In order to investigate the physicochemical properties and bioactivities of AgNPs prepared using green and chemical approaches and further explore the related antibacterial mechanism, one kind of chemical AgNPs (C-AgNPs) and three kinds of green AgNPs (G-AgNPs) mediated with aqueous extracts of Morus alba L. were prepared and characterized. All G-AgNPs displayed higher antioxidant activities in DPPH radical scavenging, reducing power and total antioxidant assays than C-AgNPs and extracts. Meanwhile, all G-AgNPs exerted significantly (P < 0.05) enhanced antimicrobial activities against various pathogens compared with C-AgNPs and extracts. Among prepared AgNPs, ML-AgNPs mediated with aqueous extract of Morus alba L. leaves exhibited the most powerful antibacterial effect with the largest inhibition zones (13.11 ± 0.76 mm for S. aureus, 13.27 ± 0.22 mm for E. coli) and the lowest minimum inhibition concentrations against S. aureus (6.125 μg/ml) and E. coli (3.125 μg/ml). ML-AgNPs could inhibit the growths of S. aureus and E. coli in time- and dose-dependent modes, and even could disrupt the bacterial structure integrality resulting in the leakage of intracellular contents. G-AgNPs, especially ML-AgNPs, with remarkable bioactivities could replace C-AgNPs as related agents applied in agriculture and medicine.

为了研究用绿色和化学方法制备的AgNPs的理化特性和生物活性，并进一步探索相关的抗菌机制，一种是由水提取物介导的化学AgNPs（C-AgNPs）和三种绿色AgNPs（G-AgNPs）。制备和表征了桑树。与C-AgNPs和提取物相比，所有G-AgNPs在DPPH自由基清除中均显示出更高的抗氧化剂活性，降低了功率并进行了总抗氧化剂测定。同时，与C-AgNPs和提取物相比，所有G-AgNPs对各种病原体均具有显着（P <0.05）增强的抗菌活性。在制备的AgNPs中，桑白水提取物介导的ML-AgNPs落叶杆菌表现出最强大的抗菌作用，具有最大的抑制区（金黄色葡萄球菌为13.11±0.76 mm，大肠杆菌为13.27±0.22 mm ），并且对金黄色葡萄球菌的最小抑菌浓度最低（6.125μg/ ml），并且大肠杆菌（3.125μg/ ml）。ML-AgNPs可以以时间和剂量依赖的方式抑制金黄色葡萄球菌和大肠杆菌的生长，甚至可以破坏细菌的结构完整性，导致细胞内内容物的泄漏。具有显着生物活性的G-AgNPs，尤其是ML-AgNPs可以代替C-AgNPs作为农业和医学中的相关药物。