Microsomal Lipid Peroxidation Research Articles

Suppression of beta-naphthoflavone induced CYP1A expression and lipid-peroxidation by berberine

Impacts of berberine, a major isoquinoline alkaloid in herbal plants, on beta-naphthoflavone (BNF)-induced CYP1A expression were determined both in primary mouse hepatocytes and in vivo. Berberine concentration-dependently suppressed BNF-induced CYP1A expression in mouse hepatocyte and it significantly down-regulated BNF-induced CYP1A in mouse liver via suppression of mRNA and protein expression, and decreases of EROD and MROD activities. Moreover, berberine showed significant potential on suppression of BNF-induced lipid peroxidation in mouse hepatic microsome. Therefore, using berberine as a health supplement or an alternative medication might provide extra-benefit due to its inhibitory regulation on CYP1A expression and anti-lipid peroxidation activity.

Bioactive Properties of Tynanthus panurensis (Bureau) Sanwith Bark Extract, the Amazonian “Clavo Huasca”

Tynanthus panurensis (Bureau) Sanwith (Bignoniaceae) is a liana vine used in traditional Amazonian medicine as a tonic and energizer as well as a treatment for rheumatism. These traditional indications prompted this study of the antioxidant and anti-inflammatory activities of T. panurensis bark extract (ETP). Phytochemical analysis of ETP showed the presence of saponins and a high concentration of phenols and flavonoids. A battery of in vitro tests revealed that the extract has free radical-scavenging antioxidant properties and reduces microsomal lipid peroxidation, uric acid synthesis, and tumor necrosis factor-α production. The anti-inflammatory properties of ETP were further confirmed in vivo in a rat carrageenan edema model, in which the extract exhibited a potent activity. These results support the idea that T. panurensis bark extract could be beneficial for treating inflammation and are in agreement with one of the main traditional uses of this plant.

Mechanism of paraquat-stimulated lipid peroxidation in mouse brain and pulmonary microsomes

Paraquat-stimulated NADPH-dependent lipid peroxidation in mouse brain and pulmonary microsomes was inhibited by superoxide dismutase and singlet oxygen quenchers, but not by catalase or hydroxyl radical scavengers. MnCl2, which might form a salt with unsaturated lipid, inhibited the lipid peroxidation in brain microsomes, but not that in pulmonary microsomes. These findings suggest that activated oxygen species, especially superoxide and singlet oxygen, may play a major role in the stimulation of microsomal lipid peroxidation by paraquat in both brain and lung, and that the nature of the lipids exposed to peroxidative attack may be different in microsomes of the two organs.

Antioxidant activity of guaiazulene and protection against paracetamol hepatotoxicity in rats.

The effect of guaiazulene, a lipophilic azulene derivative widely found in nature, on radical-mediated processes is examined. The ability of guaizulene to inhibit rat hepatic microsomal membrane lipid peroxidation and to scavenge hydroxyl radicals, as well as to interact with 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), was estimated. It was found that guaiazulene can inhibit lipid peroxidation very significantly, having an IC50 value of 9.8 microM. It can also scavenge hydroxyl radicals and interact with DPPH. The protection afforded by guaiazulene to rats with paracetamol-induced liver injury was also investigated. Paracetamol hepatotoxicity is caused by the reactive metabolite N-acetyl-p-benzoquinone imine (NAPQI), which causes oxidative stress and glutathione (GSH) depletion. Hepatic cytosolic protein, GSH, glutathione transferase and glutathione reductase levels are determined as indices of hepatic injury with or without the administration of guaiazulene. It was found that all parameters affected by paracetamol are restored to normal by guaiazulene treatment, while the administration of guaiazulene alone has no effect on the performed tests compared with the control values. It was concluded that the significant protection against paracetamol-induced GSH depletion and hepatic damage afforded by guaiazulene is probably connected with its antioxidant activity. A molecular mechanism of action of guaiazulene is suggested.

