Phenolic phytochemical displaying SARS-CoV papain-like protease inhibition from the seeds of Psoralea corylifolia

Dae Wook Kim, Kyung Hye Seo, Marcus J. Curtis-Long, Kyeong Yeol Oh, Jong Won Oh, Jung Keun Cho, Kon Ho Lee, Ki Hun Park

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152 Citations (Scopus)


Severe acute respiratory syndrome coronavirus (SARS-CoV) papain-like protease (PLpro) is a key enzyme that plays an important role in SARS virus replication. The ethanol extract of the seeds of Psoralea corylifolia showed high activity against the SARS-CoV PLpro with an IC50 of value of 15 μg/ml. Due to its potency, subsequent bioactivity-guided fractionation of the ethanol extract led to six aromatic compounds (1-6), which were identified as bavachinin (1), neobavaisoflavone (2), isobavachalcone (3), 4′-O-methylbavachalcone (4), psoralidin (5) and corylifol A (6). All isolated flavonoids (1-6) inhibited PLpro in a dose-dependent manner with IC50 ranging between 4.2 and 38.4 μM. Lineweaver-Burk and Dixon plots and their secondary replots indicated that inhibitors (1-6) were mixed inhibitors of PLpro. The analysis of KI and KIS values proved that the two most promising compounds (3 and 5) had reversible mixed type I mechanisms.

Original languageEnglish
Pages (from-to)59-63
Number of pages5
JournalJournal of Enzyme Inhibition and Medicinal Chemistry
Issue number1
Publication statusPublished - 2014 Feb

Bibliographical note

Funding Information:
This study was supported by National Research Foundation Grant founded by Korea government (MEST; no. 2012-0001112) and Technology Development Program for Agriculture and Forestry (308025-05-4-HD110), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea. All students were supported by BK21 program.

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Drug Discovery


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