Protective effects of fermented filtrate from Antrodia camphorata in submerged culture against CCl4-induced hepatic toxicity in rats

The protective effects and the possible mechanisms of dry matter of fermented filtrate (DMF) from Antrodia camphorata in submerged culture (ACSC) on H(2)O(2)-induced cytotoxicity in HepG2 and carbon tetrachloride (CCl(4))-induced hepatotoxicity in Sprague-Dawley rats were investigated. The results showed that the inhibitory effect of DMF and its crude triterpenoids on lipid peroxidation occurred in a dose-response manner in an AAPH/linoleic acid system. When HepG2 cells were pretreated with DMF at the concentration of 0.10 mg/mL for 4 h and then induced by 1 h of treatment with H(2)O(2) (100 microM), lipid peroxidation was significantly (p < 0.05) decreased, as measured by the formation of malondialdehyde. The oral pretreatment with DMF [0.25 and 0.50 mg/kg of body weight (bw)] for 5 consecutive days prior to the administration of a single dose of 40% CCl(4) (0.10 mL/100 g of bw, ip) significantly prevented the increase in serum levels of hepatic enzyme markers (alanine and aspartate aminotransferase) and liver lipid peroxidation (p < 0.05). Histopathological evaluation of the rat liver revealed that DMF reduced the incidence of liver lesions, including neutrophil infiltration, hydropic swelling, and necrosis induced by CCl(4) in rats. Moreover, reduced glutathione (GSH)-dependent enzymes (glutathione peroxidase, glutathione reductase, and glutathione S-transferase) and the GSH/GSSG ratio were significantly improved in the oral pretreatment DMF of rats (p < 0.01). The results suggest that DMF may play a role in preventing oxidative damage in living systems by up-regulating hepatic GSH-dependent enzymes to preserve the normal GSH/GSSH ratio and scavenging free radicals formed during CCl(4) metabolism.     

Blackberry extract attenuates oxidative stress through up-regulation of Nrf2-dependent antioxidant enzymes in carbon tetrachloride-treated rats

The aim of this study was to investigate the protective ability of blackberry extract (BE) against oxidative stress in carbon tetrachloride (CCl(4))-treated rats. The results showed that treatment with BE attenuated lipid peroxidation that was increased by CCl(4) and also markedly recovered the activity of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR), that were decreased by CCl(4). BE also elevated the protein expression levels of NF-E2-related factor-2 (Nrf2), CuZnSOD, MnSOD, GPx-1/2, and heme oxygenase-1 (HO-1), but not that of catalase. Furthermore, the administration of BE significantly attenuated the levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) that were increased by CCl(4). Therefore, the present study suggests that BE possesses significant protective effects against in vivo oxidative stress.     

Hepatoprotective effects of 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone on CCl4-induced acute liver injury in mice

In this paper, the hepatoprotective effects of 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) on CCl(4)-induced acute liver injury in Kunming mice were investigated. DMC was administered intraperitoneally (ip) (5, 10, or 20 mg/kg of body weight) for 7 days prior to the administration of CCl(4) (0.1%, ip). Pretreatment with DMC significantly decreased activities of serum hepatic enzymes, namely alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase, γ-glutamyl transferase, and total bilirubin, and decreased the elevation of lipid peroxidation, malondialdehyde, reactive oxygen species, and protein carbonyl content. Pretreatment with DMC markedly increased activities of enzymatic antioxidants such as superoxide dismutase, catalase, glucose-6-phosphate dehydrogenase, glutathione peroxidase, glutathione S-transferase, and glutathione reductase and increased levels of nonenzymatic antioxidant markers such as reduced glutathione, total sulfhydryl groups, vitamin C, and vitamin E in liver. These results combined with liver histopathology demonstrate that DMC has potential hepatoprotective effects, which may be related to the attenuation of oxidative stress, accelerating the antioxidant cascade and inhibition of lipid peroxidation.     

