how to calculate antioxidant activity by dpph

On the other hand, the production of ROS, can be decreased by pre-treatment of cells by NAC (N-acetylcysteine) as a systematic antioxidant [33]. Fungal silver nanoparticles: Synthesis, application and challenges. Szczniak B., Borysiuk S., Choma J., Jaroniec M. Mechanochemical synthesis of highly porous materials. AZ1 and its antimicrobial activity against several human pathogenetic bacteria. Bactericidal effects of silver nanoparticles on lactobacilli and the underlying mechanism bactericidal effects of silver nanoparticles on lactobacilli and the underlying mechanism. ztrk F., o S., Duman F. Biosynthesis of silver nanoparticles using leaf extract of Aesculus hippocastanum (horse chestnut): Evaluation of their antibacterial, antioxidant and drug release system activities. They prepared silver nanoparticles by biological method using extract of red cabbage (Brassica oleracea var. Akter M., Sikder T., Rahman M., Ullah A.K.M.A., Fatima K., Hossain B., Banik S., Hosokawa T., Saito T., Kurasaki M. A systematic review on silver nanoparticles-induced cytotoxicity: Physicochemical properties and perspectives. DPPH assay. Antioxidant properties are currently extensively studied for various materials, including the natural ones, in order to identify new compounds from natural sources. In the present state, the use of combination of different methods is always beneficial. Some microorganisms are resistant to metal, so they can survive and grow during the production of NPs, so there is no barrier to use bacteria for AgNPs synthesis [118,119,120]. NPs can be also used for scavenging activity against ROS/RNS determination [77]. DNA is damaged by deoxyribose ring cleavage, base modification or chain breaks leading to mutations, translation errors or inhibition of proteosynthesis [23]. Ou B., Huang D., Hampsch-Woodill M., Flanagan J.A., Deemer E.K. . A novel amperometric method for antioxidant activity determination using DPPH free radical. The antioxidant potential of Cassia fistula extracts significantly correlated () with the phenolic content of the methanolic extracts. It is hard to conclude which method is the most suitable because of various composition of nanoparticles synthesized by biological methods depending on the phytochemicals presented in plant extracts. There are some limitations of this method because of the detection limit of 105 M and low resolution [65]. How do you calculate the antioxidant activity of food using DPPH method Environmentally friendly procedure for in-situ coating of regenerated cellulose fibres with silver nanoparticles. In this review, we focused on methods of antioxidant activity determination in detail to find out novel and perspective techniques to solve the general problems associated with the determination of antioxidant activity of silver nanoparticles. The main disadvantage of using this assay is that DMPD radical is soluble only in water, so there are limitations in using it for hydrophobic antioxidants determination [54]. Plasma-enhanced deposition of silver nanoparticles onto polymer and metal surfaces for the generation of antimicrobial characteristics. Jacob S.J.P., Finub J.S., Narayanan A. Biointerfaces synthesis of silver nanoparticles using piper longum leaf extracts and its cytotoxic activity against Hep-2 cell line. Ilyasov I.R., Beloborodov V.L., Selivanova I.A., Terekhov R.P. Lower values of silver nanoparticles (prepared by Aesculus hippocastanum) antioxidant capacity was also obtained by Kp [126] who used three different method of scavenging activity determinationDPPH, total reducing power, and superoxide anion radical scavenging assay. The absorbance is usually measured in the range from 750765 nm [43,44]. Ferric reducing power of AgNPs was lower than that of ascorbic acid standard and was higher at lower concentrations of AgNPs. Definitely, one of the most important biological mechanism in which free radicals play an important role is the process of phagocytosis including the defense against pathogenic microorganisms [34]. Fungi also represent a