Antioxidant Effects Of Extracts Research Articles

Boswellia serrata has Beneficial Anti‐Inflammatory and Antioxidant Properties in a Model of Experimental Colitis

Ulcerative colitis is an inflammatory disease that involves only the colon and rectum, being characterized by leukocyte infiltrate and superficial ulcers in the intestinal mucosa. To evaluate the anti-inflammatory and antioxidant effects of extract from the Boswellia serrata plant in an experimental rat model of acute ulcerative colitis induced by the administration of acetic acid (AA). An extract of B. serrata (34.2 mg/kg/day) was administered by oral gavage for 2 days before and after the induction of colitis with 4 mL of 4% AA. The anal sphincter pressure in the colitis group showed a significant decrease compared to that of the control groups (p < 0.001). The analysis of the values of lipid peroxidation (LPO) obtained by substances that react with thiobarbituric acid (TBARS) showed a significantly increased LPO in the colitis group compared to the control groups (p < 0.001). The nitric oxide levels and the expression of inducible nitric oxide synthase (iNOS) showed a significant increase in the colitis group compared to control groups (p < 0.01). Both pretreatment and treatment with B. serrata exhibited significantly reduced lipid peroxidation, nitric oxide and iNOS and showed improvements in tissue injury and anal sphincter pressure in animals with ulcerative colitis. The B. serrata extract has protective anti-inflammatory and antioxidant effects that inhibit inflammatory mediators in acute experimental colitis.

The impact of strawflower and mistletoe extract on quality properties of rainbow trout fillets

SummaryMany plants, including strawflower and mistletoe, contain antioxidants and antimicrobials, which can increase the shelf life of seafood. The main aim of this study was to investigate the effect of mistletoe and strawflower extracts at doses of 0.5% (w/v) on the sensory, chemical and microbiological properties of rainbow trout fillets during 27 days of storage at 2 ± 1 °C. The phenolic compounds in these plants have been studied, but their effects on food quality and storage properties have not been reported. We found that extract of mistletoe did not extend the shelf life of the fillets; however, the strawflower extract show high antimicrobial activity in fish fillets. The shelf life of rainbow trout was 20 days for the control and fish treated with mistletoe extract and 23 days for fish treated with strawflower extract. The antioxidant effect of extracts on fish fillets was weak, whereas strawflower extract had high antimicrobial effect. Peroxide value (PV) and thiobarbituric acid (TBA) values fluctuated during storage periods around main values below 14 meq O2 kg−1 and 0.6 MA kg−1, respectively. Putrescine, cadaverine, spermine, spermidine, serotonin, tyramine and dopamine were main amine, whereas histamine accumulated at low levels (&lt;2 mg per 100 g). Strawflower suppressed biogenic amine accumulation in fish fillets. At the limit of acceptability, total viable count (TVC), Enterobacteriaceae and lactic acid bacteria count remained below 7.6, 6.83 and 8.01 log CFU g−1, respectively. The results of this study show that ethanol extracts of strawflower improve the shelf life of rainbow trout.

Antioxidative effects of extracts from Trifolium species on blood platelets exposed to oxidative stress

Clovers (Trifolium) may possess a significant therapeutic potential, but the effects of compounds from these plants on blood platelets and haemostasis have been poorly recognized. The present study was designed to evaluate the antioxidative action of extracts from three species of clovers: Trifolium pratense, Trifolium pallidum and Trifolium scabrum in the protection of human blood platelets in vitro. Platelet suspensions were pre-incubated with crude extract and phenolic fraction of T. pratense or phenolic fractions of T. scabrum and T. pallidum, at the final concentrations of 0.5-50 μg/ml. Then, for the induction of oxidative stress, 100 μM peroxynitrite was added. The antioxidative activity of plant extracts was assessed by measurements of the level of 3-nitrotyrosine, thiol groups and lipid peroxidation products (hydroperoxides and thiobarbituric acid-reactive substances). Despite the significant differences in the composition of the investigated extracts, we observed antioxidative effects of all used mixtures. The presence of Trifolium extracts considerably reduced the peroxynitrite-mediated modifications of proteins and diminished peroxidation of lipids in platelets. Our results indicate on a strong antioxidative activity of the tested extracts-statistically significant effects were found even for the lowest concentrations (0.5 μg/ml) of all extracts. This action may be useful in the protection of blood components, very susceptible to oxidative modifications. The obtained results suggest that the examined clovers are a promising source of compounds, valuable for the protection against oxidative stress-induced damage to blood platelets.

