How to highlight codes from a text by CI's highlight_code()

[eluser]mi6crazyheart[/eluser]
Actually, i've a piece of text in which some codes are also present(enclose by "HTML CodeTag"). What i want to do is , highlight those codes by CI's highlight_code() and store those in DB table.

Ex: I've a text like this $text = "All is well[codetag]echo phpinfo();[/codetag]All is well";

Any body have any idea, how to solve this kind of problem...