valuable producer of silver nanoparticles because of their capability of metals bioaccumulation [121,122]. Guidelines for antioxidant assays for food components It absorbs at 414, 645, 734, and 815 nm and gives blue-green color. HPLC is a valuable method for antioxidant capacity determination. The site is secure. From biological point of view, superoxide anion radical O2 is generated by the mitochondrial respiratory chain and phagocytic NADPH oxidase (nicotinamide adenine dinucleotide phosphate oxidase; NOX), so it is produced by respiration and component part of defense system [16]. Gurunathan S., Raman J., Abd Malek S.N., John P.A., Vikineswary S. Green synthesis of silver nanoparticles using Ganoderma neo-japonicum Imazeki: A potential cytotoxic agent against breast cancer cells. Azeez L., Lateef A., Adebisi S.A. Silver nanoparticles (AgNPs) biosynthesized using pod extract of Cola nitida enhances antioxidant activity and phytochemical composition of Amaranthus caudatus Linn. Pulido R., Bravo L., Saura-calixto F. Antioxidant activity of dietary polyphenols as determined by a modified ferric reducing/antioxidant power assay. Inclusion in an NLM database does not imply endorsement of, or agreement with, Synthesis of metallic nanoparticles using plant extracts. Comparison of ABTS/DPPH assays to measure antioxidant capacity in popular antioxidant-rich US foods. DPPH scavenging activity of (a) AgNPs prepared by Chinese plants extract [123], copyright permission by Elsevier; (b) AgNPs prepared by walnut green husk extract increasing in concentration and time [124], copyright permission by Dovepress. If free radials have been scavenged, DPPH will generated it's color to yellow. Silver nanoparticles: Synthesis, properties, and therapeutic applications. Antioxidative | definition of Antioxidative by Medical dictionary The authors observed excellent nitric oxide scavenging activity of AgNPs in a concentration-dependent manner, but the activity was in general lower than that of ascorbic acid standard. The odd electron of nitrogen atom in DPPH is reduced by receiving a hydrogen . Zhang X.-F., Liu Z.-G., Shen W., Gurunathan S. Silver nanoparticles: Synthesis, characterization, properties, applications, and therapeutic approaches. Comparison of antioxidant assays based on radical scavenging, lipid oxidation and analysis of the principal antioxidant compounds. Gahlawat G., Shikha S., Chaddha B.S., Chaudhuri S.R., Mayilraj S. Microbial glycolipoprotein-capped silver nanoparticles as emerging antibacterial agents against cholera. In recent years, a broad range of spectrophotometric assays has been developed to measure antioxidant capacity. Tian X., Jiang X., Welch C., Croley T.R., Wong T., Chen C., Fan S., Chong Y., Li R., Ge C., et al. The authors proposed that AgNPs were synthesized using antioxidant power of red cabbage extract to reduce Ag+ ions, so AgNPs may promote superoxide radicals which would consume antioxidant capacity of red cabbage [125]. ) radical scavenging activity is generally quantified in terms of inhibition percentage of the pre-formed free radical by antioxidants, and the EC(50) (concentration required to obtain a 50% Nanoscience and nanotechnology have been introduced as interdisciplinary fields in biology, chemistry, physics, and bioengineering. The analyte flows through column in a liquid mobile phase to a detector (UV/Vis, DAD, MS, etc.,). This methodology, also called mechanochemical synthesis has recently attracted a significant attention of the research world [85,86,87,88,89,90,91]. The generation of peroxyl radicals have to be induced by AAPH (2,2-azobis-(2-amidino-propane) dihydrochloride). Because of this, there is an enormous need to develop a uniform protocol for determining the antioxidant capacity of nanoparticles to precisely assess their potential. Data can be copied directly from Excel columns. Deljou A., Goudarzi S. Green extracellular synthesis of the silver nanoparticles using thermophilic bacillus Sp. Other theory was presented by Vijayan et al. Biosensors as a tool for the antioxidant status evaluation. Schwarz