The hepato-ameliorating effect of Solanum nigrum against CCl4 induced liver toxicity in Albino rats

The present study was investigated to evaluate the hepato-ameliorating and antioxidant activity of two aqueous extracts of Solanum nigrum (SN) against CCl4-induced toxicity in rats. Male Albino rats were divided in four groups with 8 animals in each group. Group (1) was normal group and group (2) was injected intraperitoneal (i.p.) with CCl4 (1ml/kg) 3 times weekly for 2 weeks (control). Group (3) was injected with CCl4 and then treated with extract from whole plant of Solanum nigrum (500 mg/kg) and group (4) was injected with CCl4 and then treated with extract from fruits of Solanum nigrum (250 mg/kg). CCl4 injection enhanced activity of hepatic enzymes (AST and ALT) while it decreased serum total protein and albumin in experimental animals. It also decreased RBC, platelets count, PCV and Hb levels. However it increased WBC count. CCl4 injection increased level of lipid peroxidation resulting in a decrease in the level of enzymatic and non enzymatic antioxidants. Treatment with two extracts of Solanum nigrum altered these changes to near normal levels. Buthepato-ameliorating and antioxidant effects of extract of Solanum nigrum fruits were found to be better than those of extract from whole plant of Solanum nigrum.

골풀 부위별 추출물의 항산화 효과

이번 연구에서 우리는 골풀의 부위별 추출물의 항산화 활성을 측정하였다. 골풀의 부위는 상층부와 하층부, 고갱이 부위로 결정하였다. 실험은 골풀 50 % 에탄올 추출물, 에틸아세테이트(ethyl acetate) 분획, 아글리콘(aglycone) 분획 세 가지로 진행하였다. 항산화 활성 중 라디칼인 DPPH (1,1-diphenyl-2-picrylhydrazyl) 소거활성(<TEX>$FSC_{50}$</TEX>)을 살펴본 결과 50 % 에탄올 추출물의 경우 고갱이 부위(42.9 <TEX>${\mu}g/mL$</TEX>)가, 에틸아세테이트 분획은 지하 부위(12.1 <TEX>${\mu}g/mL$</TEX>), 아글리콘 분획은 지하 부위(12.1 <TEX>${\mu}g/mL$</TEX>)가 가장 높은 라디칼 소거능을 나타내었다. Luminol 발광법을 이용한 <TEX>$Fe^{3+}$</TEX>-EDTA/<TEX>$H_2O_2$</TEX> 계에서 생성된 활성산소종에 대한 소거활성(총 항산화능, <TEX>$OSC_{50}$</TEX>)을 살펴본 결과, 50 % 에탄올 추출물은 고갱이 부위(0.29 <TEX>${\mu}g/mL$</TEX>), 에틸아세테이트 분획은 지하 부위(0.25 <TEX>${\mu}g/mL$</TEX>), 아글리콘 분획은 고갱이 부위(0.20 <TEX>${\mu}g/mL$</TEX>)가 가장 높은 총 항산화능을 나타내었다. Rose-bengal로 증감된 <TEX>$^1O_2$</TEX>에 의한 적혈구 파괴에 대한 세포보호 효과는 10 <TEX>${\mu}g/mL$</TEX> 농도에서 고갱이 부위의 아글리콘 분획이 <TEX>${\tau}_{50}$</TEX> 321.0 min으로 가장 높은 세포 보호 활성을 나타내었다. 이와 같은 항산화 효과로 볼 때 골풀의 지하 부분과 고갱이 부위의 추출물은 천연 항산화제로서 여러 산업 분야에 응용 가능할 것이라 생각된다. 특히 높은 <TEX>${\tau}_{50}$</TEX> 값을 갖는 것으로 보아, 태양광 노출에 의해서 <TEX>$^1O_2$</TEX>이 많이 생성되는 부위인 피부를 효과적으로 보호해줄 수 있을 것으로 생각되어진다. In this study, the antioxidative effects of extracts from different parts of Juncus effusus L. were investigated. The three parts (above-ground part, below-ground part, medulla part) were selected. 