19773
Based on the structure of these four constituents , the results indicate that the hydroxyl group in C - 2 and double bond in C20 ( 21 ) and C20 ( 22 ) positions are of importance in inhibition of A549 cell proliferation .
 Chemical: hydroxyl
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: hydroxyl