K., Bertelsen G., Nissen L.R., Gardner P.T., Heinonen M.I., Hopia A., Lambelet T.H.P., Mcphail D., Skibsted L.H., Tijburg L. Investigation of plant extracts for the protection of processed foods against lipid oxidation. Replicates can be graphed simultaneously. The chemistry behind antioxidant capacity assays. Hydrogen peroxide scavenging activity of the studied AgNPs (72.5 %) was also higher than standard (56.4%). ABTS method is also useful in studying the effect of pH on the antioxidant activity of various compounds [53]. Pluym T.C., Powell Q.H., Gurav A.S., Ward T.L., Kodas T.T., Wang L.M., Glicksman H.D. Katta R., Brown D.N. Antioxidants are nutrients (vitamins and minerals) as well as enzymes (proteins in your body that assist in chemical reactions). The relevant explanation is missing, but authors rely on the fact that reducing power may serve as a major sign of potential antioxidant activity because of the ability of reduction of the Fe3+ ferricyanide complex [126]. Some of these methods are simple and provide good control of nanoparticle size by affecting the reaction process, but on the other hand, there are still problems with stabilization of the obtained products and to achieve unimodal distribution in nano-region [79]. open access Abstract Free radicals are reactive molecules involved in many physiological processes and have been associated with many diseases, such as cancer, arthritis and liver injury. viridis and its bactericidal activity toward staphylococcus aureus KCCM 12256. In these methods, the mechanism of antioxidant action of silver nanoparticles can be ascribed to the fact that silver can exist in two oxidation states (Ag+ and Ag2+) depending on the reaction conditions and the produced AgNPs may be able to quench free radicals by donating or accepting electrons [164]. Reducing compounds are necessary for the formation of nanosuspension, so natural antioxidants are mostly used for nanoparticles preparation and this fact gives the opportunities to detect physicochemical properties including total antioxidant capacity [77]. Other method using the Fenton-like system to induce lipid peroxidation is lipid peroxidation inhibitory assay by measuring the thiobarbituric acid reactive substances (TBARS) [12,42,60]. Reaction of N,N-dimethyl-p-phenylenediamine with hydroxyl radical [55]. [11] was focused on cytotoxic activity in normal and cancer cell lines. Synthesis of Ag nanoparticles that are known mainly for their great antimicrobial activity can be achieved through various methods [78]. Review of the use of biosensors as analytical tools in the food and drink industries. Green synthesis of silver nanoparticles and characterization of their inhibitory effects on AGEs formation using biophysical techniques. [Detection of antioxidative capacity of bamboo leaf extract by scavenging organic free radical DPPH]. Genesis and development of DPPH method of antioxidant assay The amperometric technique involves the measurement of the flowing current intensity between a working and a reference electrode at a fixed value of potential generated by the oxidation-reduction reaction [42,65]. This method is mostly used for the determination of total phenolic compounds in various samples (food products, plants, plant extracts), but it can also react in alkaline conditions with non-phenolic compounds, such as amino acids, aromatic amines, ascorbic acid, sulphur dioxide, Cu+ ions, and others [43]. Rajkumar T., Sapi A., Das G., Debnath T., Ansari A. Biosynthesis of silver nanoparticle using extract of Zea mays (corn flour) and investigation of its cytotoxicity effect and radical scavenging potential. These products may initiate new radical reactions leading to damage of biomolecules (nitrosylation of DNA or proteins) [19]. Accessibility On the other hand, silver nanoparticles have a potential in the treatment of cancer [7,8] or degenerative Alzheimers disease because of their antioxidant properties [9]. Some reactive oxygen and nitrogen compounds and relationships between them, redrawn from Greguka [15]. Bookshelf Comparison of the simple