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Extraction Storage and Qualitative Analysis of Free Radicals Scavenging Substances from Sweet Potato Leaves 被引量:9
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作者 王友升 董银卯 +1 位作者 宋彦 黑维俭 《Agricultural Science & Technology》 CAS 2008年第2期1-5,9,共6页
[ Objective ] The research aimed to provide reference for the application of extracts from sweet potato leaves in anti-aging cosmetics. [ Method ] The extraction and storage conditions for free radicals scavenging sub... [ Objective ] The research aimed to provide reference for the application of extracts from sweet potato leaves in anti-aging cosmetics. [ Method ] The extraction and storage conditions for free radicals scavenging substances from sweet potato leaves were optimized by orthogonal test and the bioactive components in extracts were investigated by correlation analysis. [ Result] Sweet potato leaves contain the bioactive substances scavenging DPPH free radical and hydroxyl free radical. Extracting solvent species is the most important factor that influencing extraction yield. The optimal extraction and storage conditions are as following: water as solvent, pH 8.0 of extracting liquid, storage at 25 ℃. There is a good positive linear relationship between the content of total phenols in sweet potato leaves and corresponding scavenging rates against both the DPPH free radical and hydroxyl free radical. For the content of total flavones in sweet potato leaves, just a correlation with scavenging rate against hydroxyl free radical shown in test. [ Conclusion] The phenols in ex- tracts could effectively scavenge both the DPPH free radical and hydroxyl free radical, whereas the flavones in extracts can only function on the hydroxyl free radical. 展开更多
关键词 Sweet potato leaves free radicals scavenging Total phenol Total flavones
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Component Analysis and Free Radicals Scavenging Activity of Physalis alkekengi L. Polysaccharide 被引量:19
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作者 CHENG Ying-kun LI Lei MENG Zhao-kun HOU A-li WU Yu-jie TENG Li-rong 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2008年第2期167-170,共4页
A crude polysaccharide was extracted from Physalis alkekengi L. fruit. HPLC was used for the component analysis of the polysaccharide. The results indicate that Physalis alkekengi L. polysaccharide(PAP) was composed... A crude polysaccharide was extracted from Physalis alkekengi L. fruit. HPLC was used for the component analysis of the polysaccharide. The results indicate that Physalis alkekengi L. polysaccharide(PAP) was composed of rhamnose, xylose, arabinose, galactose, and glucose. Free radicals scavenging activity of PAP was studied through 3 free radicals scavenging tests. PAP exhibited high scavenging effects on OH and DPPH radicals, and both the scavenging rates were about 80%. The scavenging rate of O2^- radical was about 22%. 展开更多
关键词 PHYSALIS POLYSACCHARIDE Component analysis free radicals scavenging activity
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STUDIES ON FREE RADICAL SCAVENGING ACTIVITY IN CHINESE SEAWEEDS PART I. SCREENING RESULTS 被引量:4
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作者 严小军 房国明 娄清香 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1999年第3期240-246,共7页
Antioxidants have attracted the attention of researchers due to their beneficial effects as free radical scavengers. Application of a stable free radical named 1,1 diphenyl 2 picrylhydrazyl(DPPH) to screen the free ra... Antioxidants have attracted the attention of researchers due to their beneficial effects as free radical scavengers. Application of a stable free radical named 1,1 diphenyl 2 picrylhydrazyl(DPPH) to screen the free radical scavenging activity in 27 species of Chinese seaweed showed that 15 of them had significant activity in at least one of the organic solvent extracts. The most interesting seaweed species were Gelidium amansii, Gloiosiphonia capillaris, Polysiphonia urceolata, Sargassum kjellmanianum, Desmarestia viridis, and Rhodomela teres. 展开更多
关键词 SEAWEED antioxidant free radical dpph scavengING activity
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Phytochemical screening and free radical scavenging activity of Citrullus colocynthis seeds extracts 被引量:4
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作者 Nabila Benariba Rabeh Djaziri +4 位作者 Wafaa Bellakhdar Nacera Belkacem Marcel Kadiata Willy J.Malaisse Abdullah Sener 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2013年第1期35-40,共6页
