Protective Effects of Tea Polyphenol on Cerebral Ischemia-Reperfusion Injury in Rats and Its Scavenging Oxy-radical and Anticerebral Lipid Peroxidation Effects

AIM To study the protective effects of tea polyphenol (TP) on cerebral ischemia reperfusion injury in rats and its scavenging oxygen free radical(OFR) activities and antilipid peroxidation in vitro . METHODS Cerebral ischemia reperfusion injury was produced by bilateral ligation of the common carotid arteries with vagus nerves and reperfusion for 45 min. The mitochondrial lipid peroxidation of rat brain induced by oxygen free radical was measured by thiobarbituric acid spectrophotometry. Superoxide anion (O 2) from xanthine xanthine oxidase system and hydroxyl radical (·OH) from Fe 2+ -H 2O 2 system were determined with spectrophotometry. RESULTS During Cerebral ischemia reperfusion,TP improved the activities of superoxide dismutase ( P 【0 05), GSH peroxidase( P 【0 01) and catalase( P 【0 01), while decreasing the maiondialdchyde content in the brain( P 【0 05) and brain water content ( P 【0 01). Tea polyphenol possessed significantly scavenging effects on ·OH produced by Fenton reaction and O 2 produced by xanthine xanthine oxidase system (the IC 50 were 2 2 mmol·L -1 and 1 9 mmol·L -1 respectively). Tea polyphenol could significant inhibit the lipid peroxidation of cerbral mitochondrial membrane induced by ·OH in a concentration dependent manner. CONCLUSION The results indicate that tea polyphenol could protect the injury on cerebral ischemia reperfusion in rats for OFR, these effects may be related to its scavenging effects on oxygen free radicals and antilipid peroxidant.

Study on Antioxidants and Lipid Peroxidation from Pea Crops of Platean

[ Objective] The aim of this study was to discuss the effect of antioxidants and lipid peroxidation from pea crops of plateau. [ Method] SOD enzyme liquid from pea crops of plateau was extracted by means of protein concentration assay, enzyme activity assay and antioxidant activity determination by DPPH method, peroxide activity inhibition of in vitro tissues from mice by homogenate MDA colorimetry method and lipid peroxidation assay of in vitro tissues. [ Result ] IC50 of the crude enzyme liquid extracted from pea on DPPH was 55.16 mg/L, while the scavenging rate of the crude enzyme liquid was lower than that of ascorbic acid, tea polyphenol and citric acid with the same concentration. The synergistic effect was found in ascorbic acid and crude enzyme liquid, but the synergism of ascorbic acid was better than that of citric acid. IC50 of SOD enzyme liquid extracted from pea on DPPH was 11.1 mg/L, which was better than that of tea polyphenol and closely similar to that of ascorbic acid. SOD enzyme liquid extracted from pea had an inhibitory effect on MDA production from in vitro tissues such as liver, kidney and heart, especially for a significantly inhibitory effect on MDA from liver in vitro. When the concentration was 0.25 mg/ml, the inhibition rate reached 78.3%, and then the inhibition rate increased little with the concentration incresas, while its effect on heart and kidney were inferior. [ Conclusion] SOD crude enzyme liquid and SOD enzyme liquid extracted from pea all have certain DPPH scavenging capacity, while SOD enzyme liquid extracted from pea has an inhibitory effect on lipid peroxidation.

Oxidative stress and damage induced by abnormal free radical reactions and IgA nephropathy

