Instituto Biológico, Centro de Pesquisa e Desenvolvimento de Sanidade Animal, Brazil.
Int J Food Microbiol. 2010 Jan 31;137(1):55-60. doi: 10.1016/j.ijfoodmicro.2009.10.017. Epub 2009 Oct 24.
Aflatoxin B(1) (AFB(1)) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. Inhibitory effects of essential oil of Ageratum conyzoides, on the mycelial growth and aflatoxin B(1) production by Aspergillus flavus were studied. Cultures were incubated in yeast extract-sucrose (YES) broth for days at 25 degrees C at the following different concentrations of the essential oil (from 0.0 to 30mug/mL). The essential oil inhibited fungal growth to different extents depending on the concentration, and completely inhibited aflatoxin production at concentrations above 0.10microg/mL. The analysis of the oil by GC/MS showed that its main components are precocene II (46.35%), precocene I (42.78%), cumarine (5.01%) and Trans-caryophyllene (3.02%). Comparison by transmission electron microscopy of the fungal cells, control and those incubated with different concentrations of essential oil, showed ultra-structural changes which were concentration dependent of the essential oil of A. conyzoides. Such ultra-structural changes were more evident in the endomembrane system, affecting mainly the mitochondria. Degradation was also observed in both surrounding fibrils. The ability to inhibit aflatoxin production as a new biological activity of A.conyzoides L. indicates that it may be considered as a useful tool for a better understanding of the complex pathway of aflatoxin biosynthesis.
黄曲霉毒素 B(1)（AFB(1)）是一种由曲霉属物种在食品和农产品上产生的高毒性和致癌代谢物。本研究测定了藿香蓟精油对黄曲霉菌丝生长和黄曲霉毒素 B(1)产生的抑制作用。在 25℃下，于酵母提取物-蔗糖（YES）肉汤中培养培养物数天，不同浓度的精油（0.0 至 30μg/mL）。根据浓度的不同，精油在不同程度上抑制了真菌的生长，在浓度高于 0.10μg/mL 时完全抑制了黄曲霉毒素的产生。GC/MS 对油的分析表明，其主要成分是 Precoce II（46.35%）、Precoce I（42.78%）、 cumarine（5.01%）和 Trans-caryophyllene（3.02%）。通过透射电子显微镜比较了对照组和用不同浓度精油孵育的真菌细胞，显示出超微结构的变化，这些变化与藿香蓟精油的浓度有关。这种超微结构的变化在内膜系统中更为明显，主要影响线粒体。在周围的原纤维中也观察到了降解。抑制黄曲霉毒素产生的能力是藿香蓟的一种新的生物学活性，表明它可能被认为是更好地理解黄曲霉毒素生物合成复杂途径的有用工具。
