<?php
$content = 'Lorem Ipsum is simply dummy text <remove this part and all content after first <';
$content = substr($content, 0, strpos($content, "<"));

// will display:  Lorem Ipsum is simply dummy text
print_r($content);

// another example we need only output after specified word
$content = 'Lorem Ipsum is simply dummy text remove this part and all content after "remove" word';
$content = substr($content, 0, strpos($content, "remove"));

// will display:  Lorem Ipsum is simply dummy text
print_r($content);