Effect of Hydroxyethyl Rutosides and Related Compounds on Lipid Peroxidation and Free Radical Scavenging Activity. Some Structural Aspects

Four hydroxyethyl rutosides, 7,3',4'-trihydroxyethyl quercetin, quercetin and a commercial standardized mixture of hydroxyethyl rutosides were investigated on non-enzymatic lipid peroxidation, for hydroxyl radical scavenging activity and interaction with 1,1-diphenyl-2-picrylhydrazyl stable free radical (DPPH). It was found that the tested compounds exhibited a considerable inhibition of microsomal lipid peroxidation. They were less active than the reference compound quercetin, and this was attributed to their structural characteristics. They were also found to be potent hydroxyl radical scavengers and to interact with DPPH. As hydroxyl radical scavengers, they were more potent than the scavengers mannitol and dimethyl sulphoxide. These properties could be considered as a useful and exploitable combination.

Effects of saikosaponin-d on enhanced CCl4-hepatotoxicity by phenobarbitone.

The effects of saikosaponin-d extracted from the roots of Buplerum falcatum L. on increased toxicity of CCl4 and increased activities of microsomal enzymes induced by phenobarbitone have been examined. Saikosaponin-d showed protection against the CCl4-hepatotoxicity enhanced by phenobarbitone. It also inhibited increases in the content of cytochrome P450 and NADPH-cytochrome c reductase activity, which are induced by the phenobarbitone treatment, but the spectral characteristics of P450 were not altered. The rate of microsomal lipid peroxidation by NADPH and CCl4 was significantly lowered in-vitro in rats pretreated with phenobarbitone and saikosaponin-d compared with those pretreated with phenobarbitone alone.

Inhibition of lipid peroxidation by sesquiterpenoid in Heterotheca inuloides.

A sesquiterpenoid, 7-hydroxy-3,4-dihydrocadalin, isolated from a Mexican medicinal plant Heterotheca inuloides was evaluated as an antioxidant. This sesquiterpenoid inhibited mitochondrial and microsomal lipid peroxidation induced by Fe(III)-ADP/NADH or Fe(III)-ADP/NADPH. Furthermore, 7-hydroxy-3,4-dihydrocadalin protected red cells against oxidative haemolysis. This sesquiterpene was thus shown to be effective in protecting biological systems against oxidative stresses.

Hematopoietic Recovery and Amelioration of Radiation-Induced Lethality by the Vitamin E Isoform δ-Tocotrienol

δ-Tocotrienol (DT3), a vitamin E isoform, is associated with strong antioxidant and immunomodulatory properties. We confirmed the potent antioxidant activity in membrane systems and showed that DT3 is an effective radiation protector and mitigator. DT3 (4 μM, P < 0.001) inhibited lipid peroxidation in mouse liver microsomes and nitric oxide (NO) formation (20 μM DT3, P < 0.01) in RAW264.7 cells, a murine alveolar macrophage line. In CD2F1 mice exposed to lethal total-body radiation from a (60)Co γ-radiation source, a single subcutaneous (s.c.) injection of DT3 before or after irradiation produced a significant increase in 30-day survival. DT3 was effective from 18.75 to 300 mg/kg (--24 h, P < 0.001). A single dose of 150 or 300 mg/kg DT3 given 24 h before irradiation (radioprotection) resulted in dose reduction factors (DRFs) of 1.19 and 1.27, respectively (P < 0.001). Further, DT3 reduced radiation lethality when administered 2, 6 or 12 h after irradiation, and 150 mg/kg DT3 administered 2 h after exposure conferred a DRF of 1.1 (mitigation). The optimum schedule of 300 mg/kg DT3 24 h prior to 7 Gy significantly reduced pancytopenia compared to irradiated controls (P < 0.05). The large therapeutic potential of and multi-lineage hematopoietic recovery for DT3 warrants further studies.

