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| 1 | Comparison of Energy Harvesting Systems for Wireless Sensor Networks显示文摘Wireless sensor networks (WSNs) offer an attractive solution to many environmental, security, and process monitoring problems. However, one barrier to their fuller adoption is the need to supply electrical power over extended periods of time without the need for dedicated wiring. Energy harvesting provides a potential solution to this problem in many applications. This paper reviews the characteristics and energy requirements of typical sensor network nodes, assesses a range of potential ambient energy sources, and outlines the characteristics of a wide range of energy conversion devices. It then proposes a method to compare these diverse sources and conversion mechanisms in terms of their normalised power density. | James M.Gilbert Farooq Balouchi | 2008 | International Journal of Automation and computing2008，5，4： | 25 |
| 2 | Hepatoprotective and antioxidant activity of a mangrove plant Lumnitzera racemosa显示文摘Objective:To identify the hepatoprotective and in vitro antioxidant activity of Lumnitzera racemosa(L.racemosa)leaf extract.Methods:Animals in Group 1 served as vehicle control,Group 2 served as liepatoloxin(CCL_4 treated)group,Group 3 served as positive control(Silyinarin)group,and Group 4,5 and 6 served as(75,150 and 300 mg/kg bw p.o.)L.raremosa leaf extract treated groups.Moreover,in vitro antioxidant DPPH,hydroxyl radical scavenging activity(HRSA),NO,ferric reducing antioxidant power(FRAP),lipid hydroperoxide(LPO)and super oxide dismutase(SOD)were also analyzed for the leaf extract.Results:The levels of the serum parameters such as serum glutamic oxaloacetic transaminase(SCOT),serum glutamic pyruvic transaminase(SGPT),alkaline phosphatase(ALP),bilirubin,cholesterol(CHL),sugar and lactate dehydrogenase(LDU)were significantly increased in CCL_4 treated rats when compared with the control group(P<0.05).But the L.racemosa leaf extract treated rats showed maximum reduction of SGOT[(210.36±19.63)IU/L],SGPT[(82.37±13.87)IU/L],ALP[(197.63±23.43)IU/L],bilurubin[(2.15±0.84)mg/dL],cholesterol[(163.83±15.63)mg/dL],sugar[(93.00±7.65)mg/dL]and LDH[(1134.00±285.00)IU/L]were observed with the high dose(300 mg/kg bw)of leaf extract treated rats.Histopathological scores showed that,no visible changes were observed with high dose(300 mg/kg bw)of leaf extract treated rats except few mild necrosis.The IC_(50)values were observed as(56.37±4.87)μg/mL,(57.68±1.98)μg/mL,(64.I5±2.90)μg/mL,(61.94±3.98)μg/mL,(94.53±1.68)μg/mL and(69.7±2.65)μg/mL for DPPH,HRSA,NO,FRAP,LPO and SOD radical scavenging activities,respectively.Conclusions:In conclusion,the hepatoprotective effect of the L.racemosa leaf extract might be due to the presence of phenolic groups,terpenoids and alkaloids and in vitro antioxidant properties. | Sundaram Ravikumar Murugesan Gnanadesigan | 2011 | Asian Pacific Journal of Tropical Biomedicine2011，1，5： | 21 |
| 3 | Phytochemical analysis and antioxidants activities of aqueous stem bark extract of Schotia latifolia Jacq显示文摘Objective:To evaluate the phytochemical constituents and antioxidant activities of aqueous extract of Scholia latifolia(S.latifolia)bark locally used for the treatment of oxidative stress-induced ailments in South Africa.Methods:The antioxidant and free radical scavenging activity of aqueous extract of the plant was assessed against 1,1-diphenyl-2-pierylhydrazyl(DPPH),nitric oxide(NO),2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt(ABTS)and the ferric reducing agent.Total phenolics,flavonoids,flavonols and proanthocyanidins were also determined to assess their corresponding effect on the antioxidant activity of this plant.Results:The activities of plant extract against DPPH,ABTS and NO radicals were concentration dependent with IC_(50)value of 0.06,0.05 and 0.05 mg/mL,respectively.The reducing power of the extract was