Antioxidant activity of vinegar produced from distilled residues of the Japanese liquor shochu

Rice shochu distilled residue (RSDR) is a byproduct of rice shochu production. RSDR was converted into vinegar by acetate fermentation. In our present study, two major antioxidant compounds, tyrosol and ferulic acid, were identified from the RSDR-derived vinegar. Furthermore, we investigated the antioxidant activity of freeze-dried RSDR-derived vinegar, which was Acetobactor aceti fermentation powder (AFP), in vitro and in vivo. AFP at 0.25 mg/mL or higher concentrations showed an inhibitory effect against lipid peroxidation and cellular GSH depletion in HepG2 cells induced by H(2)O(2) (P < 0.05). We thus considered the potential of AFP in protecting cells against damage induced by H(2)O(2). Its antioxidant activity was evaluated in vivo using carbon tetrachloride (CCl(4))-induced acute liver injury mouse models. Five consecutive days of oral preadministration of AFP dissolved in PBS at 200, 400, and 800 mg/kg body weight significantly suppressed lipid peroxidation in the liver induced by CCl(4) (P < 0.01). Consequently, treatment with AFP at 200 mg/kg body weight or higher doses suppressed the elevation of alanine aminotransferase and aspartate aminotransferase levels in serum (P < 0.05). These findings suggest that RSDR-derived vinegar can be developed as a health food with an antioxidant effect for the prevention of oxidative injury and cancer.     

Chemical composition and hepatoprotective effects of polyphenol-rich extract from Houttuynia cordata tea

This study was designed to investigate the antioxidant activity, hepatoprotective effect, and phenolic composition of the ethyl acetate fraction (EAF) extracted from Houttuynia cordata tea. EAF was shown to exhibit strong ferric-reducing antioxidant power (FRAP) and scavenging activity against DPPH radical in vitro, and the antioxidant effects were further verified by suppressing CCl?-induced oxidative stress in mouse liver at three tested doses of EAF (250, 500, and 1000 mg/kg bw). Pretreatment with EAF (1000 mg/kg bw) prior to CCl? administration significantly (p < 0.001) decreased the CCl?-elevated levels of serum AST, ALT, alkaline phosphatase, total bilirubin, and hepatic MDA in mice and prevented the increases in GSH, SOD, and CAT caused by CCl?. HPLC analysis revealed that three predominantly polyphenolic compounds present in EAF were quercitrin (111.7 μg/mg), quercetin (43.8 μg/mg), and hyperoside (29.1 μg/mg). These results combined with liver histopathology indicate that EAF possesses a significant protective effect against acute hepatotoxicity induced by CCl?, which may be due to the strong antioxidant activity of phenolic components.     

Antioxidant activity and protective effect of anthocyanin oligomers on H₂O₂-triggered G2/M arrest in retinal cells

In this study, the free-radical-scavenging properties of anthocyanin oligomers for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, alkyl radical, and hydroxyl radical were evaluated using electron spin resonance (ESR) spectroscopy. The DPPH radical, alkyl radical, and hydroxyl radical scavenging activity of anthocyanin oligomers increased in a dose-dependent manner, with the 50% inhibitory concentration (IC??) value of 13.0, 14.0, and 448.0 μg/mL, respectively. The inhibitory effect of anthocyanin oligomers on lipid peroxidation was examined with ferric thiocyanate (FTC) and thiobarbituric acid (TBA). The inhibitory activity of anthocyanin oligomers was found to be comparable to that of vitamin E. In addition, anthocyanin oligomers enhanced the activities of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), glutathione peroxidase (GPx, EC 1.11.1.9), and glutathione-S-transferase (GST, EC 2.5.1.18) in ARPE-19 cells. In addition, anthocyanin oligomers inhibited the H?O?-induced G2/M phase arrest in ARPE-19 cells. Taken together, the present results demonstrate that anthocyanin oligomers have high antioxidative activity.     

Antioxidant activities of grape (Vitis vinifera) pomace extracts

Antioxidant-rich fractions were extracted from grape (Vitis vinifera) pomace using ethyl acetate, methanol, and water. The extracts were screened for their potential as antioxidants in different models. The ethyl acetate, methanol, and water extracts showed 76, 87.1, and 21.7% antioxidant activities at 100 ppm, respectively, using the 1,1-diphenyl-2-picrylhydrazyl model system. As the methanol extract of grape pomace showed maximum antioxidant activity among all of the extracts, it was selected to determine its effect on lipid peroxidation, hydroxyl radical scavenging activity, and human low-density lipoprotein (LDL) oxidation. The methanol extract showed 71.7, 73.6, and 91.2% inhibition using the thiobarbituric acid method, hydroxyl radical scavenging activity, and LDL oxidation, respectively, at 200 ppm. Treatment of albino rats of the Wistar strain with a single dose of CCl(4) at 1.25 mL/kg of body weight decreases the activities of catalase, superoxide dismutase (SOD), and peroxidase by 81, 49, and 89%, respectively, whereas the lipid peroxidation value increased nearly 3-fold. Pretreatment of the rats with the methanolic extract of grape pomace at 50 mg/kg (in terms of catechin equivalents) followed by CCl(4) treatment causes restoration of catalase, SOD, and peroxidase by 43.6, 73.2, and 54%, respectively, as compared with control, whereas lipid peroxidation was restored to values comparable with the control. Histopathological studies of the liver of different groups also support the protective effects exhibited by the methanol extract of grape pomace by restoring the normal hepatic architecture. Owing to this property, the studies on grape pomace can be further extended to exploit its possible application for the preservation of food products as well as a health supplement and neutraceutical.     

