A Novel spice-antioxidant-based nano-vehicle as a putative green alternative of synthetic AChE inhibitor drugs

The present treatment for Alzheimer’s disease (AD) involves well known synthetic acetylcholine esterase (AChE) inhibitor drugs which besides having short duration of action also have deleterious impact on human health. Therefore, there is a need for natural plant-based biomolecule(s) with potential AChE inhibition activity (ies). The aim of the work is to design a spice-based nano-vehicle as a novel green alternative of synthetic AD drugs by nanoencapsulating a solvent-less supercritical CO2 extract of small cardamom seeds (SCE) having a synergistic consortium of five antioxidant molecules, using polyethylene glycol and emulsifiers, selected based on Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) analyses. Ellman’s assay and enzyme inhibition kinetics of the antioxidant molecules as well as the extract and its nanoliposomal formulation (SCE-NL) were performed, followed by rigorous molecular docking and dynamics studies using MM-PBSA and umbrella sampling. The antioxidants exhibited significant AChE inhibition in vitro, individually with 1, 8-cineole having the least IC50 value of 65.53 ± 0.05 µg/mL. . Although SCE-NL had higher IC50 value (575.67 ± 0.5 µg/mL) vis-à-vis that of rivastigmine (67.52 ± 0.02 µg/mL), it is safer for usage being ‘green’.The Lineweaver-Burk plots (Vmax ∼1.04 mM/min) revealed competitive mode(s) of inhibition of AChE with each of these antioxidants. Binding energy analyses suggested very good binding free energies and stable docking/binding complexes (between the antioxidants and AChE). This study has delivered a nanoliposomal vehicle of food antioxidants as a putative ‘green’ alternative of synthetic AChE inhibitor drugs. Communicated by Ramaswamy H. Sarma

当前阿尔茨海默病（AD）的临床治疗以经典合成乙酰胆碱酯酶（AChE）抑制剂类药物为主，但此类药物不仅作用时长有限，还会对人体健康产生负面影响。因此，亟需开发具备潜在AChE抑制活性的天然植物来源生物分子。本研究旨在构建基于香辛料的纳米载体，作为合成AD治疗药物的新型绿色替代方案：以经吸收、分布、代谢、排泄与毒性（ADMET）分析筛选得到的聚乙二醇与乳化剂作为载体材料，将含有五种抗氧化分子协同复合体的无溶剂超临界CO₂萃取小豆蔻籽提取物（SCE）进行纳米包封。随后分别针对单一抗氧化分子、提取物及其纳米脂质体制剂（SCE-NL）开展Ellman法检测与酶抑制动力学分析，并采用MM-PBSA与伞形采样方法进行严谨的分子对接与分子动力学研究。体外实验结果显示，各抗氧化分子均表现出显著的AChE抑制活性，其中1,8-桉叶素的半数抑制浓度（IC₅₀）最低，为65.53 ± 0.05 µg/mL。尽管SCE-NL的半数抑制浓度（575.67 ± 0.5 µg/mL）高于卡巴拉汀（67.52 ± 0.02 µg/mL），但其属于绿色环保制剂，使用安全性更优。莱恩威弗-伯克作图（Vmax≈1.04 mM/min）结果表明，各抗氧化分子对AChE均呈现竞争性抑制模式。结合能分析显示，抗氧化分子与AChE形成的对接/结合复合物具有优异的结合自由能与稳定性。本研究成功开发出一种搭载食品源抗氧化分子的纳米脂质体载体，可作为合成AChE抑制剂类药物的推定绿色替代方案。本文由Ramaswamy H. Sarma供稿。