$data = '<?
$cachen = "2";
$site_name = "Иван-чай";
$slogan = "полезные свойства, противопоказания";
$adm_name = "admin";
?>';
preg_match_all('~\$(?<name>[\w]+) *= *"(?<value>.+)";~', $data, $matches);
foreach ($matches['name'] as $key => $name) {
$a = $matches['value'][$key];
${$name} = $matches['value'][$key];
}
var_dump($cachen);
var_dump($site_name);
var_dump($slogan);
var_dump($adm_name);