Objective: To estimate the oxidative stress and oxidative damage induced by abnormal free radical reactions in IgA nephropathy (IgAN) patients' bodies. Methods: Seventy-two IgA N patients (IgANP) and 72 healthy adult volunteers (HAV) were enrolled in a random control study design, in which the levels of nitric oxide (NO) in plasma, lipoperoxide (LPO) in plasma and in erythrocytes, and vitamin C (VC), vitamin E (VE) and β-carotene (β-CAR) in plasma as well as the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in erythrocytes were determined with spectrophotometric mothods. Results: Compared with the HAV group, the averages of NO in plasma, and LPO in plasma and in erythrocytes in the IgANP group were significantly increased (P＜0.0001), while those ofVC, VE and β-CAR in plasma as well as those of SOD, CAT and GPX in erythrocytes in the IgANP group were significantly decreased (P＜0.0001). Linear correlation analysis showed that with the increase of the values of NO, and LPO in plasma and in erythrocytes, and with the decrease of those ofVC, VE, β-CAR,SOD, CAT and GPX in the IgAN patients, the degree of histological damage of tubulointerstitial regions was increased gradually (P＜0.0001); and that with the prolongation of the duration of disease the values of NO, and LPO in plasma and erythrocytes were increased gradually, while those of VC, VE, β-CAR, SOD, CAT and GPX were decreased gradually (P＜0.005). The discriminatory correct rates of the above biochemical parameters reflecting oxidative damage of the IgAN patients were 73.8%-92.5%, and the correct rates for the HAV were 70.0%-91.3% when independent discriminant analysis was used; and the correct rate for the IgAN patients was increased to 98.8%, the correct rate for the HAV was increased to 100% when stepwise discriminant analysis was used. The above biochemical parameters' reliability coefficient (alpha) were used to estimate the oxidative damage of the IgAN patients as 0.8145, the standardized item alpha=0.9730, F=53273.5681, P＜0.0001. Conclusions: A series of free radical chain reactions caused serious pathological aggravation in the IgANP' bodies, thus resulting in oxidative damage in their bodies. In treating IgANP, therefore, it is necessary that suitable dose antioxidants should be supplemented to them so as to alleviate the oxidative damage in their bodies.

Lipid peroxidation and antioxidant status in colorectal cancer

AIM: Reactive oxygen species (ROS) can induce carcinogenesis via DNA injury. Both enzymatic and non-enzymatic parameters participate in cell protection against harmful influence of oxidative stress. The aim of the present study was to assess the levels of final lipid peroxidation products like malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4-HNE) in primary colorectal cancer. Moreover, we analysed the activity of main antioxidative enzymes, superoxide dismutase (Cu, Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GSSRG-R) and the level of non-enzymatic antioxidants (glutathione, vitamins C and E). METHODS: Investigations were conducted in 81 primary colorectal cancers. As a control, the same amount of sample was collected from macroscopically unchanged colon regions of the most distant location to the cancer. Homogenisation of specimens provided 10% homogenates for our evaluations. Activity of antioxidant enzymes and level of glutathione were determined by spectrophotometry. HPLC revealed levels of vitamins C and E and served as a method to detect terminal products of lipid peroxidation in colorectal cancer. RESULTS: Our studies demonstrated a statistically significant increase in the level of lipid peroxidation products (MDA-Adc. muc.-2.65±0.48 nmol/g, Adc.G3-2.15±0.44 nmol/g, clinical IV stage 4.04±0.47 nmol/g, P<0.001 and 4-HNE-Adc.muc. -0.44±0.07 nmol/g, Adc.G3-0.44±0.10 nmol/g, clinical IV stage 0.52±0.11 nmol/g, P<0.001) as well as increase of Cu,Zn-SOD (Adc.muc.-363±72 U/g, Adc.G3-318?8 U/g, clinical IV stage 421±58 U/g, P<0.001), GSH-Px (Adc.muc. -2143±623 U/g, Adc.G3-2005±591 U/g, clinical IV stage 2467±368 U/g, P<0.001) and GSSG-R (Adc.muc.-880±194 U/g, Adc.G3-795±228 U/g, dinical IV stage 951±243 U/g, P<0.001) in primary tumour comparison with normal colon (MDA-1.39±0.15 nmol/g, HNE-0.29±0.03 nmol/g, Cu, Zn-SOD-117±25 U/g, GSH-Px-1723±189 U/g, GSSG-R-625±112 U/g) especially in mucinous and G3-grade adenocarcinomas as well as clinical IV stage of colorectal cancer. We also observed a decrease of CAT activity (Adc.muc. -40±14 U/g, clinical IV stage 33±18 U/g vs 84±17 U/g, P<0.001) as well as a decreased level of reduced glutathione (clinical IV stage 150±48 nmol/g vs 167±15 nmol/g, P<0.05) and vitamins C and E (vit. C-clinical IV stage 325±92 nmol/g vs 513?4 nmol/g, P<0.001; vit. E-clinical IV stage 13.3±10.3 nmol/g vs 37.5±5.2 nmol/g). CONCLUSION: Colorectal carcinogenesis is associated with serious oxidative stress and confirms that gradual advancement of oxidative-antioxidative disorders is followed by progression of colorectal cancer.

