7756
Natural polyphenols were tested for their ability to protect against glyoxal - and methylglyoxal - induced cytotoxicity , reactive oxygen species formation and improved mitochondrial membrane potential maintenance .
 Chemical: polyphenols; Chemical: glyoxal; Chemical: methylglyoxal; Chemical: oxygen
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: polyphenols, glyoxal, methylglyoxal, oxygen 
Answer:
 Chemical: polyphenols; Chemical: glyoxal; Chemical: methylglyoxal; Chemical: oxygen