Objective:To study the phytochemical screening of different extracts from Citrullus colocynthis(C.colocynthis)seeds extracts and to assess their antioxidant activity on the DPPH free radical scavenging.Methods:Phytoch... Objective:To study the phytochemical screening of different extracts from Citrullus colocynthis(C.colocynthis)seeds extracts and to assess their antioxidant activity on the DPPH free radical scavenging.Methods:Phytochemical screening,total content of polyphenols and flavonoids of C.colocynthis seeds extracts,including a crude aqueous extract(E1),a defatted aqueous extract(E2),a hydromethanolic extract(HM),an ethyl acetate extract(EA)and a n-butanol extract(n-B)was carried out according to the standard methods and to assess their corresponding effect on the antioxidant activity of this plant.Results:None of these extracts contained detectable amount of alkaloid,quinone,antraquinone,or reducing sugar.Catechic tannins and flavonoids were abundant in E1,MM and EA,whilst terpenoids were abundantly present in E1 and n-B but only weekly in HM.Coumarins were found in E2,EA and n-B.Polyphenols,expressed as gallic acid equivalent,amounted,per 100 g plant matter,to 329,1002 and 150 mg in EA,HM an E1 respectively.Flavonoids,expressed as catechin equivalent,amounted.per 100 g plant matter to 620,241 and 94 mg in EA,HM and E1 respectively.Comparable values were found in n-B and E1,with lower values in E2.Quercetin,myricetin and gallic acid were found in the EA and HM extracts by thin layer chromatography,The antioxidative effect of these extracts yielded,when tested at a concentration of 2000μg/mL in a 1,1-diphenyl-2-picrylhydrazyl assay,a reducing percentage of 88.8%with EA,74.5%with HM and 66.2%with E1,and corresponding IC_(50)of 350,580and 500μg/mL as compared to 1.1μg/mL for ascorbic acid.Conclusions:These qualitative and quantitative analytical data document the presence in C.colocynthis extracts of such chemical compounds as flavonoids responsible for the antioxidant activity,as well as other biological activities of this plant. 展开更多
关键词 CITRULLUS colocynthis POLYPHENOLS FLAVONOIDS free radical scavengING
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Free radical scavenging potential of Lagenaria siceraria(Molina) Standl fruits extract 被引量:3
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作者 Vijayakumar Mayakrishnan Selvi Veluswamy +2 位作者 Krishnakumari Shanmuga Sundaram Priya Kannappan Noorlidah Abdullah 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2013年第1期20-26,共7页
Objective:To elucidate free radical scavenging activity of ethanolic extract Lagenaria siceraria (L.siceraria)(Molina) fruit.Methods:The free radical scavenging activity of the L siceraria (Molina) fruit extract... Objective:To elucidate free radical scavenging activity of ethanolic extract Lagenaria siceraria (L.siceraria)(Molina) fruit.Methods:The free radical scavenging activity of the L siceraria (Molina) fruit extract was assayed by usingα,α-diphenyl-β-picrylhydrazyl(DPPH). 2,20-azinobis 3-ethyl henzothiazoline-6-sulfonate(ABTS),FRAP,reducing power,chelating ability andβ-carotene bleaching assay.Results:The IC<sub>50</sub>values of DPPH and ABTS radicalscavenging activity was found to be 1.95 mg/mL and 19 mg/mL,respectively.In ferrous chelation assay,the percentage of inhibition was found to be 89.21%.The reducing power of ethanolic extract of L siceraria(Molina) fruit was 0.068 at 1 mg/mL and increased to 0.192 at 5 mg/mL Theβ-carotene linoleate bleaching assay was 46.7%at 5 mg/mL and antioxidant activity using FRAP at 0.305 for 1 mg/mL to 0.969 for 5 mg/mL Conclusions:The results indicate that L siceraria (Molina) fruit could be an important sources of natural radical scavengers. 展开更多
关键词 Lagenaria siceraria ANTIOXIDANT dpph ABTS free radical
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Antioxidant activity and free radical scavenging activities of Streptomyces sp.strain MJM 10778 被引量:2
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作者 Dong-Ryung Lee Sung-Kwon Lee +4 位作者 Bong-Keun Choi Jinhua Cheng Young-Sil Lee Seung Hwan Yang Joo-Won Suh 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2014年第12期962-967,共6页
