I would like to know of a method which requires less instruments and chemicals.
Screening for Antioxidant Activity: Antioxidantactivities of the plant of methanol extract was
determined on the basis of their scavenging potential of the stable DPPH free radical in both qualitative and quantitative assay.
i) Qualitative Assay:
A suitably diluted stock solutionswere spotted on pre-coated silica gel TLC plates and
the plates were developed in solvent systems of different polarities (polar, medium polar and non-polar) to resolve polar and non-polar components of the extracts. The plates were dried at room temperature and were sprayed with 0.02% DPPH in methanol. Bleaching of DPPH by the resolved band was observed for 10 minutes and the color changes (yellow on purple background) were noted [1].
هquantitative Assay: Hydrogen Donation Assay:
The hydrogen-donating ability of lyophilized extract was determined using DPPH, stable nitrogen centered radical by employing the method of Blois (1958). DPPH offers a convenient and accurate method for titrating the oxidizable groups of natural or synthetic
anti-oxidants[2]. In this assay, a known volume of extract solution 0~110 ìg ml-1 was added to 0.1mM ethanolic DPPH in a cuvette. The decrease in DPPH absorption at 517 nm as per time variation was correlated with the scavenging action of the test compound. The radical scavenging activity was expressed as the inhibition percentage and monitored as
per the equation: % DPPH radical scavenging= 1- AS/AC ×100.Here, AC=absorbance of control,
AS=absorbance of sample solution.
The DPPH solution without sample solution was used as control. IC50 value the concentration of sample mg ml-1 required to scavenge 50% DPPH free radical was calculated from the inhibition curve. Ascorbic acid was used as positive control.
reference:
(1) Sadhu, S.K., E. Okuyama, H. Fujimoto and M. Ishibashi, 2003. "Separation of Leucas aspera, a medicinal plant of Bangladesh, guided by prostaglandin inhibitory and antioxidant activities" Chemical & Pharmaceutical Bulletin, 51: 595-598.
(1)
I am very much grateful to all friends for helping me to know about DPPH and other methods. Another thing is that I have different types of extracts like hexane extract, ethyleacetate extract, ethanol extract. can i apply same method for all extracts. At this time i have crude extracts. Should i freez dry or lyophilize these samples to remoive hexane, ethyle acetate and ethanol?
Please try the following articles for reference. Regards!
1.) Apak, R., Gorinstein, S., Böhm, V., Schaich, K. M., Özyürek, M., & Güçlü, K. (2013). Methods of measurement and evaluation of natural antioxidant capacity/activity (IUPAC Technical Report). Pure and Applied Chemistry, 85(5), 957–998. doi:10.1351/PAC-REP-12-07-15
2.) Pinchuk, I., Shoval, H., Dotan, Y., & Lichtenberg, D. (2012). Evaluation of antioxidants: Scope, limitations and relevance of assays. Chemistry and Physics of Lipids, 165, 638–647.
3.) Thaipong, K., Boonprakob, U., Crosby, K., Cisneros-Zevallos, L., & Hawkins Byrne, D. (2006). Comparison of ABTS, DPPH, FRAP, and ORAC assays for estimating antioxidant activity from guava fruit extracts. Journal of Food Composition and Analysis, 19(6-7), 669–675. doi:10.1016/j.jfca.2006.01.003
Please give me your email address so I could send the articles to you.
The simplest I have in mind is to determine the levels of antioxidants like reduced ascorbate and reduced glutathione; and also the activities of antioxidative enzymes like SOD (superoxide dismutase), CAT (catalase), APX ascorbate peroxidase), and GR glutathione reductase).
Kindly send me this file at email
1.) Apak, R., Gorinstein, S., Böhm, V., Schaich, K. M., Özyürek, M., & Güçlü, K. (2013). Methods of measurement and evaluation of natural antioxidant capacity/activity (IUPAC Technical Report). Pure and Applied Chemistry, 85(5), 957–998. doi:10.1351/PAC-REP-12-07-15
Dear Jovale Vincent
could you please send these articles to me too?
My email: [email protected]
I would like to freez dry plant tissues and then analyze antioxidant in plant. Is it possible or antioxidant activity will be changed by freez drying?
thanks a lot
i am working on isolation of flavonoids from leaves of plant, can anyone help me with tips on fractionation (column chromatography) to enable me obtain pure compounds without using Prep.TLC.
Thank you
Dear all,
Is there any paper giving an overview of relevant methods for evaluating antioxidant activity with emphasis on the chemistry, basic principles involved as well as advantages and disadvantages of each assay ? Thanks.
@ Chijioke, do send the paper to me too, my email is [email protected].
Regards
Can ı take paper too ? My email is:[email protected]
Thank you
Best Regards
Dear Abid Ali ,
we recently designed NRP, a simple and cheap method for rapid assessment of total antioxidant activity in large amount of samples. You can also use it to obtain spatial distribution of antioxidant status if you are working with tissue samples. The method is very precise and accurate due to its simplicity - you only need a piece of nitrocellulose and one chemical - KMnO4 (very well defined strong oxidant).
You can find all validation steps and step-by-step protocol here:
Preprint Nitrocellulose redox permanganometry: a simple method for re...
Method Nitrocellulose Redox Permanganometry (NRP/HistoNRP)
Best, Jan
The nitrocellulose membrane can be replaced with another material?
H2O2 scavenging assay. It is a rather simple method for assessing antioxidant activity. You need a spectrophotometer and citric acid.
In short, the DPPH test is relatively simple and does not require highly specialized equipment. A basic spectrophotometer is sufficient to measure absorbance.
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