50 % ethanol extract, ethyl acetate and aglycone fractions of J. effusus L. were used in experiments. The highest DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activities (<TEX>$FSC_{50}$</TEX>) was shown by medulla part (42.9 <TEX>${\mu}g/mL$</TEX>) in 50 % ethanol extracts, below-ground part (12.1 <TEX>${\mu}g/mL$</TEX>) in ethyl acetate fractions, and below-ground part (12.1 <TEX>${\mu}g/mL$</TEX>) in aglycone fractions. Reactive oxygen species (ROS) scavenging activities (<TEX>$OSC_{50}$</TEX>) on ROS generated in <TEX>$Fe^{3+}$</TEX>-EDTA/<TEX>$H_2O_2$</TEX> system using the luminol-dependent chemiluminescence assay showed the most prominent effect of medulla part (0.29 <TEX>${\mu}g/mL$</TEX>) in 50 % ethanol extracts, below-ground part (0.25 <TEX>${\mu}g/mL$</TEX>) in ethyl acetate fractions, and medulla part (0.20 <TEX>${\mu}g/mL$</TEX>) in aglycone fractions. The cellular protective effects of extract/fractions of J. effusus L. on the rose-bengal sensitized photohemolysis of human erythrocytes were increased in a concentration dependent manner (0.5 ~ 10 <TEX>${\mu}g/mL$</TEX>). Especially, aglycone fraction of medulla part at a concentration of 10 <TEX>${\mu}g/mL$</TEX> showed the most prominent protective effect among all extracts (<TEX>${\tau}_{50}$</TEX>, 321.0 min). These results indicate that extracts from below-ground part and medulla part of J. effusus L. extracts can be used as an natural antioxidant. Particularly, J. effusus L. can protect suggesting a high <TEX>${\tau}_{50}$</TEX> skin where many <TEX>$^1O_2$</TEX> was generated by sunlight exposure.

Antibacterial and Antioxidant Effects of Brown Alga Padina australis Hauck Crude Extract

The study was conducted to investigate the antibacterial and antioxidant effects of Padina australis Hauck crude extract. The essential components of the brown algae was obtained by ethanolic extraction and analyzed by Thin Layer Chromatography (TLC) Silica gel plates. The antibacterial activities of the algal extract at different concentrations were determined using the Kirby Bauer Method and were expressed as zone of inhibition. The algal extract showed to have antibacterial effects on Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli and Neisseria gonorrhoeae. The antioxidant activity of the algal extract was determined using the methods of inhibition on DPPH Free Radical. The antioxidant effects of the extract at different concentrations were compared with standard antioxidant, such as Ascorbic Acid. The algal extract was found to be active in the decolorization of Methanolic-DPPH solution and scavenging the free radical. The antibacterial and antioxidant activities could be attributed to the presence of different secondary metabolites such as phenolic compounds, and carotenoids and the mechanism of action might be due to their individual or collective participation. The experimental findings envisaged P. australis extract as a good candidate in developing new antibacterial and antioxidant agents. Keywords – Algae, Padina australis, DPPH Free Radical, Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Neisseria gonorrhoeae, Philippines

Extracts of Paris Polyphylla Smith Mitigates Oxidative Stress in Human Umbilical Vein Endothelial Cells Induced by Oxidized Low Density Lipoprotein

