effects observed in vitro.     

Effect of the flavanolignans of Silybum marianum L. on lipid peroxidation in rat liver microsomes and freshly isolated hepatocytes.

The effect of several flavanolignans (silicristin, silidianin, silybin and isosilybin) present in silymarin, the extract of Silybum marianum fruits, was tested on lipid peroxidation in rat liver microsomes and freshly isolated hepatocytes. In microsomes lipid peroxidation was generated by ADP/Fe2+ and NADPH. All flavanolignans inhibited peroxidation in a concentration dependent manner. In hepatocytes lipid peroxidation was induced by ADP/Fe3+ complex and cell damage was evaluated as LDH activity released in the medium. The inhibition of the peroxidative process by flavanolignans was also evident in this model, even if with a potency order different from that found in microsomes. In contrast, the effect on LDH release was significant only for silybin and isosilybin, the other compounds being inactive on this parameter.     

Screening of antioxidant action of various molds and protection of Monascus anka against experimentally induced liver injuries of rats

Antioxidant action of various molds, which are traditionally used for the production of foods or alcoholic beverages in Japan, was studied in vitro and in vivo. Antioxidant action was evaluated by scavenging stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and lipid peroxidation of rat liver microsomes. Among 40 molds, 16 species showed the DPPH scavenging action, and the molds that can scavenge the DPPH radical inhibited lipid peroxidation. The mold with the strongest action, Monascus anka, was chosen for the investigation of a protective action against liver injury of rats. When galactosamine (GalN, 400 mg/kg) or GalN plus lipopolysaccharide (LPS, 0.5 microg/kg) was given intraperitoneally to rats (Sprague-Dawley), aspartate aminotransferase (AST) and glutathione (GSH) S-transferase (GST) activities in serum were significantly increased. However, such hepatotoxicities seen in the increase in serum enzyme levels were depressed when the extract prepared from M. anka was given 1 and 15 h before the toxic insultant. Liver microsomal GST activity, which is known to be activated by oxidative stress, was increased by GalN or GaIN plus LPS treatment and the increase was also inhibited by pretreatment with the extract. Pathomorphological changes in the liver caused by GalN treatment also were prevented by the mold extract. These results indicate that the extract of M. anka has radical scavenging action and ameliorates chemically induced hepatotoxicity.     

In vivo effects of indomethacin--I. Activity of antioxidant enzymes and lipid peroxidation.

1. The in vivo effects of indomethacin on the activity of antioxidant enzymes and on lipid peroxidation in erythrocytes, liver and small intestines of rats were examined. 2. The activity of the enzymes studied increased or remained unchanged depending on the preparation and model used: treatment with "therapeutic" or "ulcerogenic" dose of indomethacin. 3. Indomethacin inhibited lipid peroxidation in the liver but not in the erythrocytes. 4. The results suggest that the stimulation of antioxidant enzymes, probably through in vivo formed metal complexes, is an alternative mechanism of the antiinflammatory action of indomethacin.     

丹酚酸A对氧自由基引起的大鼠心脏和肝脏线粒体损伤的保护作用(英文)

已往的研究表明丹酚酸A有很强的抗氧化活性。本文研究了丹酚酸A对氧自由基引起的大鼠心脏和肝脏线粒体损伤的保护作用。结果表明,丹酚酸A可抑制铁一半胱氨酸引起的线粒体脂质过氧化和ATP酶活性的丧失。脂质过氧化引起的心脏和肝脏线粒体肿胀以及肝脏线粒体膜流动性下降均可被丹酚酸A抑制。同时丹酚酸A对超氧阴离子和羟自由基具有清除作用。进一步证明丹酚酸A具有抗氧化活性。     

Effects of Eriobotrya japonica seed extract on oxidative stress in rats with non‐alcoholic steatohepatitis

