6844
MDMA catechol metabolites were neurotoxic to SH - SY5Y neurons , leading to caspase 3 - independent cell death in a concentration - and time - dependent manner .
 MDMA, catechol
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 MDMA, catechol