$re = '/(?<=some standard text. )(?:.*?)([^\s]+@[^\s]+)/m';
$str = 'Eg. 1: some standard text. Bugs Bunny bugs@gmail.com 0411111111 more standard text
Eg. 2: some standard text. Bugs The Bunny bugs@gmail.com 0411111111 more standard text
Eg. 3: some standard text. Bugs-Bunny bugs.bunny@gmail.com 0411111111 more standard text
Eg. 4: some standard text. Bugs bugs.bunny@gmail.com +6141 111 111 more standard text
Eg. 1: some standard text. Bugs o\'Bunny bugs@gmail.com 0411111111 more standard text ';
preg_match_all($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