Antioxidant activity of extract from Polygonum aviculare L

Free radicals induce numerous diseases by lipid peroxidation, protein peroxidation, and DNA damage. It has been reported that numerous plant extracts have antioxidant activities to scavenge free radicals. Whether Polygonum aviculare L. (Polygonaceae) has antioxidant activity is unknown. In this study, dried Polygonum aviculare L. was extracted by ethanol, and the extract was lyophilized. The antioxidant activities of extract powder were examined by free radical scavenging assays, superoxide radical scavenging assays, lipid peroxidation assays and hydroxyl radical-induced DNA strand scission assays. The results show that the IC50 value of Polygonum aviculare L. extract is 50 microg/ml in free radical scavenging assays, 0.8 microg/ml in superoxide radical scavenging assays, and 15 microg/ml in lipid peroxidation assays, respectively. Furthermore, Polygonum aviculare L. extract has DNA protective effect in hydroxyl radical-induced DNA strand scission assays. The total phenolics and flavonoid content of extract is 677.4 +/- 62.7 microg/g and 112.7 +/- 13 microg/g. The results indicate that Polygonum aviculare L. extract clearly has antioxidant effects.     

In vitro antioxidant activity of Diospyros malabarica Kostel bark

Antioxidant activity of defatted methanol extract of D. malabarica bark was studied for its free radical scavenging property on different in vitro models e.g. 1,1-diphenyl-2-picryl hydrazyl (DPPH), nitric oxide, superoxide, hydroxyl radical and lipid peroxide radical model. The extract showed good dose-dependent free radical scavenging property in all the models except in hydroxyl radical inhibition assay. IC50 values were found to be 9.16, 13.21, 25.27 and 17.33 microg/ml respectively in DPPH, nitric oxide, superoxide and lipid peroxidation inhibition assays. In hydroxyl radical inhibition assay 1000 microg/ml extract showed only 10% inhibition with respect to the control. Measurement of total phenolic compounds by Folin-Ciocalteu's phenol reagent indicated that 1 mg of the extract contained 120.7 microg equivalent of pyrocatechol. The results indicate that the antioxidant property of the extract may be due to the high content of phenolic compounds. However, the underlying mechanism may not involve hydroxyl radical scavenging property.     

Antioxidant effects of an aqueous extract of Ilex paraguariensis

In this work we investigate the antioxidant properties of an aqueous extract prepared from an infusion of Ilex paraguariensis (Aquifoliaceae) using free radical-generating systems. The extract inhibited the enzymatic and nonenzymatic lipid peroxidation in rat liver microsomes in a concentration-dependent fashion, with IC(50) values of 18 microg/ml and 28 microg/ml, respectively. The extract also inhibited the H(2)O(2)-induced peroxidation of red blood cell membranes with an IC(50) of 100 microg/ml and exhibited radical scavenging properties toward superoxide anion (IC(50) = 15 microg/ml) and 2,2-diphenyl-1-picrylhydrazyl radical. In the range of concentrations used, the extract was not a scavenger of the hydroxyl radical. Our results suggest that ingestion of extracts of Ilex paraguariensis could contribute to increase the antioxidant defense of an organism against free radicals attack.     

Free-radical scavenging by Ouratea parviflora in experimentally-induced liver injuries