greater than that of butylated hydroxyl toluene(BHT)and ascorbic acid which were used as standard drugs in a concentration dependent manner.The total phenolics content of the aqueous bark extract was(193.33±0.03 TE/g),followed by flavonoids(72.70±0.01 QE/g),proanthocyanidins|48.76±0.00 CE/g)and flavonols(47.76±0.21 QE/g).Phytochemical analysis revealed the presence of percentage tannin(11.40±0.02),alkaloid(9.80±0.01),steroids(18.20±0.01),glycosides(29.80±0.01)and saponins(6.80±0.00).The results exhibited a positive linear correlation between these polyphenols and the free radical scavenging activities.Conclusions:Our findings provide evidence that the crude aqueous extract of S.latifolia is a potential source of natural antioxidants and this justifies its uses in folkloric medicines. | Mbaebie BO Edeoga HO Afolayan AJ | 2012 | Asian Pacific Journal of Tropical Biomedicine2012，2，2： | 15 |
| 4 | Antioxidant activities of Indigofera cassioides Rottl.Ex.DC.using various in vitro assay models显示文摘Objective:To evaluate the antioxidant potential of methanolic leaf extract of Indigofera cassioides(MEIC) using various in vilro antioxidant assay systems.Methods:Antioxidant and free radical scavenging activity of MEIC was assayed by using different in vitro models like ABTS, DPPH,nitric oxide,superoxide,hydrogen peroxide and hydroxyl radical.Reductive ability of the extract was tested by the complex formation with potassium ferricyanide.Further total phenol and flavonoid contents of the crude extract were also determined.Rutin and ascorbic acid were used as standards.Results:MEIC exhibited potent and concentration dependent free radical scavenging activity in all the tested models.Reductive ability was also found to increase with increase in MEIC concentration.Total phenol and flavonoid content determination showed that the extract is rich in phenols and flavonoids.Conclusions:All the results of the in vitro antioxidant assays reveal potent antioxidant and free radical scavenging activity of the leaves of Indigofera cassioides,equivalent to that of standard ascorbic acid and rutin.This potent antioxidant activity may be attributed to its high phenolic and flavonoid contents. | R Senthil Kumar B Rajkapoor P Perumal | 2012 | Asian Pacific Journal of Tropical Biomedicine2012，2，4： | 15 |
| 5 | The anti-photooxidation of anthocyanins-rich leaves of a purple rice cultivar显示文摘In the leaf of rice (Oryza sativa L.) cultivar Yunnan purple rice,the anthocyanins with an obvious absorption peak at 530nm were distributed in the cells of upper and lower epidermis,bulliform tissue and bristle. The maximal photosynthetic oxygen evolution rate and chlorophyll content in flag leaves were 28% and 23%,respectively,more than the common green leaf rice cultivar Chijiaoru-anzhan. Higher chlorophyll content is probably one of the physiological adaptations for enhancing light harvesting capacity of the antenna in photosystems in this cyanic leaves species. Upon the photooxidation of leaf segments mediated by methyl viologen in weak light for 3 days,the distinct bleaching of anthocyanins in purple rice was associated with the reduction of scavenging ability to DPPH· free radical ability and the increase in membrane leakage rate. But almost no changes in contents of flavonoids and total phenolics were observed. Chlorophyll fluorescence parameters Fv/Fo,qP and φPSⅡ decreased with the increase in NPQ and DES of xanthophylls cycle after photooxidation treatment. Green rice leaves showed more decrease in DPPH· scavenging rate and more increase in cell membrane leakage rate but showed a trace of anthocyanins during photooxidation. It is sug-gested that anthocyanin may be a beneficial and primary antioxidant in sun cyanic rice leaves against oxidative stress induced by environmental adversity. And photooxidation could induce different changing patterns of anthocyanins between the tested purple and green rice leaves. | PENG Changlian1,2,LIN Zhifang2,LIN Guizhu2 & CHEN Shaowei2 1. College of Life Science,South China Normal University,Guangzhou 510631,China 2. South China Botanical Garden,Chinese Academy of Sciences,Guangdong Key Laboratory of Digital Botanical Garden,Guangzhou 510650,China | 2006 | Science China(Life Sciences)2006，49，6： | 14 |