Objective:To investigate the antioxidant activity of soil-borne aetinobacteria.Methods:The total phenolic contents,the level of antioxidant potential by DPPH radical scavenging activity,MO scavenging activity,and ABTS... Objective:To investigate the antioxidant activity of soil-borne aetinobacteria.Methods:The total phenolic contents,the level of antioxidant potential by DPPH radical scavenging activity,MO scavenging activity,and ABTS radical scavenging activity in ethyl acelale extract were determined.Results:The 16 S rDNA sequencing analysis revealed that Streptomyces sp.strain MJM 10778.which was isolated from Hambak Mountain.Korea,has 99.9% similarity to Streptomyces misionensis(S.misionenis) NBRC 13063.The physiological and the morphological test revealed that the strain MJM 10778 has different characteristics from the strain NBRC.13063.The entire antioxidant assay with the ethyl acelale extract displayed good radical scavenging activity.The IC_(50) values of the strain MJM 10778 extract on DPPH,.NO.and ABTS radicals were identified to he 92.8 μg/mL,0.02 μg/ml,and 134.9 μg/mL,respectively.The ethyl acetate extract of the strain MJM 10778 showed an 81.500% of cell viability at 100 μg/mL in Raw264.7cell viability assay.Conclusions:The results obtained suggesl that the ethyl acetate extract of Streptomyces sp.strain MJM 10778 could be considered as a potential source of drug for the diseases that is caused by free radicals with its anti-oxidant activities and low cytotoxicity. 展开更多
关键词 STREPTOMYCES sp.strain MJM 10778 Antioxidant activity dpph radical scavengING ASSAY NO radical scavengING ASSAY
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Evaluation of free radical scavenging activity of various extracts of leaves from Kedrostis foetidissima(Jacq.)Cogn 被引量:7
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作者 Kalaisezhiyen Pavithra Sasikumar Vadivukkarasi 《Food Science and Human Wellness》 SCIE 2015年第1期42-46,共5页
The present study was aimed to investigate the in vitro free radical scavenging activity of various leaf extracts(aqueous,methanol,acetone chloroform and petroleum ether)of Kedrostis foetidissima.In vitro free radical... The present study was aimed to investigate the in vitro free radical scavenging activity of various leaf extracts(aqueous,methanol,acetone chloroform and petroleum ether)of Kedrostis foetidissima.In vitro free radical scavenging activities of the extracts were assessed against DPPH and hydroxyl radicals.The metal chelating activity and reducing power ability of the extracts were also determined.The free radical scavenging activity was found to be high in methanolic extract for DPPH and hydroxyl radicals in a concentration dependent manner followed by chloroform,aqueous,acetone and petroleum ether extracts.The metal chelating activity and reducing power ability was also found to be high in methanolic extract.The difference in scavenging potential of the extracts may be due to variation in the percentage of phytoconstituents extracted in various solvents.Thus the result suggests that the methanolic leaf extract of K.foetidissima could serve as a potential source of antioxidants and can be explored as a therapeutic agent in free radical induced diseases.©2015 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved. 展开更多
关键词 free radicals Kedrostis foetidissima ANTIOXIDANTS PHENOLS scavenging activity
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Constituents from Aerial Parts of Bidens ceruna L. and Their DPPH Radical Scavenging Activity 被引量:2
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作者 ZHU Na LI Xu-wen LIU Gui-ying SHI Xiao-lei GUI Ming-yu SUN Chang-qing JIN Yong-ri 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2009年第3期328-331,共4页
A new chalcone glycoside, butein-4-methoxyl-4′-O-(6"-O-acetyl)-β-D-glucopyranoside(2), along with seven known compounds, namely, quercitrin(1), luteolin-7-O-β-D-glucopyranoside(3), butein-4'-O-β-D-glucop... A new chalcone glycoside, butein-4-methoxyl-4′-O-(6"-O-acetyl)-β-D-glucopyranoside(2), along with seven known compounds, namely, quercitrin(1), luteolin-7-O-β-D-glucopyranoside(3), butein-4'-O-β-D-glucopyranoside(4), butein-4-methoxyl-4'-O-β-D-glucopyranoside(5), butin-7-O-β-D-glucopyranoside(6), isoquercitrin(7), and sulfurein(8) was isolated from aerial parts of Bidens ceruna L. Their structures were elucidated on the basis of spectroscopic studies. Compounds 1-8 were tested for their DPPH radical scavenging activity and, except compounds 2 and 5, other compounds showed scavenging activitv. 展开更多
关键词 Bidens ceruna L. CONSTITUENT Flavonoid dpph radical scavenging activity
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Butein imparts free radical scavenging, anti-oxidative and proapoptotic properties in the flower extracts of Butea monosperma 被引量:3
