2640
Antioxidant activities were evaluated for total antioxidant activity by the ferric thiocyanate method , ferric ion ( Fe ( 3 + ) ) reducing antioxidant power assay ( FRAP ) , ferrous ion ( Fe ( 2 + ) ) metal chelating activity , and DPPH free radical - scavenging activity .
 ferric thiocyanate, ferric, Fe ( 3 + ), ferrous, Fe ( 2 + ), DPPH
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 ferric thiocyanate, ferric, Fe ( 3 + ), ferrous, Fe ( 2 + ), DPPH