丹参酮对心肌肌质网脂质过氧化过程中脂类自由基的清除作用

应用自旋捕集方法和化学发光方法研究天然抗氧化剂丹参酮（Ｔａｎｓｈｉｎｏｎｅ）对心肌肌质网膜脂质过氧化过程中产生的脂类自由基的清除作用。发现在一定的浓度范围内,丹参酮对脂质过氧化有较好的保护作用,在丹参酮浓度大于１ｍｇ／ｍｇ蛋白时,对脂类自由基清除率可达６０％。丹参酮对肌质网膜脂质过氧化的保护机理可能是通过清除脂类自由基而阻断脂质过氧化的链式反应,而不是清除氧自由基而防止脂质过氧化的启动。     

Antioxidant effect of caeruloplasmin on microsomal lipid peroxidation

Microsomal NADPH-dependent lipid peroxidation catalyzed by ADP-Fe³⁺ was inhibited by the addition of caeruloplasmin. The antioxidant effect of caeruloplasmin was independent of the superoxide anion (O^?₂ scavenging activity. Since caeruloplasmin enhanced the function of ADP-Fe³⁺ acting as electron acceptor for microsomal electron transport system, the antioxidant effect of caeruloplasmin is considered to depend on the ferroxidase activity.     

Antioxidant activities of cultured Armillariella mellea

This study aimed to evaluate the antioxidant activities of a cultured medicinal fungus--Armillariella mellea (Vahl. ex Fr.) Karst. (AM). Three antioxidant assay systems, namely cytochrome c, xanthine oxidase inhibition and FeCl2-ascorbic acid stimulated lipid peroxidation in rat tissue homogenate tests, were used. Total flavonoid and phenol contents of AM extracts were also analyzed. Results showed that both aqueous (AM-H2O) and ethanolic (AM-EtOH) extracts of solid state cultured AM showed antioxidant activities in a concentration-dependent manner. At concentrations 1-100 microg/ml, the free radical scavenging activity was 73.7-92.1% for AM-H2O, and 60.0-90.8% for AM-EtOH. These extracts also showed an inhibitory effect on xanthine oxidase activity, but with a lesser potency (IC50 - 9.17 microg/ml for AM-H2O and 7.48 microg/ml for AM-EtOH). In general, AM-H2O showed a stronger anti-lipid peroxidation activity on different rat's tissues than AM-EtOH. However, both AM extracts displayed a weak inhibitory effect on lipid peroxidation in plasma. Interestingly, the anti-lipid peroxidation activity of AM-H2O (IC50 - 6.66 microg/ml) in brain homogenate was as good as alpha-tocopherol (IC50 - 5.42 microg/ml). AM-H2O (80.0 mg/g) possessed a significant higher concentration of total flavonoids than AM-EtOH (30.0 mg/g), whereas no difference was noted in the total phenol content between these two extracts. These results conclude that AM extracts possess potent free radical scavenging and anti-lipid peroxidation activities, especially the AM-H20 in the brain homogenate.     

Phospholipid Hydroperoxides and Lipid Peroxidation in Liver and Plasma of ODS Rats Supplemented with α-Tocopherol and Ascorbic Acid

Forty-five mutant male ODs rats, unable to synthesize ascorbic acid, were fed nine diets containing 5, 50 or 250 mg of vitamin E/kg diet and 150,300 or 900 mg of vitamin C/kg diet for 21 days. The concentrations of vitamins C and E increased in liver and plasma in relation to the level of these vitamins in the diet. Vitamin C dietary supplementation increased the plasma vitamin E content at low levels of vitamin E intake, supporting the concept of an in vivo synergism between both antioxidant vitamins. Vitamin C, at the dietary levels studied, did not affect the lipid peroxidation. Vitamin E decreased liver and plasma endogenous levels of thiobarbituric acid-reactive substances and liver sensitivity to non-enzymatic lipid peroxidation. This was confirmed by a highly specific assay of lipid hydroperoxides using high performance liquid chromatography with chemiluminescence detection. The hepatic concentration of both phosphatidylcholine and phosphatidylethanolamine hydroperoxides decreased as the vitamin E content of the diet increased. The results show for the first time the capacity of vitamin E to protect against peroxidation of major phospho-lipids in vivo under basal unstressed conditions.     

Lipid peroxidation in the blood in pneumonia

In rabbits with pneumonia induced by introduction of a foreign body to the trachea, a correlation was found between the morphological features of pneumonia (the degree and spreading of alterative-exudative and proliferative processes) and lipid peroxidation in the blood (the concentration of diene conjugates in plasma lipids, catalase activity, the intensity of hydrogen-peroxide-stimulated chemiluminescence of plasma and erythrocytes).     