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作者 ANURADHA SEHRAWAT VIJAY KUMAR 《BIOCELL》 SCIE 2012年第2期63-71,共9页
The flower of Butea monosperma(Lam.)(Fabaceae)has been used in traditional Indian medicine in the treatment of many ailments including liver disorders.To understand the pharmacological basis of its beneficial effects,... The flower of Butea monosperma(Lam.)(Fabaceae)has been used in traditional Indian medicine in the treatment of many ailments including liver disorders.To understand the pharmacological basis of its beneficial effects,the extracts of dried flowers in water,methanol,butanol,ethyl acetate and acetone were evaluated for free radical scavenging and pro-apoptotic activities in cell cultures(human hepatoma Huh-7 cell line and immortalized AML-12 mouse hepatocytes).Butrin and butein-the active constituents of flower extracts-were used as reference molecules.The levels of cell injury markers like lactate dehydrogenase,glutathione and lipid peroxidation and primary antioxidant enzymes glutathione S-transferase and catalase were also measured.The aqueous and butanolic extracts exhibited better 2,2-diphenyl-1-picrylhydrazyl scavenging and cytotoxic activities in hepatoma cells than in immortalized hepatocytes.Interestingly,butein inhibited 2,2-diphenyl-1-picrylhydrazyl radical better than butrin.The aqueous and butanolic extracts were further investigated for hepatoprotection against carbon tertrachloride-induced biochemical changes and cell death.Both extracts,just as butrin and butein,significantly reversed the cellular glutathione levels and lipid peroxidation,and glutathione–S-transferase activity.Lactate dehydrogenase leakage and cell death were also prevented.However,only butein revived the catalase activity.Thus,the butein content of Butea monosperma flower extracts is important for free radical scavenging activity,apoptotic cell death and protection against oxidative injury in hepatic cells. 展开更多
关键词 butrin CYTOTOXICITY HEPATOPROTECTION methanol extract free radical scavenging
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In vitro evaluation of anti-acetylcholinesterase and free radical scavenging potential of leaf extracts of some selected medicinal plants 被引量:1
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作者 Annie Jessica Toppo Sheela Chandra +1 位作者 Dhruv Jha Papiya Mitra Mazumder 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2019年第2期60-65,共6页
Objective: To evaluate the phytochemical present in various solvent extracts from leaves of Ocimum sanctum(L.), Swertia chirayita(L.), Butea monosperma(Lam.) and Stevia rebaudiana(Bert.) as well as antioxidant and ant... Objective: To evaluate the phytochemical present in various solvent extracts from leaves of Ocimum sanctum(L.), Swertia chirayita(L.), Butea monosperma(Lam.) and Stevia rebaudiana(Bert.) as well as antioxidant and anticholinergic activities employing different in vitro models. Methods: Total phenol content of diethyl ether, chloroform and methanolic extracts obtained from leaves of different medicinal plants was determined by Folin-Ciocalteau's spectrophotometric method. Moreover, antioxidant and anticholinergic studies were conducted by four different in vitro methods which included diphenyl picrylhydrazyl radical scavenging, 2,2-azinobis(3-ethylbezoline-6-sulphonic acid), reducing activity by ferrous reduced antioxidant power and anti-acetylcholinesterase assay, in order to ensure pharmacological potential of the plants. Results: The methanolic leaf extract of Ocimum sanctum showed the highest total phenol content which was(21.13±1.04) GAE/g DW and antioxidant activities compared to other plants with the IC50 value of 40.43 μg/mL in diphenyl picrylhydrazyl radical scavenging assay and 53.5 μg/mL in 2,2-azinobis(3-ethylbezoline-6-sulphonic acid) assay as well as metal ion reduced by(78.22±0.38) TE/g DW in ferrous reduced antioxidant power assay. The inhibition percentage of the anti-acetylcholinesterase assay was(94.22±0.26)%. Conclusions: The results of our current study show that Ocimum sanctum leaf is the most significant source of phytochemicals that possesses antioxidant and anticholinergic properties. However, further investigation on isolation and characterization of active compound which is responsible for the pharmacological potential is needed. 展开更多
关键词 dpph ASSAY Antioxidant free radical Anti-acetylcholinesterase Phenolics content
