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Kynurenic acid ( KYNA ) , one of the main product of the kynurenine pathway originating from tryptophan , is considered to be neuroprotective .
 Chemical: Kynurenic acid; Chemical: KYNA; Chemical: kynurenine; Chemical: tryptophan
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: Kynurenic acid; Chemical: KYNA; Chemical: kynurenine; Chemical: tryptophan