use strict;
use Email::Valid;

my $subject="Subject: You've Won a Million Dollars!!!(xstebxz)"
if ( $subject =~ /(\(.*\))$/ ) {
        if (  Email::Valid->address(
                          -address => $1,
                          -mxcheck => 0,
                          )) {
         print "Subject contains email address";
        }
}