茉莉花挥发油清除自由基活性的研究

目的：从清除1,1－二苯基－2－苦苯肼自由基（DPPH?）、羟自由基（? OH）、超氧阴离子自由基（O2?－）3个方面,研究茉莉花挥发油清除自由基活性。方法采用水蒸气蒸馏法提取茉莉花挥发油,从其清除DPPH?、? OH和O2?－能力3个方面进行考察,并以常用抗氧化剂L－抗坏血酸为对照作比较,通过计算半数抑制浓度（ IC50）评价茉莉花挥发油清除,在供试质量浓度范围内,呈一定量效关系,其 IC50分别为153．548μg?mL －1、56．481μg? mL －1和133．586μg? mL －1。结论茉莉花挥发油具有良好的清除自由基活性,是一种新型天然抗氧化物质来源。     

红景天中8种成分体外抗氧化作用的比较

目的比较性研究红景天中8种苷及醇类化合物———芦丁苷、红景天苷、异槲皮苷、酪醇、络塞琳、熊果苷、络塞维、肉桂醇红景天的体外抗氧化作用。方法测定8种成分对DPPH自由基、超氧阴离子自由基、一氧化氮自由基、羟自由基的清除能力,以及总抗氧化能力和抑制脂质过氧化反应的能力。结果除清除羟自由基实验外,异槲皮苷和芦丁苷作用明显强于其他化合物,其中在清除DPPH、超氧阴离子能力和抑制脂质过氧化实验中的IC50分别为5.72和10.46,23.63和36.39,10.78和56.49 mg.L-1;而在清除羟自由基实验中,酪醇和红景天苷的作用则强于其他化合物,IC50分别为10.84和18.97 mg.L-1。结论红景天中苷及醇类成分对多种自由基具有清除作用,有良好的综合抗氧化性和开发应用前景。     

Antioxidant Activities of the Chloroform Extract of Solanum trilobatum

A chloroform extract from the anticancer herb Solanum trilobatum (CST) (Nadkarni, 1979) was analyzed and compared with reference antioxidants for its in vitro antioxidative properties such as scavenging of α,α-diphenyl-β-picryl hydrazyl (DPPH) and superoxide radicals, protection to deoxyribose degradation, reducing power, as well as inhibition of lipid peroxidation. Preliminary phytochemical analysis of CST by silica gel thin-layer chromatography showed the presence of simple phenols, phenolic acids, isoflavones, xanthones, and lignans. The antioxidative effect of CST was found to be concentration dependent to a certain extent and then leveled off with further increase in concentration. The IC₅₀ for each antioxidative reaction studied was calculated. When compared to the reference antioxidant butylated hydroxytoluene (BHT), CST exhibited less scavenging effect on DPPH radicals and reducing power but a better superoxide radical scavenging effect. From a comparison of the hydroxyl radical scavenging effect of CST with catechin, it seemed that CST was four-times more effective than catechin. CST was also able to prevent the formation of ·OH-induced malondialdehyde (MDA) in rat liver homogenate.     

Antioxidant and Free Radical Scavenging Effects of Lippia nodiflora

This study evaluated the in vitro antioxidant potential of methanol extract of Lippia nodiflora Mich. (Verbenaceae) (MELN). The different antioxidants assays, including total antioxidant activity, reducing power, free radical, superoxide anion radical, hydroxyl radical, hydrogen peroxide, nitric oxide scavenging, and total phenolic content, were studied. MELN exhibited potent total antioxidant activity that increased with increasing amount of extract concentration (50, 100, 200, and 400 μg/mL), which were compared with standard drug α -tocopherol (400 μg/mL). The different concentrations of MELN and α -tocopherol showed inhibition of 49.07%, 58.96%, 63.07%, 68.29%, and 74.59%, respectively, on peroxidation in linoleic acid emulsion. In addition, MELN had effective reducing power, free radical scavenging, superoxide anion radical scavenging, hydroxyl radical scavenging, hydrogen peroxide radical scavenging, and nitric oxide scavenging activity, and total phenolic content depending on concentration. These various antioxidant activities were compared with standard antioxidants such as BHA, BHT, catechin, and α -tocopherol.     

