If you just want to run a command as root (i.e. without logging in and running .bash_profile) then sudo's probably the easiest way:
ssh email@example.com sudo command
I just tried that on my Ubuntu box, and it worked - although it did print the admin password the second time. You could always configure sudo to allow the user to run the specific command without a password.
You can't run su from the ssh command-line, because it needs a terminal of some sort. You could create a virtual terminal, then attach it to the standard input and output streams provided by sshd, but that's much more work than the sudo route.
Hope that helps,
—Robert J Lee