A provident, cost-effective, and environmentally benign plant-mediated approach is adopted for the synthesis of Fe₂MgO₄ nanoparticles (NPs), using Alstonia scholaris and Polyalthia longifolia leaves’ extracts. The method results in NPs with cubic crystal structure having particle size in range of 8.14–13.4 nm as confirmed by UV–Vis, FTIR, XRD and AFM. The prepared NPs are assessed for their antibacterial, antioxidant and larvicidal activities. Both NPs are found active against gram-positive (Bacillus subtilis, Staphylococcus aureus) and gram-negative bacteria (Pseudomonas aeruginosa, Salmonella typhimurium, and Escherichia coli) obeying the order: NPs A. scholaris > NPs P. longifolia > A. scholaris extract > P. longifolia extract. Similar order is observed for the larvicidal activity against Aedes albopictus larvae; both NPs showed excellent activity with LD₅₀ of 5-10 μg/ml which is much less than the simple plant extracts. Antioxidant potential of NPs is also evaluated using DPPH free radical scavenging and phospho-molybdenum assays and in both cases, NPs of A. scholaris perform better than the control, P. longifolia-based NPs and plant extracts. Hence, the prepared NPs can be potentially applied as antimicrobial and larvicidal agents, as well as for food packaging and medicinal applications.

使用Alstonia Academicis和Polyalthia longifolia叶提取物，采用了一种明智、经济且环境友好的植物介导方法来合成Fe ₂ MgO ₄纳米颗粒(NPs) 。该方法产生了具有立方晶体结构的纳米颗粒，其粒径范围为 8.14-13.4 nm，由 UV-Vis、FTIR、XRD 和 AFM 证实。评估制备的 NPs 的抗菌、抗氧化和杀幼虫活性。发现这两种纳米颗粒对革兰氏阳性菌（枯草芽孢杆菌、金黄色葡萄球菌）和革兰氏阴性菌（铜绿假单胞菌、鼠伤寒沙门氏菌和大肠杆菌）均有活性) 服从顺序： NPs槐花 > NPs P. longifolia  > 槐花提取物>  P. longifolia提取物。对白纹伊蚊幼虫的杀幼虫活性观察到类似的顺序；两种 NP 都显示出优异的活性，LD ₅₀为 5-10 μg/ml，远低于简单的植物提取物。NP的抗氧化能力是利用DPPH自由基清除和磷酸钼测定也评估，并在这两种情况下，纳米颗粒的A.胶树比对照表现得更好，P.长叶基于 NPs 和植物提取物。因此，制备的 NPs 有可能用作抗菌剂和杀幼虫剂，以及用于食品包装和医药应用。