16045
The natural alkaloid ( - ) - huperzine A is a potent inhibitor of AChE and has been demonstrated to exert neuroprotection at an appropriate dose .
 ( - ) - huperzine A
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 ( - ) - huperzine A