25988
However , until future studies elucidate the magnitude of functional change , caution is warranted in rare instances of extensive metabolism by catechol - O - methyltransferase in Bcrp - knockouts and intestinal carboxylesterase in Mdr1a - knockout rats , specifically for molecules with free catechol groups and esters subject to gut wall hydrolysis .
 Chemical: catechol; Chemical: O; Chemical: catechol
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: catechol; Chemical: O; Chemical: catechol