hmmm....this might work
$first=true;
$new_content='';
$con=explode('(',$content);
foreach($con as $arr){
if ($first){//don't look for the other )
$first=false;
$new_content=$arr;
}else{
$mid=explode( ')',$arr,2);
$new_content.=" ".$mid[1];
}
}
Note: if the number of ( is not equal to ) in $content, than this won't work as expected
Now, $new_content should be the $content without any emails in ().