21032
Synthesis , in vitro antitumor evaluation and DNA - binding study of novel tetrahydroquinolines and some derived tricyclic and tetracyclic ring systems .
 tetrahydroquinolines
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 tetrahydroquinolines