Рецепт от dmitry_stas

$dispatcher =JDispatcher::getInstance();
JPluginHelper::importPlugin('content');
$obj = new stdClass;
$params = JFactory::getApplication()->getParams('com_content');
$obj->title = '';
$obj->text = Краткое описание;
$results = $dispatcher->trigger('onContentPrepare', array('com_content.article', &$obj, &$params, 0));
$short_desc = $obj->text;