Combined Effect of N-Acetyl Cysteine, Zinc, and Selenium Against Chronic Dimethylmercury-Induced Oxidative Stress: A Biochemical and Histopathological Approach

Mercury (Hg), widely used in industry, is a great environmental health problem for humans and animals. Despite several reports regarding Hg toxicity, there is scarcity of data on its toxic manifestations on Sprague Dawley rats under realistic exposure conditions. Experimental studies have shown that sulphur-containing antioxidants have beneficial effects against the detrimental properties of Hg. The present work was aimed to study the therapeutic potential of combined administration of N-acetyl cysteine (NAC; 2 mmol/kg ip), zinc (Zn; 2 mmol/kg po), and selenium (Se; 0.5 mg/kg po) against dimethylmercury (DMM; 1 mg/kg po)-intoxicated male rats for 12 weeks. Exposure to DMM caused significant alterations in cytochrome P450 (CYP) activity, microsomal lipid peroxidation, and proteins. Activities of transaminases (aspartate aminotransferase/alanine aminotransferase), alkaline phosphatase, and lactate dehydrogenase in serum, as well as activities of CYP enzymes aniline hydroxylase (AH), amidopyrine-N-demethylase (AND) in liver microsomes and activities of acid phosphatase, alkaline phosphatase, glucose-6-phophatase, and succinic dehydrogenase in the liver and kidney, were significantly altered after DMM administration. DMM exposure also induced severe hepato-renal alterations at the histopathological level. NAC, along with Zn and Se, dramatically reversed the alterations in all of the variables more toward control. The study results conclude that protective intervention of combined treatment of NAC, along with Zn and Se, is beneficial in attenuating DMM-induced systemic toxicity.

Antioxidant potential, cytotoxic activity and phenolic content of Clematis flammula leaf extracts

Five fractions of Clematis flammula, a plant widely used in the Mediterranean traditional medicine, were isolated from the leaves using a selective extraction procedure and their total antioxidant capacity was measured by both the ABTS and ORAC tests. Furthermore, their capacities to inhibit microsomal lipid peroxidation and to scavenge the hydroxyl radical were assessed. The cytotoxic potential of the crude ethanolic extract and the aqueous fraction obtained from chloroform was also evaluated on three human hepatoma cell lines CHL, PLC and HuH7. The results showed a stronger antioxidant capacity for the two aqueous phases obtained from ethyl acetate and chloroform concerning ABTS (7.9 and 10.5 mmoles Trolox eq/g of plant extract, respectively), ORAC (487 and 387 mmoles Trolox eq/g of plant extract, respectively) and hydroxyl radical scavenging activity (IC50 = 56.5 and 48.4 µg/mL, respectively), compared to their organic counterparts which, however, inhibited microsomal lipid peroxidation more efficiently (IC50 = 390.7 and 523.5 µg/mL, respectively). The ethanol crude extract exhibited a fairly good cytotoxic potential on the two cell lines CHL and PLC (IC50 = 58.5 and 47.3 µg/mL, respectively), in contrast to the aqueous phase obtained from chloroform (IC50 = 457.7 and 304.9 µg/mL, respectively). A positive correlation was also found between the phenol content and the different activities. These results provide experimental support for the therapeutic virtues ofClematis flammula leaf extracts. Key words: Clematis flammula, chloroform extract, antioxidant, caffeic acid, lipid peroxidation.

Surfactant and antioxidant properties of an extract from Chenopodium quinoa Willd seed coats

Chenopodium quinoa Willd (quinoa) has been a source of food for millennia by the Andes region native population. Because of its bitter taste, quinoa seeds are commercialized without their coat for human consumption. Quinoa coats are surfactant sub-products of the quinoa food industry, which have been only characterized to contain triterpene saponins. We postulated that this coat should also contain antioxidant molecules as part of the defense system of the quinoa seed. We found that a quinoa seed coats hydroalcoholic extract, displayed thiol compounds in addition to polyphenols, recognized antioxidants. Accordingly, it inhibited microsomal lipid peroxidation and the loss of microsomal thiol content, both oxidative phenomena promoted by Cu2+/ascorbate. Microsomal glutathione S-transferase (GST) is inhibited by reducing agents, which decrease the content of catalytically active disulfide-linked dimers. The effects of this quinoa extract on microsomal GST are consistent with it displaying disulfide reducing properties. The occurrence of thiol compounds in this quinoa extract is discussed in terms of the potential of their antioxidant properties.