Spontaneous lung chemiluminescence upon paraquat administration

In vivo rat lung chemiluminescence was measured at different times after a single injection of either 30 or 60 mg paraquat/kg b.w. The lungs were isolated to determine myeloperoxidase (index of polymorphonuclear leukocytes), lung wet weight (lung edema) and malondialdehyde (lipid peroxidation). The highest chemiluminescence was reached 30 hours after injection of 30 mg/kg or 6 hours after a 60 mg/kg dose. The peak chemiluminescence was coincident with the maximum concentration of myeloperoxidase and lung wet weight suggesting that most chemiluminescence was the consequence of polymorphonuclear activation after migration to the injured areas.     

Plasma phosphatidylcholine hydroperoxide as a new marker of oxidative stress in alcoholic patients

Quantitative analysis of plasma phosphatidylcholine hydroperoxide (PCOOH) is an important step in evaluating the biochemical processes leading to oxidative injury. However, secondary products of lipid peroxidation are now used as indices. One hundred nine alcoholic patients, aged 22-81 years (mean +/- SEM, 52.0 +/- 1.3 years), and 21 healthy volunteers, aged 41-79 years (51.2 +/- 2.2 years), participated in this study. Plasma PCOOH was measured by HPLC with chemiluminescence detection. Plasma PCOOH concentration was significantly higher in alcoholic patients (46.1 +/- 4.1 pmol/ml) than in controls (15.6 +/- 1.8 pmol/ml). It was significantly higher in patients with blood alcohol (88.0 +/- 10.5 pmol/ml) than in those without alcohol (32.6 +/- 3.1 pmol/ml). The patients with high levels of aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase (gamma-GTP), and triglyceride (TG) showed significantly higher PCOOH concentrations than did patients with normal levels. The PCOOH level was positively correlated with levels of gamma-GTP, HDL, blood alcohol concentration, and TG. Plasma PCOOH levels in 29 alcoholic patients after a 6 week abstinence were decreased significantly (22.8 +/- 11.1 pmol/ml), which was associated with improvement on liver function tests. This is the first measurement of plasma PCOOH in alcoholic patients. These results suggest the involvement of lipid peroxidation in alcohol-induced liver damage and confirm that the PCOOH plasma concentration is a new marker of alcohol consumption as well as oxidative stress in alcoholic patients.     

鲍姆木层孔菌（桑黄）脂溶性提取物对PC12神经元细胞衰老的保护作用

鲍姆木层孔菌（桑黄）Phellinus baumii脂溶性提取物对叠氮钠诱导PC12神经元细胞衰老的保护作用。用叠氮钠作用于体外培养的PC12细胞,并用该菌脂溶性提取物对其进行保护,分别用MTT法、流式细胞仪法、细胞核染色法和β-半乳糖苷酶检测试剂盒检测细胞活力、早期凋亡率、晚期凋亡率和β-半乳糖苷酶阳性细胞率变化,筛选出具有延缓细胞衰老的有效部位和有效作用浓度。通过细胞活力检测发现正丁醇萃取的活性部位可以有效保护叠氮钠诱导的细胞活力下降,其有效工作浓度为200mg/L。流式细胞仪和细胞核染色测定结果均表     

Modification of human low-density lipoprotein by the lipid peroxidation product 4-hydroxynonenal

The effects of the lipid peroxidation product 4-hydroxynonenal on freshly prepared human low-density lipoprotein (LDL) were studied. At a fixed LDL concentration (5.7 mg/ml) the amount of 4-hydroxynonenal incorporated into the LDL increased with increasing aldehyde concentration from 28-30 (0.2 mM) to 140 (1 mM) mol per mol LDL, whereas at a fixed aldehyde concentration (0.2 mM) its incorporation into LDL decreased with increasing LDL concentration from 48 (1 mg LDL/ml) to 26 (12 mg LDL/ml) mol 4-hydroxynonenal bound per mol LDL. Of the total hydroxynonenal taken up 78% was bound to the protein and 21% to the lipid moiety; the remaining 1% was dissolved as free aldehyde in the lipid fraction. Amino acid analysis of the apolipoprotein B revealed that 4-hydroxynonenal attacks mainly the lysine and tyrosine residues and to a lesser extent also serine, histidine and cysteine. Treatment of LDL with 4-hydroxynonenal results in a concentration-dependent increase of the negative charge of the LDL particle as evidenced by its increased electrophoretic mobility. Moreover, 4-hydroxynonenal treatment leads to a partial conversion of the apolipoprotein B-100 into higher molecular weight forms most probably apolipoproteins B-126 and B-151. Compared to malonaldehyde, 4-hydroxynonenal exhibits a much higher capacity to modify LDL and it is therefore believed that this aldehyde is a more likely candidate for being responsible for LDL modification under in vivo lipid peroxidation conditions.     

Surfactant protein A inhibits the non-enzymatic lipid peroxidation of porcine lung surfactant.

