23003
The activity was further supported by its considerable iron chelation with half - maximal inhibitory concentration of 70 . 24 +/- 2 . 74 mu g ml ( - 1 ) and the protection on ferrous ion - mediated DNA breakdown with 50 % protection ( [ P ] 50 ) of 1 . 04 +/- 0 . 01 mu g ml ( - 1 ) .
 Chemical: iron; Chemical: ferrous
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: iron; Chemical: ferrous