oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 56 )

2018 ( 158 )

2017 ( 164 )

2016 ( 186 )

Custom range...

Search Results: 1 - 10 of 6007 matches for " antioxidant activities "
All listed articles are free for downloading (OA Articles)
Page 1 /6007
Display every page Item
Atividade antioxidante de pimentas do gênero Capsicum
Costa, Luciene Mendon?a da;Moura, Neusa Fernandes de;Marangoni, Cristiane;Mendes, Caroline Eliza;Teixeira, Alexandre de Oliveira;
Ciência e Tecnologia de Alimentos , 2010, DOI: 10.1590/S0101-20612009005000004
Abstract: the antioxidant activity was evaluated by the β-carotene/linoleic acid system, dpph? (2,2-diphenyl-1-picrylhydrazyl) radical assay, to the crude extract (eb) and fractions hexanic (fh), chloroformic (fc), and ethyl acetate (fa) of malagueta peppers (c. frutescens), cambuci (c. baccatum var. pendulum), cumari (c. baccatum var praetermissum), and pepper magali (c. annuum var. annuum). the concentration of total phenolics and capsacinoids present in the peppers was also determined. the results showed that the fc and the fa peppers showed higher concentrations of total phenolics and capsacinoids, and that the cumari pepper was the species with higher concentrations of these compounds. the best antioxidant activity according to the β-carotene/linoléico acid system were obtained for the eb and the fa cambuci pepper, followed by the eb malagueta pepper. according to the dpph method, the fc and fa showed lower values of ec50, and the cumari and cambuci peppers were the most effective. the results show that cumari, cambuci, and malagueta peppers can be used as natural antioxidant agents in food.
In Vitro Antibacterial, Antifungal and Other Medical Properties of Endangered Medicinal Plant Seeds  [PDF]
Mohammed A. Almalki
Pharmacology & Pharmacy (PP) , 2017, DOI: 10.4236/pp.2017.85013
Abstract: The risk created by infectious microorganisms to humans attracted the development of common medicine. To find an alternative source, medicinal plants with diverse metabolites play an important role in curing the diseases and human disorders caused by microbial pathogens. Medicinal plants namely, Citrullus colocynthis, Hyoscyamus muticus, Ocimum basilicum, Amaranthus lividus, Salvia aegyptiaca and Ruta chalepensis are commonly used as a traditional medicine in Gulf countries. The present study aimed to investigate the antibacterial, antifungal and antioxidant potential of the organic crude extracts obtained from the seeds. Besides, the possible antimicrobial mechanisms of the extracts were evaluated by determining the enzyme activities. The antibacterial and antifungal activities of the crude extracts were evaluated by the broth micro dilution method and the effect of the extracts on the pathogens were determined by quantifying the alkaline phosphatase (ALP), lactate dehydrogenase (LDH) enzymes and intracellular protein leakage. Besides, the antioxidant properties were determined using hydroxyl radical scavenging assay, DPPH radical scavenging assay, reducing power assay and superoxide radical scavenging assay. Results indicated that the extracts of C. colocynthis showed promising activity against all the tested pathogens, especially the MIC values were ranged from 100 to 150 μg/ml for Gram positive bacteria and 100 to 250 μg/ml for Gram negative bacteria respectively. The MIC values of H. muticus, O. basilicum and R. chalepensis against the fungal pathogens were ranged from 100 to 500 μg/mL respectively. The ALP activity was higher in extract treated Klebsiella pneumoniae compared with control, whereas the LDH and protein concentrations for Escherichia coli and Staphylococcus aureus were comparatively higher. Furthermore, all the studied seed extract showed good antioxidant activities. In conclusion, the studied plant seed extracts documented good antimicrobial and antioxidant activities. Therefore, the medicinal plants would be the excellent source for natural antioxidant and antibacterial agents for medical and applications.