| 6 | Pedalium murex Linn(Pedaliaceae) fruits:a comparative antioxidant activity of its different fractions显示文摘Objective:To examine the antioxidant activity and total phenolic content of different solvent fractions of Pedulium murex(P.murex)Linn fruits(Family:Pedaliaceae)as well as the correlation between the total antioxidant capacity and total phenolic content.Methods:In the present study,the antioxidant activities of P.murex were evaluated using six in-vitro assays,namely total antioxidant assay,DPPH assay,reducing power,nitric oxide scavenging,hydrogen peroxide scavenging and deoxyribose scavenging assays,and total phenol contents were also investigated.Results:The ethyl acetate(EA)fraction was found to have high levels of phenolic content(298.72±2.09 mg GAE/g).The EA fraction exhibit higher total antioxidant capacity,higher percentage of DPPH radical scavenging activity(135.11±2.95μg/mL),nitric oxide(200.57±4.5lμg/mL),hydrogen peroxide(2I7.91±6.12μg/mL),deoxyribose(250.01±4.68μg/mL)and higher reducing power.Correlation coefficient(r^2=0.914)was found to be significant between total phenolic content and total antioxidant activity.Conclusions:In general,the results indicate that the EA fractions are rich in phenolic antioxidants with potent free radical scavenging activity implying their importance to human health. | DK Patel R Kumar SK Prasad S Hemalatha | 2011 | Asian Pacific Journal of Tropical Biomedicine2011，1，5： | 12 |
| 7 | Role of Moringa oleifera in regulation of diabetes-induced oxidative stress显示文摘Objective:To evaluate the antioxidant activity of aqueous extract of Atoringa oleifeta M.oleifera) young leaves by in vivo as well as in vitro assays.Methods:In vitro study included estimation of total phenolic,total ilavonol,total flavonoid and total antioxidant power(FRAP assay).Tn addition, in vivo study was done with the identified most effective dose of 200 nig/kg of its lyophilized powder on normal and diabetic rats.Its effect on different oxidative free radical scavenging enzymes,viz,superoxide dismutase(SOD),catalase(CAT),glutathione-S-transferase(GST),lipid peroxide(LPO) contents were measured.Results:Significant increase in activities of SOD.CAT, GST while,a decrease in LPO content was observed.Whereas,total phenolic,flavonoid and ilavonol contents in the extract were found to be 120 mg/g of CAK,40.5 mg/g of QEK and 12.12 mg/g of QE,respectively.On the other hand.FRAP assay results of M.oleifera leaves was(85.00±5.00)μM of Fe^+/g of extract powder.Conclusions:The significant antioxidant activities of M.oleifera leaves from both in vivo as well as in vitro studies suggests that the regular intake of its leaves through diet can protect normal as well as diabetic patients against oxidative damage. | Dolly Jaiswal Prashant Kumar Rai Shikha Mehta Sanjukta Chatterji Surekha Shukla Devendra Kumar Rai Gaurav Sharma Bechan Sharma Shahidul khair Geeta Watal | 2013 | Asian Pacific Journal of Tropical Medicine2013，6，6： | 11 |
| 8 | Antioxidant activity and phytochemical screening of the methanol extracts of Euphorbia hirta L显示文摘Objective:To assess antioxidant activities of different parts of Euphorbia hirta(E.hirta),and to search for new sources of safe and inexpensive antioxidants.Methods:Samples of leaves,stems, flowers and roots from E.hirta were tested for total phenolic content,and flavonoids content and in vitro antioxidant activity by diphenyl-1-picrylhydrazyl(DPPH) assay and reducing power was measured using cyanoferrate method.Results:The leaves extract exhibited a maximum DPPH scavenging activity of(72.96±0.78)%followed by the flowers,roots