Booyens J, Labuschagne M C, Thantsha M S
Department of Microbiology and Plant Pathology, Faculty of Natural and Agricultural Sciences, University of Pretoria, New Agricultural Sciences Building Room 9-10, Lunnon road, Pretoria, 0002, South Africa.
Probiotics Antimicrob Proteins. 2014 Jun;6(2):82-7. doi: 10.1007/s12602-013-9145-z.
There has been much research on the effects of garlic (Allium sativum) on numerous pathogens, but very few, if any, studies on its effect on beneficial, probiotic bifidobacteria. We have recently shown that garlic exhibits antibacterial activity against bifidobacteria. The mechanism by which garlic kills bifidobacteria is yet to be elucidated. This study sought to determine the mechanism of action of garlic clove extract on selected Bifidobacterium species using scanning and transmission electron microscopy and SDS-PAGE analysis. SEM micrographs revealed unusual morphological changes such as cell elongation, cocci-shaped cells with cross-walls, and distorted cells with bulbous ends. With TEM, observed changes included among others, condensation of cytoplasmic material, disintegration of membranes, and loss of structural integrity. SDS-PAGE analysis did not reveal any differences in whole-cell protein profiles of untreated and garlic clove extract-treated cells. The current study is the first to reveal the mechanism of action of garlic clove extract on probiotic Bifidobacterium species. The results indicate that garlic affects these beneficial bacteria in a manner similar to that exhibited in pathogens. These results therefore further highlight that caution should be taken especially when using raw garlic and probiotic bifidobacteria simultaneously as viability of these bacteria could be reduced by allicin released upon crushing of garlic cloves, thereby limiting the health benefits that the consumer anticipate to gain from probiotics.
关于大蒜（蒜属植物）对多种病原体的影响已有大量研究，但关于其对有益的益生菌双歧杆菌影响的研究却极少，即便有也寥寥无几。我们最近发现大蒜对双歧杆菌具有抗菌活性。大蒜杀死双歧杆菌的机制尚待阐明。本研究旨在通过扫描电子显微镜、透射电子显微镜和SDS - PAGE分析来确定大蒜丁香提取物对选定双歧杆菌菌株的作用机制。扫描电子显微镜图像显示出异常的形态变化，如细胞伸长、带有横壁的球菌形细胞以及末端呈球状的变形细胞。通过透射电子显微镜观察到的变化包括细胞质物质凝聚、膜解体以及结构完整性丧失等。SDS - PAGE分析未揭示未处理细胞和经大蒜丁香提取物处理细胞的全细胞蛋白质谱有任何差异。本研究首次揭示了大蒜丁香提取物对益生菌双歧杆菌菌株的作用机制。结果表明，大蒜对这些有益细菌的影响方式与对病原体的影响方式类似。因此，这些结果进一步强调，尤其在同时使用生大蒜和益生菌双歧杆菌时应谨慎，因为大蒜蒜瓣被碾碎时释放的蒜素可能会降低这些细菌的活力，从而限制消费者期望从益生菌中获得的健康益处。