Paris Polyphylla Smith is widely used in traditional Chinese medicine. For its effective of antipyretic detoxicate, its active component is steroid saponin[1]. The present study was designed to evaluate the antioxidative effect of extracts of Paris Polyphylla Smith (PPSE) and its capacity to protect human umbilical vein endothelial cells (HUVECs) against oxidative damage induced by oxidized low density lipoprotein (ox-LDL). Cytotoxicity was determined by MTT assay. Flow cytometer (FCM) demonstrated that the increased apoptosis induced by oxidized low density were inhibited, and the blocked transition of cells from static phase (G0/G1) to DNA synthesis (S) were restored by PPSE, these effect were all in a dose-dependent manner. The actions by PPSE to reduce apoptosis may help protect endothelial function and inhibit atherogenesis, while the novel actions to mitigates oxidative stress may weaken the ability of endothelial injury. Further studies are needed to identify the chemical compounds responsible in order to develop its clinical application.

Anticholinesterase and antioxidant effects of the ethanol extract, ethanol fractions and isolated flavonoids from Cistus laurifolius L. leaves

In the current study, the n-hexane, chloroform, ethyl acetate, water, and n-butanol fractions obtained from the main ethanol extract of Cistus laurifolius L. were evaluated for their cholinesterase inhibitory effects against acetyl- (AChE) and butyrylcholinesterase (BChE), at 50, 100, and 200μg/ml, using an ELISA microplate reader. The antioxidative effect of the extract and fractions was also determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferrous ion-chelation capacity, and ferric-reducing antioxidant power (FRAP) test systems. Total phenol and flavonoid contents of the extract and fractions were calculated using Folin-Ciocalteau and aluminium chloride reagents. Three flavonoid derivatives; 3-O-methylquercetin (1), 3,7-O-dimethylquercetin (2), and 3,7-O-dimethylkaempferol (3) isolated from the CHCl3 fraction were also tested in the same manner. Our experimental findings indicated that the ethanol extract exerted the highest AChE inhibition (80.07±1.06% at 200μg/ml). The ethyl acetate and n-butanol fractions displayed the best activity against DPPH and FRAP assays.

Antioxidant effects of solvent extracts from the dried jujube (Zizyphus jujube) sarcocarp, seed, and leaf via sonication

Antioxidant effects of extracts from sarcocarp, seed, and leaf of dried jujube (Zizyphus jujube) were investigated. The highest amount of flavonoids and polyphenol was found in 80% methanol leaf extract at value of 43.04±0.34 and 324.75±6.01 mg/g, respectively. For 2,2′-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS) radical scavenging activity analysis at a concentration of 1,000 μg/mL, 70% ethanol seed extract (94.76±0.23%), and 80% methanol leaf extract (95.46±0.14%) were observed to have higher activity than those of controls, such as butylated hydroxyl anisole (BHA) (89.60±0.00%), butylated hydroxyl toluene (BHT) (84.07±0.50%), vitamin C (89.27±0.12%), and vitamin E (88.53±0.12%). All solvent extracts from leaf showed higher ABTS radical scavenging activity (over 98%) than those of controls with their activity values around 94% (500 g/mL). All extracts from sarcocarp and seed showed superoxide dismutase (SOD)-like activity of 24.46–34.84% on the concentrations (100–1,000 g/mL), and 80% methanol leaf extract showed the highest activity (43.66±0.37%) among samples. These results indicate that sarcocarp, seed of dried jujube are all excellent antioxidants, and especially leaf showed higher antioxidant effect than those of vitamin C and E.