Synthesis of New Substituted Chromen[4,3-c]pyrazol-4-ones and Their Antioxidant Activities
Abdullah Sulaiman Al-Ayed
Molecules , 2011, DOI: 10.3390/molecules161210292
Abstract: A series of new coumarin derivatives 4 containing a 4-arylbut-3-en-2-one moiety were synthesized by condensation of 3-acetylcoumarin 1 with aryl aldehydes 2 in chloroform in the presence of piperidine. The interactions of 3-formyl-4-chlorocoumarin (3) with nitrogen-containg nucleophiles leading to the corresponding substituted chromen-[4,3-c]pyrazol-4-ones 5 are described. The structures of the obtained compounds were established on the basis of 1D NMR, 2D NMR and IR and further the compounds were evaluated for possible antioxidant activities. The coumarinic chalcone 4a has been found to be the most active (IC50 = 2.07 μM) in this study.
In vitro antimicrobial and antioxidant activities of a crude extract and fractions from Buddleja thyrsoides Lam. Leaves
Mahlke, Janaina Dorneles;Boligon, Aline Augusti;Machado, Michel Mansur;Spader, Tatiana Borba;Alves, Sydney Hartz;Canto-Dorow, Thais do;Athayde, Margareth Linde;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000200002
Abstract: crude extract and fractions of buddleja thyrsoides were investigated regarding antioxidant activities by dpph, total phenolic contents by folin-ciocalteau and antimicrobial activity by the broth microdilution method. total phenolics varied from 214.07 ± 3.6 to 438.4 ± 0.3 mg g-1. crude extract, ethyl acetate, dichloromethane and butanolic fractions exhibited a weak scavenging activity (sc50=186.04 ± 10.8, 137.70 ± 8.5, 146.89 ± 9.0 and 165.71 ± 3.2 μg ml-1, respectively). a correlation between the antioxidant activities and total phenolic contents could be shown (r=0.857, p<0.01). the lowest value of mic was observed with butanolic fraction against saccharomyces cerevisiae (mic and mfc at 62.5 μg ml-1). dichloromethane and ethyl acetate fractions were effective against staphylococcus aureus with mic value at 250 and 500 μg ml-1 respectively.
Antibacterial Potential of Aqueous Acetone Extracts From Five Medicinal Plants used Traditionally to Treat Infectious Diseases in Burkina Faso
K. Konaté,M. Kiendrébéogo,M.B. Ouattara,A. Souza
Current Research Journal of Biological Sciences , 2011,
Abstract: Polyphenol contents, in vitro antioxidant and antimicrobial activities of leaves and barks from of Anogeissus leiocarpus, Khaya senegalensis, Sterculia setigera, Solanum incanum and Pterocarpus erinaceus extracts obtained with aqueous acetone 80% (WAE) were investigated in this study. The present study was conducted to evaluate the total phenolic contents, in vitro antioxidant and antibacterial properties. Folin-ciocalteu and AlCl3 methods respectively were used for polyphenol content. The antioxidant potential of the samples was evaluate using two separate methods, inhibition of free radical 2,2-diphenyl-1- picrylhydrazyl (DPPH) and Iron (III) to iron (II) reduction activity (FRAP). In vitro antibacterial capacity of aqueous acetone extracts were investigated by agar disc diffusion, micro-well dilution (MIC) and Minimum Bactericidal Concentration (MBC) assay against five bacteria. Our extracts contained high levels of phenolics and exhibited antibacterial activity against bacteria. S. aureus and B. cereus were the most sensitive; while E. coli was the most resistant. There were highly positive relationships (R2 = 0.8454-0.9780) between phenolic contents and antioxidant, activity antibacterial capacity and phenolic contents of the tested extracts against each bacterium. This suggested that the antibacterial activity of the tested extracts was closely associated with their phenolic constituents. In this study, the extract of Anogeissus leiocarpus leaves was presented the best results among all extracts.
Antioxidant and Antimicrobial Attributes and Phenolics of Different Solvent Extracts from Leaves, Flowers and Bark of Gold Mohar [Delonix regia (Bojer ex Hook.) Raf.]
