5787
In the current study , derivatives of 25 - hydroxyprotopanaxadiol ( 25 - OH - PPD ) were prepared and their in vitro anti - tumor activities were tested on six different human tumor cell lines by standard MTT assay .
 Chemical: 25 - hydroxyprotopanaxadiol; Chemical: 25 - OH - PPD; Chemical: MTT
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: 25 - hydroxyprotopanaxadiol; Chemical: 25 - OH - PPD; Chemical: MTT