16784
For this purpose , we employed theoretical methods for the selection of antioxidant drugs and the rapid methods of evaluation : the 1 , 1 - diphenyl - 2 - picrylhydrazyl radical and the thiobarbituric acid reactive substances in the lipid peroxidation initiated by Fe ( 2 + ) and ascorbic acid in human erythrocytes .
 1 , 1 - diphenyl - 2 - picrylhydrazyl, thiobarbituric acid, Fe ( 2 + ), ascorbic acid
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 1 , 1 - diphenyl - 2 - picrylhydrazyl, thiobarbituric acid, Fe ( 2 + ), ascorbic acid