The antioxidant potential of crude extracts and fractions from leaves of Ouratea parviflora, a Brazilian medicinal plant used for the treatment of inflammatory diseases, was investigated in vitro through the scavenging of radicals 2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), hydroxyl radical (HO*), superoxide anion (O2*-), and lipid peroxidation in rat liver homogenate. The crude extract (CEOP) and hydro-alcoholic fraction (OP4) showed strong inhibitory activity toward lipid peroxidation induced by tert-butyl peroxide (IC50 = 2.3 +/- 0.2 and 1.9 +/- 0.1 microg/ml, respectively). The same products exhibited a strong concentration-dependent inhibition of deoxyribose oxidation (14.9 +/- 0.2 and 0.2 +/- 0.1 microg/ml, respectively), and also showed a considerable antioxidant activity against O2*- (87.3 +/- 0.1 and 73.1 +/- 0.4 microg/ml, respectively) and DPPH radicals (55.4 +/- 0.3 and 38.3 +/- 0.4 microg/ml, respectively). The protective effects of CEOP and OP4 were also studied in mouse liver. CCl4 significantly increased (by 90%) levels of lipid hydroperoxides, carbonyl protein content (64%), DNA damage index (133%), aspartate aminotransferase (261%), alanine aminotransferase (212%), catalase activity (23%), and also caused a decrease of 60% in GSH content. The results showed that CEOP and OP4 exerted cytoprotective effects against oxidative injury caused by CCl4 in rat liver, probably related to the antioxidant activity showed by the in vitro free radical scavenging property.     

Antioxidant properties and protective effects of a standardized extract of Hypericum perforatum on hydrogen peroxide-induced oxidative damage in PC12 cells

Free radical scavenging and antioxidant activities of a standardized extract of Hypericum perforatum (SHP) were examined for inhibition of lipid peroxidation, for hydroxyl radical scavenging activity and interaction with 1,1-diphenyl-2-picrylhydrazyl stable free radical (DPPH). Concentrations between 1 and 50 microg/ml of SHP effectively inhibited lipid peroxidation of rat brain cortex mitochondria induced by Fe2+/ascorbate or NADPH system. The results showed that SHP scavenged DPPH radical in a dose-dependent manner and also presented inhibitory effects on the activity of xanthine oxidase. In contrast, hydroxyl radical scavenging occurs at high doses. The protective effect of the standardized extract against H2O2-induced oxidative damage on the pheochromocytoma cell line PC 12 was investigated by measuring cell viability via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) assays, caspase-3-enzyme activity and accumulation of reactive oxygen species [2',7'-dichlorofluorescin (DCF) assay]. Following 8-h cell exposure to H2O2 (300 microM), a marked reduction in cell survival was observed, which was significantly prevented by SHP (pre-incubated for 24 h) at 1-100 microg/ml. In a separate experiment, different concentrations of the standardized extract (0.1-100 microg/ml) also attenuated the increase in caspase-3 activity and suppressed the H2O2 -induced reactive oxygen species generation. Taken together, these results suggest that SHP shows relevant antioxidant activity both in vitro and in a cell system, by means of inhibiting free radical generation and lipid peroxidation.     

Evaluation of antioxidant properties of root bark of Hemidesmus indicus R. Br. (Anantmul).

Hemidesmus indicus R. Br. (Asclepiadaceae) is a well known drug in Ayurveda system of medicine. In the present study, antioxidant activity of methanolic extract of H. indicus root bark was evaluated in several in vitro and ex vivo models. Further, preliminary phytochemical analysis and TLC fingerprint profile of the extract was established to characterize the extract which showed antioxidant properties. The in vitro and ex vivo antioxidant potential of root bark of H. indicus was evaluated in different systems viz. radical scavenging activity by DPPH reduction, superoxide radical scavenging activity in riboflavin/light/NBT system, nitric oxide (NO) radical scavenging activity in sodium nitroprusside/Greiss reagent system and inhibition of lipid peroxidation induced by iron-ADP-ascorbate in liver homogenate and phenylhydrazine induced haemolysis in erythrocyte membrane stabilization study. The extract was found to have different levels of antioxidant properties in the models tested. In scavenging DPPH and superoxide radicals, its activity was intense (EC50 = 18.87 and 19.9 microg/ml respectively) while in scavenging NO radical, it was moderate. It also inhibited lipid peroxidation of liver homogenate (EC50 = 43.8 microg/ml) and the haemolysis induced by phenylhydrazine (EC50 = 9.74 microg/ml) confirming the membrane stabilization activity. The free radical scavenging property may be one of the mechanisms by which this drug is effective in several free radical mediated disease conditions.     

