Polyphenols derived from a variety of plants have demonstrated antimicrobial activity against diverse microbial pathogens. Legionella pneumophila is an intracellular bacterial pathogen that opportunistically causes a severe inflammatory pneumonia in humans, called Legionnaires' Disease, via replication within macrophages. Previous studies demonstrated that tea polyphenols attenuate L. pneumophila intracellular replication within mouse macrophages via increased tumor necrosis factor (TNF) production. Sorghum bicolor is a sustainable cereal crop that thrives in arid environments and is well-suited to continued production in warming climates. Sorghum polyphenols have anticancer and antioxidant properties, but their antimicrobial activity has not been evaluated. Here, we investigated the impact of sorghum polyphenols on L. pneumophila intracellular replication within RAW 264.7 mouse macrophages. Sorghum high-polyphenol extract (HPE) attenuated L. pneumophila intracellular replication in a dose-dependent manner but did not impair either bacterial replication in rich media or macrophage viability. Moreover, HPE treatment enhanced both TNF and IL-6 secretion from L. pneumophila infected macrophages. Thus, polyphenols derived from sorghum enhance macrophage restriction of L. pneumophila, likely via increased pro-inflammatory cytokine production. This work reveals commonalities between plant polyphenol-mediated antimicrobial activity and provides a foundation for future evaluation of sorghum as an antimicrobial agent.

中文翻译：

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双色高粱的高多酚提取物减弱了 RAW 264.7 巨噬细胞内嗜肺军团菌的复制。

来自多种植物的多酚已显示出对多种微生物病原体的抗菌活性。嗜肺军团菌是一种细胞内细菌病原体，通过在巨噬细胞内的复制机会性地导致人类严重的炎症性肺炎，称为军团病。先前的研究表明，茶多酚通过增加肿瘤坏死因子 (TNF) 的产生来减弱小鼠巨噬细胞内嗜肺军团菌的细胞内复制。双色高粱是一种可持续的谷类作物，在干旱环境中茁壮成长，非常适合在气候变暖的情况下继续生产。高粱多酚具有抗癌和抗氧化特性，但尚未对其抗菌活性进行评估。在这里，我们研究了高粱多酚对 L. RAW 264.7 小鼠巨噬细胞内的嗜肺杆菌细胞内复制。高粱高多酚提取物 (HPE) 以剂量依赖性方式减弱嗜肺军团菌细胞内复制，但不损害富培养基中的细菌复制或巨噬细胞活力。此外，HPE 处理增强了嗜肺军团菌感染巨噬细胞的 TNF 和 IL-6 分泌。因此，来自高粱的多酚可能通过增加促炎细胞因子的产生来增强嗜肺军团菌的巨噬细胞限制。这项工作揭示了植物多酚介导的抗菌活性之间的共性，并为未来评估高粱作为抗菌剂提供了基础。pneumophila 以剂量依赖性方式进行细胞内复制，但不损害富培养基中的细菌复制或巨噬细胞活力。此外，HPE 处理增强了嗜肺军团菌感染巨噬细胞的 TNF 和 IL-6 分泌。因此，来自高粱的多酚可能通过增加促炎细胞因子的产生来增强嗜肺军团菌的巨噬细胞限制。这项工作揭示了植物多酚介导的抗菌活性之间的共性，并为未来评估高粱作为抗菌剂提供了基础。pneumophila 以剂量依赖性方式进行细胞内复制，但不损害富培养基中的细菌复制或巨噬细胞活力。此外，HPE 处理增强了嗜肺军团菌感染巨噬细胞的 TNF 和 IL-6 分泌。因此，来自高粱的多酚可能通过增加促炎细胞因子的产生来增强嗜肺军团菌的巨噬细胞限制。这项工作揭示了植物多酚介导的抗菌活性之间的共性，并为未来评估高粱作为抗菌剂提供了基础。肺炎，可能是通过增加促炎细胞因子的产生。这项工作揭示了植物多酚介导的抗菌活性之间的共性，并为未来评估高粱作为抗菌剂提供了基础。肺炎，可能是通过增加促炎细胞因子的产生。这项工作揭示了植物多酚介导的抗菌活性之间的共性，并为未来评估高粱作为抗菌剂提供了基础。