In Italian normally adjectives come after the noun; hence "Anna gentile" and "professore gentile". But if the use is a special one, as with a book title, would it normally be reversed, so to say, giving "Gentile Anna - Gentile Professore"?
It depends on the context:
If you want specify that they are gentle or kind, say: "Anna è gentile, il professore è gentile".
If you are speaking with an important person say "gentile Anna, gentile professore" to open a formal speech.
N.B: "gentile Anna" and "gentile professore" don't mean that Anna and the teacher are gentle or kind, but only that you are speaking in a formal language to them.