In vitro antioxidant studies in leaves of Annona species

Antioxidant potential of leaves of three different species of Annona was studied by using different in vitro models eg., 1,1-diphenyl-2-picryl hydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothizoline-6-sulphonate) (ABTS), nitric oxide, superoxide, hydroxy radical and lipid peroxidation. The ethanolic extract of A. muricata at 500 microg/ml showed maximum scavenging activity (90.05%) of ABTS radical cation followed by the scavenging of hydroxyl radical (85.88%) and nitric oxide (72.60%) at the same concentration. However, the extract showed only moderate lipid peroxidation inhibition activity. In contrast, the extract of A. reticulata showed better activity in quenching DPPH (89.37%) and superoxide radical (80.88%) respectively. A.squamosa extract exhibited least inhibition in all in vitro antioxidant models excepting hydroxyl radical (79.79%). These findings suggest that the extracts of A. muricata possess potent in vitro antioxidant activity as compared to leaves of A. squamosa and A. reticulata suggesting its role as an effective free radical scavenger, augmenting its therapeutic     

Antioxidant activity and protective effect on DNA strand scission of Rooibos tea (Aspalathus linearis)

Rooibos tea (Aspalathus linearis) was extracted by refluxing with water and 75% ethanol as a solvent. Antioxidant activity and protective effect on DNA strand scission were investigated by using different antioxidant assay systems and DNA strand nicking assay, respectively. 75% Ethanol extract has higher content of total soluble phenolics and flavonoid than water extract. Antioxidant activities such as hydrogen donating capacity and scavenging activity of hydrogen peroxide were higher in 75% ethanol extract than in water extract except the rate constant with hydroxyl radical. Peroxyl radical induced DNA strand scission was prevented by both 75% ethanol and water extract and hydroxyl radical induced DNA strand scission was not. This result indicates that total soluble phenolics, specially flavonoid, of Rooibos tea are responsible for several kinds of antioxidant activities and preventive activity on peroxyl radical induced DNA strand scission.     

Antioxidant activity of 50% aqueous--ethanol extract from Acantholippia deserticola

The antioxidant properties oí Acantholippia deserticola, a herb used in traditional northern Chilean medicine was studied using free radical-generating systems. The 50% aqueous-ethanol extract oí Acantholippia deserticola protected against non-enzymatic lipid peroxidation in microsomal membranes of rat, induced by an Fe++-ascorbate system and measured spectrophotometrically by the TBARS test, and had strong free radical scavenging capacities on stable ABTS and DPPH radicals. The results shows that the IC50 value of the 50% aqueous-ethanolic extract of A.deserticola is 18 +/- 0.5 microg/mL in DPPH radical-scavenging, 15 +/- 0.8 microg/mL in lipid peroxidation , Total Antioxidant Activity (TAA) is 0.95 mM of Trolox per mg/mL of extract. The total phenolics content of extract is 725 +/- 12 mg of gallic acid equivalent per g of dried extract. The results indicate that the 50% aqueous-ethanol extract of Acantholippia deserticola clearly has antioxidant properties.     

Neuroprotection and free radical scavenging effects of <Emphasis Type="Italic">Osmanthus fragrans</Emphasis>

The ethanol extract of dried flowers Osmanthus fragrans (OFE) was assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the hydroxyl anion, investigation of the ferric reducing/antioxidant power (FRAP) and lipid-peroxidation inhibition in rat tissues. OFE contained a high amount of total flavonoid and polyphenol. OFE presented the effects in the metal reducing power, FRAP assay with IC₅₀ values of 0.23 μg/ml, and 7.74 μg/ml, respectively. OFE presented similar activities toward the DPPH and hydroxyl anion scavenging ability with IC₅₀ values of 10 μg/ml. OFE with IC₅₀ values between 46 and 97 μg/ml inhibited lipid peroxidation initiated by ferrous chloride in rat brain, liver, heart and kidney mitochodrias. Moreover, the neuroprotective activity of OFE was investigated under different insults (glutamate, arachidonic acid, and 6-hydroxydopamine) in Wistar rat primary cortical neurons. OFE with EC₅₀ values between 66 and 165 μg/ml attenuated the neurotoxicity on MTT and LDH assays. In addition, the AKT protein expression of excitotoxicity and oxidative stress was displayed by western blotting analysis. OFE could up-regulate the glutamate and 6-OHDA decreased AKT expression. This is the first demonstration of the neuroprotective, free radical scavenging and anti-oxidative effects of O. fragrans.     