and stems whose scavenging activities were(52.45±0.66)%,(48.59±0.97)%,and(44.42±0.94)%,respectively.The standard butylated hydroxytoluene(BHT) was(75.13±0.75)%.The IC50,for leaves,flowers,roots,stems and BHT were 0.803,0.972,0.989,1.358 and 0.794 mg/mL,respectively.The reducing power of the leaves extract was comparable with that of ascorbic acid and found to be dose dependent. Leaves extract had the highest total phenolic content[(206.17±1.95) mg GAE/g],followed by flowers,roots and stems extracts which were(117.08±3.10) mg GAE/g,(83.15±1.19) mg GAE/g,and (65.70±1.72) mg GAE/g,respectively.On the other hand,total flavonoids content also from leave had the highest value[(37.970±0.003) mg CEQ/g],followed by flowers,roots and stems extracts which were(35.200±0.002) mg CEQ/g,(24.350±0.006) mg CEQ/g,and(24.120±0.004) mg CEQ/ g,respectively.HPTLC bioautography analysis of phenolic and antioxidant substance revealed phenolic compounds.Phytochemical screening of E.hirta leaf extract revealed the presence of reducing sugars,terpenoids,alkaloids,steroids,tannins,flavanoids and phenolic compounds. Conclusions:These results suggeste that E.hirta have strong antioxidant potential.Further study is necessary for isolation and characterization of the active antioxidant agents,which can be used to treat various oxidative stress-related diseases. | Abu Arra Basma Zuraini Zakaria Lacimanan Yoga Latha Sreenivasan Sasidharan | 2011 | Asian Pacific Journal of Tropical Medicine2011，4，5： | 7 |
| 9 | In vitro antioxidant and anti-inflammatory activities of Korean blueberry(Vaccinium corymbosum L.) extracts显示文摘Objective:To investigate in vitro antioxidant and anti-inflammatory activities of Korean blueberry(Vaccinium corymbosum L.).Methods:Total phenolic and flavonoid contents of the Korean blueberry water and ethanol extracts were determined before determining the potential of the extracts as antioxidant.Antioxidant activity of the extracts was determined by following some well established methods for free radical scavenging such as 2,2-diphenyl-picrylhydrazyl hydrate,1,2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonicacid),free radical induced DNA damage,superoxide dismutaselike and catalase assay etc.Furthermore,1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan and nitric oxide assay were performed to determine the anti-inflammatory activity of the extracts.Results:Total phenolic contents were found(115.0±3.0) and(4.2±3.0) mg GAE/100 g fresh mass for both extracts,respectively and flavonoid contents were(1 942.8±7.0) and(1 292.1±6.0) mg CE/100 g fresh mass for water and ethonal extracts,respectively.Both the extracts displayed significant scavenging activity of some radicals such as 2,2-diphenyl-picrylhydrazyl hydrate(IC_(50) at 1.8 mg/mL and 2.05 mg/mL,respectively),l,2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonicacid)(IC_(50) at1.5 mg/mL and 1.6 mg/mL,respectively) and nitrite(IC_(50) at 1.7 mg/mL and 1.5 mg/mL,respectively)etc.The extracts were found to prevent inflammation as well by reducing nitric oxide production and cytotoxicity in cell.Conclusions:The findings suggest that the fresh Korean blueberry could be used as a source of natural antioxidants and anti-inflammatory agents. | Nadira Binte Samad Trishna Debnath Michael Ye Md.Abul Hasnat Beong Ou Lim | 2014 | Asian Pacific Journal of Tropical Biomedicine2014，4，10： | 6 |