5,7,4’-三羟基异黄酮基-8-对偶氮苯磺酸的合成及其抗氧化活性研究

目的合成未见文献报道的化合物5,7,4’-三羟基异黄酮基-8-对偶氮苯磺酸,并探讨其抗氧化活性。方法采用IR、1H-NMR、元素分析对其结构进行表征。利用荧光光谱法研究目标物对羟基自由基的清除活性,采用紫外光谱法研究目标物对超氧阴离子自由基和1,1-二苯基-2-苦肼基自由基(DPPH·)的清除活性。结果与结论目标化合物对1,1-二苯基-2-苦肼基自由基、羟基自由基和超氧阴离子自由基都有良好的清除活性,而且对羟基自由基的清除活性远高于对超氧阴离子自由基和1,1-二苯基-2-苦肼基自由基的清除活性。     

In vitro antioxidant activity of pet ether extract of black pepper

Objective:

To investigate the in vitro antioxidant activity of different fractions (R1, R2 and R3) obtained from pet ether extract of black pepper fruits (Piper nigrum Linn.)

Materials and Methods:

The fractions R1, R2 and R3 were eluted from pet ether and ethyl acetate in the ratio of 6:4, 5:5 and 4:6, respectively.1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitric oxide radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract.

Results:

The free radical scavenging activity of the different fractions of pet ether extract of P. nigrum (PEPN) increased in a concentration dependent manner. The R3 and R2 fraction of PEPN in 500 µg/ml inhibited the peroxidation of a linoleic acid emulsion by 60.48±3.33% and 58.89±2.51%, respectively. In DPPH free radical scavenging assay, the activity of R3 and R2 were found to be almost similar. The R3 (100µg/ml) fraction of PEPN inhibited 55.68±4.48% nitric oxide radicals generated from sodium nitroprusside, whereas curcumin in the same concentration inhibited 84.27±4.12%. Moreover, PEPN scavenged the superoxide radical generated by the Xanthine/Xanthine oxidase system. The fraction R2 and R3 in the doses of 1000µg/ml inhibited 61.04±5.11% and 63.56±4.17%, respectively. The hydroxyl radical was generated by Fenton''s reaction. The amounts of total phenolic compounds were determined and 56.98 µg pyrocatechol phenol equivalents were detected in one mg of R3.

Conclusions:

P. nigrum could be considered as a potential source of natural antioxidant.     

Hepatoprotection by chemical constituents of the marine brown alga Spatoglossum variabile: A relation to free radical scavenging potential

Context: In the course of searching hepatoprotective agents from natural sources, the protective effect of chemical constituents of the marine brown alga Spatoglossum variabile Figaro et DE Notar (Dictyoaceae) against CCl₄-induced liver damage in Wistar rats was investigated. The compounds were first investigated for in vitro radical scavenging potential and were also tested for β-glucuronidase inhibition to further explore the relationship between hepatoprotection and antiradical potential.

Methods: The compounds cinnamic acid esters 1 and 2 and aurone derivatives 3 and 4 were first investigated for in vitro radical scavenging potential against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), and superoxide anion radicals. In vivo hepatoprotective studies were performed in seven groups (n = 6) of Wistar rats. The test groups were pretreated with compounds (10?mg/kg body weight, po) orally for 30?min before the intraperitoneal administration of a dose of 20% CCl₄ diluted with dietary cooking oil. Moreover, compounds were also tested for β-glucuronidase inhibition to explore the relationship between hepatoprotection and radical scavenging potential.

Results: The test compounds 1–4 were found to exhibit antiradical activity against 1,1-diphenyl-2-picrylhydrazyl radicals with IC₅₀ values ranging between 54 and 138 µM, whereas aurone derivatives 3 and 4 additionally exhibited superoxide anion scavenging effects with IC₅₀ values of 95 and 87 µM, respectively. In addition, these compounds were found to be weak inhibitors of xanthine oxidase (IC₅₀ ≥1000 µM). In animal model, pretreatment with compounds 2–4 significantly blocked the CCl₄-induced increase in the levels of the serum biochemical markers.

Conclusion: It appears that the hepatoprotection afforded by these compounds was mainly due to their radical scavenging activity that protected the cells from the free radicals generated by CCl₄-induced hepatotoxicity.     

芙蓉菊多糖体外抗氧化活性研究

目的研究芙蓉菊多糖的体外抗氧化活性。方法采用1,1-二苯基苦基苯肼(DPPH)自由基、还原力、超氧阴离子、羟自由基4种体外抗氧化模型研究芙蓉菊多糖的抗氧化活性,用维生素C作对照。结果芙蓉菊粗多糖对DPPH自由基、还原力、超氧阴离子、羟自由基均有明显的清除能力,其中DPPH、超氧阴离子、羟自由基的EC50值分别为0.273、0.669、0.594mg/mL,对羟自由基清除能力强于维生素C。芙蓉菊多糖对自由基清除率与其质量浓度存在着明显的量效关系。结论芙蓉菊多糖具有良好的体外抗氧化活性,作为天然抗氧化剂和自由基清除剂有进一步研究的价值。     