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Study on the Free Radical Scavenging Activity of Sea Cucumber (Paracaudina chinens var.) Gelatin Hydrolysate 被引量:1
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作者 ZENG Mingyong XIAO Feng ZHAO Yuanhui LIU Zunying LI Bafang DONG Shiyuan 《Journal of Ocean University of China》 SCIE CAS 2007年第3期255-258,共4页
Gelatin from the sea cucumber(Paracaudina chinens var.) was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltr... Gelatin from the sea cucumber(Paracaudina chinens var.) was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltration membrane with 5 kDa molecular weight cutoff(MWCO). The portion(less than 5 kDa) was further separated by Sephadex G-25. The active peak was col-lected and assayed for free radical scavenging activity. The scavenging rates for superoxide anion radicals(O2·-) and hydroxyl radi-cals(·OH) of the fraction with the highest activity were 29.02% and 75.41%,respectively. A rabbit liver mitochondrial free radical damage model was adopted to study the free radical scavenging activity of the fraction. The results showed that the sea cucumber gelatin hydrolysate can prevent the damage of rabbit liver and mitochondria. 展开更多
关键词 Paracaudina chinens var. gelatin hydrolysate free radical scavenging activity MITOCHONDRIA
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Sonme Factors that Affect the Free Radical-scavenging Activity of Tea Extracts 被引量:9
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作者 Zhao Xinhuai ( Northeast Agricultural University, Harbin 150030 PRC) 《Journal of Northeast Agricultural University(English Edition)》 CAS 1999年第1期62-67,共6页
Some factors that affect the free radical-scavenging activety of two tea extracts were studied in vitro. It was found that concentration of tea extract or heating tea extract or treating with activated carbon and di... Some factors that affect the free radical-scavenging activety of two tea extracts were studied in vitro. It was found that concentration of tea extract or heating tea extract or treating with activated carbon and diatomite all had obvious effect on the scavenging activety of green tea extract ,but heating or treating with diaomite had less effect on the scavenging activity of black tea extract. Ascorbic acid, for having synergic effect with tea extracts, could enhance the scavenging activity of tea extracts markedly, and the contrary was cupric ion. Reducing sugars such as fructose and glucose also had some syncrgic effect to tea extracts. 展开更多
关键词 Tea extract. hydroxyl radical. free radival-scavenging activity
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Effects of Chuanxiongqin hydrochloride on increasing the fluidity of brain cell membrane and scavenging free radicals in model rats with ischemia/reperfusion injury 被引量:1
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作者 Chenxu Li Institute of Brain Sciences Department of Physiology, Medical College, Datong University, Datong 037008, Shanxi Province, China 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第8期721-724,共4页
BACKGROUND: The fluidity of cell membrane can be affected by various factors. Many experiments have confirmed that the ischemia/reperfusion of organic tissue can increase the contents of free radicals, which lead to h... BACKGROUND: The fluidity of cell membrane can be affected by various factors. Many experiments have confirmed that the ischemia/reperfusion of organic tissue can increase the contents of free radicals, which lead to high rigidity and low fluidity of cell membrane, and the conditions can be changed by Chuanxiongqin. OBJECTIVE: To observe the effect and mechanism of Chuanxiongqin hydrochloride on the fluidity of brain cell membrane in rat models of ischemia/reperfusion. DESIGN: A completely randomized controlled animal trial. SETTINGS: Institute of Brain Sciences; Department of Physiology, Medical College, Datong University. MATERIALS: Twenty male grade Ⅰ Wistar rats of 170-220 g were randomly divided into model group (n =10) and control group (n =10). Chuanxiongqin hydrochloride (molecular mass was 172.2) was purchased from the National Institute for the Control of Pharmaceutical and Biological Products (batch number: 0817-9803); Spin labelers: 5-doxyl-stearlic acid methylester (5DS), 16-doxyl-stearlic acid methylester (16DS), xanthine, xanthine oxidase (XOD) and 5,5-dimeth-1-pyrroline- N-oxide (DMPO) from Sigma Company; Bruker ESP 300 electron paramagnetic