Studies on antioxidant activity of pomegranate (Punica granatum) peel extract using in vivo models

Pomegranate (Punica granatum) peel extracts have been shown to possess significant antioxidant activity in various in vitro models. Dried pomegranate peels were powdered and extracted with methanol for 4 h. The dried methanolic extract was fed to albino rats of the Wistar strain, followed by carbon tetrachloride (CCl4), and the levels of various enzymes, such as catalase, peroxidase, and superoxide dismutase (SOD), and lipid peroxidation were studied. Treatment of rats with a single dose of CCl4 at 2.0 g/kg of body weight decreases the levels of catalase, SOD, and peroxidase by 81, 49, and 89% respectively, whereas the lipid peroxidation value increased nearly 3-fold. Pretreatment of the rats with a methanolic extract of pomegranate peel at 50 mg/kg (in terms of catechin equivalents) followed by CCl4 treatment causes preservation of catalase, peroxidase, and SOD to values comparable with control values, wheres lipid peroxidation was brought back by 54% as compared to control. Histopathological studies of the liver were also carried out to determine the hepatoprotection effect exhibited by the pomegranate peel extract against the toxic effects of CCl4. Histopathological studies of the liver of different groups also support the protective effects exhibited by the MeOH extract of pomegranate peel by restoring the normal hepatic architecture.     

Protective effect of Mesona procumbens against tert-butyl hydroperoxide-induced acute hepatic damage in rats

The protective effect of Hsian-tsao (Mesona procumbens Hemsl.) and its active compounds on liver damage was evaluated using the model of tert-butyl hydroperoxide (t-BHP)-induced acute hepatic damage in rats. Male Sprague-Dawley rats (200 +/- 10 g) were orally pretreated with a water extract of Hsian-tsao (WEHT) (0.1, 0.5, and 1.0 g/kg) or caffeic acid (0.1 g/kg of body weight) for 13 days before a single dose of t-BHP (0.2 mmol/kg, intraperitoneally) to each animal, and the rats were sacrificed 18 h later by decapitation; blood samples were collected for the assays of serum biochemical values. The livers were excised from the animals and assayed for oxidative injury, antioxidant enzyme, and pathological histology. The result showed that the oral pretreatment of WEHT (0.1, 0.5, and 1.0 g/kg) or caffeic acid (0.10 g/kg) before t-BHP (0.2 mmol/kg) treatment significantly lowered the serum levels of the hepatic enzyme markers (alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase) and reduced oxidative stress of the liver by evaluation of malondialdehyde, glutathione, 8-hydroxy-2'-deoxyguanosine, glutathione peroxidase, and glutathione reductase. The histopathological evaluation of the rat livers showed that WEHT and caffeic acid reduced the incidence of liver lesions including cloudy swelling, pyknosis, and cytolysis induced by t-BHP in rats. On the basis of the results of this study, it can be speculated that M. procumbens protects liver against t-BHP-induced hepatic damage in rats.     

Antioxidant activity of extracts from Acacia confusa bark and heartwood.

The antioxidant activity of extracts from bark and heartwood of Acacia confusa was evaluated by various antioxidant assays, including free radical and superoxide radical scavenging assays and lipid peroxidation assay as well as hydroxyl radical-induced DNA strand scission assay. In addition, an ex vivo antioxidant assay using a flow cytometric technique was also employed in this study. The results indicate that both bark and heartwood extracts clearly have strong antioxidant effects. Similar inhibitory activities for each test sample were found for both 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical generation and lipid peroxidation. As for the superoxide radical scavenging activity, the heartwood extract was more effective than the bark extract. Furthermore, the heartwood extract protected PhiX174 supercoiled DNA against strand scission induced by ultraviolet photolysis of H2O2, and it reduced the amounts of intracellular hydrogen peroxide, a reactive oxygen species, when it was co-incubated with human promyelocytic leukemia (HL-60) cells under oxidative stress.     

