Roshan N, Riley T V, Hammer K A
School of Biomedical Sciences (M504), The University of Western Australia, Crawley, WA, Australia.
Department of Microbiology, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Nedlands, WA, Australia.
J Appl Microbiol. 2017 Jul;123(1):92-103. doi: 10.1111/jam.13486. Epub 2017 Jun 8.
To investigate the antimicrobial activity of various natural products against Clostridium difficile in vitro.
The antibacterial activity of 20 natural products was determined by the agar well diffusion and broth microdilution assays against four C. difficile strains, three comparator organisms and four gastrointestinal commensal organisms. Of the raw natural products, garlic juice had the highest activity. The most active processed products were peppermint oil and the four pure compounds trans-cinnamaldehyde, allicin, menthol and zingerone. Furthermore, Bacteroides species had similar susceptibility to C. difficile to most natural products; however, Lactobacillus casei was less susceptible. The combined effect of natural products with vancomycin or metronidazole was determined using the conventional checkerboard titration method and the fractional inhibitory concentration index was calculated. The results showed a possible synergism between trans-cinnamaldehyde and vancomycin and partial synergy between trans-cinnamaldehyde and metronidazole.
The study indicates a range of antimicrobial activity of natural products against C. difficile and suggests that they may be useful as alternative or complementary treatments for C. difficile infection (CDI), particularly as most are able to be given orally.
This study encourages further investigation of natural products for treatment of CDI.
体外研究多种天然产物对艰难梭菌的抗菌活性。
采用琼脂孔扩散法和肉汤微量稀释法测定了20种天然产物对4株艰难梭菌菌株、3种对照菌和4种胃肠道共生菌的抗菌活性。在天然产物原料中，大蒜汁活性最高。活性最强的加工产物是薄荷油以及4种纯化合物反式肉桂醛、大蒜素、薄荷醇和姜辣素。此外，拟杆菌属对艰难梭菌的敏感性与大多数天然产物相似；然而，干酪乳杆菌的敏感性较低。使用传统棋盘滴定法测定天然产物与万古霉素或甲硝唑的联合作用，并计算分数抑制浓度指数。结果显示反式肉桂醛与万古霉素之间可能存在协同作用，反式肉桂醛与甲硝唑之间存在部分协同作用。
该研究表明天然产物对艰难梭菌具有一系列抗菌活性，并表明它们可能作为艰难梭菌感染（CDI）的替代或补充治疗方法，特别是因为大多数天然产物能够口服给药。
本研究鼓励进一步研究天然产物用于治疗CDI。