The ability of surfactant protein A (SP-A) to inhibit the ascorbate-Fe(2+) induced lipid peroxidation of polyunsaturated fatty acids found in porcine lung surfactant (surfacen) was assessed by measuring the light emission - chemiluminescence during a 180-min incubation period at 37 degrees C. The light emission (chemiluminescence) was concentration dependent. Changes in the fatty acid composition of surfacen were observed when the lung surfactant was incubated in an ascorbate-Fe(2+) system. The main polyunsaturated fatty acids C18:2 n6 and C20:4 n6 found in the lung surfactant decreased considerably after a 180-min lipid peroxidation process. Native SP-A isolated from pig lungs inhibited oxidation of surfactant long chain polyunsaturated fatty acids, mainly arachidonic acid, in a dose-dependent fashion that was half-maximal (60% inhibition) at a concentration of 2.0 microg/ml and almost complete (73.6% inhibition) at 4.0 microg/ml, as indicated by inhibition of light emission and fatty acid composition analysis. At the highest concentration of lung SP-A used a very good correlation between the protection of the most polyunsaturated fatty acids and inhibition of light emission was observed.     

Lipid peroxidation and function of some antioxidant enzyme systems in corn and oats in acute injury by hydrogen fluoride

Experimental research showed the HF main harmful effect at the maximal exposure time (12 h). Intensity of chemiluminescence processes was enhanced almost in 1.5-fold. In the maize leaves the reduced chemiluminescence intensity was observed under the maximal toxicant concentration (1 mg/m3) effect, whereas the further growth of chemiluminescence intensity was observed in the oat plants. The total amount of the lipid peroxidation products was increased dependently on the toxicant concentration in all experimental variants. Changes in the studied enzymatic system activities were multidirected. Analysis of all activities dynamics for the SOD, GGTP, GST, GR and GP showed that GGTP and sometimes GP were involved more rapidly then SOD into the processes of detoxication of lipid peroxidation products and metabolites formed under the HF effect. However, the correlation between changes both in the SOD and GP activities failed to be found. The obtained data give a basis to conclude that during period between 8 and 12 h of HF exposure the essential changes in the activities of SOD and glutathione enzymatic systems took place as an adaptive response of plant cell to the investigated stress-factor impact.     

Lipid peroxidation and antioxidant enzymes in vanadate-treated rats

Male Wistar rats received an aqueous solution of ammonium metavanadate (AMV) of 0.15 mg/V/ml concentration instead of water for 14 days. The erythrocyte count and haemoglobin level in blood were not changed; the haematocrit index was slightly increased. The spontaneous lipid peroxidation in kidney and liver homogenates was increased. The Fe(II)- or ascorbate-induced lipid peroxidation was more pronounced in the kidney than in the liver. No changes in lipid peroxidation were observed in erythrocytes after AMV treatment. The AMV treatment resulted in a decrease in the activity of the antioxidant enzymes, catalase and glutathione peroxidase in the kidney and liver; the cytosolic Cu,Zn-SOD and mitochondrial Mn-SOD were unchanged. The activity of the enzymes in blood was not changed. The results are discussed with a view to the participation of lipid peroxidation in vanadium toxicity.     

Inhibition of the Fenton reaction by the protein caeruloplasmin and other copper complexes. Assessment of ferroxidase and radical scavenging activities

The copper-containing protein caeruloplasmin is an important biological extracellular protein. By catalysing the oxidation of ferrous ions to the ferric state (ferroxidase activity) it can inhibit lipid peroxidation and the Fenton reaction. This activity is readily destroyed by heat-denaturation. When a ferric-EDTA complex is added to hydrogen peroxide, OH X radicals are formed in a reaction inhibitable by superoxide dismutase (SOD). This reaction is also inhibited by caeruloplasmin both before and after heat-denaturation, suggesting a non-catalytic scavenging role for the protein. A combination of ferroxidase and radical scavenging activities in fluids containing iron complexes and hydrogen peroxide, but no SOD or catalase, would make caeruloplasmin an important extracellular antioxidant.     

Antioxidant effect of diethyldithiocarbamate on microsomal lipid peroxidation assessed by low-level chemiluminescence and alkane production

Different thiol-containing compounds, such as diethyldithiocarbamate (DDC), glutathione, penicillamine, and dithioerythritol have been chosen to study their effect on ascorbate/Fe-ADP-induced lipid peroxidation, detected by low-level chemiluminescence and alkane production. In the concentration range used, these thiols exerted a temporary protection against lipid peroxidation by lengthening the induction period; after overcoming this induction period, no substantial inhibition of either chemiluminescence or alkane production was observed. DDC was effective in protecting against lipid peroxidation in the nanomolar range, whereas the group of other thiol-containing molecules operated in the millimolar range.     