乌梅抗氧化作用的实验考察

目的:研究乌梅提取物抗氧化作用。方法:通过检测还原力和清除DPPH、ABTS和超氧阴离子自由基的能力,分析和评价乌梅提取物的抗氧化活性。结果:乌梅醇提物对DPPH、ABTS自由基的IC50分别为0.500 mg.mL-1及0.253 mg.mL-1;乌梅水提物对DPPH、ABTS自由基的IC50分别0.510 mg.mL-1及0.500 mg.mL-1;乌梅醇提物还原能力大于乌梅水提物,且乌梅醇提物对超氧阴离子自由基的清除作用显著,其清除作用优于乌梅水提物及对照品BHT。结论:乌梅提取物有不同程度的抗氧化活性,其中以醇提物抗氧化作用最强。     

Appraisal of anti-inflammatory and free radical scavenging activities of ethanol extract of Ilex ficoidea Hemsl and Ilex centrochinensis S.Y. Hu

This study was to appraise the anti-inflammatory and free radical scavenging activities of ethanol extracts of Ilex ficoidea Hemsl (EIFH) and Ilex centrochinensis S.Y. Hu (EICC). Anti-inflammatory activities were evaluated using xylene-induced ear edema and the cotton pellet granuloma tests. Some antioxidants produced during chronic inflammation were quantitated and the DPPH, superoxide anion and hydroxyl free radicals scavenging activities in vitro were also investigated. EICC showed a significant anti-inflammatory effect during the acute inflammation and chronic inflammation without any acute oral toxicity. However, EIFH exhibited a negligible anti-acute inflammatory and a moderate anti-chronic inflammatory activity. EICC significantly inhibited the formation of MDA and markedly raised the activities of SOD, CAT and GSH-Px. EIFH could reduce the level of MDA and elevate the activity of SOD only at the high dose. The free radical scavenging activities of EICC are higher than that of EIFH. These results suggest that EICC possesses significant anti-inflammatory and free radical scavenging activities. The anti-inflammatory mechanism is attributed, in part, to enhance the activities of antioxidant enzymes.     

“新冠三方”的体外抗氧化作用比较

目的 平行比较“新冠三方”(清肺排毒汤、化湿败毒方和宣肺败毒方,以下简称“三方”)的体外抗氧化作用。方法在非细胞体系中,采用FRAP法考察三方的总抗氧化能力;通过DPPH法考察三方对DPPH自由基的清除作用;采用NBT还原法考察三方对超氧阴离子的清除作用;通过基于终产物丙二醛的荧光测定法考察三方对羟自由基的清除作用;用FeSO4体外诱导大鼠肝匀浆MDA法考察三方对抗脂质过氧化的作用。依据以上5个抗氧化指标,平行比较三方提取物在非细胞体系的抗氧化能力。进一步地,在脂多糖活化的RAW264.7细胞模型上,分别使用L-012探针和MitoSOX线粒体超氧化物红色荧光探针检测胞质与线粒体活性氧(reactive oxygen species,ROS)的生成情况;通过光泽精探针检测胞质NADPH氧化酶活性,以平行比较三方提取物在细胞体系的抗氧化能力。结果 在非细胞体系中,三方均能剂量依赖地清除DPPH自由基、超氧阴离子和羟自由基,并且能有效对抗脂质过氧化的发生。在等提取物浓度下,三方对DPPH自由基与超氧阴离子的清除作用相当,总抗氧化能力相当,而化湿败毒方在清除羟自由基和对抗脂质过氧化方面表现更...     

Free radical scavenging activity of conjugated linoleic acid as single or mixed isomers

Context: Conjugated linoleic acids (CLAs) are a mixture of positional and geometric isomers of linoleic acid (LA) and believed to have many positive biological activities.

Objective: The present study was undertaken to assess the antioxidant activity of cis-9, trans-11 and trans-10, cis-12 as single or mixed CLA isomers at two ratios, 1:6 and 1:13 (trans-10, cis-12/cis-9, trans-11).

Materials and methods: A microplate reader was used to determine the free radical scavenging properties of CLAs against DPPH radical in ethanol.

Results: The kinetic reactions of CLA-DPPH^? showed that all tested CLAs have exerted radical scavenging activities in a dose-dependent manner and observed to immediately react and quench DPPH radicals at all tested levels and no lag phase was noticed in CLA-DPPH^? reactions. The median inhibitory concentration (IC₅₀) value for cis-9, trans-11 CLA was observed to be more effective than other tested CLA. Total antioxidant capacity (TAC) of all tested CLAs were less effective radical scavengers as compared to vitamin E and butylated hydroxytoluene, although all tested CLAs were quenched a high amount (P?<?0.05) of DPPH free radicals.