Antidiabetic and antioxidant effects of extracts from Potentilla discolor Bunge on diabetic rats induced by high fat diet and streptozotocin

Potentilla discolor Bunge, commonly found at the north temperate and boreal zone, has been used for diabetes in China for a long time. Flavonoids and triterpenoids are two major types of compounds in P. discolor. This study was designed primarily to investigate the effects of total flavonoids extract (TFE) and total triterpenoids extract (TTE) of P. discolor Bunge on blood glucose, lipid profiles and antioxidant parameters on diabetic rats induced by high fat diet and streptozotocin. High fat diet-fed and streptozotocin-induced diabetic rats were treated with the TFE and TTE for 15 days, respectively. A range of parameters were tested including fasting blood glucose (FBG), serum insulin (SI), blood lipid profile, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), glycosylated serum protein (GSP), and nitric oxide (NO). Diabetic rats treated with TFE or TTE had decreased concentration of FBG and GSP compared with the control group. Meanwhile, the levels of serum total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-c) in the TFE or TTE treated diabetic rats were lower, and the high-density lipoprotein cholesterol (HDL-c) level was higher than in the control diabetic rats. Furthermore, the extracts treatment decreased the MDA and NO level, while increased SOD and GSH levels in diabetic rats. Histopathologic examination also showed that the extracts have protective effects on β-cells in diabetic rats which are supported by the increase of SI. All these experimental results highlighted the hypoglycemic and hypolipidemic properties of the two extracts from Potentilla discolor Bunge on diabetes and its complications, possibly through a strong antioxidant activity and a protective action on β-cells.

DNA-protective effects of sumach ( Rhus coriaria L.), a common spice: Results of human and animal studies

Sumach ( Rhus coriaria L.) is widely used as a spice. The aim of this study was the investigation of its DNA-protective effects in humans and animals. Prevention of the formation of strand breaks and oxidized DNA bases as well as the protection against H 2O 2- and (±)- anti-benzo[a]pyrene-7,8-dihydro-diol-9,10-epoxide (BPDE)-induced DNA-damage were monitored in human lymphocytes in a placebo controlled trial ( N = 8/group) with ethanolic extract of sumach (3.0 g/day, 3 days) in single cell gel electrophoresis assays. Furthermore, DNA-protective effects of sumach were monitored in different inner organs of rats under identical conditions. No alteration of DNA-migration was detectable in human lymphocytes under standard conditions, but a decrease of the tail-lengths due to formation of oxidized purines and pyrimidines (52% and 36%) was found with lesion-specific enzymes. Also damage caused by H 2O 2 and BPDE was significantly reduced by 30% and 69%, respectively. The later effect may be due to induction of glutathione S-transferase (GST). After the intervention, the overall GST (CDNB) activity in plasma was increased by 40%, GST-α by 52% and GST-π by 26% (ELISA). The antioxidant effects of extract are probably due to scavenging which was observed in in vitro experiments, which also indicated that gallic acid is the active principle of sumach. The animal experiments showed that sumach also causes protection in inner organs. Supplementation of the drinking water (0.02 g/kg per animal) decreased the formation of oxidized DNA bases in colon, liver, lung and lymphocytes; also after γ-irradiation pronounced effects were seen.

Contenido de flavonoides y compuestos fenólicos de mieles chilenas e índice antioxidante

A comparison of the phenolic content of several Chilean honeys showed great variations in flavonoid concentration among the samples analysed. Higher amounts of phenolics are found in honey from dry climates. The antioxidant effect of extracts, using ORAC analysis, did not correlate with the flavonoid content or with the total phenolic concentration.

Croton cajucara BENTH. Leaf Extract Scavenges the Stable Free Radical DPPH and Protects Against Oxidative Stress Induced by Paraquat