resonance (EPR) spectrometer by Bruker Company (Germany). METHODS: The experiments were carried out in the State Key Laboratory of Natural and Biomimetic Drugs, Peking University from June 2001 to July 2002. In the model group, rats were made into models of cerebral ischemia by 30-minute ligation and 2-hour reperfusion of common carotid arteries; The rats in the control group were not made into models. The order parameter (S) and rotational correlation time (τc) were detected with the ESR spectrometer by means of spin labeling. The greater the S and τc, the smaller the fluidity. Meanwhile, the clearance rate of free radicals was detected with ESR spin trapping. The measurement data were compared using the t test. MAIN OUTCOME MEASURES: The S, τc and clearance rates of O2 · and OH· free radicals were compared between the model group and control group. RESULTS: The S and τc in the model group [0.738 4±0.003 5; (8.472±0.027)×10-10 s/circle] were obviously different from those in the control group [0.683 9±0.008 3; (7.945±0.082)×10-10 s/circle, t =5.731, 5.918, P < 0.05], which suggested that ischemia/reperfusion injury decreased the fluidity of brain cell membrane. After adding Chuanxiongqin hydrochloride, there were no obvious differences between the model group [0.688 5±0.030 5; (7.886±0.341)×10-10 s/circle] and control group (P > 0.05), indicating that Chuanxiongqin hydrochloride could recover the fluidity of brain cell membrane after ischemia/reperfusion injury close to the level in the normal control group. Chuanxiongqin hydrochloride could directly scavenge the O2 · and OH· free radicals, and the maximal clearance rates were 83.92% and 44.99% respectively. CONCLUSION: Chuanxiongqin hydrochloride increases the fluidity of membrane of ischemia-injured brain cell by scavenging both O2 ·and OH· free radicals. 展开更多
关键词 Effects of Chuanxiongqin hydrochloride on increasing the fluidity of brain cell membrane and scavenging free radicals in model rats with ischemia/reperfusion injury cell free
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Comparative Analysis of the Antioxidant and Free-Radical Scavenging Activities of Different Water-Soluble Extracts of Green, Black and Oolong Tea Samples 被引量:2
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作者 Jesús Tejero Sara Gayoso +5 位作者 Irma Caro Damián Cordoba-Diaz Javier Mateo José E. Basterrechea Tomás Girbés Pilar Jiménez 《Food and Nutrition Sciences》 2014年第22期2157-2166,共10页
Extracts of 40 green, black or oolong high quality tea samples from China, Japan or India among others, have been prepared according to the manufacturer instructions and assayed for total polyphenols content using the... Extracts of 40 green, black or oolong high quality tea samples from China, Japan or India among others, have been prepared according to the manufacturer instructions and assayed for total polyphenols content using the Folin-Ciocalteu phenol reagent. In addition, the antioxidant activity was assessed by the CUPRAC method and the free-radical scavenging activity was determined using the antioxidant-promoting decay of the stable free-radical DPPH. Caffeine and the most important catechins were identified using RP-HPLC previously validated method. Results from this study suggest that teas, even though they content similar amounts of caffeine, differ considerably in polyphenolic content and therefore in antioxidant and free-radical scavenging activities, depending on the part of the plant used and the process applied to the material for the preparation of the final tea presentation. Correlations among Folin-Ciocalteau’s reactivity of tea samples, the neocuproine reactivity, the DPPH decolourization and the HPLC analysis suggest that the antioxidant activity is due essentially to polyphenolic compounds present in teas, mainly EGCG. The best extraction method of tea powder was the one indicated by dealers. In general, the richest samples belong to green teas and the poorest samples belong to the black teas. 展开更多
关键词 TEA POLYPHENOLS ANTIOXIDANTS free-radical scavengING
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Evaluation of lipid peroxidation inhibition and free radical scavenging abilities of 5,6,7-trimethoxy dihydroflavonols
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作者 Kc Xin Huang Yu Bing Feng +10 位作者 Wei Yao Lei Xiang Yang Feng Wang Hai Bo Li Su Zeng Jing Xu Gong Ming Hui Hu Yu Zhao Xiu Mei Wu Xiao Kun Li Jia Qu 《Chinese Chemical Letters》 SCIE CAS CSCD 2009年第10期1187-1190,共4页