Discussion and conclusion: All tested CLAs have the ability to directly react and quench DPPH free radicals in ethanol. Furthermore, trans-10, cis-12 CLA has greater maximal efficacy than other tested CLAs as free radical scavenger, while cis-9, trans-11 CLA is the most potent isomer to directly react and quench free radicals at low concentrations in the system, suggesting that the free radical scavenging activity of CLA isomers may contribute to their diverse biological activities.     

Evaluation of the antioxidant effects of polysaccharides extracted from <Emphasis Type="Italic">Lycium barbarum</Emphasis>

Lycium barbarum, a famous Chinese medicinal herb, has a long history of use as a traditional remedy for many diseases. Polysaccharides are the most important functional constituent in Lycium barbarum fruits. In the present study, the antioxidant activity of polysaccharides extracted from Lycium barbarum fruits growing in Xin Jiang, a northwest province of China, was evaluated. Six established in vitro methods, including superoxide radical (O₂ ^-) scavenging activity, reducing power, β-carotene linoleate model, inhibition of mice erythrocyte hemolysis mediated by peroxyl free radicals, 1,1- diphenyl-2 picrylhydrazyl (DPPH) radical-scavenging, and metal chelating activity were used in our evaluation. The polysaccharides showed considerable inhibitory activity in the β-carotene–linoleate model system in a concentration-dependent manner. Further, they exhibited moderate concentration-dependent inhibition of the DPPH radical. The multiple antioxidant activity of the polysaccharides was evidenced by significant reducing power, superoxide scavenging ability, inhibition of mice erythrocyte hemolysis mediated by peroxyl free radicals, and also ferrous ion chelating potency. The data obtained in the in vitro models clearly establish the antioxidant potency of the polysaccharides extracted from Lyceum barbarum fruits.     

Medicinal cuisines: Diet and ethopharmacology

Abstract

The in vitro antioxidant potential of Triphala and its constituents was tested with the following systems: radical scavenging activity measured by DPPH reduction, and superoxide radical and peroxy radical scavenging properties measured by riboflavin/light/NBT reduction and linoleic acid peroxidation, respectively. Alcohol extracts of Triphala and its constituents were studied comparatively and found to be strong anti-oxidants. Triphala was also effective in preventing superoxide-induced haemolysis of red blood cells. The extracts also prevented lipid peroxidation induced by Fe³⁺/ADP/Ascorbate system in rat liver mitochondria. The major phenolic compounds of the alcohol extracts were confirmed as tannins.     

In vitro and in vivo antioxidant properties of different fractions of Moringa oleifera leaves

The antioxidant potency of different fractions of Moringa oleifera leaves were investigated by employing various established in vitro systems, such as β-Carotene bleaching, reducing power, DPPH/superoxide/hydroxyl radical scavenging, ferrous ion chelation and lipid peroxidation. On the basis of in vitro antioxidant properties polyphenolic fraction of M. oleifera leaves (MOEF) was chosen as the potent fraction and used for the DNA nicking and in vivo antioxidant properties. MOEF shows concentration dependent protection of oxidative DNA damage induced by HO and also found to inhibit the toxicity produced by CCl₄ administration as seen from the decreased lipid peroxides (LPO) and increased glutathione (GSH) levels. Among the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) levels were restored to almost normal levels compared to CCl₄ intoxicated rats. The HPLC analysis indicated the presence of phenolic acids (gallic, chlorogenic, ellagic and ferulic acid) and flavonoids (kaempferol, quercetin and rutin). Thus, it may be concluded that the MOEF possess high phenolic content and potent antioxidant properties, which may be mediated through direct trapping of the free radicals and also through metal chelation.     

Evaluation of antioxidant and free-radical scavenging potential of Artemisia absinthium

Context: Currently there has been an increased global interest to identify antioxidant compounds for use in preventive medicine and the food-industry that are pharmacologically potent and have low or no side effects. As plants produce significant amount of antioxidants to prevent oxidative stress, they represent a potential source of new compounds with antioxidant activity.

Objective: The current study was designed to evaluate the methanol extract of Artemisia absinthium Linn. (Asteraceae; MAB) for its in vitro free-radical scavenging effects using different classical assays, and in vivo antioxidant activity using global cerebral ischemia and reperfusion (I/R)-induced oxidative stress in mice.

Materials and methods: The in vitro scavenging activity was studied on the superoxide anions, hydrogen peroxide, hydroxyl, nitric oxide radical, and reducing power. Further, in the in vivo studies, the animal model of global cerebral I/R was established by occluding the bilateral carotid artery for 15?min followed by 24-h reperfusion. The thiobarbituric acid reactive substances (TBARS) concentration, superoxide dismutase (SOD) activity and glutathione (GSH) content were determined by colorimetric assays.

