Effects of Mulberry Leaves on Glycemic Control in Patients With Obesity and Patients With Type 2 Diabetes

Diabetes remains a common leading cause of morbidity and mortality among population worldwide over decades. Obesity, a crucial risk factors for developing T2DM, commonly exists with insulin resistance and impaired beta-cell function. Early management in individuals at high risk of T2DM should be therefore considered for preventing or delaying the progression of diabetes and diabetic complications.

Since 1-deoxynojirimycin (DNJ), the major antihyperglycemic compound of mulberry leaves, inhibits alpha-glucosidase activities, ingestion of mulberry leaves results in the suppression of postprandial hyperglycemia. Long-term effects of mulberry leaves on glycemic profiles have been demonstrated in numerous clinical studies; however, the results were controversial. In addition, no study was conducted in patients with obesity. As a result, this open-label, randomized controlled study aims to investigate efficacy and safety of mulberry leaves in combination with lifestyle intervention (diet control) on glycemic control in non-diabetic patients with obesity and patients with early-stage T2DM. Efficacy of the interventions will be assessed based on the changes in glycemic indexes, expression of proteins related to insulin resistance and T2DM, and lipid profiles. Meanwhile, safety will be measured by the changes in renal and hepatic enzymes and patient-self reports. The outcomes will be monitored at 4-week interval throughout 12 weeks of the study period.

Inclusion criteria

• Women or men age 20-65 years
• Have 1 of 3 characteristics as follows;

• Non-diabetic obese patients (BMI ≥25 kg/m2)
• Patients with T2DM: drug naïve and newly diagnosed within 6 months before study enrollment
• Patients with T2DM: inadequate control (A1c ≥7%, but not >8%) with metformin therapy (>1,000 mg/day) alone at least 3 months before study enrollment
• Well communicate in the Thai language

Exclusion criteria

• Allergy to mulberry leaves products
• FPG ≥180 mg/dL
• A1c >8%
• AST and ALT >40 U/L
• Cr <0.6 or >1.2 mg/dL
• BUN >20 mg/dL
• Existing or having history of gastrointestinal surgery or abnormal conditions affecting digestion and intestinal absorption
• Existing or having history of hematological disorders, thyroid diseases, CVD, ischemic stroke, CKD, or other uncontrolled and life-threatening conditions
• Presence of significant diabetic complications
• Taking drugs, supplements, and herbs affecting blood glucose level: corticosteroids, second-generation antipsychotics, niacin, thiazide diuretics, and ß-blockers, within 1 month before study enrollment
• Taking unnecessary drugs, supplements, and herbs affecting lipid level within 1 month before study enrollment
• Women during pregnancy or lactation