| 10 | Total phenols, flavonoids, and procyanidins levels and total antioxidant activity of different Korean pine(Pinus koraiensis) varieties显示文摘Total phenols,flavonoids,procyanidins,and total antioxidant capacity,measured with ferric reducing antioxidant power,radical scavenging capacity,and oxygen radical absorption capacity assays were first evaluated in the extracts of the shells,skins and kernels of 10 varieties of Pinus koraiensis.Results indicate that these varieties had strong radical scavenging capacities,ferric reducing antioxidant power and oxygen radical absorption capacities.Phenolic,flavonoid and procyanidin values ranged from 138.6(#3 kernel)to 518.6(#10 shell)mg GAE/g,from 23.3(#2 kernel)to 70.8(#5 skin)mg RE/g,from 2.5(#2 kernel)to 142.1(#7 skin)mg CE/g,respectively.Radical scavenging capacity and ferric reducing antioxidant power values were positively correlated to the polyphenol contents which play a major role in antioxidant properties.The varieties may be divided into two groups by cluster analysis and the variables being measured.These results will be useful for breeding varieties and guiding their production. | Sitong Zhang Ligang Zhang Lu Wang Yuhong Zhao | 2019 | Journal of Forestry Research2019，30，5： | 5 |
| 11 | An improved piezoelectric harvester available in scavenging-energy from the operating environment with either weaker or stronger vibration levels显示文摘An improved harvester available in scavenging energy from the operating environment with either weaker or stronger vibration levels is studied. To ensure the optimal harvester performance, a Cuk dc-dc converter is employed into the modulating circuit. This paper reports how this harvester scav- enges maximal energy from varying-level vibrations and store energy into an electrochemical battery. Dependence of the duty cycle upon the external vibration level is calculated, and it is found that: 1) for weaker vibrations, the charging current into the battery is smaller than the allowable current, and thus all the optimal output power of the harvesting structure can be absorbed by the battery. In this case, the duty cycle should be fixed at 1.86%; 2) for stronger external forcing, the allowable charging current of the battery is smaller than the optimal harvested current. This indicates that just a portion of the sca- venged energy can be accepted by the battery. Thus, the duty cycle should be decreased gradually with the increase of the vibration level. Finally the energy transmission process and the roles of each elec- tronic element are analyzed. It is shown that a Cuk converter can greatly raise the efficiency of such a harvester, particularly when subjected to a weaker ambient vibration. | XUE Huan HU HongPing HU YuanTai CHEN XueDong | 2009 | Science China(Physics,Mechanics & Astronomy)2009，52，2： | 5 |
| 12 | The zero-dimensional model of the scavenging process in the opposed-piston two-stroke aircraft diesel engine显示文摘The analysis of the scavenging process in two-stroke engines is important in terms of achieved performance and emission of toxic substances.The amount of mass of air used for the scavenging process and the amount mass of gas retained in the cylinder affect engine effi-ciency.When designing two-stroke engines,the most efficient charge exchange process defined by the scavenging efficiency parameter is desirable.The process of charge exchange in a twostroke opposed-piston aircraft diesel engine based on the assumed scavenging model was analyzed in this work.The charge exchange process was performed by a mechanical centrifugal compressor.A zero-dimensional engine model created in the AVL BOOST program was used for the research.The simulation tests were performed for the selected operating conditions,i.e.maximum continuous power.The analysis of the charge exchange process was accompanied by obtaining the basic engine operating parameters from the simulation calculations. | Ł.Grabowski K.Pietrykowski P.Karpinski | 2019 | Propulsion and Power Research2019，8，4： | 4 |
