5719
Results suggest that the naphthenic acids may act via a generally toxic mechanism rather than by specific toxic effects on immune cells .
 Chemical: naphthenic acids
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: naphthenic acids 
Answer:
 Chemical: naphthenic acids