17640
Among three compounds , obovatol most strongly scavenged 2 , 2 - diphenyl - 1 - picrylhydrazyl radicals and inhibited the elevation of intracellular reactive oxygen species levels in glutamate - stressed HT22 cells .
 Chemical: obovatol; Chemical: 2 , 2 - diphenyl - 1 - picrylhydrazyl; Chemical: oxygen; Chemical: glutamate
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: obovatol; Chemical: 2 , 2 - diphenyl - 1 - picrylhydrazyl; Chemical: oxygen; Chemical: glutamate