This question is not about sleep, but really about the antioxidant benefits of melatonin down to the mitochondrial level. e.g. https://www.hindawi.com/journals/ijad/2011/326320/ , http://www.mdpi.com/1420-3049/23/3/530/htm Specifically how might melatonin help the diabetic? It seems like a good agent. Crosses the blood brain barrier. Inexpensive. But it may raise blood sugar. Here is an article that touches on the potential risks: https://blog.humanos.me/research-reveals-an-odd-connection-between-melatonin-and-type-2-diabetes/
If anyone is aware of any (further) studies etc. on this subject I would appreciate knowing about them: use of melatonin in diabetes, risks and benefits.