Objectives Non‐alcoholic steatohepatitis is associated with the deposition of lipid droplets in the liver, and is characterised histologically by the infiltration of inflammatory cells, hepatocellular degeneration and liver fibrosis. Oxidative stress may play an important role in the onset and deterioration of non‐alcoholic steatohepatitis. We previously reported that an Eriobotrya japonica seed extract, extracted in 70% ethanol, exhibited antioxidant actions in vitro and in vivo. In this study, we examined the effect of this extract in a rat model of non‐alcoholic steatohepatitis. Methods The seed extract was given in the drinking water to fats being fed a methionine‐choline‐deficient diet for 15 weeks. Key findings Increases in alanine aminotransferase and aspartate aminotransferase levels were significantly inhibited in rats fed the seed extract compared with the group on the diet alone. Formation of fatty droplets in the liver was also inhibited. Antioxidant enzyme activity in liver tissue was higher than in the diet‐only group and lipid peroxidation was reduced compared with rats that also received the extract. Expression of 8‐hydroxy‐2′‐deoxyguanosine and 4‐hydroxy‐2‐nonenal was lower in the rats given the seed extract than in the diet‐only group. In the former, liver tissue levels of transforming growth factor‐β and collagen were also decreased. Conclusions Thus, the E. japonica seed extract inhibited fatty liver, inflammation and fibrosis, suggesting its usefulness in the treatment of non‐alcoholic steatohepatitis.     

大籽獐牙菜抗氧化作用的实验研究

目的：研究大籽獐牙菜的抗氧化作用。方法：通过测定大籽獐牙菜不同提取部位的总抗氧化能力和对肝脏自发性脂质过氧化作用,获得总抗氧化能力较强的提取部位以及抗脂质过氧化作用较强的提取部位,同时考察这两个提取部位不同浓度对总抗氧化能力以及抗脂质过氧化作用的影响。进一步考察酮类化合物对兔肝脏自发性脂质过氧化的影响,同时考察不同浓度酮类化合物的影响。结果：大籽獐牙菜的乙酸乙酯提取部位具有较强的总抗氧化能力和脂质抗氧化作用,并呈现量效关系;酮类化合物具有抗脂质过氧化作用,并呈现量效关系。结论：大籽獐牙菜具有很强的提高血浆总抗氧化能力及抗肝脏自发性脂质过氧化的作用,同时酮类化合物具有很强的抗肝脏自发性脂质过氧化的作用。     

Protection of liver microsomal membranes from lipid peroxidation by garlic extract

Garlic extract, the ethanol-soluble fraction of garlic, prevented formation of thiobarbituric-acid-reactive substances and fluorescent substances during lipid peroxidation of rat liver microsomes. Lipid peroxidation increased the fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene labelled to the microsomes while this increase was prevented by the garlic extract. It thus seems probable that the garlic extract serves to maintain membrane fluidity. These effects were dependent on its concentration and particularly prominent on exceeding a certain concentration of garlic extract. These results suggest its possible role of protecting the membranes from lipid peroxidation.     

Antioxidative effect of rhizome of Zinziber officinale on paraben induced lipid peroxidation: an in vitro study

Antioxidative effect of aqueous extract of rhizome of Ginger (Zinziber officinale) was examined on p-hydroxybenzoic acid (paraben) induced lipid peroxidation. Addition of paraben (25-150 microg/mL) to liver and kidney homogenates significantly increases H2O2 induced lipid peroxidation in vitro. Effect was dose dependent up to 100 microg/mL concentration. An addition of aqueous extract of ginger significantly reduced paraben (100 microg/mL) induced lipid peroxidation in liver and kidney homogenates. The effect was concentration dependent.     