Evaluation of in vitro antioxidant activity of Indian bay leaf, Cinnamomum tamala (Buch. -Ham.) T. Nees & Eberm using rat brain synaptosomes as model system

The study investigated the perturbation of oxidant-antioxidant balance in brain synaptosomes of diabetic rats and determined the antioxidant and free radical-scavenging property of the Indian bay leaf. Brain synaptosomes were isolated from control and streptozotocin-induced diabetic animals and oxidative stress parameters were assayed. A methanolic extract of bay leaf (BLE) was tested for the polyphenolic content and antioxidant activity by in vitro assays. A significant increase in the levels of lipids and lipid peroxidation products and a decline in antioxidant potential were observed in diabetic rat brain synaptosomes. The total polyphenolic content of BLE was found to be 6.7 mg gallic acid equivalents (GAE)/100g. BLE displayed scavenging activity against superoxide and hydroxyl radicals in a concentration-dependent manner. Further, BLE showed inhibition of Fe(2+)-ascorbate induced lipid peroxidation in both control and diabetic rat brain synaptosomes. Maximum inhibition of lipid peroxidation, radical scavenging action and reducing power of BLE were observed at a concentration of 220 microg GAE. These effects of BLE in vitro were comparable with that of butylated hydroxyl toluene (BHT), a synthetic antioxidant. It can be concluded that synaptosomes from diabetic rats are susceptible to oxidative damage and the positive effects of bay leaf in vitro, could be attributed to the presence of antioxidant phytochemicals.     

Structure and protective effect of exopolysaccharide from P. Agglomerans strain KFS-9 against UV radiation

The water-soluble exopolysaccharide (WSEPS) from Pantoea agglomerans strain KFS-9 isolated from mangrove forest was prepared by removing bacterial cell from the fermentation liquid following by concentration and cold ethanol precipitation of the supernatant. The polysaccharide material was purified by gel permeation chromatography on a Sephacryl S-300HR column and characterized using chemical and spectral methods. The results show that WSEPS is protein-bound polysaccharide, and it is composed of arabinose, glucose galactose and gulcuronic acid in the molar ratio of 1.0:2.2:2.8:0.9. Their antioxidant activities in vitro were studied by various antioxidant assays, including hydroxyl radical scavenging, superoxide radical scavenging and antilipid peroxidation. The results show that the WSEPS extracted had a high antioxidant activity in a concentration-dependent manner (except the activity of antilipid peroxidation). WSEPS quenched hydroxyl radicals, superoxide radicals at low amounts, the IC(50) of which were 0.07 and 0.15 mg/ml, respectively. These results indicate that the protective effect of WSEPS against UV radiation is most likely to be due to the free radicals-scavenging ability.     

Antioxidant Activities of Aqueous Extract from Cultivated Fruit-bodies of Cordyceps militaris （L.） Link In Vitro

Biological antloxldants extracted from plants and fungi have potential abilities to scavenge free radicals and Inhibit lipid peroxldatlon, playing Important roles in preventing diseases, for example, cancer, and aging Induced by reactive oxygen species, which may cause oxidative damage to DNA, proteins and other macromolecules. The antloxldant potency of cultivated fruit-bodies of Cordyceps militarls （L.） Link was investigated In this study. Five established In vitro systems were employed, including the 1,1-dlphenyl-2- plcryldrazyl （DPPH） free radical scavenging, hydroxyl radical eliminating, iron chelating, Inhibition of Ilnolelc acid lipid peroxldatlon and reducing power. The aqueous extract from cultivated fruit-bodies was subjected to the test of amino acid, polysaccharlde and mannitol. Ascorblc acid （Vc）, butylated hydroxytoluene （BHT） and ethylenedlamlnetetraacetlc acid （EDTA） were used as positive controls for comparisons. Among the assays, the aqueous extract of C. mllltarls frult-bodles shows a significant scavenging effect on DPPH, eliminating the capability on hydroxyl radicals and the chelating effect on ferrous Iron. The extract also shows positive results of Inhibiting Ilnoleic acid lipid peroxldatlon and reducing power.     