cyclic voltammetry (CV) and DPPH assays for the determination of antioxidant capacity of active principles. Asfaw TB, Woldemariam HW, Tadesse MG, Tessema FB, Admassie ZG, Esho TB. want to know how to. eCollection 2023 Apr. Copyright 2012 Elsevier Ltd. All rights reserved. The level of disappearance of purple color depends on the concentration of the antioxidant. Reaction of DPPH radical with hydrogen donor [46]. (Biology) biology a substance, such as vitamin C, vitamin E, or beta carotene, that counteracts the damaging effects of oxidation in a living organism. eki S.D., Avan A.N., Uzunboy S., Apak R. A colourimetric sensor for the simultaneous determination of oxidative status and antioxidant activity on the same membrane: Folin O., Ciocalteau V. On tyrosine and tryptophane in proteins. Electrochemical methods for the determination of total antioxidant capacity are widely used because of their sensitivity, speed, and low cost [65]. Nanoparticles have been shown to have a more complicated mechanism of action in biological systems using in vivo activity-based methods. Measurement of antioxidant activity - ScienceDirect Methods for antioxidant capacity evaluation. The Trolox equivalent antioxidant capacity ( TEAC) assay measures the antioxidant capacity of a given substance, as compared to the standard, Trolox. European research in focus: Mechanochemistry for sustainable industry (COST Action MechSustInd). Received 2020 Jun 16; Accepted 2020 Jul 12. DPPH Test (with calculation of IC50) for evaluation of Antioxidant Journal A.I., Johnson P., Krishnan V., Loganathan C., Govindhan K., Raji V., Sakayanathan P., Vijayan S., Palvannan T. Rapid biosynthesis of Bauhinia variegata flower extract-mediated silver nanoparticles: An effective antioxidant scavenger and -amylase inhibitor. It is a rapid, simple, and an inexpensive method for antioxidant capacity determination, but it has some limitations. This method is based on the reduction of DPPH radical at a glassy carbon electrode [65,66,67]. As an example, the study on the use of Trichoderma atroviride for this purpose can be mentioned [153]. Batch-injection analysis with amperometric detection of the DPPH radical for evaluation of antioxidant capacity. In Table 2 we show the list of some AgNPs synthesis techniques and several of them are briefly described below. Mello L.D., Kubota L.T. Stalmach A., Mullen W., Nagai C., Crozier A. On-line HPLC analysis of the antioxidant activity of phenolic compounds in brewed, paper-filtered coffee. Babior B.M. Khan S.A., Shahid S., Lee C. Green synthesis of gold and silver nanoparticles using leaf extract of clerodendrum inerme; characterization, antimicrobial, and antioxidant activities. sharing sensitive information, make sure youre on a federal Please enable it to take advantage of the complete set of features! Neuroscience and Biobehavioral Reviews Oxidative stress in schizophrenia: An integrated approach. Antioxidant Food Chart - Medindia Shanmugasundaram T., Radhakrishnan M., Gopikrishnan V. Colloids and Surfaces B: Biointerfaces A study of the bactericidal, anti-biofouling, cytotoxic and antioxidant properties of actinobacterially synthesised silver nanoparticles. How do you calculate the antioxidant activity of food using DPPH method? Analytical Methods Used in Determining Antioxidant Activity: A Review The results of DPPH and superoxide anion radical scavenging assays lead to reduced antioxidant capacity of prepared nanoparticles in comparison to plant extract, but the total reducing power of AgNPs indicated more reducing activity than plant extract. They observed that the reduction of silver ions and stabilization of prepared AgNPs were mainly because of the action of flavonoids. Ghaffari S. Oxidative stress in the regulation of normal and neoplastic hematopoiesis. In any case, it is better to express or compare the activity with a standard (ascorbic acid, trolox, gallic acid, quercetin, etc.). The mean percentage of DPPH free-radical . Beside the application of AgNPs in diverse areas, the large number of articles dealing with antioxidant properties of