<?php
header('Content-Type: text/html; charset=utf-8');
$db = mysql_connect('localhost', 'db_name', 'db_pass');
mysql_select_db('db_name');
mysql_set_charset('utf8');
$res = mysql_query("SELECT * FROM product_description WHERE description like '%'");
while($row = mysql_fetch_array($res)){

$anchor = strval($row['description']); //Only this string changed!

    $anchor = preg_replace(
        '@\<a\b[^\>]*\>(.*?)\<\/a\b[^\>]*\>@',
        '\1',
        $anchor
    );

echo $anchor;

}


mysql_close($db);
?>

<?php
header('Content-Type: text/html; charset=utf-8');
$db = mysql_connect('localhost', 'db_name', 'db_pass');
mysql_select_db('db_name');
mysql_set_charset('utf8');
$res = mysql_query("SELECT * FROM product_description WHERE description like '%'");
while($row = mysql_fetch_array($res)){

$anchor = 'Lorem ipsum <a href="http://www.google.es">Google</a> Lorem ipsum <a href="http://www.bing.com">Bing</a>'; //Only this string changed!

    $anchor = preg_replace(
        '@\<a\b[^\>]*\>(.*?)\<\/a\b[^\>]*\>@',
        '\1',
        $anchor
    );

echo $anchor;

}
mysql_close($db);
?>