Water and Ethanol Extracts of Piper nigrum in Regulating Thyroid Function and Lipid Peroxidation in Mice

Abstract

An investigation was made to evaluate the effects of water and ethanol extracts of Piper nigrum L. fruits in the alteration of the serum thyroid hormone concentrations and tissue lipid peroxidation in liver, the main target organ of many drugs. The alcohol extract, at a dose of 4.0 mg/kg for 15 days, caused thyrotoxicosis as evidenced by increased concentrations of thyroxine and triiodothyronine. A concomitant increase in hepatic lipid peroxidation with a decrease in superoxide dismutase and/or catalase activities also indicated its peroxidative effect. However, a trial with the aqueous extract did not exhibit any toxic effect either on thyroid or in liver functions. Rather, the latter extract appeared to be antithyroidic and antiperoxidative in nature as it could decrease serum thyroid hormone concentrations and hepatic lipid peroxidation, respectively. It is suggested that the aqueous extract of Piper nigrum may be preferred over the alcohol extract for therapeutic uses.     

In Vivo and In Vitro Sevoflurane-Induced Lipid Peroxidation in Guinea-pig Liver Microsomes

Abstract: Sevoflurane is a recently introduced volatile inhalation anaesthetic and is already used commonly in Japan. We investigated the potential of sevoflurane to cause lipid peroxidation in vivo and in vitro. For the in vitro study, pentane formation in a mixture of guinea pig liver microsomes and sevoflurane in the presence of nicotinamide adenine dinucleotide phosphate (NADPH) was analyzed by gas chromatography. Under anaerobic conditions, pentane formed without sevoflurane, but sevoflurane potentiated this anaerobic pentane formation. Two antioxidant agents, vitamine E and glutathione, reduced the pentane formation induced by sevoflurane. In the in vivo study, 18 guinea pigs were exposed to air (control), 0.5% halothane, or 1.2% sevoflurane. The extent of lipid peroxidation and liver damage was investigated by measuring the level of thiobarbituric acid reactive products and serum transaminase (alanine-aminotransferase: ALAT and aspartate-aminotransferase: ASAT) activity 12 hr after exposure. Both halothane and sevoflurane significantly increased thiobarbituric acid-reactive products. The increase in thiobarbituric acid-reactive products seen with sevoflurane administration was half that seen with halothane. Sevoflurane increased the ALAT activity to the same extent as did halothane but did not increase the ASAT activity. We conclude that sevoflurane potentiates lipid peroxidation in guinea pig liver microsomes in vivo and in vitro. However, because the degree of liver damage as measured by transaminase activity was minimal and the mechanism of sevoflurane-induced lipid peroxidation is still unknown, we must be cautious in applying these results to humans.     

Lipid peroxidation activity mediated by NADPH-cytochrome C reductase purified from rabbit liver microsomes.

Purified NADPH-cytochrome c reductase of rabbit liver microsomes was examined to determine whether or not the reported low lipid peroxidation activity of rabbit liver microsomes is due to the enzyme, NADPH-cytochrome c reductase. NADPH-cytochrome c reductase was purified from phenobarbital-treated rabbit liver microsomes to a specific activity of 14.9 to 21.4 unit per mg of protein with a yield of 15.2 to 16.4%. The purified sample (21.4 unit/mg of protein) was almost homogenous as determined by sodium dodecylsulfate gel electrophoresis. This sample was used for determining lipid peroxidation activity. EDTA and ferrous ion but not ADP were essential requirements for the activity. FMN enhanced the activity when low concentrations of the NADPH-cytochrome c reductase were used for the assay. NADP and 2'-AMP, which are inhibitors of NADPH-cytochrome c reductase, inhibited the lipid peroxidation activity. a-Tocopherol and p-chloromercuribenzoate (PCMB) also inhibited the activity. From these results, we confirmed the rabbit liver microsomal enzyme NADPH-cytochrome c reductase plays a role in lipid peroxidation activity. The reported low lipid peroxidation activity in rabbit liver microsomes does not appear to be caused by the NADPH-cytochrome c reductase.     

Ameliorative effects of black tea extract on aflatoxin-induced lipid peroxidation in the liver of mice.

