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Malondialdehyde level in BCNU - exposed group was higher than those in control groups and melatonin decreased malondialdehyde levels in BCNU group ( P < 0 . 01 ) , while there were no significant differences in the superoxide dismutase levels between these groups .
 Chemical: Malondialdehyde; Chemical: BCNU; Chemical: melatonin; Chemical: malondialdehyde; Chemical: BCNU; Chemical: superoxide
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: Malondialdehyde; Chemical: BCNU; Chemical: melatonin; Chemical: malondialdehyde; Chemical: BCNU; Chemical: superoxide