Current research indicates that changes in gut microbiota can impact the host, but it is not always clear how dietary and environmental factors alter gut microbiota. One potential factor is antimicrobial activity of compounds ingested by the host. The goal of this study was to determine the antimicrobial activity of common plant secondary metabolites against pure cultures of paired, structurally and phylogenetically distinct gastrointestinal bacteria of human or bovine origin: Prevotella bryantii B₁4, Bacteroides fragilis 25285, Acetoanaerobium (Clostridium) sticklandii SR and Clostridioides difficile 9689. When growth media were amended with individual phytochemicals (the alkaloids: berberine, capsaicin, nicotine, piperine and quinine and the phenolic: curcumin), growth of each species was inhibited to varying degrees at the three greatest concentrations tested (0.10–10.00 mg mL⁻¹). The viable cell numbers of all the cultures were reduced, ≥4-logs, by berberine at concentrations ≥1.00 mg mL⁻¹. Quinine performed similarly to berberine for B₁4, 25285, and SR at the same concentrations. The other phytochemicals were inhibitory, but not as much as quinine or berberine. Nicotine had activity against all four species (≥2-log reduction in viable cell number at 10.00 mg mL⁻¹), but had stronger activity against the Gram-positive bacteria, SR and 9689, (≥4-log reductions at 10.00 mg mL⁻¹). In conclusion, the phytochemicals had varying spectra of antimicrobial activity. These results are consistent with the hypothesis that ingested phytochemicals have the ability to differentially impact gut microbiota through antimicrobial activity.

当前的研究表明，肠道菌群的变化会影响宿主，但饮食和环境因素如何改变肠道菌群并不总是很清楚。一种潜在的因素是宿主摄入的化合物的抗菌活性。本研究的目的是确定对的成对的纯培养物常见的植物次生代谢物的抗微生物活性，在结构上与人或牛来源的系统发育不同胃肠细菌：普雷沃bryantii乙₁ 4 ，脆弱拟杆菌25285 ，Acetoanaerobium（梭状芽孢杆菌）sticklandii SR和艰难梭菌9689.当用单独的植物化学物质（生物碱：小ber碱，辣椒素，尼古丁，胡椒碱和奎宁以及酚类：姜黄素）修正生长培养基时，每种物种的生长在所测试的三个最大浓度（0.10-10.00 mg）下均受到不同程度的抑制。 mL ^-1）。小碱浓度≥1.00mg mL ^-1时，所有培养物的活细胞数均减少了≥4-log 。奎宁在相同浓度下对B ₁ 4、25285和SR的表现与小碱相似。其他植物化学物质具有抑制作用，但不如奎宁或小ber碱那么多。尼古丁具有针对所有四个物种的活性（10.00 mg mL ^-1时活细胞数减少≥2-log），但对革兰氏阳性细菌SR和9689的活性更强（在10.00 mg mL ^-1时减少≥4-log ）。总之，植物化学物质具有变化的抗菌活性谱。这些结果与以下假设相吻合：摄入的植物化学物质具有通过抗菌活性差异影响肠道菌群的能力。