Sonme Factors that Affect the Free Radical-scavenging Activity of Tea Extracts

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.

Free Radical-Scavenging Properties and Antioxidant Activity of Fractions from Cranberry Products

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.

Radical-scavenging activity,ACE-inhibiting capability and identification of rapeseed albumin hydrolysate

Albumin derived from rapeseed was hydrolyzed sequentially using alcalase and flavorzyme to produce antioxidant peptides.To identify antioxidant peptides,rapeseed albumin hydrolysate(RAH)was fractionated using size exclusion chromatography(G-25).The antioxidant activity and angiotensin I-converting enzyme(ACE)inhibiting activity of rapeseed peptides(RSP)purified from RAH were evaluated.The results revealed that RSP-4 had the highest ABTS radical-scavenging activity(TEAC value=0.24)and ACE-inhibiting capacity(IC50=0.19 mg/mL)compared to other fractions.Moreover,RSP-4 was identified as PFDSYFVC(977 D)by electrospray ionization(ESI)mass spectrometry and tandem mass spectrometry(MS/MS).©2013 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

Component Analysis and Free Radicals Scavenging Activity of Physalis alkekengi L. Polysaccharide

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%.

STUDIES ON FREE RADICAL SCAVENGING ACTIVITY IN CHINESE SEAWEEDS PART I. SCREENING RESULTS

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.

Evaluation of free radical scavenging activity of various extracts of leaves from Kedrostis foetidissima(Jacq.)Cogn

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.

Balancing sub‐reaction activity to boost electrocatalytic urea synthesis using a metal‐free electrocatalyst

Electrocatalytic urea synthesis via coupling of nitrate with CO_(2)is considered as a promising alternative to the industrial urea synthetic process.However,the requirement of sub-reaction(NO_(3)RR and CO_(2)RR)activities for efficient urea synthesis is not clear and the related reaction mechanisms remain obscure.Here,the construction,breaking,and rebuilding of the sub-reaction activity balance would be accompanied by the corresponding regulation in urea synthesis,and the balance of sub-reaction activities was proven to play a vital role in efficient urea synthesis.With rational design,a urea yield rate of 610.6 mg h−1 gcat.−1 was realized on the N-doped carbon electrocatalyst,superior to that of noble-metal electrocatalysts.Based on the operando SRFTIR measurements,we proposed that urea synthesis arises from the coupling of^(*)NO and^(*)CO to generate the key intermediate of^(*)OCNO.This work provides new insights and guidelines into urea synthesis from the aspect of activity balance.

Chemical composition and free radicals restraining activity of extracts from three Manglietia species leaves

The extracts from leaves of Manglietia insignis （Wall） Blume, Manglietia chingii Dandy and Manglietia yuyuanensis Law were prepared by organic solvent extraction and their components were analyzed by GC/MS and quantified. Meanwhile, the free radicals restraining activities were detected. The 21 compounds in M. insignis, 36 compounds in M. chigii and 20 compounds in M. yuyuanensis were identified. There were 11 common components in the extracts from three Manglietia species, and 12 components in two Manglietia species. The results of relative contents of every component in three extracts showed that the main constituents of M. insignis were terpenoids and alkene, amounting to 38.93%, followed by alkane （28.18%）, the nitrogen containing compounds （15.73%） and aromatic compounds （7.23 %）. The main constituents of leaf extract from M. chingii were the terpenoids and alkene, carboxylic acid, alkane and aromatic compounds, amounting to 30.22%, 14.17%, 13.87% and 13.29%, respectively, The main constituents of M. yuyuanensis were alcohol compounds, the terpenoids and alkene, and aromatic compounds, amounting to 28.00%, 25.38% and 18.00% respectively. The results showed that the three extracts had strong function of restraining oxygen free radicals. The ultra oxygen anions activity was restrained at the highest level, when the three extracts were diluted by hundred-fold, whereas the restraining capacity of hydroxyl free radicals reached maximum, when the three extracts were diluted by twenty-fold. The above results provide scientific evidences for further approaching the ecological healthy function of three MangUetia species

Antioxidant Activity of Anthocyanins Extracted from Iraqi <i>Iresine herbstii</i>L. Flowers after Drying and Freezing

Any processing method that maintains the level of compounds known for their health benefits will be of interest to the food industries. Therefore, the effects of vacuum drying, storage and freezing on the anthocyanin content and their antioxidant properties of Iresine herbstii L. flowers were investigated. The results showed that fresh samples (AEFF) had the highest amount of total anthosyanin content (8.31 ± 0.23 mg/g dry matter, expressed as cyaniding 3-glucoside equivalents), followed by 7.17 ± 0.12 mg/g solid content, 13.72% loss of vacuum dried samples (AEDF). In comparison with fresh samples, total anthocyanins in stored samples for two weeks at 5°C (AESF) and frozen samples during 1 (AEZF1) and 3 months (AEZF3) of storage were significantly (P < 0.01) reduced to 6.43 ± 0.24 mg/g solid content, 22.63% loss, 5.65 ± 0.33 mg/g solid content, 32.01% loss and 4.71 ± 0.51 mg/g solid content, 43.33% loss, respectively. Anthocyanins from I. herbstii L. flowers exhibited a dose-dependent (AEFF > AEDF > AESF > AEZF1 > AEZF3, respectively) antioxidant activity against lipid peroxidation in a linoleic acid model system as well as strong reducing power and ferrous ion chelating abilities. Moreover, the anthocyanins extracted were found to show remarkable scavenging activity on superoxide anion radicals, hydroxyl radicals, hydrogen peroxide, nitric oxide radicals and deoxyribose degradation. Based on the results obtained, we can concluded that the Iresine herbstii L. flowers may be valuable natural antioxidant sources and are potentially applicable in both pharmacy and food

