17139
Since two of the presently approved drugs for AD are based on natural products ( galantamine and the physostigmine - derivative rivastigmine ) , many plants are now under investigation as a potential source of new drugs .
 Chemical: galantamine; Chemical: physostigmine; Chemical: rivastigmine
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: galantamine; Chemical: physostigmine; Chemical: rivastigmine