| 13 | Reaction of hydroxyl radical with phenylpropanoid glycosides from Pedicularis species: a pulse radiolysis study显示文摘Using pulse radiolysis technique, the reaction between hydroxyl radical and 7 phenylpropanoidglycosides: echinacoside, verbascoside, leucosceptoside A, martynoside, pediculariosides A, M and N which were isolated from Pedicularis were examined. The rate constants of these reactions were determined by transient absorption spectra. All 7 phenylpropanoid glycosides react with hydroxyl radical at high rate constants within (0.97-1.91)×1010L · mol-1 · s-1. suggesting that they are effective hydroxyl radical scavengers. The results demonstrate that the numbers of phenolic hydroxyl groups of phenylpropanoid glycosides are directly related to their scavenging activities. The scavenging activities are likely related to o-dihydroxy group of phenylpropanoid glycosides as well. | 王潘奋 郑荣梁 高建军 贾忠建 王文峰 姚思德 张加山 林念芸 | 1996 | Science China(Life Sciences)1996，39，2： | 4 |
| 14 | Single-Crystalline Organoiridium Complex for Gas-Triggered Chromogenic Switches and Its Applications on CO Detection and Reversible Scavenging显示文摘Summary of main observation and conclusion Nonporous molecular single crystals of coordinatively unsaturated 16-electron metallacycle are found to undergo highly selective-yet reversible-binding of CO over CH4,H2,N2,CO2,various volatile organic compounds and water,through binding of the molecule to its metal centers.Carbon monoxide is taken up by black crystals and subsequently liberated from the corresponding orange CO adduct by reversible metal coordination,the structural evidence obtained from in situ X-ray diffraction.The single-crystallinity of the metallacycle is retained even after several cycles.The material,when adsorbed on silica,shows remarkable sensitivity and selectivity for CO,allowing visual CO sensing in the solid state.The metallacycle offer the possibility of serving as readily regenerable scavenger for removing trace CO from gas mixtures with N2. | Li-Ying Sun Yuan-Yuan An Li-Li Ma Ying-Feng Han | 2019 | Chinese Journal of Chemistry2019，37，8： | 4 |
| 15 | STUDIES ON FREE RADICAL SCAVENGING ACTIVITY IN CHINESE SEAWEEDS PART I. SCREENING RESULTS显示文摘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. | 严小军 房国明 娄清香 | 1999 | Chinese Journal of Oceanology and Limnology1999，17，3： | 4 |
| 16 | Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract显示文摘Objective:To investigate thein vitroantioxidant potential of Carica papaya(C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation.Methods:Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract(at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage.Results:Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities usingin vitro models in a concentration dependent manner(P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid(P<0.05). The IC50values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid(the reference antioxidant) possessed higher activity than the extract.Conclusions:The findings show that C. papayaleaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy.Thus, the leaves can be exploited for pharmaceutical and nutritional purposes. | Tebekeme Okoko Diepreye Ere | 2012 | Asian Pacific Journal of Tropical Biomedicine2012，2，6： | 3 |
| 17 | Antioxidant activity of newly discovered lineage of marine actinobacteria显示文摘Objective:To investigate the antioxidant activity of marine actinobacteria.Methods:The content of total phenolics,the level of antioxidant potential by DPPH radical scavenging activity,metal chelating activity,FRAP method,βcarotene assay and NO scavenging activity in extract were determined.Results:In all the methods the extract exhibited good scavenging activity except NO scavenging activity.The IC50 values of marine actinobacteria extract on DPPH radical were found to be 41.09μg/mL.The zone of color retention was 12 mm inβ-carotene bleaching assay. DNA protective efficiency of the extracts was also studied using UV- photolysed H2O2-driven oxidative damage to pBR322.HPLC analysis identified some of the major phenolic compounds in extracts,which might he responsible for the antioxidant potential and cyto-protection.It showed a 100%cytotoxic effect in brine shrimp lethality assay within 10 mins.The novel actinobacteria was identified as Streptomyces LK-3(JF710608) through I6S rDNA Sequencing.Conclusions:The results obtained suggest that the extracts bear anti-cancer metabolites and could be considered as a potential source for anti-cancer drug development. | Loganathan Karthik Gaurav Kumar Kokati Venkata Bhaskara Rao | 2013 | Asian Pacific Journal of Tropical Medicine2013，6，4： | 3 |
