Diabetes Res Clin Pract. 2006. Department of Diabetes and Clinical Nutrition, Kyoto University, Kyoto, Japan.
In this study, 31 subjects were orally administered 10mg corosolic acid or a placebo, on different occasions, in a capsule 5min before the 75-g oral glucose tolerance test (OGTT) in a double-blind and cross-over design. Nineteen subjects had diabetes, seven had impaired glucose tolerance, one had impaired fasting glucose, and four had normal glucose tolerance according to the 1998 WHO criteria. There were no significant differences in plasma glucose levels before and 30min after the administration. Corosolic acid treatment subjects showed lower glucose levels from 60min until 120min and reached statistical significance at 90min. In this study, we have shown for the first time that corosolic acid has a lowering effect on postchallenge plasma glucose levels in vivo in humans.