add action for unknown custom post type in plugin

I am developing a plugin where i run a function when a custom post type is published. But the name of custom post types will be unknown. I have tried following code but its not working.

foreach ($pn_opt_post_types as $pn_opt_post_type){
  $pn_action_cpt = 'publish_'.$pn_opt_post_type;
  add_action($pn_action_cpt,'pn_notification_publish');
}

via Chebli Mohamed