Earticle

In order to develop a potent antidementia β-secretase inhibitor from phytochemicals, β-secretase inhibitory activities of extracts from many medicinal plants and herbs were determined. Water extracts from Rubus coreanus showed the highest β-secretase inhibitory activity of 84.5%. After purification of the β-secretase inhibitor from R. coreanus using systematic solvent extraction, ultrafiltration, Sephadex G-10 column chromatography, and reverse-phase high performance liquid chromatography (HPLC), a purified β-secretase inhibitor with IC50 inhibitory activity of 6.3×10³㎍/mL (1.56×10-6 M) was obtained with a 0.08% solid yield. The molecular mass of the purified β-secretase inhibitor was estimated to be 576 Da by liquid chromatography-mass spectrometry (LC-MS) and β-secretase inhibitor also is a new tetrapeptide with the sequence Gly-Trp-Trp-Glu. The purified β-secretase inhibitory peptide inhibited β-secretase non-competitively and also show less inhibition on trypsin, however no inhibition on other proteases such as β-secretase, chymotrypsin, and elastase.