Wang Xinfang, Li Yue, Liu Suwen, Wang Hao, Chang Xuedong, Zhang Jingzheng
College of Food Science & Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China.
Engineering Research Center of Chestnut Industry Technology of Ministry of Education, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China.
Foods. 2023 Sep 2;12(17):3312. doi: 10.3390/foods12173312.
The microbial contamination of food poses a threat to human health. Chestnut shells, which are byproducts of chestnut processing, contain polyphenols that exert various physiological effects, and thus have the potential to be used in food preservation. This study investigates the bacteriostatic effect and mechanism(s) of the action of chestnut shell polyphenols (CSPs) on three food-spoilage bacteria, namely , , and . To this end, the effect of CSPs on the ultrastructure of each bacterium was determined using scanning electron microscopy and transmission electron microscopy. Moreover, gene expression was analyzed using RT-qPCR. Subsequent molecular docking analysis was employed to elucidate the mechanism of action employed by CSPs via the inhibition of key enzymes. Ultrastructure analysis showed that CSPs damaged the bacterial cell wall and increased permeability. At 0.313 mg/mL, CSPs significantly increased the activity of alkaline phosphatase and lactate dehydrogenase, as well as protein leakage ( < 0.05), whereas the activity of the tricarboxylic acid (TCA) cycle enzymes, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase, were inhibited ( < 0.05). The expression levels of the TCA-related genes , , , , , , , and are also significantly downregulated by CSP treatment ( < 0.05). Moreover, CSPs inhibit respiration and energy metabolism, including ATPase activity and adenosine triphosphate (ATP) synthesis ( < 0.05). Molecular docking determined that proanthocyanidins B1 and C1, the main components of CSPs, are responsible for the antibacterial activity. Therefore, as natural antibacterial substances, CSPs have considerable potential for development and application as natural food preservatives.
食品中的微生物污染对人类健康构成威胁。栗壳作为栗子加工的副产品，含有具有多种生理作用的多酚，因此具有用于食品保鲜的潜力。本研究调查了栗壳多酚（CSPs）对三种食品腐败细菌，即[细菌名称1]、[细菌名称2]和[细菌名称3]的抑菌作用及其作用机制。为此，使用扫描电子显微镜和透射电子显微镜测定了CSPs对每种细菌超微结构的影响。此外，使用RT-qPCR分析基因表达。随后采用分子对接分析来阐明CSPs通过抑制关键酶所采用的作用机制。超微结构分析表明，CSPs破坏了细菌细胞壁并增加了通透性。在0.313 mg/mL时，CSPs显著增加了碱性磷酸酶和乳酸脱氢酶的活性以及蛋白质泄漏（P<0.05），而三羧酸（TCA）循环酶异柠檬酸脱氢酶和α-酮戊二酸脱氢酶的活性受到抑制（P<0.05）。CSP处理也显著下调了TCA相关基因[基因名称1]、[基因名称2]、[基因名称3]、[基因名称4]、[基因名称5]、[基因名称6]、[基因名称7]和[基因名称8]的表达水平（P<0.05）。此外，CSPs抑制呼吸和能量代谢，包括ATP酶活性和三磷酸腺苷（ATP）合成（P<0.05）。分子对接确定，CSPs的主要成分原花青素B1和C1是抗菌活性的原因所在。因此，作为天然抗菌物质，CSPs作为天然食品防腐剂具有相当大的开发和应用潜力。
