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. 2018 Sep;125(3):710-723. doi: 10.1111/jam.13889. Epub 2018 Jun 26.
To investigate the effect of natural products on the spore cycle of Clostridium difficile in vitro.
Twenty-two natural products were investigated using four C. difficile strains. Effects on sporulation, determined using microscopy and a conventional spore recovery assay, showed that fresh onion bulb extract (6·3% v v ) and coconut oil (8% v v ) inhibited sporulation in all four isolates by 66-86% and 51-88%, respectively, compared to untreated controls. Fresh ginger rhizome extract (25% v v ) was also inhibitory, although to a lesser extent. Using a standard spore germination and outgrowth assay, germination was unaffected by the 22 products, whereas outgrowth was significantly reduced by artichoke extract (18·8 mg ml ), fresh onion bulb extract (25% v v ), Leptospermum honeys (8% w v ) and allicin (75 mg ml ; P < 0·01). Sporicidal activity, investigated using a standard plate recovery assay, was minimal.
Three of the 22 natural products (13%) showed inhibitory effects on sporulation of C. difficile and six products (27%) reduced vegetative outgrowth of C. difficile.
This study shows the potential of natural products to inhibit different stages of C. difficile sporulation and encourages further investigation in this field.
研究天然产物对艰难梭菌孢子周期的体外影响。
使用四种艰难梭菌菌株研究了 22 种天然产物。显微镜和传统孢子回收检测法评估的孢子形成结果表明，与未处理的对照组相比，新鲜洋葱鳞茎提取物（6.3%v/v）和椰子油（8%v/v）分别使所有 4 种分离株的孢子形成抑制了 66-86%和 51-88%。新鲜生姜根茎提取物（25%v/v）也有一定抑制作用，尽管程度较小。使用标准孢子发芽和生长检测法，22 种产物对发芽均无影响，而朝鲜蓟提取物（18.8mg/ml）、新鲜洋葱鳞茎提取物（25%v/v）、Leptospermum honeys（8%w/v）和大蒜素（75mg/ml）显著降低了生长（P<0.01）。使用标准平板回收检测法检测杀菌活性，效果甚微。
22 种天然产物中有 3 种（13%）对艰难梭菌的孢子形成具有抑制作用，有 6 种（27%）产物降低了艰难梭菌的营养生长。
本研究表明天然产物具有抑制艰难梭菌不同阶段孢子形成的潜力，鼓励在该领域进一步研究。
