Zhou Huan, Chen Lingli, Ouyang Kehui, Zhang Qingfeng, Wang Wenjun
Jiangxi Key Laboratory of Natural Products and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang, China.
College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China.
Front Microbiol. 2023 Jan 10;13:1103476. doi: 10.3389/fmicb.2022.1103476. eCollection 2022.
S. Y. Hu. (FCS) possess many biological activities, but the antibacterial activity and underlying mechanisms of flavonoids from Chimonanthus salicifolius S. Y. Hu. (FCS) is still unknown.
Maximum diameter of inhibition zone (DIZ), maximum diameter of inhibition zone (DIZ), the lowest minimum inhibition concentration (MIC), and the lowest minimum bactericide concentration (MBC) were used to detect the antibacterial activity. Meanwhile, related enzyme activities, the transcriptome analysis and quantitative RT-PCR were used to investigate the antibacterial activity mechanisms.
The results showed that FCS (with a purity of 84.2 ± 2.0%) has potential effects on tested strains with the maximum diameter of inhibition zone (DIZ) was 15.93 ± 2.63 mm, the lowest minimum inhibition concentration (MIC) was 1.56 mg/ml and the lowest minimum bactericide concentration (MBC) was 6.25 mg/ml. In addition, the bacterial growth curve test, release of extracellular alkaline phosphatase (AKP), loss of intracellular components, DNA damage and transmission electron microscope (TEM) suggested that FCS could destroy the cell wall and membrane, cause the loss of intracellular substance, cause DNA damage and even lead to cell death. Moreover, the antibacterial mechanism of FCS against (, Gram-positive bacteria) was further confirmed by the transcriptome analysis and quantitative RT-PCR at the molecular level for the first time. A total of 671 differentially expressed genes (DEGs) were identified after treated with FCS (1/2 MIC), with 338 and 333 genes showing up-regulation and down-regulation, respectively. The highlighted changes were those related to the biosynthesis of bacteria wall and membrane, DNA replication and repair, and energy metabolism.
Overall, our research provides theoretical guidance for the application of FCS, which is expected to be potentially used as a natural antimicrobial agent in food safety.
柳叶蜡梅黄酮（FCS）具有多种生物活性，但其抗菌活性及潜在机制尚不清楚。
采用抑菌圈最大直径（DIZ）、最低抑菌浓度（MIC）和最低杀菌浓度（MBC）检测抗菌活性。同时，通过相关酶活性、转录组分析和定量RT-PCR研究抗菌活性机制。
结果表明，纯度为84.2±2.0%的FCS对受试菌株有潜在作用，抑菌圈最大直径（DIZ）为15.93±2.63mm，最低抑菌浓度（MIC）为1.56mg/ml，最低杀菌浓度（MBC）为6.25mg/ml。此外，细菌生长曲线试验、细胞外碱性磷酸酶（AKP）释放、细胞内成分损失、DNA损伤和透射电子显微镜（TEM）表明，FCS可破坏细胞壁和细胞膜，导致细胞内物质损失，引起DNA损伤甚至导致细胞死亡。此外，首次通过转录组分析和定量RT-PCR在分子水平上进一步证实了FCS对革兰氏阳性菌的抗菌机制。用FCS（1/2 MIC）处理后，共鉴定出671个差异表达基因（DEG），其中338个基因上调，333个基因下调。突出的变化与细菌细胞壁和细胞膜的生物合成、DNA复制和修复以及能量代谢有关。
总体而言，我们的研究为FCS的应用提供了理论指导，有望作为一种天然抗菌剂应用于食品安全领域。
