Brazilian Journal of Biological Sciences (ISSN 2358-2731)

Home Archive v. 6, no. 12 (2019) Oso


Vol. 6, No. 12, p. 53-61 - Apr. 30, 2019


Antioxidant assays by reducing potential and 2,2-diphenyl-1-picrylhydrazyl radical scavenging techniques as affected by pH and ion concentrations

Babatunde J. Oso and Clement O. Ogidi

The aim of the study is to investigate the effect of varying pH and different metal ion concentrations on the analyses of antioxidants by reducing potential (RP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging techniques. The investigation was conducted by examining the effects of various pH values (4, 5, 6, 7, 8 and 9) and potassium chloride concentrations (50, 100, 150, 200, 250 and 300 μg/mL) on the optical densities of reducing potential and DPPH radical scavenging potential of aqueous infusions of Cassia alata (L.) Roxb. The determinations were also conducted on the extraction media with the intention of identifying the probable source of variation in the investigation. The antioxidant potentials for both the aqueous infusion and media were most efficient at the least pH 4.0. Moreover, the antioxidant potentials decrease as the ion concentrations increase. The study revealed that the colorimetric methods for the determinations of DPPH radical scavenging and RP could be liable to errors arising from slight changes in acidity and concentrations of the metal ions thus affecting the performance characteristics in terms of repeatability and reproducibility of reports and meaningful comparisons of antioxidant capacity of dietary products among different authors.

2,2-diphenyl-1-picrylhydrazyl; Cassia alata; Ionic strength; pH; Reducing power.


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Amorati, R.; Pedulli, G. F.; Cabrini, L.; Zambonin, L.; Landi, L. Solvent and pH effects on the antioxidant activity of caffeic and other phenolic acids. Journal of Agricultural and Food Chemistry, v. 54, no. 8, p. 2932 2937, 2006.

Apak, R.; Güçlü, K.; Demirata, B.; Özyürek, M.; Çelik, S. E.; Bektaşoğlu, B.; Berker, K. I.; Özyurt, D. Comparative evaluation of various total antioxidant capacity assays applied to phenolic compounds with the CUPRAC assay. Molecules, v. 12, p. 1496-1547, 2007.

Apak, R.; Özyürek, M.; Güçlü, K.; Çapanolu, E. Antioxidant activity/capacity measurement. 2. Hydrogen atom transfer (HAT)-based, mixed-mode (electron transfer (ET)/HAT), and lipid peroxidation assays. Journal of Agricultural and Food Chemistry, v. 64, no. 5, p. 1028-1045, 2016.

Azizah, A. H.; Ruslawati, N. M.; Sweetee, T. Extraction and characterization of antioxidants from cocoa by-products. Food Chemistry, v. 64, no. 2, p. 199-202, 1999. 121-6

Cai, Y. Z.; Sun, M.; Xing, J.; Luo, Q.; Corke, H. Structure-radical scavenging activity relationships of phenolic compounds from traditional Chinese medicinal plants. Life Science, v. 78, no. 25, p. 2872-2888, 2006.

Friedman, M.; Jurgens, H. S. Effect of pH on the stability of plant phenolic compounds. Journal of Agricultural and Food Chemistry, v. 48, no. 6, p. 2101-2110, 2000.

Gosh, S.; Chakraborty, R.; Raychaudhuri, U. Determination of pH-dependent antioxidant activity of palm (Borassus flabellifer) polyphenol compounds by photoluminol and DPPH methods: A comparison of redox reaction sensitivity. 3 Biotech, v. 5, no. 5, p. 633-640, 2015.

Lemańska, K.; Szymusiak, H.; Tyrakowaska, B.; Zieliński, R.; Soffers, A. E. M. F.; Rietjens, I. M. C. M. The influence of pH on antioxidant properties and the mechanism of antioxidant action of hydroxylflavones. Free Radical Biology and Medicine, v. 31, no. 7, p. 869-881, 2001.

Leopoldini, M.; Russo, N.; Toscano, M. Gas and liquid phase acidity of natural antioxidants. Journal of Agricultural and Food Chemistry, v. 54, no. 8, p. 3078-3085, 2006.

Li, J. R.; Jiang, Y. M. Litchi flavonoids: Isolation, identification and biological activity. Molecules, v. 12, no. 4, p. 745-758, 2007.

Muzolf-Panek, M.; Gliszczyńska-Świgło, A.; Szymusiak, H.; Tyrakowska, B. The influence of stereochemistry on the antioxidant properties of catechin epimers. European Food Research and Technology, v. 235, no. 6, p. 1001-1009, 2012.

Oancea, S.; Drăghici, O. pH and thermal stability of anthocyanin-based optimised extracts of Romanian red onion cultivars. Czech Journal of Food Science, v. 31, no. 3, p. 283-291, 2013.

Oyaizu, M. Studies on products of browning reactions: Antioxidant activities of products of browning reaction prepared from glucosamine. The Japanese Journal of Nutrition and Dietetics, v. 44, no. 6, p. 307 315, 1986.

Padmaja, M.; Srinivasulu, A. Influence of pH and temperature on total phenol content of Ocimum sanctum leaves. Indian Journal of Pharmaceutical Science & Research, v. 6, no. 2, p. 69-72, 2016.

Pękal, A.; Pyrzynska, K. Effect of pH and metal ions on DPPH radical scavenging activity of tea. International Journal of Food Sciences and Nutrition, v. 66, no. 1, p. 58-62, 2015.

Prior, R. L.; Wu, X.; Schaich, K. Standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements. Journal of Agricultural and Food Chemistry, v. 53, p. 4290-4302, 2005.

Ruenroengklin, N.; Zhong, J.; Duan, X.; Yang, B.; Li, J.; Jiang, Y. Effects of various temperatures and pH values on the extraction yield of phenolics from litchi fruit pericarp tissue and the antioxidant activity of the extracted anthocyanins. International Journal of Molecular Science, v. 9, no. 7, p. 1333-1341, 2008.

Settharaksa, S.; Jongjareonrak, A.; Hmadhlu, P.; Chansuwan, W.; Siripongvutikorn, S. Flavonoid, phenolic contents and antioxidant properties of Thai hot curry paste extract and its ingredients as affected of pH, solvent types and high temperature. International Food Research Journal, v. 19, no. 4, p. 1581-1587, 2012.

Shirwaikar, A.; Rajendran, K.; Punithaa, I. S. In vitro antioxidant studies on the benzyl tetra isoquinoline alkaloid berberine. Biological and Pharmaceutical Bulletin, v. 29, no. 9, p. 1906-1910, 2006.

Silas, N. E.; Murungi, J. I.; Wanjau, R. N. The pH of leaf water extracts and amount of acid required lowering the pH of leaf water extracts to 5.0. American International Journal of Contemporary Research, v. 2, no. 11, p. 72-78, 2012.

Stupka, G.; Gremaud, L.; Williams, A. F. Control of redox potential by deprotonation of coordinated 1H-imidazole in complexes of 2-(1H-imidazol-2-yl) pyridine. Helvetical Chimica Acta, v. 88, no. 3, p. 487-495, 2005.

Wright, J. S.; Johnson, E. R.; DiLabio, G. A. Predicting the activity of phenolic antioxidants: Theoretical method, analysis of substituent effects, and application to major families of antioxidants. Journal of the American Chemical Society, v. 123, no. 6, p. 1173-1183, 2001.

Yen, G. C.; Duh, P. D. Antioxidant properties of methanolic extracts from peanut hulls. Journal of the American Oil Chemists' Society, v. 70, no. 4, p. 383-386, 1993.