preferred_name: a 16alpha-hydroxysteroid <=> a 16beta-hydroxysteroid
preferred_name_lc: a 16alpha-hydroxysteroid <=> a 16beta-hydroxysteroid
label: a 16alpha-hydroxysteroid <=> a 16beta-hydroxysteroid
label_lc: a 16alpha-hydroxysteroid <=> a 16beta-hydroxysteroid