I've no experience of taking them, but there is nothing in them that can affect your diabetes control as far as I am aware. As with any medication designed to relieve anxiety or aid sleep there is a tiny risk of addiction, psychological rather than physical. Remember, Heroin is the ultimate herbal anxiety relief, makes you feel wonderful. Just because things are herbal doesn't make them better, or safer.
And if you are on any other medication, particularly anti anxiety or antidepressant, you should discuss this with your doctor before starting them.