Exploring 3-Benzyloxyflavones as new lead cholinesterase inhibitors: synthesis, structure–activity relationship and molecular modelling simulations

In this protocol, a series of 3-benzyloxyflavone derivatives have been designed, synthesized, characterized and investigated <i>in vitro</i> as cholinesterase inhibitors. The findings showed that all the synthesized target compounds (<b>1–10</b>) are potent dual inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes with varying IC₅₀ values. In comparison, they are more active against AChE than BChE. Remarkably, amongst the series, the compound <b>2</b> was identified as the most active inhibitor of both AChE (IC₅₀ = 0.05 ± 0.01 μM) and BChE (IC₅₀ = 0.09 ± 0.02 μM) relative to the standard Donepezil (IC₅₀ = 0.09 ± 0.01 for AChE and 0.13 ± 0.04 μM for BChE). Moreover, the derivatives <b>5</b> (IC₅₀ = 0.07 ± 0.02 μM) and <b>10</b> (0.08 ± 0.02 μM) exhibited the highest selective inhibition against AChE as compared to the standard. Preliminary structure-activity relationship was established and thus found that cholinesterase inhibitory activities of these compounds are highly dependent on the nature and position of various substituents on Ring-B of the 3-Benzyloxyflavone scaffolds. In order to find out the nature of binding interactions of the compounds and active sites of the enzymes, molecular docking studies were carried out. HIGHLIGHTS3-benzyloxyflavone analogues were designed, synthesized and characterized.The target molecules (<b>1–10</b>) were evaluated for their inhibitory potential against AChE and BChE inhibitory activities.Limited structure-activity relationship was developed based on the different substituent patterns on aryl part.Molecular docking studies were conducted to correlate the <i>in vitro</i> results and to identify possible mode of interactions at the active pocket site of the enzyme. 3-benzyloxyflavone analogues were designed, synthesized and characterized. The target molecules (<b>1–10</b>) were evaluated for their inhibitory potential against AChE and BChE inhibitory activities. Limited structure-activity relationship was developed based on the different substituent patterns on aryl part. Molecular docking studies were conducted to correlate the <i>in vitro</i> results and to identify possible mode of interactions at the active pocket site of the enzyme. Communicated by Ramaswamy H. Sarma

本研究设计、合成、表征并体外（in vitro）评价了一系列3-苄氧基黄酮（3-benzyloxyflavone）衍生物作为胆碱酯酶（cholinesterase）抑制剂的活性。研究结果显示，所有合成的目标化合物（1~10）均为兼具活性的乙酰胆碱酯酶（acetylcholinesterase, AChE）与丁酰胆碱酯酶（butyrylcholinesterase, BChE）双重抑制剂，且半数抑制浓度（IC₅₀）存在差异。相较而言，此类化合物对AChE的抑制活性强于BChE。值得注意的是，在该系列化合物中，化合物2对AChE（IC₅₀=0.05±0.01 μM）与BChE（IC₅₀=0.09±0.02 μM）均表现出最强的抑制活性，其活性优于阳性对照多奈哌齐（Donepezil：AChE的IC₅₀为0.09±0.01 μM，BChE的IC₅₀为0.13±0.04 μM）。此外，与阳性对照相比，衍生物5（IC₅₀=0.07±0.02 μM）与10（IC₅₀=0.08±0.02 μM）对AChE展现出最高的选择性抑制活性。本研究初步建立了构效关系（structure-activity relationship, SAR），发现此类化合物的胆碱酯酶抑制活性高度依赖于3-苄氧基黄酮母核B环上不同取代基的类型与位置。为阐明此类化合物与酶活性位点的结合作用模式，本研究开展了分子对接（molecular docking）实验。

**研究亮点**：
3-苄氧基黄酮（3-benzyloxyflavone）类似物经设计、合成与表征。
对目标化合物1~10的乙酰胆碱酯酶与丁酰胆碱酯酶抑制活性进行了评价。
基于芳环部分的不同取代模式，初步构建了该系列化合物的构效关系。
开展分子对接实验，以关联体外实验结果并阐明化合物在酶活性口袋中的潜在结合模式。
3-苄氧基黄酮（3-benzyloxyflavone）类似物经设计、合成与表征。
对目标化合物1~10的乙酰胆碱酯酶与丁酰胆碱酯酶抑制活性进行了评价。
基于芳环部分的不同取代模式，初步构建了该系列化合物的构效关系。
开展分子对接实验，以关联体外实验结果并阐明化合物在酶活性口袋中的潜在结合模式。

由Ramaswamy H. Sarma转交。