Four naturally rare 5,6,7-trimethoxy-2,3-cis-dihydroflavonols (3-6) and two 5,6,7-trimethoxy-2,3-trans-dihydroflavonols (7-8) were designed and synthesized. Their antioxidative properties were evaluated by way of ... Four naturally rare 5,6,7-trimethoxy-2,3-cis-dihydroflavonols (3-6) and two 5,6,7-trimethoxy-2,3-trans-dihydroflavonols (7-8) were designed and synthesized. Their antioxidative properties were evaluated by way of examining their scavenging capacities towards DPPH and O2^*- free radicals, as well as by measuring their inhibitory ability against LPO. Both the 2,3-trans and the 2,3- cis conformers exhibited certain quenching abilities to DPPH and O2^*- radicals, while most of the synthetic dihydroflavonols demonstrated remarkable inhibition to LPO. 展开更多
关键词 5 6 7-Trimethoxy-2 3-dihydroflavonols cis-Dihydroflavonols ANTIOXIDANT Lipid peroxidation free radical scavenger
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Why Static O-H Bond Parameters Cannot Characterize the Free Radical Scavenging Activity of Phenolic Antioxidants: ab initio Study
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作者 Hong Yu ZHANG You Min SUN De Zhan CHEN 《Chinese Chemical Letters》 SCIE CAS CSCD 2001年第1期75-78,共4页
The static O-H bond parameters including O-H bond length, O-H charge difference, O-H Mulliken population and O-H bond stretching force constant (k) for 17 phenols were calculated by ab initio method HF/6-31G**. In com... The static O-H bond parameters including O-H bond length, O-H charge difference, O-H Mulliken population and O-H bond stretching force constant (k) for 17 phenols were calculated by ab initio method HF/6-31G**. In combination with the O-H bond dissociation enthalpies (BDE) of the phenols determined by experiment, it was found that there were poor correlationships between the static O-H bond parameters and O-H BDE. Considering the good correlationship bt tween O-H BDE and logarithm of free radical scavenging rate constant for phenolic antioxidant, it is reasonable to believe that the ineffectiveness of static O-H bond parameters in characterizing antioxidant activity arises from the fact that they cannot measure the O-H BDE. 展开更多
关键词 ANTIOXIDANTS free radical scavenging effect O-H bond dissociation enthalpy O-H bond length O-H bond stretching force constant O-H charge difference O-H Mulliken population QSAR
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Free Radical-Scavenging Properties and Antioxidant Activity of Fractions from Cranberry Products
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作者 Stéphane Caillet Guillaume Lorenzo +2 位作者 Jacinthe Coté Jean-Francois Sylvain Monique Lacroix 《Food and Nutrition Sciences》 2012年第3期337-347,共11页
Lipid peroxidation inhibition capacity and antiradical activity were evaluated in HPLC fractions of different polarity obtained from two cranberry juices and three extracts isolated from frozen cranberries and pomace ... Lipid peroxidation inhibition capacity and antiradical activity were evaluated in HPLC fractions of different polarity obtained from two cranberry juices and three extracts isolated from frozen cranberries and pomace containing antho-cyanins, water-soluble and apolar phenolic compounds, respectively. Compounds with close polarities were collected to obtain between three and four fractions from each juice or extract. The cranberry phenols are good free radi-cal-scavengers, but they were less efficient at inhibiting the lipid peroxidation. Of all the samples tested, the intermediate polarity fraction of extract rich in apolar phenolic compounds of fruit presented the highest antiradical activity while the most hydrophobic fractions of the anthocyanin-rich extract from fruit and pomace appeared to be the most efficient at inhibiting the lipid peroxidation. The antioxidant or pro-oxidant activity of fractions increased with the con-centration. The phenol polarity and the technological process to manufacture cranberry juice can influence the antioxidant and antiradical activities of fractions. 展开更多
关键词 HPLC Fractions Cranberry Juices Phenolic Extracts free radical scavenging Capacity Antioxidant Activity
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Conformationally regulated“nanozyme-like”cerium oxide with multiple free radical scavenging activities for osteoimmunology modulation and vascularized osseointegration 被引量:1
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作者 Shusen Bao Dongmei Yu +8 位作者 Zhen Tang Hao Wu Hao Zhang Ning Wang Yichao Liu Hai Huang Chaozong Liu Xiaokang Li Zheng Guo 《Bioactive Materials》 SCIE CSCD 2024年第4期64-79,共16页