In vitro evaluation on the antioxidant capacity of triethylchebulate, an aglycone from Terminalia chebula Retz fruit

Objectives:To evaluate the antioxidant and free-radical scavenging activities of triethylchebulate (TCL), an aglycone isolated from the fruit of Terminalia chebula Retz.Materials and Methods:Microsomes, mitochondria and red blood cells (RBCs) were isolated from rat liver. The antioxidant capacities were evaluated by determining the inhibitory effects of TCL on lipid peroxidation, hydrogen peroxide (H2O2)-induced RBCs hemolysis and RBCs autoxidative hemolysis. The free-radical scavenging activities were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and 2´,7´-dichlorodihydrofluorescin diacetate (DCFH2-DA) assay.Result:TCL significantly inhibited FeSO4/Cys-induced microsomes lipid peroxidation and protected both H2O2--induced RBCs hemolysis and RBCs auto-hemolysis in a dose-dependent manner. Furthermore, TCL demonstrated potent DPPH free-radical scavenging ability with IC50 at 2.4×10-5 M. In addition, TCL also moderately suppressed azide-induced mitochondria ROS formation.Conclusion:These results demonstrated that TCL was a strong antioxidant and free-radical scavenger, which might contribute to the anti-oxidative ability of Terminalia chebula Retz.

In vitro hepatoprotective and antioxidant activities of crude extract and isolated compounds from Ficus gnaphalocarpa

The in vitro hepatoprotective effect of the methanolic extract from Ficus gnaphalocarpa (Miq.) Steud. ex A. Rich (Moraceae) on the CCl₄-induced liver cell damage as well as the possible antioxidant mechanisms involved in this protective effect, were investigated. The phytochemical investigation of this methanolic extract led to the isolation of six compounds identified as: betulinic acid (1); 3-methoxyquercetin (2); catechin (3); epicatechin (4); quercetin (5); and quercitrin (6). The hepatoprotective activity of these compounds was tested in vitro against CCl₄-induced damage in rat hepatoma cells. In addition, radical-scavenging activity, β-carotene-linoleic acid model system, ferric-reducing antioxidant parameter and microsomal lipid peroxidation assays were used to measure antioxidant activity of crude extract and isolated compounds. Silymarin and trolox were used as standard references and, respectively, exhibited significant hepatoprotective and antioxidant activities. (5), (6) and (2) showed significant antioxidant and hepatoprotective activities as indicated by their ability to prevent liver cell death and lactate dehydrogenase leakage during CCl₄ intoxication. These results suggest that the protective effects of crude extract of F. gnaphalocarpa against the CCl₄-induced hepatotoxicity possibly involve the antioxidant effect of these compounds.

Constituents of Gymnadenia conopsea

To investigate the chemical constituents of tuber of Gymnadenia conopsea. The constituents were isolated by using a combination of various chromatographic techniques including column chromatography over silica gel, Sephadex LH-20, and C-18, as well as reversed-phase HPLC. Structures of the isolates were identified by spectroscopic data analysis. Thirty-four compounds were isolated. Their structures were identified as six 2-isobutyltartrate benzyl ester glucosides: coelovirin A (1), coelovirin B (2), coelovirin E (3), coelovirin D (4), dactylorhin B (5) and loroglossin (6). Three 2-isobutylmalate benzyl ester glucosides: dactylorhin A (7), dactylorhin E (8) and militarine (9). Three lignans: arctigenin (10), lappaol A (11) and lappaol F (12). Six aromatic acid (alhyde or alcohol) derivatives: 4-beta-D-glucopyranosyloxyl-trans-phenylpropenoic acid (13), 4-beta-D-glucopyranosyloxyl-cis-phenylpropenoic acid (14), gastrodin (15), 4-beta-D-glucopyranosyloxylphenylaldehyde (16), 4-beta-D-glucopyranosyloxylbenzyl methyl ether (17), 4-beta-D-glucopyranosyloxyloxylbenzyl ethyl ether (18), and bis(4-hydroxybenzyl) ether mono 4-O-beta-D-glucopyranoside (19). Four cyclodipeptides: cyclo(L-Leu-L-Tyr) (20), cyclo(L-Leu-L-Pro) (21), cyclo(L-Val-L-Tyr) (22), and cyclo(L-Ala-D-Phe) (23). One N6-substituted andenosine: N6-(4-hydroxybenzyl)-adenine riboside (24). An aromatic amide: N-trans-feruloyltyramine (25). Nine aromatic acids (or aldehyde or alcohol): 3-hydroxybenzoic acid (26), 4-hydroxyisophthalic acid (27), 4-hydroxybenzyl alcohol (28), 4-hydroxybenzyl methyl ether (29), 4-hydroxybenzylaldehyde (30), 4-hydroxybenzoic acic (31), 4-hydroxy-3-methoxybenzoic acid (32), trans-p-hydroxyphenylpropenoic acid (33), and cis-p-hydroxyphenylpropenoic acid (34). At a concentration of 1.0 x 10(-6) mol x L(-1), compounds 10-12 showed antioxidative activity inhibiting Fe(+2) -cystine induced rat liver microsomal lipid peroxidation with inhibitory rates of 53%, 59%, and 52%, respectively(positive control VE with 35% inhibition). These compounds were obtained from the genus Gymnadenia for the first time except for 5-7, 9, 15, 28-34. Compounds 10-12 possess antioxidant activity.

