In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: The potential protective effect of the dietary antioxidant curcumin ( 120 mg / Kg / day for 6 days ) against the renal injury induced by maleate was evaluated .
### Output Text:
The potential protective effect of the dietary antioxidant <span class="chemical">curcumin</span> ( 120 mg / Kg / day for 6 days ) against the renal injury induced by <span class="chemical">maleate</span> was evaluated . 