Synthesis of two new thiazolidines and their hepatoprotective effects

Two new 2-substituted thiazolidine-4（R）-carboxylic acids （TCAs）, 2-glusosaminal-TCA （GIcNH2Cys） and 2-N-acetyl-glueosanlinal-TCA （GlcNAeCys）, were synthesized. Their protective effects against liver toxicity induced by acetaminophen （APAP） were investigated in a mice model. The resuits demonstrate that administration of TCAs （ i. p. , 800 mg/kg） 30 min after APAP challenge efficiently decrease ALF, AST, and LDH levels in liver. GlcNAcCys shows the best proteetive eftects, decreasing ALT, AST and LDH levels to 63%, 18.4% and 37% of the APAP group respectively. Comparison with the control showed that APAP greatly decreases total sulfhydlyl （T-SH） levels （43%）, non-protein hound sulfhydryl （NP-SH） levels （50%） and total antioxidative capabilities （57%） in the liver 24 hr after challenge. TCAs treatments 30min after APAP challenge significantly elevate sulfhydryl levels and total antioxidative capabilities. APAP administration also markedly （P 〈 0.05） increases liver lipid peroxidation to 1.65 and 1.17 times that of the control 4 hr and 24 hr after APAP administration respectively. TCAs treatments can inhibit lipid peroxidation as measured by decreased malondialdehyde （MDA） contents in liver. The histopathological results also further confirm the hepatoprotective effects of TCAs. In conclusion, our data show that TCAs, GleNAcCys particularly, have hepatoprotective anti antioxidant etfects.

Characterization and Biological Activities of Protein-Bound Polysaccharides Produced by Cultures of Pleurotus ostreatus

Several species of mushrooms, as Pleurotus ostreatus, have been valued as edible and medicinal resources. These mushrooms may be an important source of polysaccharides with medicinal properties as antioxidant, antitumoral, antimicrobial and immunological properties. The aim of this work was to produce and to evaluate the biological properties of protein-bound polysaccharide complexes, extra intracellular （E-PPS and I-PPS）, extracted from P. ostreatus cultures, using agricultural sunflower wastes as carbon source. Three main compounds in the E-PPS and four main compounds in the I-PPS were identified by SEC-UV-RI-HPLC. These complexes of P. ostreatus present no toxicity in Artemia salina cultures, after 24 h of incubation. Antioxidant properties of the complexes were evaluated by radical scavenging activity using DPPH method and lipid peroxidation inhibition capacity, determined by erytbsocytes hemolysis. Additionally, E-PPS and I-PPS extracts revealed capacity to mimetize superoxide dismutase and catalase enzymatic activities. The hepatoprotector effect of E-PPS extracts in Wistar rats was evaluated by AST, ALT, ALP and y-GT activities, showing capacity to reduce the liver damage induced by ethanol-administration. This hepatoprotective effect is equivalent to that observed by silymarin, a standard drug. Our results suggests that the extracts of E-PPS and I-PPS produced by P. ostreatus cultures, using agricultural sunflower wastes as main carbon source, can be used as an important source of bioactive compounds with potential medicinal value.

Efficacy of Betel Leaf Extracts as Antioxidant in Moisturizing Cream

This work aims to study the appropriate method for extract Betel leaf as crude extracts to prepare as a natural antioxidant in moisturizing hand cream. Betel leaf was treated by 7 methods and the optimized method was selected for preparation of Betel leaf extract. The fresh Betel leaf and dried Betel leaf were used in this study. Betel leaf extracts were analysed for total phenolic content and essential oil as eugenol content. Then Betel leaf extracts were used as the one component for moisturizing hand cream. The lipid oxidation was evaluated by measurement on malondialdehyde content. The results revealed that an extracts solution from dried Betel leaf contained total phenolic content and eugenol content more than flesh Betel leaf. The ethanol extraction method was the optimum method since this method showed the maximum total phenolic content and eugenol content in dried Betel leaf as 5.26 g/100 g and 138.95 mg/100 g, respectively. The moisturizing creams were formulated by using crude Betel leaf extracts as the one composition compare with base cream （no addition of Betel leaf extracts）. The moisturizing cream samples were analysed for malondialdehyde. its showed that the cream that contained Betel leaf extract contained malondialdehyde content lower than in cream base. Thus, crude extracts from Betel leaf showed the efficacy to reduce lipid oxidation reaction in moisturizing hand cream.