"everything EXCEPT" is too huge to describe so your question is actually, "How do I match an email adresse, then I can drop the rest". and it have been often asked over here. an the usual response is use Email::Valid. in your case if you want to rely on a regex look at this example from Mastering regular expression
anyway keep in mind : what should you match here ? q/to: "me@me.fr" <to@to.pf> /