825
Both species were investigated for their angiotensin - converting enzyme ( ACE ) inhibitory activity and antioxidant properties through three in vitro models [ 2 , 2 - diphenyl - 1 - picrylhydrazyl ( DPPH ) , 2 , 2 ' - azino - bis ( 3 - ethylbenzothiazoline - 6 - sulphonic acid ) ( ABTS ) and ferric reducing antioxidant power ( FRAP ) assay ] .
 2 , 2 - diphenyl - 1 - picrylhydrazyl, DPPH, 2 , 2 ' - azino - bis ( 3 - ethylbenzothiazoline - 6 - sulphonic acid ), ABTS
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 2 , 2 - diphenyl - 1 - picrylhydrazyl, DPPH, 2 , 2 ' - azino - bis ( 3 - ethylbenzothiazoline - 6 - sulphonic acid ), ABTS