Isolation and Identification of α-Glucosidase Inhibitors from Morus Root Bark

ABSTRACT Among the four different parts of mulberry ( Morus alba L.) tree, ethanol extract of Morus root bark showed the highest α-glucosidase inhibitory activity (IC 50 =12.01 μg/mL). Bioassay-guided fractionation of the ethanolic extract of root bark by Diaion HP-20, silica gel, ODS-A, and Sephadex LH-20 column chromatographies led to the isolation of four compounds, including Compound (Comp.) 1 (IC 50 =5.22 μg/mL), Comp. 2 (IC 50 =1.78 μg/mL), Comp. 3 (IC 50 =2.94 μg/mL), and Comp. 4 (IC 50 =1.54 μg/mL) with strong α-glucosidase inhibitory activities. Their chemical structures were elucidated as morusin (Comp. 1), kuwanon H (Comp. 2), chalcomoracin A (Comp. 3), and chalcomoracin B (Comp. 4) by UV and NMR spectral analyses. These results suggest that prenylflavonoid and mulberrofuran of Morus root bark may be useful as potential therapeutic agents for diabetes. Key words: Morus root bark, α-glucosidase inhibitors, morusin, kuwanon H, chalcomoracin A & BReceived 3 March 2015; Accepted 22 April 2015 Corresponding author: Sang Won Choi, Department of Food Science and Nutrition, Catholic University of Daegu, Gyeongsan,Gyeongbuk 712-702, Korea E-mail: swchoi@cu.ac.kr, Phone: +82-53-850-3525