25411
Antibacterial activity - guided purification and identification of a novel C - 20 oxygenated ent - kaurane from Rabdosia serra ( MAXIM . ) HARA .
 C - 20 oxygenated ent - kaurane
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 C - 20 oxygenated ent - kaurane