We have evaluated the ameliorative effect of black tea extract on aflatoxin-induced lipid peroxidation in the liver of mice. Adult male albino mice were orally administered with 25 and 50 microg of aflatoxin in 0.2 ml olive oil/animal/day for 30 days. Results revealed dose-dependent and significantly (p<0.05) higher lipid peroxidation in the liver of aflatoxin-treated mice than that of vehicle control. As compared with vehicle control, the levels of non-enzymatic antioxidants such as glutathione and ascorbic acid, as well as the enzymatic antioxidants such as superoxide dismutase, glutathione peroxidase and catalase were significantly (p<0.05) lowered in the liver of aflatoxin-treated mice. Oral administration of two percent aqueous black tea extract along with aflatoxin for 30 days (groups 6 and 7) caused significant (p<0.05) amelioration in aflatoxin-induced lipid peroxidation by increasing significantly (p<0.05) the activities of enzymatic (superoxide dismutase, glutathione peroxidase, catalase) and contents of non-enzymatic (glutathione and ascorbic acid) antioxidants in the liver of mice as compared with those given aflatoxin alone (groups 4 and 5). Thus, oral administration of black tea along with aflatoxin significantly (p<0.05) ameliorates aflatoxin-induced lipid peroxidation in the liver of mice.     

Lipid peroxidation induced by indomethacin with horseradish peroxidase and hydrogen peroxide: involvement of indomethacin radicals

Some of the side-effects of using indomethacin (IM) involve damage to the gastric mucosa and liver mitochondria. On the other hand, neutrophils infiltrate inflammatory sites to damage the tissues through the generation of reactive oxygen species by myeloperoxidase. The stomach and intestine have large amounts of peroxidase. These findings suggest that peroxidases are involved in tissue damage induced by IM. To clarify the basis for the tissue damage induced by IM in the presence of horseradish peroxidase (HRP) and H2O2 (HRP-H2O2), lipid peroxidation was investigated. When IM was incubated with liver microsomes in the presence of HRP-H2O2 and ADP-Fe3+, lipid peroxidation was time-dependent. Catalase and desferrioxamine almost completely inhibited lipid peroxidation, indicating that H2O2 and iron are necessary for lipid peroxidation. Of interest, superoxide dismutase strongly inhibited lipid peroxidation, and it also inhibited the formation of bathophenanthroline-Fe2+, indicating that reduction of the ferric ion was due to superoxide (O2-). ESR signals of IM radicals were detected during the interaction of IM with HRP-H2O2. However, the IM radical by itself did not reduce the ferric ion. These results suggest that O2- may be generated during the interaction of IM radicals with H2O2. Ferryl species, which are formed during the reduction of iron by O2-, probably are involved in lipid peroxidation.     

In vitro and in vivo anti-oxidant activity of hot water extract of basidiomycetes-X, newly identified edible fungus

Basidiomycetes-X (BDM-X) is a novel edible mushroom recently identified as a new fungi species and registered to the database of the NPO organization for International Patent Organism Depositing (IPOD) in the Industrial Technology Institute of Japan (PCT/JP2004/006418). In the present study, we examined anti-oxidant activity of hot water extract of this novel fungus both in vitro and in vivo together with Agaricus Blazei Murill (ABM), a commercially available medicinal mushroom, and other reference antioxidants. As results, the hot water extract of BDM-X showed more potent anti-oxidative actions compared with that of ABM, when evaluated by 1,1'-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, Ferric Reducing Potential (FRP), and also the inhibition of 2,2'-azobis(2-amidino-propane) dihydrochloride (AAPH)-induced lipid peroxidation of rat liver homogenates. Further, the protective activity of BDM-X extract towards lipopolysaccharide (LPS)-induced hepatic oxidative damage was compared with ABM and alpha-lipoic acid in the mice pre-administered with these antioxidants. It was revealed that all of these antioxidants inhibited the LPS-induced oxidative tissue damage but the hot water extract of BDM-X showed the strongest protection among them. For example, the dose for 50% inhibition of carbonyl formation in liver was 0.53 g dry weight/kg body weight/d for BDM-X and the value corresponded to 16 mmol of alpha-lipoic acid as an antioxidant reference/kg body weight/d.