Given post-operative aseptic loosening in orthopedic disease treatment,osteointegration occurs at the bone-implant interface as a holistic process,including immunoregulation(e.g.,macrophage polarization),angiogenesis ... Given post-operative aseptic loosening in orthopedic disease treatment,osteointegration occurs at the bone-implant interface as a holistic process,including immunoregulation(e.g.,macrophage polarization),angiogenesis and osteogenesis in sequence.In order to achieve early rapid and satisfactory osseointegration,different nano-shaped(nanocone,nanopolyhedron and nanoflower abbr.NC,NP&NF)cerium oxide(CeO_(2-x))coatings,endowed with“nanozyme-like”activities for multiple free radical elimination and osteoimmunology regulation,were hydrothermally synthesized on titanium alloy(TC4).In vitro cell experiments showed that nano-CeO_(2-x) coated TC4 not only induced polarization of RAW264.7 cells toward M2 phenotype,but also promoted angiogenesis and vascularization of endothelial cells along with differentiation and mineralization of osteogenic precursor cells.Improvements in M2-polarized macrophage,angiogenesis,and bone regeneration were further confirmed in a rat femoral condyle model.Among the above three nano-morphologies,NF exhibited the best osseoinetegration.RNA sequencing and mechanism exploration suggested that the inhibition of PI3K-AKT signaling pathway was essential for immunomodulatory capacity of NF.In conclusion,it provided promising insights into the immunomodulatory exploitation of orthopedic implants. 展开更多
关键词 Nanozyme-like”cerium oxide Durable redox activation free radical scavenging Osteoimmunology modulation Vascularized osseointegration
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Radical scavenging and antibacterial activity of Arnebia benthamii methanol extract 被引量:1
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作者 Showkat A Ganie Asima Jan +3 位作者 Sabeera Muzaffar Bilal A Zargar Rabia Hamid M Afzal Zargar 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2012年第10期766-772,共7页
Objective:To evaluate in vitro antioxidant and antibacterial activity of methanolic extract of Arnebia benthamii(A.benthamii) whole plant.Methods:Plasmid damage was analyzed by agarose gell electrophoresis.Calf thym... Objective:To evaluate in vitro antioxidant and antibacterial activity of methanolic extract of Arnebia benthamii(A.benthamii) whole plant.Methods:Plasmid damage was analyzed by agarose gell electrophoresis.Calf thymus DNA was monitored by TBARS formation.DPPH, reducing power and lipid peroxidation was evaluated by using standard procedures.Antibacterial assay was monitored by disc diffusion method.Results:DPPH radical scavenging and hydroxyl radical scavenging potential of the plant revealed that the extract to be active radical scavenger.Reducing(Fe<sup>3+</sup>-Fe<sup>2+</sup>) power and lipid peroxidation inhibition efficiency(TBARS assay) of the extract was also evaluated and the extract showed promising activity in preventing lipid peroxidation and might prevent oxidative damages to biomolecules.The extract offered a significant protection against plasmid and calf thymus UNA damage induced by hydroxyl radicals. The extract was also evaluated on different bacterial strains and the maximum antibacterial activity was exhibited against Escherichia coli(E.coli) when compared with standard drug. Conclusions:These findings demonstrate that the methanol extract of A.benthamii has excellent anti-oxidant activities and could be considered as a potential source of lead molecules for pharmaceutical industries. 展开更多
关键词 free radicalS LIPID PEROXIDATION dpph TBARS DNA damage ANTIBACTERIAL activity Arnebia benthamii
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含喹啉杂环席夫碱的合成及清除DPPH自由基活性研究
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作者 蒋飘飘 李思奇 +3 位作者 钟妍 罗珍琪 张政泓 张运良 《广东化工》 CAS 2024年第8期18-20,30,共4页
以水杨醛及衍生物(水杨醛、5-甲基水杨醛、5-甲氧基水杨醛)和2-肼基喹啉为原料,合成了3种含喹啉杂环的腙类希夫碱(L1=水杨醛缩-2-肼基喹啉、L2=5-甲基水杨醛-缩-2-肼基喹啉、L3=5-甲氧基水杨醛-缩-2-肼基喹啉),并用红外、紫外可见-吸收... 以水杨醛及衍生物(水杨醛、5-甲基水杨醛、5-甲氧基水杨醛)和2-肼基喹啉为原料,合成了3种含喹啉杂环的腙类希夫碱(L1=水杨醛缩-2-肼基喹啉、L2=5-甲基水杨醛-缩-2-肼基喹啉、L3=5-甲氧基水杨醛-缩-2-肼基喹啉),并用红外、紫外可见-吸收光谱、质谱和核磁共振谱等手段表征其结构,采用1,1-二苯基-2-三硝基苯肼(DPPH)自由基法测试了它们的抗氧化活性,并考察了溶剂、温度、光照对清除DPPH自由基活性的影响。结果表明:以乙醇为溶剂,3种含喹啉杂环的希夫碱对DPPH自由基均具有较好的清除能力,温度、光照对其清除效果影响都较小。 展开更多
关键词 喹啉杂环 希夫碱 合成 清除dpph自由基活性
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