A randomized, double-blind, placebo-controlled clinical trial to investigate the anti-diabetic effect of Citrus junos Tanaka peel

The effect of ethanol extracts of Citrus junos Tanaka (yuja) peel (YE) on glucose control in subjects with impaired fasting glucose was evaluated. In this double-blind, crossover, placebo-controlled study, the participants were randomly assigned to one of two groups, placebo control or YE intervention group. We determined fasting plasma glucose (FPG), postprandial glucose (PPG), and fasting plasma insulin (FPI) concentrations; homeostatic model assessment-insulin resistance (HOMA-IR); and safety before and after the 8-week supplementation with YE or placebo. After 8 weeks of intervention, the YE group showed significantly lower FPG levels, FPI, and HOMA-IR compared to the placebo group. PPG and c-peptide were slightly reduced in the YE groups. There was no significant difference between the groups in safety parameters. Thus, these results suggest that YE may be effective for controlling fasting blood glucose levels and may serve as a useful supplement in subjects with prediabetes.