Hi there. I need to compare a measurement of antioxidant capacity (DPPH in fruits of chili pepper) expressed in ascorbic acid equivalents, to values reported in the literature, but most studies express DPPH in Trolox equivalent. Is there a 'factor' we can use to convert each other? Are they comparable?
The response of Tilahun abera, 4 months ago in researchgate is the following (can i use trolose instead of DPPH):
Yes, you can use Trolox instead of ascorbic acid. May you follow the following analytical procedure.
Analysis of DPPH
Reagents:0.1mMDPPH (weigh 0.0039g of DPPH into 100mL flask and fill up to mark)
100% methanol
1. standard: trolox make stock of 1000mg/L by measuring 10mg trolox into 10ml 100% methanol
2. then: prepare 0.1, 0.2, 0.4, 0.8, standards by taking 100µL , 200, 400 and 800 µL from stock to each standard, respectively and add 900 µL, 800 µL, 600 µL, 200 µL of 90%methanol.
3. prepare 0.01,0.02,0.04,0.08 by taking 100 µL of 0.1, 0.2,0.4,0.8 standard, respectively + 900µL of methanol and use 0.1 standard as fifth.
From the above, you will get your first result in mg/L using the linear equation which has generated from a series of working standards. To convert into mg/g, divide the previous result by your sample weight on dry matter basis which will give you the final result in mg/g(db). I hope it is clear.
Every procdure have a unique equation and parameters also, some of this determoined as % and others equivalent.
Hello Diego Muñoz-Concha You might consider expressing DPPH reducing activity as IC50 value. It will help you to get rid of conversion. Take a standard like ascorbic acid and compare sample IC50 with ascorbic acid IC50.
Below check some references:
Article Antinociceptive and Antioxidant Activity of Zanthoxylum budr...
Article Bioactivity studies on Musa seminifera Lour
Article Preliminary pharmacological evaluation of Alocasia indica Schott tuber
Thanks.
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