Walnut polyphenols prevent liver damage induced by carbon tetrachloride and d-galactosamine: hepatoprotective hydrolyzable tannins in the kernel pellicles of walnut

The polyphenol-rich fraction (WP, 45% polyphenol) prepared from the kernel pellicles of walnuts was assessed for its hepatoprotective effect in mice. A single oral administration of WP (200 mg/kg) significantly suppressed serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) elevation in liver injury induced by carbon tetrachloride (CCl 4), while it did not suppress d-galactosamine (GalN)-induced liver injury. In order to identify the active principles in WP, we examined individual constituents for the protective effect on cell damage induced by CCl 4 and d-GalN in primary cultured rat hepatocytes. WP was effective against both CCl 4- and d-GalN-induced hepatocyte damages. Among the constituents, only ellagitannins with a galloylated glucopyranose core, such as tellimagrandins I, II, and rugosin C, suppressed CCl 4-induced hepatocyte damage significantly. Most of the ellagitannins including tellimagrandin I and 2,3- O-hexahydroxydiphenoylglucose exhibited remarkable inhibitory effect against d-GalN-induced damage. Telliamgrandin I especially completely suppressed both CCl 4- and d-GalN-induced cell damage, and thus is likely the principal constituent for the hepatoprotective effect of WP.     

Effect of long-term dietary administration of oregano on the alleviation of carbon tetrachloride-induced oxidative stress in rats

This study aimed at evaluating the protective effect of long-term dietary oregano on the alleviation of carbon tetrachloride-induced oxidative stress in rats. Twenty-four female Wistar rats were allocated to four groups of six animals each. Groups 1 (control) and 2 (CCl 4) were fed a basal diet, while groups 3 (oregano) and 4 (oregano + CCl 4) were fed the basal diet supplemented further with ground oregano at 1% level. Following six-week feeding, the rats of groups 2 and 4 were given a single intraperitoneal injection of CCl 4 at a dose of 1 mL/kg bw. Six hours after the CCl 4 injection, all animals were sacrificed, and serum, liver, kidney, and heart tissue samples were collected. Analysis results showed that the addition of oregano significantly increased the total phenolic content and the Trolox equivalent antioxidant capacity of the basal diet but had no effect on its lipid peroxidation index. Treatment with CCl 4 of rats from the CCl 4 group caused a significant increase in aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) in serum, whereas it decreased cholesterol and triglyceride content as compared to the control. It also increased the lipid peroxidation index and decreased the scavenging activities of the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS) radical cation, the hydroxyl anion radical, the superoxide anion radical, and the hydrogen peroxide in all tested tissues, as compared to that of the control. Without CCl 4 treatment, diet supplementation with oregano had no effect on these biochemical parameters, excluding the hydroxyl radical scavenging activity, which was increased in all tested tissues as compared to that of the control. Feeding oregano before CCl 4 treatment resulted in a significant decline of the increase in AST, ALT, and ALP activities ( P < 0.05 vs CCl 4 group), but the recorded values could not attain those of the control group ( P < 0.05 vs control group). It significantly increased the reduced cholesterol and triglycerides ( P < 0.05 vs CCl 4 group) to values not differing from those of the control. It also resulted in a significant reduction of the increased malondialdehyde ( P < 0.05 vs CCl 4 group) to values that could not attain the levels of the control but had no significant effect ( P > 0.05) on the reduced ABTS radical cation scavenging activity. It increased significantly the reduced hydroxyl anion radical scavenging activity ( P < 0.05 vs CCl 4 group) to values that could not attain those of the control in all tested tissues except kidney. Additionally, it resulted in a significant elevation of the decreased superoxide anion radical scavenging activity in serum and liver but had no effect in kidney and heart, whereas it also resulted in a significant elevation of the decreased hydrogen peroxide scavenging activity in liver, kidney, and heart but had no effect in serum. These results suggest that dietary oregano may effectively improve the impaired antioxidant status in CCl 4-induced toxicity in rats.     