silver nanoparticles have been published spreading in the recent decade. IC50 Calculator | AAT Bioquest official website and that any information you provide is encrypted Bhat R., Deshpande R., Ganachari S.V., Huh D.S., Venkataraman A. Photo-irradiated biosynthesis of silver nanoparticles using edible mushroom Pleurotus florida and their antibacterial activity studies. As it can be seen, the number of publications reporting on biosynthesis (especially using plant extract), has prevailed over any other method of synthesizing AgNPs, which may be justified by simplicity, availability, low cost of this approach (Table 3). antioxidant. Physical approaches for AgNPs synthesis include evaporation-condensation, which has some disadvantages, such as high energy consumption, long time for achieving thermal stability [80,81]. Synergistic effects between silver nanoparticles and antibiotics and the mechanisms involved. The most common representative of RNS is nitroxide (NO) produced by nitrogen oxidation catalyzed by NO-synthase [18]. [155], who studied antioxidant capacity of silver nanoparticles prepared by exopolysaccharides isolated from Streptomyces violaceus. Spectroscopic Characterization, Cyclic Voltammetry, Biological Investigations, MOE, and Gaussian Calculations of VO(II), Cu(II), and Cd(II) Heteroleptic Complexes. The antioxidant capacities of structurally different phenolic compounds were evaluated. Raveendran P., Fu J., Wallen S.L. Rai M., Yadav A., Gade A. For these reasons, various physical techniques were developed. DMPD radical scavenging assay is based on the conversion of transparent N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) into the colored radical DMPD+ in the presence of Fe ions or reactive species, such as hydroxyl radicals (Scheme 3). Here we propose a protocol to evaluate the antioxidant capacity of compounds by the DPPH method through the scavenging capacity of free radicals by reducing the DPPH radical. doi: 10.1016/j.heliyon.2023.e16227. The antioxidant capacity was determined at different concentrations (100, 200, 300, 400 and 500 mM). The antioxidant capacity of green-synthesized AgNPs was similar to that of plant extract. Apak R., zyrek M., Gl K., apanolu E. Antioxidant activity/capacity measurement. This is accompanied by a color change from yellow original color of the solution of Na2WO4/Na2MO4 to blue because of the formation of complexes with phenols (Phenol-MoW11O404). The separation process depends on affinity of analyte toward the stationary and mobile phases. Anker J.N., Hall W.P., Lyandres O., Shah N.C., Zhao J., VanDuyne R.P. Authors explained this phenomenon by the role of phytochemicals. This method was developed by Blois with the viewpoint to determine the antioxidant activity in a like manner by using a stable free radical , -diphenyl--picrylhydrazyl (DPPH; C 18 H 12 N 5 O 6, M = 394.33).The assay is based on the measurement of the scavenging capacity of antioxidants towards it. Biology rapid biosynthesis and characterization of silver nanoparticles from the leaf extract of tropaeolum majus L. and its enhanced in-vitro antibacterial, antifungal, antioxidant and anticancer properties. (Elements & Compounds) any substance that retards deterioration by oxidation, esp of fats, oils, foods, petroleum products, or rubber. Cyclic voltammetry (CV) is a method based on the measurement of oxidation potential (E1/2) intensity of the sample [43]. Method optimization for the determinations of selected phytochemicals and antioxidant activities of wild Ethiopian. DPPH Radical Scavenging Method-Total Antioxidant Capacity - YouTube Mittal A.K., Chisti Y., Banerjee U.C. Pivec T., Hribernik S., Kolar M., Kleinschek K.S. These methods are based on the reaction of colored radical or complex with the antioxidant molecule capable of donating a hydrogen atom. They observed that the alfalfa root is able to absorb silver from agar medium to produce AgNPs. The focus was on nitric oxide, DPPH, and hydrogen peroxide radical scavenging activity. Nagaoka S., Nagai K., Fujii Y., Ouchi A., Mukai K. Development of a new free