19798
The production of general reactive oxygen species ( ROS ) and superoxide anions during differentiation of preosteoclastic RAW 264 . 7 cells into osteoclasts was attenuated by compounds 1 and 2 .
 Chemical: oxygen; Chemical: superoxide
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: oxygen; Chemical: superoxide