General description. 2,2-diphenyl-1-picrylhydrazyl is a free radical, which shows hydrogen acceptor ability towards antioxidants. Hence, it is commonly used in DPPH assay for measuring the antioxidant activity of different natural samples such as wine, fruits, herbal tea etc.

DPPH is a common abbreviation for the organic chemical compound 2,2-diphenyl-1-picrylhydrazyl. It is a dark-colored crystalline powder composed of stable free-radical molecules.

 strong absorption band centered at about 520 nm, the DPPH radical has a deep violet color in solution, and it becomes colorless or pale yellow when neutralized. 

PPH has two major applications, both in laboratory research: one is a monitor of chemical reactions involving radicals, most notably it is a common antioxidant assay,[1] and another is a standard of the position and intensity of electron paramagnetic resonance signals.

DPPH 2 2 Diphenyl 1 picrylhydrazyl