Serum Antioxidant Parameters are Significantly Increased in Patients with Type 2 Diabetes Mellitus after Consumption of Chinese Propolis: A Randomized Controlled Trial Based on Fasting Serum Glucose Level

INTRODUCTION: Propolis is a natural product with many biological activities. The present study was designed to evaluate the effects of Chinese propolis on glucose metabolism, antioxidant function, and inflammatory cytokines in patients with type 2 diabetes mellitus (T2DM). METHODS: In the 18-week study, recruited T2DM patients were randomly divided into a Chinese propolis group (900 mg/day) (n = 31) and a control group (n = 30) according to fasting serum glucose levels at baseline. RESULTS: At the end of the study, no significant difference was found between the groups in serum glucose, glycosylated hemoglobin, insulin, aldose reductase, or adiponectin. However, serum GSH, flavonoids, and polyphenols were significantly increased, and serum lactate dehydrogenase activity was significantly reduced in the Chinese propolis group. Meanwhile, serum IL-6 was significantly increased in the Chinese propolis group. CONCLUSION: Chinese propolis is effective at improving antioxidant function in T2DM patients, partly by increasing serum antioxidant parameters.