How can I list recent posts excerpts?

I am using this directly from the codex to list 3 recent articles titles.

<ul>
<?php
$args = array( 'numberposts' => '3');
$recent_posts = wp_get_recent_posts( $args );
foreach( $recent_posts as $recent ){
echo '<li><a href="' . get_permalink($recent["ID"]) . '" title="Look '.esc_attr($recent["post_title"]).'" >' .   $recent["post_title"].'</a> </li> ';
}
?>
</ul>

This works fine however, when I change the post_title to post_excerpt it does not show the excerpt.

How can I solve this?