In vitro Screening for Antioxidant, Antimicrobial, and Antidiabetic Properties of Some Korean Native Plants on Mt. Halla, Jeju Island

In this study, Prunus padus, Lonicera caerulea, Berberis amurensis, and Ribes maximowiczianum, which are mainly distributed on Mt. Halla, Jeju Island, have been investigated for their antioxidant, antimicrobial, and antidiabetic activities. The methanol extracts of R. maximowiczianum leaves and P. padus branches exhibited significant and dose-dependent antioxidant activity including electron-donation ability and reducing power. To analyze the antimicrobial activity, each extract was tested by a serial two-fold dilution method against five selected gram-positive bacteria and four gram-negative bacteria, and this suggested that P. padus branches possessed the maximum antimicrobial activity against most of the gram-positive bacteria tested. In addition, the methanol extracts of P. padus branches exhibited the highest α-glucosidase inhibitory activity with an IC(50) value of 1.0±0.1 μg/ml, indicating that P. padus is a promising source as a herbal medicine.