A randomized, double-blind, placebo-controlled crossover clinical trial to evaluate the anti-diabetic effects of Allium hookeri extract in the subjects with prediabetes

Background Allium hookeri is widely consumed as a vegetable and herbal medicine in Asia. A. hookeri has been reported anti-inflammatory, anti-obesity, osteoblastic, anti-oxidant, and anti-diabetic effects in animal studies. We investigated the anti-diabetic effects of A. hookeri aqueous extract (AHE) in the Korean subjects. Methods Prediabetic subjects (100 ≤ fasting plasma glucose (FPG) < 126 mg/dL) who met the inclusion criteria were recruited for this study. The enrolled subjects ( n = 30) were randomly divided into either an AHE ( n = 15, 486 mg/day) or placebo (n = 15) group. Outcomes were measurements of FPG, glycemic response to an oral glucose tolerance test (OGTT), insulin, C-peptide, hemoglobin A1c (HbA1c), total cholesterol, triglyceride, HDL-cholesterol, and LDL-cholesterol. The t -test was used to assess differences between the groups. A p -value < 0.05 was considered statistically significant. Results Eight weeks after AHE supplementation, HbA1c level was significantly decreased in the AHE group compared with the placebo group. No clinically significant changes in any safety parameter were observed. Conclusion The findings suggest that AHE can be effective in reducing HbA1c, indicating it as an adjunctive tool for improving glycemic control. Trial registration The study protocol was retrospectively registered at www.clinicaltrials.gov ( NCT03330366 , October 30, 2017).