Ghulam Shabir,Farooq Anwar,Bushra Sultana,Zafar M. Khalid,Muhammad Afzal,Qaiser M. Khan,M. Ashrafuzzaman
Molecules , 2011, DOI: 10.3390/molecules16097302
Abstract: This paper describes the antioxidant and antimicrobial activities and phenolic components of different solvent (absolute methanol, absolute ethanol, absolute acetone, 80% methanol, 80% ethanol, 80% acetone and deionized water) extracts of leaves, flowers and bark of Gold Mohar [Delonix regia (Bojer ex Hook.) Raf.]. The extract yields from leaves, flowers and bark ranged from 10.19 to 36.24, 12.97 to 48.47 and 4.22 to 8.48 g/100 g dry weight (DW), respectively. Overall, 80% methanol extract produced from the leaves exhibited significantly (P < 0.05) higher antioxidant activity, with high phenolic contents (3.63 g GAE/100 g DW), total flavonoid contents (1.19 g CE/100 g DW), inhibition of peroxidation (85.54%), DPPH scavenging capacity (IC50 value 8.89 μg/mL) and reducing power (1.87). Similarly, this 80% methanol leaves extract also showed superior antimicrobial activity. HPLC analysis of the 80% methanol extracts for individual phenolics revealed the presence of gallic, protocatechuic and salicylic acid in leaves; gallic, protocatechuic, salicylic, trans-cinnamic and chlorogenic acid in flowers, and gallic acid in bark as the main (amount > 1.50 mg/100 g DW) phenolic acids. Besides, small amounts ( < 1.50 mg/100 g DW) of some other phenolic acids such as sorbic, sinapic, p-coumaric, m-coumaric, ferulic, caffeic, 3-hydroxybenzoic, 4-hydroxycinnamic and 4-hydroxybenzoic acids were also detected. The extracts of the tested parts of Gold Mohar, especially, the leaves, might be valuable for functional food and therapeutic applications.
Antioxidant Activity of Papaya Seed Extracts
Kaibing Zhou,Hui Wang,Wenli Mei,Xiaona Li,Ying Luo,Haofu Dai
Molecules , 2011, DOI: 10.3390/molecules16086179
Abstract: The antioxidant activities of the ethanol, petroleum ether, ethyl acetate, n-butanol and water extract fractions from the seeds of papaya were evaluated in this study. The ethyl acetate fraction showed the strongest DPPH and hydroxyl free radical-scavenging activities, and its activities were stronger than those of ascorbic acid and sodium benzoate, respectively. The n-butanol fraction demonstrated the greatest ABTS+ radicals scavenging activity. The ethyl acetate fraction and the n-butanol fraction not only showed higher antioxidant activities than the petroleum ether fraction, water fraction and ethanol fraction, but also showed higher superoxide anion and hydrogen peroxide radicals scavenging activities than those of the other extract fractions. The high amount of total phenolics and total flavonoids in the ethyl acetate and n-butanol fractions contributed to their antioxidant activities. The ethyl acetate fraction was subjected to column chromatography, to yield two phenolic compounds, p-hydroxybenzoic acid (1) and vanillic acid (2), which possessed significant antioxidant activities. Therefore, the seeds of papaya and these compounds might be used as natural antioxidants.
