Silver nanoparticles (AgNPs) were successfully synthesized by different extracts of Lavandula stoechas, which have an antibacterial effect on pathogenic strains, such as Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. Among them, AgNPs-E4 that synthesized by EtOAc extract (E4) have greater antibacterial activity than that by other extracts. The highest inhibition zone diameter (18.6 mm) appeared in C. albicans, at a dosage of 1,000 ppm AgNPs-E4. It was identified as optimal antibacterial AgNPs, which are spherical in shape with an average size at 35.5 nm and maximum absorbance peak at 525 nm. The combined use of penicillin G and AgNPs-E4 exhibited a significant synergistic inhibition effect on the growth of C. albicans, which could produce a maximum inhibition zone of about 21.0 mm. Synergism between antibiotics and AgNPs-E4 was greater than the sum of their individual effects on pathogenic strains. Also, vancomycin, tetracycline, and AgNPs-E4 have slight or no inhibition effect on Escherichia coli. But combined use of the above antibiotics and AgNPs-E4 could exhibit antibacterial activity against E. coli, and the inhibition zone achieved 14.5 and 12.6 mm, respectively, suggesting combined use was able to realize antibacterial effect from nonexistence to pass into existence. HPLC analysis revealed polyphenols were the main compositions of EtOAc extract (E4), such as oleanolic fruit-12-en-3-ol, 19-hydroxyl wusu ester, and lanolin-8-en-3-alcohol. These polyphenols might be particularly useful for the synthesis of antibacterial AgNPs. Therefore, AgNPs synthesized by EtOAc extract of L. stoechas have potential value as antimicrobial agents and also enhance the antibacterial activity of antibiotics by combined use.

银纳米颗粒（的AgNPs）成功地被不同的提取物合成的薰衣草头状，这对致病菌株，如抗菌效果白色念珠菌，铜绿假单胞菌，和金黄色葡萄球菌。其中，由EtOAc提取物（E4）合成的AgNPs-E4比其他提取物具有更大的抗菌活性。最高抑菌圈直径 (18.6 mm) 出现在白色念珠菌中，剂量为 1,000 ppm AgNPs-E4。它被确定为最佳抗菌 AgNPs，其形状为球形，平均尺寸为 35.5 nm，最大吸收峰为 525 nm。青霉素 G 和 AgNPs-E4 的联合使用对青霉素的生长表现出显着的协同抑制作用。C. albicans，可产生约 21.0 mm 的最大抑菌圈。抗生素和 AgNPs-E4 之间的协同作用大于它们对致病菌株的个体影响的总和。此外，万古霉素、四环素和 AgNPs-E4 对大肠杆菌有轻微的抑制作用或没有抑制作用。但上述抗生素与AgNPs-E4联合使用可对大肠杆菌表现出抗菌活性，抑菌圈分别达到14.5和12.6mm，表明联合使用能够实现从无到有的抗菌效果。HPLC 分析表明多酚是 EtOAc 提取物 (E4) 的主要成分，如齐墩果果 12-en-3-ol、19-羟基乌苏酯和羊毛脂-8-en-3-醇。这些多酚可能对合成抗菌 AgNPs 特别有用。因此，由L. stoechas的 EtOAc 提取物合成的 AgNPs具有作为抗菌剂的潜在价值，并且还可以通过联合使用来增强抗生素的抗菌活性。