The synergistic effect of daidzein and α-tocopherol or ascorbic acid on microsome and LDL oxidation

Isoflavone daidzein brings potential health benefits. Its antioxidant properties are considered to be responsible in part for its protective effects. We investigated the antioxidant effects of daidzein and its interactive effects with&lt;br /&gt;&amp;alpha;-tocopherol or ascorbic acid on Fe&lt;sup&gt;2+/&lt;/sup&gt;ascorbate-induced oxidation of rat liver microsomes and copper-induced human low-density lipoprotein (LDL) oxidation. Although the inhibitory effect of daidzein on lipid peroxidation in microsome was weak, it effectively prevented LDL against oxidative modification by prolonging the lag time, decreasing the propagating rate, and suppressing malonaldehyde (MDA) and carbonyls formation. When daidzein was combined with &amp;alpha;-tocopherol in microsomes oxidation and with ascorbic acid in LDL oxidation, the protection was significantly greater than the calculated additive effect of the two individual actions. Thus, daidzein can protect LDL from oxidative modification, and its combination with nutrients may be superior to the action of it alone. These results can help to get a better understanding of the interactions of different antioxidants in vivo.

Hepato-protective, antioxidant activities and acute toxicity of a stem bark extract of &lt;i&gt;Erythrina senegalensis&lt;/i&gt; DC.

This study aimed at evaluating the in vitro antioxidant and hepatoprotective activities of different stem bark extracts of Erythrina senegalensis prepared with ethanol, and the in vivo hepatoprotective activity and acute toxicity of the best extract. The 2, 4-diphenyl-1-picryl-hydrazil (DPPH) and microsomal lipid peroxidation (MLP) models, and the rat liver slices system were respectively used for the in vitro study. The Methylene chloride/methanol (1:1 v/v) (Emc) and 40% ethanolic (E40) extracts were more efficient in inhibiting MLP and in scavenging DPPH radical. However, E40 was most effective with regards to lactate dehydrogenase (LDH) leakage inhibition from rat liver slices intoxicated with carbon tetrachloride (CCl4). The in vivo hepatoprotective activity was evaluated against CCl4-induced hepatotoxicity in rats. The E40 extract (100 mg/Kg) significantly reduced the increase in ALT, AST and lipid peroxidation in liver homogenate, showing that the extract is as protective as silymarin at the same dose. Acute toxicity was evaluated in mice and E40 did not produce any behavioural changes or mortality even at an oral dose of 16 g/kg. The extract was found to contain antioxidant classes of compounds (flavonoids and polyphenols). In conclusion, the E40 extract of E. senegalensis could be an important source of hepatoprotective compounds. Key words: Erythrina senegalensis , stem bark extract, antioxidant, hepatoprotective, carbon tetrachloride.

