In the practise for diabetes, asanas have limited effect.
All types of forward and reverse bends, sideward twists as well as inversions help . Pranayama has bigger impact than asanas. Shatkarma techniques (especially laghoo shankha prakshalana and kunjal ) provide much more benefits than asanas or pranayamans. Infact people practising shatkarmas and diet restrictions have reported to be cured of diabetes.
PS: Shatkarmas should be only learnt from an experienced teacher.