$re = ';[a-zA-Z0-9!#$%&\'*+/=?^_`{|}~-]+(?:.[a-zA-Z0-9!#$%&\'*+/=?^_`{|}~-]+)*@(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]*[a-zA-Z0-9])?.)+[a-zA-Z0-9](?:[a-zA-Z0-9-]*[a-zA-Z0-9])?;';
$str = ' string << \'"Test test Real Estate - Test\\\'s International Real Estate" <test@test.com>\'';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php