radical absorption capacity assay method for antioxidants: Aroxyl radical absorption capacity (ARAC). Generally, there are three methods for AgNPs synthesisbiological, physical, and chemical. Gonzlez-ballesteros N., Rodrguez-argelles M.C., Prado-lpez S., Lastra M., Grimaldi M., Cavazza A., Nasi L., Salviati G. Macroalgae to nanoparticles: Study of Ulva lactuca L. role in biosynthesis of gold and silver nanoparticles and of their cytotoxicity on colon cancer cell lines. On the contrary to NOx assay, the ability to scavenge both free radicals of silver nanoparticles was higher than that of the standard used. Ashraf J.M., Ansari M.A., Khan H.M., Alzohairy M.A., Choi I. Bal M., Bedloviov Z., Kovov M., Balov ., Salayov A. Similar results were published by Shahid et al. How Antioxidants Work | HowStuffWorks Guidelines for antioxidant assays for food components - Xiao - 2020 This. NO is able to rapidly react with reactive oxygen species (mainly with superoxide anion radical) and produce further reactive nitrogen compounds, for example peroxynitrite or peroxynitrous acid which can be further transformed to NO2 or OH (Figure 1). Our objective in this review article is to find out relevant information about methods of determination of antioxidant activity of silver nanoparticles. FOIA Kharissova O.V., Dias H.V.R., Kharisov B.I., Prez B.O., Prez V.M.J. Nazem A., Mansoori G.A. A comparative study of stability, antioxidant, DNA cleavage and antibacterial activities of green and chemically synthesized silver nanoparticles. Nanda A., Saravanan M. Biosynthesis of silver nanoparticles from Staphylococcus aureus and its antimicrobial activity against MRSA and MRSE. Amer AA, Elgohary R, Ibrahim FM, Taha HS. FRAP values are calculated from increasing absorbances measured at 593 nm [39,42,43]. Methods of antioxidant capacity determination of prepared silver nanoparticles. Durackova Z. Kowshik M., Deshmukh N., Vogel W., Urban J., Kulkarni S.K., Paknikar K.M. How can I calculate %RSA (radical scavenging activity) using DPPH [128], who indicate that the increased antioxidant properties of nanoparticles compared to extract can be attributed to the adsorption of bioactive compounds of leaf extract over spherically shaped nanoparticles. Because of this, metallic nanoparticles (NPs) have interesting attributes such as intensive color which can be detected in visible region of spectra [76]. Vigneshwaran N., Nachane R.P., Balasubramanya R.H., Varadarajan P.V. Essential electrochemical methods encompass cyclic voltammetry, amperometry, and biamperometry. The AgNPs showed the DPPH radical scavenging effect of 89.5% at concentration of 50 g/mL, which was higher than in the case of ascorbic acid standard (49.6%). Extraction and determination of total polyphenols and antioxidant Lower values of antioxidant capacity against NOx were explained by the difference in the reaction mechanism [138]. Food Chem. Elucidation of prospective mechanism and therapeutic potential. Mittal A.K., Bhaumik J., Kumar S., Banerjee U.C. The aim of this review is to provide a brief overview on antioxidant activity of silver nanoparticles, its measurement, and future perspectives in relationship between AgNPs and antioxidant activity. If entering data manually, only enter one X-Value per line. 2023 Apr 8;12(8):1584. doi: 10.3390/foods12081584. In this article, we studied the identification of antioxidants using (DPPH) 2,2-Diphenyl-1-picrylhydrazylradical scavenging activity in Ficus religiosa, as F. religiosa is an important herbal plant, and every part of it has various medicinal properties such as antibacterial . Arnao M.B. This method is limited by the possibility of MDA reaction with amino group to form Schiff base [62]. Pedan V., Fischer N., Rohn S. An online NP-HPLC-DPPH method for the determination of the antioxidant activity of condensed polyphenols in cocoa. Before How to express the antioxidant properties of substances properly? The total phenolic content was lower (8.1 0.1%) than the total flavonoid content (81.2 0.27%), so they concluded that the amount of flavonoids present in silver