Neuroprotective Effects of Longan ( Dimocarpus longan Lour.) Flower Water Extract on MPP(+)-Induced Neurotoxicity in Rat Brain

In this study, the neuroprotective effect of Dimocarpus longan Lour. flower water extract (LFWE) was investigated. First, an in vitro study showed that LFWE concentration-dependently inhibited lipid peroxidation of brain homogenates incubated at 37 °C. The antioxidative activity of LFWE was more potent than that of glutathione or Trolox. Furthermore, an ex vivo study found that the basal lipid peroxidation (0 °C) and lipid peroxidation incubated at 37 °C were lower in the brain homogenates of LFWE-treated (500 mg/day) rats, indicating that the brain of LFWE-treated rats was more resistant to oxidative stress. Moreover, a Parkinsonian animal model was employed to demonstrate that oral administration of LFWE (125-500 mg/kg/day) dose-dependently attenuated 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity in the nigrostriatal dopaminergic system of rat brain. In conclusion, this study suggests that LFWE is antioxidative, anti-inflammatory, and anti-apoptotic. Furthermore, oral administration of LFWE appears to be useful in preventing and/or treating central nervous system neurodegenerative diseases, including Parkinsonism.     

Antioxidant properties of Antrodia camphorata in submerged culture

The biologically active compounds, antioxidant activities, and free radical scavenging effects of dry matter of cultural medium (DMCM), filtrate (DMF), and different solvent extracts of mycelia from Antrodia camphorata in submerged culture (ACSC) were investigated. DMF showed the strongest inhibition of lipid peroxidation as a function of its concentration, and was comparable to the antioxidant activity of BHA at the same concentration of 0.2 mg/mL. The hexane extract of mycelia had the weakest antioxidant ability, whereas other mycelial extracts exhibited a modest inhibition of lipid peroxidation. DMF and water extract of mycelia (WEM) showed marked activity in free radical scavenging. The antioxidant activities of filtrate and mycelial extracts were correlated with the presence of total polyphenols, the crude triterpenoids, and the protein/polysaccharide ratio of the crude polysaccharides. It was found that DMCM had lower antioxidant ability than DMF in different model systems, indicating that the major antioxidant components in DMF must be derived from the secondary metabolites of mycelia. The results presented herein indicate that DMF could possibly act as a chemopreventing agent with respect to free radical-related diseases.     

Isolation of an in vitro and ex vivo antiradical melanoidin from roasted barley

The antiradical properties of water-soluble components of both natural and roasted barley were determined in vitro, by means of DPPH* assay and the linoleic acid-beta-carotene system, and ex vivo, in rat liver hepatocyte microsomes against lipid peroxidation induced by CCl4. The results show the occurrence in natural barley of weak antioxidant components. These are able to react against low reactive peroxyl radicals, but offer little protection against stable DPPH radicals deriving from peroxidation in microsomal lipids. Conversely, roasted barley yielded strong antioxidant components that are able to efficiently scavenge free radicals in any system used. The results show that the barley grain roasting process induces the formation of soluble Maillard reaction products with powerful antiradical activity. From roasted barley solution (barley coffee) was isolated a brown high molecular mass melanoidinic component, resistant to acidic hydrolysis, that is responsible for most of the barley coffee antioxidant activity in the biosystem.     

Antioxidant activities of extracts from Barkleyanthus salicifolius (Asteraceae) and Penstemon gentianoides (Scrophulariaceae)

Various extracts of the aerial parts of Barkleyanthus salicifolius (Asteraceae) and Penstemon gentianoides (Scrophulariaceae) have been used in folk medicine to treat many ailments, particularly inflammation and migraine. Neither the bioactive components responsible nor the mechanisms involved have been evaluated. Here are reported antioxidant activities of their methanol, dichloromethane, and ethyl acetate extracts. Samples were evaluated for oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, and inhibition of the formation of thiobarbituric acid reactive species (TBARS), a measure of lipid peroxidation. Antioxidant activities were strongly correlated with total polyphenol content. The most active extracts from P. gentianoides in scavenging DPPH radicals and inhibiting TBARS formation were the methanol extract (A) and a further ethyl acetate extract of this (E). Partition E was further divided into eight fractions, and both E and the fractions were compared for activity against butylated hydroxytoluene, quercetin, and tocopherol. Partition E and the most active fractions, 5 and 6, were found to have I(50) values of 14.1, 38.6, and 41.8 ppm, respectively, against DPPH and 18.5, 26.0, and 12.7 ppm, respectively, against TBARS formation. Consistent with this finding, partition E and fractions 4-6 had the greatest ORAC and FRAP values. These results show that these plants could be useful antioxidant sources.     

