Nig QJ Hosp Med. 2008 Jul-Sep;18 (3):162-5
Morinda citrifolia fruit juice augments insulin action in Sprague-Dawley rats with experimentally induced diabetes.
Horsfall AU, Olabiyi O, Aiyegbusi A, Noronha CC, Okanlawon AO.

Feeding of Morinda citrifolia (noni) fruit juice to diabetic rats for 4 weeks lowered fasting blood glucose. When noni juice ingestion was combined with insulin treatment, fasting blood glucose levels were lower even further than with either noni juice or insulin alone.  (view original abstract at https://www.ncbi.nlm.nih.gov/pubmed/19062482).