Essential oils which contain phenols are particularly toxic to cats and cause liver damage. These include Oregano, Thyme, Eucalyptus, Clove, Cinnamon, Bay Leaf, Parsley and Savory
Essential oils which contain ketones cause neurological symptoms. These include: Cedar Leaf*, Sage*, Hyssop*, Cyprus*, Lavender, Eucalyptus, Mint ,Caraway*, Citronella ,Clove*, Ginger*, Chamomile, Thyme and Rosemary (those marked * give particular cause for concern).
http://www.messybeast.com/teatree.htm
I know the above is talking about the oils but unless you are using a trained Holistic vet, I wouldn't go putting anything in your cat that you have no idea of the effects on your cat. What humans can use and what dogs can use could kill a cat.
I have never, in over 12 years on this board, read one thing about cloves being used for diabetes in cats. There have been other questionable theories of other different remedies but bottom line is......canned food only, hometesting, and insulin. The minute you start trying different human meds without a vets advice you are risking the life of your cat. Always search for as much info as you can get before trying something new.