Antihepatotoxic and Antioxidant Activities of Methanol Extract and Isolated Compounds from Ficus Chlamydocarpa

Free radicals, in particular radical oxygen species (ROS), play an important role in the aetiology and pathogenesis of various diseases. Current research in many countries focuses on the use of local medicinal plants as a promising source of liver protective agents. This paper describes the hepatoprotective effects of the methanol extract and four isolated compounds from Ficus chlamydocarpa on CCl4-induced liver damage, as well as the possible antioxidant mechanisms involved in this protection. The DPPH test, along with the beta-Carotene-Linoleic Acid Model System and Ferric-Reducing Antioxidant Power assays, as well as the inhibition of microsomal lipid peroxidation were used to measure radical-scavenging and antioxidant activities. Pretreatment of rats with the methanol extract of F. chlamydocarpa before CCl4 administration, significantly prevented serum increase of hepatic enzyme markers, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT), in a dose-dependent manner. The hepatoprotection was also associated with a significant enhancement in hepatic reduced glutathione (GSH) and a marked decrease of liver malondialdehyde (MDA). Among the four compounds 1-4, isolated from the methanol extract, alpha-amyrin acetate (1) and luteolin (4) showed a significant hepatoprotective activity, as indicated by their ability to prevent liver cell death and lactate dehydrogenase (LDH) leakage during CCl4 intoxication.

Polyphenolic content and antioxidant activity of Eugenia pollicina leaf extract in vitro and in model emulsion systems

The polyphenolic profile of a leaf extract of the Mauritian endemic plant, Eugenia pollicina, was assessed as a source of natural antioxidants. The amounts of flavan-3-ol derivatives determined by HPLC, were in the order of (−)-epicatechin (EC)>(−)-epigallocatechin gallate (EGCG)>(+)-catechin (C)>(−)-epicatechin gallate (ECG) with the levels of Procyanidin B2 and B1 dimers ranging from 1 to 3mg g−1 FW. The trolox equivalent antioxidant capacity and ferric reducing antioxidant power values were 796μmol g−1 FW and 302μmol g−1 FW respectively. E. pollicina extracts also strongly inhibited the FeCl3 and ascorbate-dependent microsome lipid peroxidation, a function that is linked to their flavonoid contents. The extent of DNA damage induced by the extract under study in the copper-phenanthroline assay was lower than the effect of a reference of 240μM ascorbate. E. pollicina extracts also inhibited lipid autoxidation in the 30% (v/v) olive oil and soybean oil oil-in-water (O/W) emulsions and was effective in slowing down the formation of hydroperoxides in the emulsions during 13days storage at 40°C as determined by the peroxide, conjugated diene and para-anisidine values. The high levels of total phenolics, flavonoids and procyanidins measured indicate that E. pollicina is a potential source of antioxidants relevant to the maintenance of oxidative stability of the food matrix, cosmetics and/or pharmaceutical preparations.

Flavonoids from Cleistocalyx operculatus Buds and their Cytotoxic Activity

Cleistocalyx operculatus (Roxb.) Merr and Perry (Myrtaceae) is a well-known medicinal plant, widely distributed and propagated in China, Vietnam and some other tropical countries. Several species of Cleistocalyx are used in folk medicine. In Vietnam, C. operculatus is commonly called “Voi”. The flower buds (“Nu Voi”) and leaves (“La Voi”) have been used to make a beverage since ancient times. 1 The buds are commonly used as an ingredient for tonic drinks in Southern China. 2 The water extract of C. operculatus buds was shown to increase the contractility and decrease the frequency of contraction in an isolated rat heart perfusion system. 3 It showed strong protective effects on lipid peroxidation in rat liver microsomes and on the H2O2induced trauma of PC12 cells. 4 C. operculatus extract showed inhibitory activity against the α-glucosidase, rat-intestinal maltase, sucrase activities, and is considered a promising material for preventing and treating diabetes. 5 Recently, the essential oil of the C. operculatus buds was investigated for its in vitro and in vivo anti-inflammatory activities. These results suggested that its essential oil might exert an anti-inflammatory effect by suppressing the expression of pro-inflammatory cytokines, which is mediated, at least in part, by blocking the NF-κB activation. 6

Evaluation of Antioxidant Activity of Medicinal Plant Extracts Produced for Commercial Purpose

The antioxidant potential of some herbal plant extracts (commercial products) was measured using various in vitro assays. Among the extracts from Curcuma longa, Caffea arabica, Tribulus terrestris, Bacopa monnieri and Trigonella foenum- graecum, the Curcuma longa and coffee bean extract (Caffea Arabica) showed greater antioxidant activity measured as scavenging of DPPH, superoxide radicals, reducing power and inhibition of microsomal lipid peroxidation.