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: Garcinielliptone FC ( GFC ) isolated from hexanic fraction seed extract of species Platonia insignis Mart .
### Output Text:
<span class="chemical">Garcinielliptone FC</span> ( <span class="chemical">GFC</span> ) isolated from hexanic fraction seed extract of species Platonia insignis Mart . 