function my_bp_opengraph() {
	// see if the activity component is active and if we're currently on an activity permalink page
	if ( bp_is_active( 'activity' ) && bp_is_single_activity() ) :
		// add our mini activity loop
		if ( bp_has_activities( 'include=' . bp_current_action() ) ) :
			while ( bp_activities() ) : bp_the_activity();
?>

	        <meta property="og:description" content="<?php  bp_activity_content_body(); ?>"/>

<?php
			endwhile;
		endif;
	endif;
}
add_action( 'bp_head', 'my_bp_opengraph' );