17571
Drug release is triggered by the nitro reductase action of the colonic microflora , liberating a cyclization competent species .
 Chemical: nitro
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: nitro 
Answer:
 Chemical: nitro