Antioxidant activities of dioscorin, the storage protein of yam (Dioscorea batatas Decne) tuber

Dioscorin, the storage protein of yam (Dioscorea batatas Decne) tuber (which is different from dioscorine found in tubers of Dioscorea hirsuta), was purified to homogeneity after DE-52 ion exchange column according to the methods of Hou et al. (J. Agric. Food Chem. 1999, 47, 2168-2172). A single band of 32 kDa dioscorin was obtained on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel with 2-mercaptoethanol treatment. This purified dioscorin was shown by spectrophotometric method to have scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical in a pH-dependent manner. There is a positive correlation between scavenging effects against DPPH (8-46%) and amounts of 32 kDa dioscorin (5.97-47.80 nmol) added in Tris-HCl buffer (pH 7.9), which are comparable to those of glutathione at the same concentrations. Using electron paramagnetic resonance (EPR) spectrometry for DPPH radical detection, it was found that the intensities of the EPR signal were decreased by 28.6 and 57 nmol of 32 kDa dioscorin in Tris-HCl buffer (pH 7.9) more than in distilled water compared to controls. EPR spectrometry was also used for hydroxyl radical detection. It was found that 32 kDa dioscorin could capture hydroxyl radical, and the intensities of the EPR signal were significantly decreased dose-dependently by 1.79-14.32 nmol of 32 kDa dioscorin (r = 0.975) compared to the control. It is suggested that 32 kDa dioscorin, the storage protein of yam tuber, may play a role as antioxidant in tubers and may be beneficial for health when people take it as a food additive or consume yam tubers.     

Free radical scavengers and antioxidants from Lemongrass (Cymbopogon citratus (DC.) Stapf.)

Methanol, MeOH/water extracts, infusion, and decoction of Cymbopogon citratus were assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion, and inhibition of the enzyme xanthine oxidase (XO) and lipid peroxidation in human erythrocytes. The extracts presented effect in the DPPH and superoxide anion assay, with values ranging between 40 and 68% and 15-32% at 33 and 50 microg/mL, respectively, inhibited lipid peroxidation in erythrocytes by 19-71% at 500 microg/mL and were inactive toward the XO at 50 microg/mL. Isoorientin, isoscoparin, swertiajaponin, isoorientin 2' '-O-rhamnoside, orientin, chlorogenic acid, and caffeic acid were isolated and identified by spectroscopic methods. Isoorientin and orientin presented similar activities toward the DPPH (IC(50): 9-10 microM) and inhibited lipid peroxidation by 70% at 100 microg/mL. Caffeic and chlorogenic acid were active superoxide anion scavengers with IC(50) values of 68.8 and 54.2 microM, respectively, and a strong effect toward DPPH. Caffeic acid inhibited lipid peroxidation by 85% at 100 microg/mL.     

Effect of foliar application of selenium on the antioxidant activity of aqueous and ethanolic extracts of selenium-enriched rice

Selenium fertilizer was foliar applied to determine the effects of antioxidant activity of selenium-enriched rice assessed by alpha,alpha-diphenyl-beta-picylhydrazyl (DPPH) radical scavenging and the ferric thiocyanate (FTC) method. Results showed that selenium concentration in rice was significantly enhanced dose dependently. Aqueous or ethanolic extracts of rice displayed significantly higher antioxidant activity against lipid peroxidation. The activities of aqueous extracts were significantly higher than those of ethanolic extracts and increased with the increasing selenium concentration in rice. The DPPH assay showed that the kinetic behaviors of aqueous extracts were complex and slow, while ethanolic extracts reacted quickly with DPPH radical. Aqueous extracts of rice exhibited higher antiradical efficiencies than ethanolic extracts, and rice (1.275 mg Se kg(-)(1)) presented the lowest EC(50) values of 533.46 +/- 0.58 microg mL(-)(1). As compared to rice extracts, all of the reference antioxidants showed more than 4-fold antiradical efficiencies than rice extracts. This radical scavenging activity was significantly correlated with selenium concentrations in rice (R = 0.862, p < 0.05), while ethanolic extracts were inversely correlated with selenium concentration in rice.