21110
Objective : To investigate astaxanthin ( ATX ) neuroprotection , and its mechanism , on a 1 - methyl - 4 - phenyl - pyridine ion ( MPP + ) - induced cell model of Parkinson ' s disease .
 Chemical: astaxanthin; Chemical: ATX; Chemical: 1 - methyl - 4 - phenyl - pyridine; Chemical: MPP +
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: astaxanthin; Chemical: ATX; Chemical: 1 - methyl - 4 - phenyl - pyridine; Chemical: MPP +