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: Protective effect of Terminalia chebula against experimental myocardial injury induced by isoproterenol .
### Output Text:
Protective effect of <span class="chemical">Terminalia chebula</span> against experimental myocardial injury induced by <span class="chemical">isoproterenol</span> . 