Why do you need to use Regex for this?
You can simply do this:
string email = "<[email protected]>";
email = email.TrimStart('<').TrimEnd('>');
Of course if you really need to be sure there’s no spaces, or that there might be multiple spaces:
string email = "<[email protected]>";
email = email.Trim().TrimStart('<').TrimEnd('>');
solved Regular Expression to remove leading and trailing Angle Brackets