Results: In the in vitro assays, methanol extract of A. absinthium showed significant (p?<?0.05) superoxide anion, hydrogen peroxide, hydroxyl and nitric oxide radical scavenging activities, and significant reducing power. Furthermore, in the in vivo studies, oral administration of MAB (100 or 200?mg/kg) inhibited cerebral I/R-induced oxidative stress by decreasing TBARS, and restoring levels of SOD and GSH.

Conclusion: The results indicated that A. absinthium possess potent antioxidant properties, and may be used as a protective agent against disorders associated with oxidative stress.     

Antioxidant activity and protective effects of Trapa japonica pericarp extracts against tert-butylhydroperoxide-induced oxidative damage in Chang cells

In this study, the antioxidant properties of Trapa japonica pericarp extracts were evaluated through several biochemical assays: 2,2-diphenyl-1-picrylhydrazyl (DPPH), alkyl radical scavenging activity, hydroxyl radical scavenging, ferric reducing antioxidant power (FRAP) assay, ABTS radical scavenging activity and oxygen radical absorbance capacity (ORAC). The antioxidant activities were compared with other natural and synthetic antioxidants. The results showed that higher radical scavenging activity and antioxidant capacity in FRAP than those of vitamin C as a positive control. T. japonica pericarp extracts have antioxidant properties through its ability to prevent tert-butylhydroperoxide (t-BHP)-induced toxicity which enhance the cell viability, reduce reactive oxygen species (ROS) production, inhibits of oxidative damage and mitochondria dysfunction in Chang liver cells. Therefore, based on these finding, it seems reasonable to suggest that T. japonica pericarp extracts has the potential to protect liver against t-BHP-induced cell damage and should be considered as a potential functional food.     

2种西番莲叶中黄酮的抗氧化活性研究

目的:研究紫果和黄果西番莲叶中黄酮提取物的抗氧化作用。方法:以芦丁、Vc为对照,测定紫果和黄果西番莲叶中黄酮提取物对超氧阴离子自由基(O2-·)、羟自由基(·OH)及二苯代苦味酰基苯肼(DPPH·)自由基的清除率。结果:2种西番莲叶中黄酮提取物均具有不同程度的清除自由基能力,其中黄果西番莲提取物对·OH的清除率优于Vc和紫果西番莲提取物;2种西番莲提取物对O2-·和DPPH·自由基有清除效果,但总体偏低。结论:2种西番莲叶中黄酮均具有不同程度的抗氧化能力。     

Characterization of the radical scavenging and antioxidant activities of danshensu and salvianolic acid B.

Danshensu (3-(3,4-dihydroxyphenyl) lactic acid) and salvianolic acid B, two natural phenolic acids of caffeic acid derivatives isolated from Salvia miltiorrhiza root of the most widely used traditional Chinese medicine for the treatment of various cardiovascular diseases, have been reported to have potential protective effects from oxidative injury. To better understand their biological functions, the in vitro radical scavenging and antioxidant activities of danshensu and salvianolic acid B were evaluated along with vitamin C. Both danshensu and salvianolic acid B exhibited higher scavenging activities against free hydroxyl radicals (HO()), superoxide anion radicals (O(2)(-)), 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals and 2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radicals than vitamin C. In contrary, danshensu and salvianolic acid B showed weaker iron chelating and hydrogen peroxide (H(2)O(2)) scavenging activities than vitamin C. As expressed as vitamin C equivalent capacity (VCEAC), the relative VCEAC values (mg/100ml) were in the order of salvianolic acid B (18.59) > danshensu (12.89) > vitamin C (10.00) by ABTS radical assay. The protective efficiencies against hydrogen peroxide induced human vein vascular endothelial cell damage were correlated with their antioxidant activities. Analysis of structure-activity relationship of these two compounds showed that the condensation and conjugation of danshensu and caffeic acid appears important for antioxidant activity. These results indicated that danshensu and salvianolic acid B are efficient radical scavengers and antioxidants, and salvianolic acid B is superior to danshensu. Their radical scavenging and antioxidant properties might have potential applications in food and healthcare industry.     

Free Radical Scavenging Activity of Linum arboreum.

Abstract

The methanol and water extracts of Linum arboreum.. aerial parts were screened for free radical scavenging activity. The free radical scavenging activity was determined spectrophotometrically on the basis of inhibition of cytochrome c reduction and the ability to bleach the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The methanol extracts of Linum arboreum. were shown to have potent antioxidant activity.