Data_Sheet_1_Antibacterial Activity of the Essential Oil From Litsea cubeba Against Cutibacterium acnes and the Investigations of Its Potential Mechanism by Gas Chromatography-Mass Spectrometry Metabolomics.DOCX

Cutibacterium acnes (C. acnes) is an anaerobic Gram-positive bacterium generally considered as a human skin commensal, but is also involved in different infections, such as acne and surgical infections. Although there are a variety of treatments, the side effects and the problem of bacterial drug resistance still limit their clinical usage. In this study, we found that essential oil (EO) distilled from fresh mature Litsea cubeba possessed promising antibacterial activity against C. acnes. In order to elucidate its potential mechanism, bacteriostatic activity test, Live/Dead kit assay, scanning electron microscope (SEM), transmission electron microscope (TEM), and metabolomics were employed. In addition, the content of adenosine triphosphate (ATP) in bacterium and the activities of key enzymes involved in critical metabolic pathways were detected using a variety of biochemical assays. The results showed that EO exhibited significant antibacterial activity against C. acnes at a minimum inhibitory concentration (MIC) of 400 μg/mL and a minimum bactericidal concentration (MBC) of 800 μg/mL, and EO could destroy C. acnes morphology and inhibit its growth. Moreover, results from our study showed that EO had a significant effect on the C. acnes normal metabolism. In total, 86 metabolites were altered, and 34 metabolic pathways related to the carbohydrate metabolism, energy metabolism, amino acid metabolism, as well as cell wall and cell membrane synthesis were perturbed after EO administration. The synthesis of ATP in bacterial cells was also severely inhibited, and the activities of key enzymes of the glycolysis and Wood-Werkman cycle were significantly affected (Pyruvate Carboxylase, Malate Dehydrogenase and Pyruvate kinase activities were decreased, and Hexokinase was increased). Taken together, these results illustrated that the bacteriostatic effect of EO against C. acnes by breaking the bacterial cell morphology and perturbing cell metabolism, including inhibition of key enzyme activity and ATP synthesis. The results from our study may shed new light on the discovery of novel drugs with more robust efficacy.

痤疮丙酸杆菌（Cutibacterium acnes，简称C. acnes）是一类厌氧革兰氏阳性菌，通常被视为人体皮肤共生菌，但同时也可引发痤疮、外科感染等多种感染性疾病。尽管目前已有多种治疗手段，但其副作用与细菌耐药性问题仍制约了其临床应用。本研究发现，从新鲜成熟山鸡椒（Litsea cubeba）中蒸馏得到的精油（essential oil，以下简称EO）对C. acnes具有良好的抗菌活性。为阐明其潜在作用机制，本研究采用了抑菌活性试验、死活染色试剂盒检测、扫描电子显微镜（scanning electron microscope，SEM）、透射电子显微镜（transmission electron microscope，TEM）及代谢组学分析等方法。此外，通过多种生化检测手段测定了细菌细胞内三磷酸腺苷（adenosine triphosphate，ATP）的含量，以及关键代谢通路中的关键酶活性。结果显示，EO在最低抑菌浓度（minimum inhibitory concentration，MIC）为400 μg/mL、最低杀菌浓度（minimum bactericidal concentration，MBC）为800 μg/mL时，对C. acnes表现出显著抗菌活性，且可破坏C. acnes的菌体形态并抑制其生长。此外，研究结果表明EO对C. acnes的正常代谢具有显著干预作用：经EO处理后，共有86种代谢物发生显著改变，涉及碳水化合物代谢、能量代谢、氨基酸代谢以及细胞壁与细胞膜合成等34条代谢通路出现扰动。细菌细胞内ATP的合成也受到严重抑制，糖酵解与Wood-Werkman循环的关键酶活性亦受到显著影响——丙酮酸羧化酶、苹果酸脱氢酶及丙酮酸激酶活性降低，而己糖激酶活性升高。综上，上述结果证实，EO可通过破坏细菌细胞形态、扰动细胞代谢（包括抑制关键酶活性与ATP合成）来发挥对C. acnes的抑菌作用。本研究结果可为开发更高效的新型抗菌药物提供新的研究思路。