11971
In the 15 compounds that were tested , the level of substitution on the A - ring was found to directly influence the activity against Leishmania donovani whilst the activity against Plasmodium falciparum was influenced by numerous substitution and stereochemical factors .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None