Design, Synthesis, and Biological Evaluation of 5,8-Dimethyl Shikonin Oximes as SARS-CoV-2 M<sup>pro</sup> Inhibitors

We have designed, synthesized, and characterized a small library of shikonin derivatives and demonstrated their inhibitory activity against the main protease, M<sup>pro</sup>, of SARS-CoV-2. One analog, 5,8-dimethyl shikonin oxime (<b>15</b>), exhibited the highest activity a...

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Main Authors: Jiahua Cui, Shouyan Xiang, Qijing Zhang, Shangqing Xiao, Gaoyang Yuan, Chenwu Liu, Shaoshun Li
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/6/1321
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author Jiahua Cui
Shouyan Xiang
Qijing Zhang
Shangqing Xiao
Gaoyang Yuan
Chenwu Liu
Shaoshun Li
author_facet Jiahua Cui
Shouyan Xiang
Qijing Zhang
Shangqing Xiao
Gaoyang Yuan
Chenwu Liu
Shaoshun Li
author_sort Jiahua Cui
collection DOAJ
description We have designed, synthesized, and characterized a small library of shikonin derivatives and demonstrated their inhibitory activity against the main protease, M<sup>pro</sup>, of SARS-CoV-2. One analog, 5,8-dimethyl shikonin oxime (<b>15</b>), exhibited the highest activity against SARS-CoV-2 M<sup>pro</sup> with an IC<sub>50</sub> value of 12.53 ± 3.59 μM. It exhibited much less toxicity as compared with the parent compound, shikonin, in both in vitro and in vivo models. Structure–activity relationship analysis indicated that the oxime moieties on the naphthalene ring and the functional groups attached to the oxygen atom on the side chain play a pivotal role in enzymatic inhibitory activity. Molecular docking results implied that the inhibitor <b>15</b> is perfectly settled in the core of the substrate-binding pocket of M<sup>pro</sup> by possibly interacting with three catalytic residues, His41, Cys145, and Met165. Overall, the shikonin oxime derivative <b>15</b> deserves further investigation as an antiviral agent against SARS-CoV-2.
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series Molecules
spelling doaj-art-661efbe8f32a4645ad148c7a4ba18db62025-08-20T02:42:22ZengMDPI AGMolecules1420-30492025-03-01306132110.3390/molecules30061321Design, Synthesis, and Biological Evaluation of 5,8-Dimethyl Shikonin Oximes as SARS-CoV-2 M<sup>pro</sup> InhibitorsJiahua Cui0Shouyan Xiang1Qijing Zhang2Shangqing Xiao3Gaoyang Yuan4Chenwu Liu5Shaoshun Li6School of Pharmacy, Gannan Medical University, Ganzhou 341000, ChinaSchool of Pharmacy, Gannan Medical University, Ganzhou 341000, ChinaSchool of Pharmacy, Shanghai Jiaotong University, Shanghai 200240, ChinaSchool of Pharmacy, Gannan Medical University, Ganzhou 341000, ChinaSchool of Pharmacy, Gannan Medical University, Ganzhou 341000, ChinaSchool of Pharmacy, Gannan Medical University, Ganzhou 341000, ChinaSchool of Pharmacy, Shanghai Jiaotong University, Shanghai 200240, ChinaWe have designed, synthesized, and characterized a small library of shikonin derivatives and demonstrated their inhibitory activity against the main protease, M<sup>pro</sup>, of SARS-CoV-2. One analog, 5,8-dimethyl shikonin oxime (<b>15</b>), exhibited the highest activity against SARS-CoV-2 M<sup>pro</sup> with an IC<sub>50</sub> value of 12.53 ± 3.59 μM. It exhibited much less toxicity as compared with the parent compound, shikonin, in both in vitro and in vivo models. Structure–activity relationship analysis indicated that the oxime moieties on the naphthalene ring and the functional groups attached to the oxygen atom on the side chain play a pivotal role in enzymatic inhibitory activity. Molecular docking results implied that the inhibitor <b>15</b> is perfectly settled in the core of the substrate-binding pocket of M<sup>pro</sup> by possibly interacting with three catalytic residues, His41, Cys145, and Met165. Overall, the shikonin oxime derivative <b>15</b> deserves further investigation as an antiviral agent against SARS-CoV-2.https://www.mdpi.com/1420-3049/30/6/1321SARS-CoV-2 M<sup>pro</sup>shikonindimethyl shikonin oximesinhibitorsCOVID-19
spellingShingle Jiahua Cui
Shouyan Xiang
Qijing Zhang
Shangqing Xiao
Gaoyang Yuan
Chenwu Liu
Shaoshun Li
Design, Synthesis, and Biological Evaluation of 5,8-Dimethyl Shikonin Oximes as SARS-CoV-2 M<sup>pro</sup> Inhibitors
Molecules
SARS-CoV-2 M<sup>pro</sup>
shikonin
dimethyl shikonin oximes
inhibitors
COVID-19
title Design, Synthesis, and Biological Evaluation of 5,8-Dimethyl Shikonin Oximes as SARS-CoV-2 M<sup>pro</sup> Inhibitors
title_full Design, Synthesis, and Biological Evaluation of 5,8-Dimethyl Shikonin Oximes as SARS-CoV-2 M<sup>pro</sup> Inhibitors
title_fullStr Design, Synthesis, and Biological Evaluation of 5,8-Dimethyl Shikonin Oximes as SARS-CoV-2 M<sup>pro</sup> Inhibitors
title_full_unstemmed Design, Synthesis, and Biological Evaluation of 5,8-Dimethyl Shikonin Oximes as SARS-CoV-2 M<sup>pro</sup> Inhibitors
title_short Design, Synthesis, and Biological Evaluation of 5,8-Dimethyl Shikonin Oximes as SARS-CoV-2 M<sup>pro</sup> Inhibitors
title_sort design synthesis and biological evaluation of 5 8 dimethyl shikonin oximes as sars cov 2 m sup pro sup inhibitors
topic SARS-CoV-2 M<sup>pro</sup>
shikonin
dimethyl shikonin oximes
inhibitors
COVID-19
url https://www.mdpi.com/1420-3049/30/6/1321
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