18931
Twelve derivatives of oleanolic acid ( 1 ) have been synthesized and evaluated for their inhibitory activities against the growth of prostate PC3 , breast MCF - 7 , lung A549 , and gastric BGC - 823 cancer cells by MTT assays .
 Chemical: oleanolic acid; 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: oleanolic acid; Chemical: MTT