this is example text <a href="www.1.com">hello</a> and
this is second link <a href="www.2.com">hello word two</a>
this is third link <a href="www.3.com">hello word three</a>
this is fourth link <a href="www.4.com">hello word four</a>

preg_replace( '/<a[^>]+>([^<]+)</a>/i','1', $content )