Free radical scavenging and antioxidant effects of lactate ion: an in vitro study.

Divergent literature data are found concerning the effect of lactate on free radical production during exercise. To clarify this point, we tested the pro- or antioxidant effect of lactate ion in vitro at different concentrations using three methods: 1) electron paramagnetic resonance (EPR) was used to study the scavenging ability of lactate toward the superoxide aion (O(2)(-).) and hydroxyl radical (.OH); 2) linoleic acid micelles were employed to investigate the lipid radical scavenging capacity of lactate; and 3) primary rat hepatocyte culture was used to study the inhibition of membrane lipid peroxidation by lactate. EPR experiments exhibited scavenging activities of lactate toward both O(2)(-). and.OH; lactate was also able to inhibit lipid peroxidation of hepatocyte culture. Both effects of lactate were concentration dependent. However, no inhibition of lipid peroxidation by lactate was observed in the micelle model. These results suggested that lactate ion may prevent lipid peroxidation by scavenging free radicals such as O(2)(-). and.OH but not lipid radicals. Thus lactate ion might be considered as a potential antioxidant agent.     

Antioxidant activity of anti-inflammatory plant extracts

The antioxidant properties of twenty medical herbs used in the traditional Mediterranean and Chinese medicine were studied. Extracts from Forsythia suspensa, Helichrysum italicum, Scrophularia auriculata, Inula viscosa, Coptis chinensis, Poria cocos and Scutellaria baicalensis had previously shown anti-inflammatory activity in different experimental models. Using free radical-generating systems H. italicum. I. viscosa and F. suspensa protected against enzymatic and non-enzymatic lipid peroxidation in model membranes and also showed scavenging property on the superoxide radical. All extracts were assayed at a concentration of 100 microg/ml. Most of the extracts were weak scavengers of the hydroxyl radical and C. chinensis and P. cocos exhibited the highest scavenging activity. Although S. baicalensis inhibited the lipid peroxidation in rat liver microsomes and red blood cells, the extract showed inhibitory actions on aminopyrine N-demethylase and xanthine oxidase activities as well as an pro-oxidant effect observed in the Fe3+-EDTA-H2O2 system. The results of the present work suggest that the anti-inflammatory activities of the same extracts could be explained, at least in part, by their antioxidant properties.     

Purification and characterization of antioxidant peptide from hoki (Johnius belengerii) frame protein by gastrointestinal digestion

To extract antioxidant peptide from hoki frame protein hydrolysate (APHPH), we employed six proteases (pepsin, trypsin, papain, alpha-chymotrypsin, Alcalase and Neutrase) for enzymatic hydrolysis, and the antioxidant activities of their hydrolysates were investigated using both lipid peroxidation inhibition assay and free radical scavenging assay by electron spin resonance spin-trapping technique. Among hydrolysates, peptic hydrolysate, having the highest antioxidant activity, further separated into four groups using ultrafiltration membranes and purified consecutive chromatographic methods. Finally, the purified peptide had a molecular mass of 1801 Da, and amino acid sequence was identified as Glu-Ser-Thr-Val-Pro-Glu-Arg-Thr-His-Pro-Ala-Cys-Pro-Asp-Phe-Asn. APHPH inhibited lipid peroxidation higher than that of alpha-tocopherol as positive control and efficiently quenched different sources of free radical: 1,1-diphenyl-2-pycryl-hydrazyl (IC(50)=41.37 microM), hydroxyl (IC(50)=17.77 microM), peroxyl (IC(50)=18.99 microM) and superoxide radicals (IC(50)=172.10 microM). Furthermore, APHPH decreased t-butylhydroperoxide-induced cytotoxicity on human embryonic lung fibroblasts and efficiently protected free-radical-induced DNA damage.     

