• Applied Biological Chemistry
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• v.42 no.4
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• pp.351-355
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• 1999

In order to find anti-dementia drugs from natural products, prolyl endopeptidase inhibitors were purified from Puerariae Flos by consecutive solvent partition, followed by silica gel, Sephadex LH-20, and HPLC. Four isoflavonoid inhibitors were isolated and identified as tectorigenin, genistein, 5,7-dihydroxy-4',6-dimethoxyisoflavone, and 5-hydroxy-6,7,4'-trimethoxyisoflavone by means of instrumental analyses including $^{1}H-$, $^{13}C-$, $^{2}D-NMR$ and MS and $IC_{50}$ values against PEP were 5.30 ppm$(17.7\;{\mu}M)$, 10.39 ppm$(38.5\;{\mu}M)$, 13.92 ppm$(44.3\;{\mu}M)$, and 20.61 ppm$(62.8\;{\mu}M)$, respectively. Some previous mistakes in $^{13}C-NMR$ assignment were revised by careful investigation of HMBC and HMQC data.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.47-49
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• 1995

• Food Science and Biotechnology
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• v.15 no.4
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• pp.617-624
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• 2006

Various plant phenolics were assessed for (${\beta}$-secretase (BACE1) inhibitory activity in order to screen for anti-dementia agents. Among 39 phenolics, eight compounds, 1,2,3-trigalloyl glucopyranoside, acetonyl geraniin, euphorscopin, furosine, helioscopinin A, helioscopinin B, jolkinin, and rugosin E exhibited strong inhibition of BACE1 with $IC_{50}$ values of $5.87{\times}10^{-8}-54.93{\times}10^{-6}\;M$. Among them, rugosin E was the most potent ($IC_{50}$ $5.87{\times}10^{-8}\;M$). The active compounds were shown to be non-competitive inhibitors by Dixon plot. All the phenolic BACE1 inhibitors except furosin also suppressed prolyl endopeptidase (PEP) activity. However, these phenolic compounds caused less inhibition of ${\alpha}$-secretase (tumor necrosis factor a converting enzyme; TACE) and no significant inhibition of other serine proteases such as trypsin, chymotrypsin, and elastase was seen, demonstrating that they are relatively specific to both BACE1 and PEP. No significant structure-activity relationships were found.