Complement-component-C3-opsonized immunoglobulin G anti-DNA antibodies do not bind effectively to red blood cells unless aggregated on a high-Mr DNA matrix.

The significance of microsomal vitamin E in protecting against the free-radical process of lipid peroxidation was evaluated with the low-level-chemiluminescence technique in microsomal fractions from vitamin E-deficient and control rats. The induction period that normally precedes the ascorbate/ADP/Fe3+-induced lipid peroxidation was taken as reflecting the microsomal vitamin E content and was found to be 5-6-fold decreased in microsomal fractions from vitamin E-deficient rats. Supplementation of microsomal fractions from vitamin E-deficient rats with exogenous vitamin E partially restores the induction period observed in that from control rats. The decrease in chemiluminescence intensity and the increase in the induction period both correlate linearly with the amount of vitamin E added. However, the efficiency of exogenous vitamin E is about 50-fold lower than that exerted by the naturally occurring vitamin E in microsomal membranes. These observations are discussed in terms of the process of re-incorporation of vitamin E into membranes, the experimental model for lipid peroxidation selected, and the method to evaluate lipid peroxidation, namely low-level chemiluminescence.     

Detection of chemiluminescence in lipid peroxidation of biological systems and its application to HPLC

A combined system of chemiluminescence detection and high performance liquid chromatography (CL–HPLC) was developed to determine primary peroxidation products in biological tissues, such as phosphatidylcholine hydroperoxide (PCOOH). The CL–HPLC assay consists of separation of lipid classes with HPLC and detection of hydroperoxide-specific chemiluminescence. Hydroperoxides react with heme compounds to produce oxidants as suggested by our early studies on tissue low-level chemiluminescence in which singlet molecular oxygen is generated as one of the excited species in several biological systems involving free radical events. In the CL–HPLC method, a cytochrome c–luminol mixture was used as a hydroperoxide-specific luminescent reagent, and the quantification of hydroperoxide was performed by detecting chemiluminescence due to the luminol oxidation caused by the oxidant produced during the lipid hydroperoxides with heme. The detection limit of PCOOH was 10 pmole hydroperoxide–O₂. PCOOH in normal human blood was found to be 10–500 pmol/ml plasma and significantly higher levels of PCOOH were observed in some hospitalized patients.     

Oxidative stress of liver in hamsters infected with Leishmania (L.) chagasi

Oxidative stress as a mediator of hepatic tissue damage concurrent with Leishmania (L.) chagasi infection was investigated. Chemiluminescence in liver supernatant of hamsters infected with Leishmania (L.) chagasi showed a ratio of 1.53/ mg protein and 2.10/liver weight 90 days after infection when compared with the control. The malondialdehyde (MDA) levels also increased significantly both with and without addition of Fe3+/ascorbic acid in the reaction mixture, with a ratio of 2.12 and 1.55/mg protein or 2.91 and 2.12/liver weight, respectively. The parasite burden in the spleen, as a measure of infection severity, was 9.1+/-1.33 x 10(8) parasites/organ. On the 10th day of infection, the chemiluminescence also was significantly higher in infected hamsters than in the controls (ratio = 1.36/mg protein or 1.34/liver weight); however, the MDA levels were not different from those of controls. After 90 days of infection, significant correlations were observed between chemiluminescence and MDA concentration with and without the presence of Fe3+/ascorbic acid (r = 0.54, P = 0.0001; r = 0.56, P = 0.0001; respectively). The high infection/control ratio of both chemiluminescence and MDA concentration and the significant correlation between those events strongly indicate the occurrence of oxidative stress and lipid peroxidation as a mechanism of liver damage in cases of chronic infection by L. chagasi. The significant increase in chemiluminescence at 10 days of infection demonstrates that oxidative stress occurs very early, first consuming the antioxidants and then inducing lipid peroxidative damage later in the chronic stage of this disease.     

Hypoglycemic effect of methanol extract of Phyllanthus amarus Schum & Thonn on alloxan induced diabetes mellitus in rats and its relation with antioxidant potential

Methanolic extract of P. amarus was found to have potential anti-oxidant activity as it could inhibit lipid peroxidation, and scavenge hydroxyl and superoxide radicals in vitro. The amount required for 50% inhibition of lipid peroxide formation was 104 microg/ml and the concentrations needed to scavenge hydroxyl and superoxide radicals were 117 and 19 microg/ml respectively. The extract was found to reduce the blood sugar in alloxan diabetic rats at 4th hr by 6% at a dose level of 200 mg/kg body wt and 18.7% at a concentration of 1000 mg/kg body wt. Continued administration of the extract for 15 days produced significant (P < 0.001) reduction in blood sugar. On 18th day after alloxan administration values were almost similar to normal in the group taking 1000 mg/kg body wt.