Antioxidant and antiradical activities of L-carnitine

L-carnitine plays an important regulatory role in the mitochondrial transport of long-chain free fatty acids. In this study, the antioxidant activity of L-carnitine was investigated as in vitro. The antioxidant properties of the L-carnitine were evaluated by using different antioxidant assays such as 1, 1-diphenyl-2-picryl-hydrazyl free radical (DPPH.) scavenging, total antioxidant activity, reducing power, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities. Total antioxidant activity was measured according to ferric thiocyanate method. alpha-tocopherol and trolox, a water-soluble analogue of tocopherol, were used as the reference antioxidant compounds. At the concentrations of 15, 30 and 45 microg/mL, l-carnitine showed 94.6%, 95.4% and 97.1% inhibition on lipid peroxidation of linoleic acid emulsion, respectively. On the other hand, 45 microg/mL of standard antioxidant such as alpha-tocopherol and trolox indicated an inhibition of 88.8% and 86.2% on peroxidation of linoleic acid emulsion, respectively. In addition, L-carnitine had an effective DPPH. scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, total reducing power and metal chelating on ferrous ions activities. Also, those various antioxidant activities were compared to alpha-tocopherol and trolox as references antioxidants.     

Evaluation of antioxidant activity of <Emphasis Type="Italic">Melothria maderaspatana in vitro</Emphasis>

In this study, an aqueous extract of leaves from Melothria maderaspatana was tested for in vitro antioxidant activity. Free radical scavenging assays, such as hydroxyl radical, hydrogen peroxide, superoxide anion radical and 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2’-azinobis-(3-ethyl-enzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, and reducing power assay, were studied. The extract effectively scavenged hydroxyl radical, hydrogen peroxide and superoxide anion radicals. It also scavenged DPPH and ABTS radicals. Furthermore, it was found to have reducing power. All concentrations of leaf extract exhibited free radical scavenging and antioxidant power, and the preventive effects were in a dose-dependent manner. The antioxidant activities of the above were compared to standard antioxidants such as butylated hydroxytoluene (BHT), ascorbic acid, and α-tocopherol. The results obtained in the present study indicate that the M. maderaspatana extract could be considered a potential source of natural antioxidant.     

Antioxidant and nitric oxide synthase activation properties of Auricularia auricula

In vitro evaluation of antioxidant activities of Auricularia auricula showed significant inhibition of lipid peroxidation, and potent hydroxyl radical scavenging activity when compared with standard drug catechin. IC5o value of crude, boiled and ethanolic extracts of A. auricula represented 403, 510, and 373 microg/ml respectively in case of hydroxyl radical scavenging activity and 310, 572 and 398 microg/ml respectively in case of lipid peroxidation. Furthermore, crude, boiled and ethanolic extracts also increase significantly nitric oxide production (664, 191 and 850 pmole/mg dry wt/hr respectively) over the control. The present results revealed that A. auricula had potential therapeutic use.     

Antioxidant and nitric oxide synthase activation properties of Ganoderma applanatum

In vitro evaluation of antioxidant activities of Ganoderma applanatum showed significant inhibition of lipid peroxidation, and potent hydroxyl radical scavenging activity when compared with standard drug catechin. IC50 values of crude, boiled and ethanolic extracts of G. applanatum were 604.8, 624 and 267 microg/ml, respectively in case of hydroxyl radical scavenging activity, and 441, 520.5 and 166.16 microg/ml, respectively in case of lipid peroxidation. Furthermore, crude, boiled and ethanolic extracts also increased significantly nitric oxide production (156.67, 121.88 and 742 pmole/mg dry wt/hr, respectively) over the control. The results of present investigation revealed that G. applanatum have potential therapeutic use.