Evaluation of phenolic contents and antioxidant activity of various solvent extracts of Sonchus asper (L.) Hill
Rahmat Khan, Muhammad Khan, Sumaira Sahreen, Mushtaq Ahmed
Chemistry Central Journal , 2012, DOI: 10.1186/1752-153x-6-12
Abstract: To achieve these goals, several parameters including free-radical (DPPH?, ABTS?+, H2O2 and ?OH) scavenging, iron chelating activity, scavenging of superoxide radicals, total flavonoids and total phenolic content (TPC) were examined.The SA extracts presented a remarkable capacity to scavenge all the tested reactive species with IC50 values being found at the μg ? ml level. The SAME was shown to have the highest TPCs while lowest IC50 values for the DPPH?, ABTS?+ radical scavenging capacities and iron chelating scavenging efficiency, moreover, SAME had best activities in scavenging of superoxide radicals and hydrogen peroxide as well as potently scavenged the hydroxyl radicals.These results suggest the potential of S. asper as a medicine against free-radical-associated oxidative damage.Sonchus asper (Compositae) is used in the treatment of wound healing and possesses anti-burning properties [1]. It has diuretic, refrigerant, sedative and antiseptic properties, used in the treatment of cough, bronchitis and asthma [2], tonsils [3], kidney inflammation [4], erectile dysfunction in male [5], fever, constipation, diabetes, scabies and heart diseases [6]. Chemical studies of the SA revealed the presence of ascorbic acid, carotenoids and fatty acids [7].Phenolic compounds which are secondary metabolites in plants are one of the most widely occurring groups of phytochemicals that exhibit antiallergenic, antimicrobial, antiartherogenic, antithrombotic, antiinflammatory, vasodilatory and cardioprotective effects [8,9]. Due to the presence of the conjugated ring structures and hydroxyl groups; many phenolic compounds have the potential to function as antioxidants by scavenging or stabilizing free radicals involved in oxidative processes through hydrogenation or complexing with oxidizing species that are much stronger than those of vitamins C and E [10]. Tannic acid, quercetin and catechin were reported earlier in SA [11], and could therefore; contribute to antioxidant activitie
ANTIOXIDANT PROPERTIES OF LIGNANS AND FERULIC ACID FROM THE RESINOUS EXUDATE OF LARREA NITIDA
TORRES,RENé; URBINA,FRANCISCO; MORALES,CLAUDIA; MODAK,BRENDA; MONACHE,FRANCO DELLE;
Journal of the Chilean Chemical Society , 2003, DOI: 10.4067/S0717-97072003000300012
Abstract: from the resinous exudate of twigs end leaves of larrea nitida, two lignans nor isoguaiacine 1 and meso-nor-dihydroguaiaretic acid 2 and ferulic acid 3 were isolated. the antioxidant activities of resin and pure compounds were assesed by bleaching of the abts derived radical-cation
Avalia??o do potencial alelopático, atividade antimicrobiana e antioxidante dos extratos organicos das folhas de Pyrostegia venusta (Ker Gawl.) Miers (Bignoniaceae)
Silva, P.B.;Medeiros, A.C.M.;Duarte, M.C.T.;Ruiz, A.L.T.G.;Kolb, R. M.;Frei, F.;Santos, C.;
Revista Brasileira de Plantas Medicinais , 2011, DOI: 10.1590/S1516-05722011000400010
Abstract: this paper presents the results of allelopathic, antimicrobial and antioxidant activities of organic extracts (hexane, ethyl acetate and methanol) from the leaves of pyrostegia venusta (ker gawl.) miers (bignoniaceae). allelopathic activity was assessed based on cucumis sativus (cucumber) development for the parameters main root length, number of secondary roots and hypocotyl length. all tested extracts affected the first two parameters, while the hypocotyl length was not affected only by the ethyl acetate extract. for antimicrobial activity, assessed by mic assay, hexane extract showed moderate inhibition for staphylococcus aureus (0.9 mg ml-1) and strong inhibition for enterococcus hirae (0.5 mg ml-1). ethyl acetate extract showed strong activity against candida albicans (0.3 mg ml-1), whereas methanolic extract was not active against the tested microorganisms. on the other hand, methanol extract showed the most promising radical scavenging capacity (effective concentration 50% - ec50 = 102.0 ± 56.9 mg ml-1, with tec50 = 30 min) in dpph assay (2,2-diphenyl-1-picryl-hidrazil) and the highest level of phenolic compounds (116.2 ± 83.0 mg acid garlic g sample-1), as indicated by folin-ciocalteau assay.
Page 1 /6007
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.