Instead of passing first argument to MenuItem constructor as name of the menu you can pass as below to apply h2 header for it :-
MenuItem menuItem = new MenuItem("<h2>" + row["menu_name"].ToString() + "</h2>", row["menu_id"].ToString());
This will display it as h2 header.
Not sure what do you mean by title here, as if you do as above it will display menu name as display text and id as value for it.If you mean by html tip to view on its hover then
menuItem.ToolTip = "TitleText";
should work for you here.
Hope this will help you to proceed further.