Antioxidant effects of extracts from Croton cajucara BENTH. leaves was investigated in different in vitro and in vivo models. Extracts showed inhibitory radical scavenging activity against the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) (75%, 43% and 25% of the standard trolox at 1, 10 and 100 mg/ml, respectively; IC50 218 mg/ml). Percentage survival of Saccharomyces cerevisiae cells treated with 10 mM paraquat increased by 21% and 55%, when 1 mg/ml and 10 mg/ml concentrations of the extract, respectively, were added. The cytosolic concentration of TBARS increased in animals treated with paraquat (+283%), while values did not significantly differ from the controls in rats additionally receiving the leaf extract. Paraquat administration also induced a significant increase in hydroperoxide-initiated chemiluminiscence (+76%), that was partially prevented by the leaf extract (+31%). Liver SOD activity was a 158% higher in animals receiving paraquat as compared to the controls. This effect was abolished by administration of the leaf extract. Paraquat administration did not significantly modify the activity of GPx or catalase. Croton cajucara extract increased GPx and catalase activities in paraquat treated-animals by 342% and 70%, respectively. Our results confirm that Croton cajucara leaf extract present radical scavenging activity and reduce oxidative stress induced by paraquat, suggesting the beneficial use as a potential source of antioxidant agents of natural origin.

Phenolic Antioxidant Compounds Produced by in Vitro. Cultures of Rosemary (Rosmarinus officinalis.) and Their Anti-inflammatory Effect on Lipopolysaccharide-Activated Microglia

Different culture types (shoot culture, callus culture, and cell suspension culture) of Rosmarinus officinalis. L. were established and their ability to biosynthesize the phytochemicals carnosic acid, carnosol, and rosmarinic acid were assessed and compared with subcultures of the same stem plant over time. Furthermore, we examined the antioxidative effect of extracts from different culture types by measuring their scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals as well as their anti-inflammatory potential on neonatal microglial rat cells activated by means of the inflammogen lipopolysaccharide (LPS) taking nitric oxide (NO) as parameter. Our results show that during an investigation period of 17 months, the shoot culture accumulated varying amounts of carnosic acid and carnosol, which were also present in callus culture but about 20- to 80-fold lower than in the shoot culture. In suspension culture, only carnosic acid and no carnosol could be detected. The level of carnosic acid in suspension culture was threefold less than detected for the callus culture on average. The amount of rosmarinic acid produced in shoot culture and callus culture were comparable, whereas in suspension culture higher concentrations of rosmarinic acid could be measured than in shoot and callus culture. Thus, the content of carnosic acid, carnosol, and rosmarinic acid in the extracts depended on the differentiation grade of the cell culture type. The DPPH radical-scavenging activity of the extracts depended on the amount of all three phytochemicals, in particular of rosmarinic acid. The anti-inflammatory character of the extracts was mainly based on their carnosic acid content.

Antioxidative and prooxidative effects of extracts made from cherry liqueur pomace

The effect of phenolics extracted from cherry liqueur pomace on the Fenton reaction was tested in a model system, where hydroxyl radicals from iron (II) reduction of H 2O 2 reacted with ethanol, forming 1-hydroxyl radicals. The extent of the radical formation was monitored by electron spin resonance (ESR) detection of spin adducts formed from 1-hydroxyethyl radicals and 4-pyridyl-1-oxide- N- tert-butylnitrone (POBN). Small phenol–iron ratios gave low amounts of detected radicals, indicating an antioxidative effect of the extracts, whereas high phenol–iron ratios gave high levels of radicals, indicating decreasing antioxidant or dominating prooxidant effects. Extracts made with pure solvents (water, methanol, ethanol, acetone or 2-propanol) gave higher antioxidant effects than extracts made with 70% aqueous solvent mixtures. The prooxidant effect of the extracts increased with the polarity of the extraction solvent. Gallic acid gave a prooxidative effect, p-coumaric acid only an antioxidative effect, while epicatechin gave an antioxidative effect at low concentrations and a prooxidative effect at high concentrations.