Antioxidant Activity of Ethyl Acetate Extract of Amomum villosum Lour.

[Objectives]To study the antioxidant activity of the ethyl acetate extract of Amomum villosum Lour.[Methods]The removal rate of chelated iron ions,hydroxyl radicals,superoxide anion free radicals and DPPH free radicals by the ethyl acetate extract of A.villosum Lour.was determined by UV spectrophotometer.[Results]0.5000μg/mL ethyl acetate extract of A.villosum Lour.had the strongest ability to chelate with ferrous ions and to remove hydroxyl radicals,superoxide anion free radicals and DPPH free radicals.The ability to chelate with ferrous ions was 95.14%,and the removal rate of the above free radicals was 86.217%,81.44%,and 85.16%.[Conclusions]The ethyl acetate extract of A.villosum Lour.had a strong antioxidant effect,and its antioxidant capacity was related to the sample concentration,which provides a theoretical basis for its application in the development of antioxidant skin care products.

Study on the Free Radical Scavenging Activity of Sea Cucumber (Paracaudina chinens var.) Gelatin Hydrolysate

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.

Free Radical Activity as Diagnostic and Prognostic Criteria in Solid Tumors and Their Therapy

Blood plasma of 39 cancer patients who had not previously undergone anti-tumor treatment, and 21 patients with recurrent epithelial tissues cancer before treatment and after the first course of chemotherapy were investigated. The treatment effectiveness of patients with relapse was evaluated throughout the year. The control group was the blood plasma of 14 healthy people. Free radical activity and oxidative modification of proteins were assessed in blood plasma. In malignant neoplasms of epithelial tissues, free radical activity and oxidative modification of plasma proteins are significantly higher. At the initial stages of carcinogenesis, the oxidative modification level of plasma proteins increases both due to aldehyde and ketone carbonyl derivatives. In the terminal stage of malignant tumors, an increase in the oxidative modification of proteins occurs due to aliphatic ketone dinitrophenyl hydrazones, which are the markers of protein aggregation characteristic of the late stages of oxidative stress. In case of an objective response to polychemotherapy, there is a significant decrease in free radical plasma activity after the first course of therapy and a significant increase in carbonyl derivatives recorded at a wavelength of 230 nm, which can serve as a marker of its effectiveness.

Reliability of Passive Physical Activity Assessment for Inpatients Using Marker⁃Free Motion Tracking System

Evidence⁃based practices of public health will benefit from quantification of passive physical activity assessment.This study aims to investigate the reliability of marker⁃free system(MFS)such as Microsoft Kinect in measuring upper extremity motion from different angles.Ten healthy participants performed elbow and shoulder extension/flexion along frontal and median anatomical planes for ten pace⁃controlled repetitions,during which the spatiotemporal positions of upper extremity joints were concurrently recorded by two sensors from 0°and 45°viewing angles.Reliability between the two sensors were evaluated using Pearson correlation coefficient,intra⁃class correlation coefficients,and 95%limits of agreement and coefficient of variation.Worse reliability was observed when possibility of occlusion was higher.However,better reliability was found when longer observation interval(10 s)was used as elementary measuring unit than shorter observation interval(2 s).The overall angular reliability of activity as displacement or changes in angle was not satisfactory.The results are expected to inform the industry for the extension of MFS to clinic applications.

The Scavenging of Free Radical and Oxygen Species Activities and Hydration Capacity of Collagen Hydrolysates from Walleye Pollock(Theragra chalcogramma) Skin

Fish skin collagen hydrolysates （FSCH） were prepared from walleye pollock （Theragra chalcogramrna） using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of 〈1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical （DPPH）, superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione （GSH）. FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore FSCH may have potential applications in the medicine and food industries.

The Maturation and Senescence in Relation to Ca^2+,CaMContent and Ca^2+-ATPase Activity and Active OxygenMetabolism in Strawberry Fruits

The changes in content of Ca2 + and CaM, Ca2 + -ATPase activity and active oxygen metabolism during strawberry (Fragaria ananassa Duch. cv. Chunxing) fruits maturation and senescence were investigated in this study. The results showed that the soluble Ca2+ content and SOD activity in fruits tended to decline and O2 production rate to increase, the Ca2 + -ATPase activity peaked at first and then declined during fruits maturation and senescence. There were the highest CaM content at white stage in preharvest fruits and at marked senescence stage in postharvest ones. The above biochemical changes in fruits stored at low temperature (4℃)were slower than those stored at normal temperature(25℃). Thus, it indicated that the stimulation of calcium messenger system and accumulation of active oxygen free radical were closely related to fruits maturation and senescence.

