In vitro determination of bioactive fraction of blueberry for type 2 diabetes prevention (647.17)

Abstract

The present study investigates the carbohydrate hydrolysis enzyme inhibitory activity of blueberries and if this activity is proanthocaynidin (PAC) or low molecular weight phenolic (LMP) dependent. Freeze‐dried blueberry powder was extracted using 70% acetone solution (BAE) and in deionized water (BWE). Sugars were removed from both extracts using C18 cartridges. BAE resulted to higher PAC and total phenolic content (TPC), so BAE was used for the remaining experiment. LMP and PAC were separated from BAE using a LH‐20 column by washing using 30%methanol solution (LMP recovery) and eluting using 70% acetone solution (PAC recovery). PAC contents were determined as 0.86 mg/mL, 0.56 mg/g, 0.11 mg/g and 0.61 mg/mL for BAE, BWE, LMP and PAC, respectively. The TPC of BAE, BWE, LMP and PAC were determined to be 3.88 mg/mL, 2.64 mg/mL, 1.90 mg/mL and 1.85 mg/mL, respectively. Evaluation of rat α‐glucosidase inhibitory activity, revealed that LMP (IC50 0.24 mg/mL TPC basis) had the highest inhibitory activity followed by BAE (IC50 0.39 mg/mL TPC basis), PAC (IC50 0.92 mg/mL TPC basis). Evaluation of specific maltase and sucrase inhibitory activities confirmed same trend as with observed rat α‐glucosidase inhibitory activities (LMP>BAE>PAC). Our findings suggest that blueberry extract has α‐glucosidase inhibitory activity, which is low molecular weight phenolic dependent.Grant Funding Source: Supported by US Army Natick Soldier Research Engineering Center