| 18 | GC-MS analysis,determination of total phenolics,flavonoid content and free radical scavenging activities of various crude extracts of Moringa peregrina(Forssk.) Fiori leaves显示文摘Objective:To perform phytochemical screening,estimate total phenolics,flavonoids and to evaluate antioxidant potential of Moringa peregrina(M.peregrina) leaves.Methods:The dried powdered leaves of M.peregrina(150 g) were extracted exhaustively by Soxhlet with ethanol and then fractionated into hexane,chloroform,ethy alacetate and methanol.All the prepared extracts were also analyzed by gas chromatography-mass spectrometry to identify and characterize the chemical compounds present in the crude extracts.Folin- Ciocalteu reagent and aluminium chloride colorimetric methods were used to estimate total phenolic and flavonoid content of extracts.Hydrogen peroxide and 1,1 diphenyl-2-picrylhydrazyl were used to determine in vitro antioxidant activity.Results:Phytochemical analysis of ethanol extract showed presence of major classes of phytochemicals.Gas chromatography-mass spectrometry results revealed presence of 19 phytoconstituents in hexane extract,6 in ethyl acetate and 7 compounds in methanolic extract.Methanol extract was found to contain the highest phenolic content and flavonoids.In vitro antioxidant activities of all crude extracts were significant and comparable with the standard ascorbic acid.Conclusions:Results of this study show that the leaves of M.peregrina are the rich source of phenolic compounds that can play an important role in preventing the progression of many diseases. | Mooza Al-Owaisi Nora Al-Hadiwi Shah Alam Khan | 2014 | Asian Pacific Journal of Tropical Biomedicine2014，4，12： | 3 |
| 19 | Phytochemical screening and free radical scavenging activity of Citrullus colocynthis seeds extracts显示文摘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. | Nabila Benariba Rabeh Djaziri Wafaa Bellakhdar Nacera Belkacem Marcel Kadiata Willy J.Malaisse Abdullah Sener | 2013 | Asian Pacific Journal of Tropical Biomedicine2013，3，1： | 3 |
| 20 | Below-Cloud Aerosol Scavenging by Different-Intensity Rains in Beijing City显示文摘Below-cloud aerosol scavenging process by precipitation is important for cleaning the polluted aerosols in the atmosphere, and is also a main process for acid rain formation. However, the related physical mechanism has not been well documented and clarified yet. In this paper, we investigated the below-cloud PM_(2.5)(particulate matter with aerodynamic diameter being 2.5 μm or less) scavenging by different-intensity rains under polluted conditions characterized by high PM_(2.5) concentrations, based on in-situ measurements from March 2014 to July 2016 in Beijing city. It was found that relatively more intense rainfall events were more efficient in removing the polluted aerosols in the atmosphere. The mean PM_(2.5) scavenging ratio and its standard deviation(SD) were 5.1% ± 25.7%, 38.5% ± 29.0%,and 50.6% ± 21.2% for light, moderate, and heavy rain events, respectively. We further found that the key impact factors on below-cloud PM_(2.5) scavenging ratio for light rain events were rain duration and wind speed rather than raindrop size distribution. However, the impacts of rain duration and wind speed on scavenging ratio were not important for moderate and heavy rain events. To our knowledge, this is the first statistical result about the effects of rain intensity, rain duration, and raindrop size distribution on below-cloud scavenging in China. | Tian LUAN Xueliang GUO Tianhang ZHANG Lijun GUO | 2019 | Journal of Meteorological Research2019，33，1： | 3 |
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