The Influence of Free Water Content on Dielectric Properties of Alkali Active Slag Cement Paste

The dielectric performance of alkali activated slag （AAS） cement paste was investigated in the frequency range of 1 to 1000 MHz. The experimental results showed the unstable dielectric properties of harden paste were mostly influenced by the fraction of free water in paste or absorbed water from ambient, but not including hydration water and microstructure. The free water was completely eliminated by heat treatment at 105 ℃ about 4 hours, and then its dielectric loss was depressed; but with the exposure time in air increasing, the free water adsorption in ambient air made the dielectric property of harden cement paste to be bad. The temperature and relative humidity of environment was the key factors of free water adsorption; hence, if the influence of free water on dielectric constant was measured or eliminated, the cement-based materials may be applied in humidity sensitive materials or dielectric materials domains.

Investigation of antioxidant and anti-inflammatory activity of leaves of Dalbergia paniculata(Roxb)

Objective:To investigate the antioxidant and anti-inflammatory activity of orally administered methanolic leaf extract of Dalbergia paniculala(D.paniculata) in Carrageenan induced inflammation in rats.Methods:In vitro antioxidant activity was evaluated for superoxide radical, Hydroxyl radical and DPPH radical scavenging activity.Three doses 200 mg/kg,400 mg/kg and 800 mg/kg of D.paniculala were tested for anti-inflammatory activity in Carrageenan induced rat paw edema model and paw thickness was measured every one hour up to 6 h. Results:The melhanolic leaf extract of D.paniculala produced dose dependent inhibition of Superoxide radical,Hydroxyl radical and OPPH radicals.In Carrageenan induced inflammation model,all three doses produced significant percentage inhibition of rat paw edema and 800 mg/kg dose produced maximum percent inhibition of rat paw edema(47.83%) at 3h compared to control group.Conclusions:In the present study we found that methanolic leaf extract of D.paniculata showed good in vitro antioxidant activity and in vivo anti-inflammatory activity in rats.

Radical scavenging and antibacterial activity of Arnebia benthamii methanol extract

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(Fe3+-Fe2+) 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.

Liver Nuclear Activation of Carbon Tetrachloride or Bromotrichloromethane to Trichloromethyl and Trichloromethylperoxyl Free Radicals.Their Reactions With Lipids and Proteins

The formation of·CCl3 radicals in liver nuclei was suggested by spin trapping of them with N-t-butyl-α-phenylnitrone followed by GC/MS detection of the resulting adduct. Comparison of its formation in microsomal biotransformation of CCl4 was made. In aerobic nuclear activation mixtures containing NADPH and CCl4, significant decrease in the arachidonic acid content of nuclear lipids was observed (27. 8%, compared to control), the intensity of this decrease was lower than that occurring in the corresponding microsomal incubation mixtures (29.1%). Significant decreases in arachidonic acid content of nuclear and endoplasmic reticulum lipids were also observed in animals at 6 hours of poisoning with the haloalkane. During aerobic nuclear metabolism of CCl4 or CBrCl3, cholesterol oxidation products were detected: a ketocholesterol, an epoxide like structure and 7-ketocholesterol. Nuclear protein carbonyl formation was not promoted during nuclear CCl4 biotransformation. NADPH by itself may lead to protein carbonyl formation during prolonged periods of incubation. CBrCl3 in contrast, led to decreased protein carbonyl formation. No increase in nuclear protein carbonyl formation was observed in CCl4 intoxicated animals during periods of time between 1 to 6 hours after treatment. The results indicate that during nuclear biotransformation of CCl4 or CBrCl3 reactive free radicals, PUFA degradation, reactive aldehydes and cholesterol oxidation products are formed, nearby DNA and regulatory proteins.

Synthesis of crystal-phase and color tunable mixed anion co-doped titanium oxides and their controllable photocatalytic activity

B and N mixed anions co-doped titania with various crystal phases such as anatase,brookite,and rutile were successfully synthesized by a hydrothermal synthesis followed by heat treatment in an ammonia gas atmosphere at 550-650℃(denoted as BN-Ana_x,BN-Bro_x,and BN-Rut_x,x is the treatment temperature).The colors of as-prepared BN-Ana,BN-Bro,and BN-Rut are red,yellow-green,and cyangreen,respectively.The color changing mechanism of titania was related to their various band gap structure and the existence of B-N bonding.The nitridation temperature exhibits effective color changing compared to that of nitridation time.The different phases of the mixed anion codoped titania possess different photocatalytic deNO_(x) activity.The BN-Ana and BN-Rut show poor photocatalytic deNO_(x) activity,while the BN-Bro shows excellent photocatalytic deNO_(x) activity,better than that of standard titania photocatalyst Degussa P25.The colorful titania with low-photocatalytic activity is heavy metal elements free,indicating their possible applications as nontoxic color pigments or novel cosmetic raw materials.