Antimicrobial agents are substances that, when present at low concentrations, can delay microbial growth. For many years, several powerful antimicrobial substances have been synthetized. However, because of their significant side effects, there is a growing interest nowadays to find natural alternatives to the synthetic one. The present study aims to recover extracts with antimicrobial activity from Picea abies residues using two different extraction technologies, respectively, Soxhlet and supercritical carbon dioxide. Their antimicrobial activity was tested on the growth of Enterococcus faecalis and Streptococcus thermophilus. Isothermal calorimetry was used as a technique to quantify the antimicrobial effect of the extracts. The heat flow curves, obtained during the microbial growth, were fitted by a modified Gompertz function obtaining the lag time (λ) and the maximum growth rate (μ_max) parameters. High-resolution mass spectrometry was used to identify the phenolic compounds responsible for the antimicrobial activity of the extracts. Regardless to the technology used, both extracts showed similar antimicrobial activity. For both microbial strains, the addition of the extract induced longer lag times (λ), while the maximum growth rate (μ_max) decreased. S. thermophilus showed a higher resistance compared to E. faecalis suggesting a different capacity to metabolize the substrate in the presence of Picea abies extracts. Catechin, dihydroquercetin, astringin and isorhapontin were the identified phenolic compounds responsible for such effect. In conclusion, the results of this study provided an exciting potential for the future in light of the shift away from artificial preservatives and the trend toward natural alternative compounds coming from sustainable sources.

抗菌剂是当以低浓度存在时会延迟微生物生长的物质。多年来，已经合成了几种有效的抗菌物质。然而，由于其显着的副作用，如今人们对寻找天然替代品的兴趣日益浓厚。本研究旨在使用两种不同的提取技术（分别为索氏提取法和超临界二氧化碳）从云杉云杉残渣中回收具有抗菌活性的提取物。测试了它们对粪肠球菌和嗜热链球菌生长的抗菌活性。等温量热法用作量化提取物抗微生物作用的技术。热流曲线中，微生物生长过程中获得的，被一个改进Gompertz函数获得的滞后时间（嵌合λ）和最大生长速率（μ_最大）的参数。高分辨率质谱法用于鉴定负责提取物抗菌活性的酚类化合物。无论使用哪种技术，两种提取物均显示出相似的抗菌活性。对于这两种微生物菌株，添加引起的提取物的较长的滞后时间（λ），而最大生长速率（μ_最大）降低。嗜热链球菌表现出比粪肠球菌更高的抗性，表明在云杉云杉提取物存在下代谢底物的能力不同。儿茶素，二氢槲皮素，丁香和异佛尔汀是导致这种作用的酚类化合物。总之，鉴于人工防腐剂的转变以及来自可持续来源的天然替代化合物的发展趋势，这项研究的结果为未来提供了令人兴奋的潜力。