Antioxidative effect of extracts from red grape seed and peel on lipid oxidation in oils of sunflower

The antioxidative effect of red grape seed (RGS) and red grape peel (RGP) ethanolic extracts on primary and secondary lipid oxidation in sunflower and conjugated sunflower (SF/CSF) oils was evaluated. Lipid oxidation was analysed at 60 °C using three methods; conjugated diene (CD) measurements for primary oxidation product development, static headspace gas chromatography (SHGC), and proton transfer reaction-mass spectrometry (PTR-MS) to follow the formation of secondary lipid oxidation products (propanal, 1-penten-3-one, hexanal and octanal). The phenolic content (200 mg/kg) in extracts did not have any effect on the conjugated diene hydroperoxides. After 6 days, high antioxidative effect was found for the secondary oxidation products in CSF for peel extract followed by seed extract. The antioxidative activity for the peel extract was up to 41.2% for propanal measured by PTR as compared with 17.1% for seed extract. On the other hand, at 6 days the peel and seed extracts were shown to expect prooxidative effect on SF for the secondary oxidation products. It has been noticed that SF has high stability for lipid oxidation among all the mixtures tested using the three determination methods. Obviously, PTR-MS succeeded, as an accurate method, to measure the concentration as low as 10 μg/kg, and also to solve the solvent interference.

Effect of sumach (Rhus coriaria L.) extracts on the oxidative stability of peanut oil.

The antioxidant activities of sumach (Rhus coriaria L.) extracts and butylated hydroxyanisole (BHA) at various concentrations were tested in natural peanut oil stored at 65 degrees C for 35 days. The concentrations (weight/volume) of extracts added into oil were 1.0%, 3.0%, and 5.0%, and those of BHA were 0.1%, 0.3%, and 0.5%. Antioxidant effect was determined by the measurement of peroxide value. After 7 days of storage, BHA and extracts of sumach were active in varying degrees against autoxidation of peanut oil, compared with the control test (P <.01). The sumach extracts generally inhibited the formation of hydroperoxide, as did BHA. After 28 days of storage, antioxidant effects of extracts were significantly decreased when compared with BHA. The decrease in the antioxidant activity of extracts might have resulted from the decrease of polyphenolic constituents. The results showed that high concentrations can enhance the potency of the antioxidant effect of sumach extract.

Antioxidant Activity of Extracts from Du-zhong (Eucommia ulmoides) toward Various Lipid Peroxidation Models in Vitro

The antioxidant effect of extracts from leaves, raw cortex, and roasted cortex of Du-zhong was evaluated using various lipid peroxidation models. The inhibitory activity of extracts of Du-zhong (200 μg/mL) on the peroxidation of linoleic acid measured by thiocyanate method followed the order leaves (99.9%) > roasted cortex (95.9%) > raw cortex (77.2%) at 60 h of incubation. The IC20 for leaves, roasted cortex, and raw cortex on the peroxidation of liposome, induced by Fe3+/H2O2/ascorbic acid, was <0.06, 0.24, and 0.81 mg/mL, respectively. The thiobarbituric acid reactive substances values for leaves, roasted cortex, and raw cortex were 0.12, 1.54, and 1.81 μmol of malondialdehyde/mg of protein in enzyme-mediated microsomal peroxidation and 0.08, 0.69, and 0.88 μmol of malondialdehyde/mg of protein in the nonenzyme-mediated microsomal peroxidation, respectively. The antioxidant activity of extracts of Du-zhong correlates to their polyphenol content. The results presented herein indicate that extracts of Du-zhong leaves may be useful in inhibiting membrane lipid peroxidation and preventing free radical-linked disease. Keywords: Du-zhong tea; water extracts; antioxidant activity; lipid peroxidation; free radical

Antioxidative Effect of Extracts from Erodium cicutarium L.

Extracts from Erodium cicutarium L. (EC) and some standard substances present in EC extracts were tested for their antioxidative properties during Fe(2+)-induced triglyceride oxidation. Hydrophobic fractions such as petroleum ether (PEE), benzene (BE) and chloroform I (ChE I) extracts as well as hydrophilic fractions i.e. water (WE) and ethyl acetate (EAE) showed an antioxidative effect. Among the tested substances vitamin C and some polyphenolic compounds: tannin, (+)-catechin and gallic acid exhibited antioxidative activity, stronger than the one of the mentioned extracts.