nanoparticles was ten times higher which was in good agreement with the isolated flavonoids from extract. Shape-controlled synthesis of gold and silver nanoparticles. Evanoff D.D., Chumanov G. Size-controlled synthesis of nanoparticles. The higher degree of hydroxylation in chemical structures of phenolic compounds demonstrated the higher radical scavenging capacity and higher tendency to reduce Ag+ to AgNPs [161]. Prakash A., Sharma S., Ahmad N., Ghosh A., Sinha P. Synthesis of AgNPs by bacillus cereus bacteria and their antimicrobial potential. Kaysen G.A., Eiserich J.P. Careers. The effect of silver nanoparticles on antioxidant/pro-oxidant balance in a murine model. Chinnasamy G., Chandrasekharan S., Bhatnagar S. Biosynthesis of silver nanoparticles from Melia azedarach: Enhancement of antibacterial, wound healing, antidiabetic and antioxidant activities. Hydrogen peroxide and DPPH scavenging activity of AgNPs was also compared with ascorbic acid. Voetsch B., Jin R.C., Loscalzo J. Nitric oxide insufficiency and atherothrombosis. Then AgNPs yield greater amounts of hydrogen peroxide and induce inflammasome formation leading to the production of superoxide and H2O2 in the mitochondrias membrane [155]. The most common technique for nanoparticles preparation is the reduction by reducing agents of organic or inorganic character, for example sodium ascorbate, hydrogen, N,N-dimethyl formamide, or sodium borohydride. Greguka O. Kyslkov radikly, oxid dusnat a antioxidan systm v kboch postihnutch zpalom. EGethylene glycol; EG/PVPethylene glycol/poly(vinyl pyrollidine); PABA-PVApoly(3-aminophenyl boronic acid- poly(vinyl alcohol); PLA/PEGpoly lactic acid/poly ethylene glycol. Trolox equivalent antioxidant capacity - Wikipedia Elemike E.E., Fayemi O.E., Ekennia A.C., Onwudiwe D.C., Ebenso E.E. Oxidative stress, caused by endogenous factors such as reactive oxygen species (ROS) including the hydroxyl radical, superoxide anion radical, hydrogen peroxide, singlet oxygen, nitric oxide radical, hypochlorite radical, etc., and exogenous factors such as smoking, ionizing radiation, pollution, organic solvents, pesticides, etc., are able to a. The scavenging capacity is usually determined in organic solvents, not in aqueous media [12,39,41,42,45,46]. Diagnostic methods and therapeutic agents. However, understanding the roles of various antioxidants and their activities is challenging. The authors explained the results based on the hypothesis that in the presence of H2O2 the dispersed nanoparticles may induce the formation of reactive oxygen species and hydrogen peroxide inside a cell. The first approach to measure the antioxidant activity of a drug, an extract, or other biological sources is the alpha-diphenyl--picrylhydrazyl (DPPH) free radical scavenging process. Nowadays, there are too many analytical methods, but there is no one universal . Demirbas A., Welt B.A., Ocsoy I. Biosynthesis of red cabbage extract directed Ag NPs and their effect on the loss of antioxidant activity. The biology of oxygen radicals. Oxidative stress, associated with an imbalance between the oxidants (reactive oxygen species) and the antioxidants in the body, contributes to the development of many diseases. Current achievements in the mechanically pretreated conversion of plant biomass. The results are contradictory, as some authors observed higher antioxidant capacity of AgNPs, whereas on the other hand, there are also studies with the opposite results. Characterization, antibacterial and antioxidant properties of silver nanoparticles synthesized from aqueous extracts of allium sativum, zingiber officinale, and capsicum frutescens. Analogically, they found higher total antioxidant activity of AgNPs compared to the standard. ABTS is usually first oxidized by potassium persulphate [49], manganese dioxide [50], or AAPH (2,2-azobis-(2-amidino-propane) dihydrochloride) [51] which gives rise to the cation radical ABTS+. This assay is based on the reaction of 2-thiobarbituric acid (TBA) with malondialdehyde (MDA) as one of the products of unsaturated lipids oxidation (Scheme 5) [61].