Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
Microbiol Res. 2013 May 6;168(4):204-10. doi: 10.1016/j.micres.2012.11.007. Epub 2012 Dec 7.
Fungi are some of the most important organisms in the production of bioactive secondary metabolites. This success is related to the advances in biotechnology and also to the possibility of working with techniques such as the "OSMAC" (one strain-many compounds) to achieve different fungal secondary metabolites profiles upon modifying the culturing conditions. Using this approach, the fungal species Paecilomyces lilacinus was cultivated in potato dextrose broth under 14 different fermentative conditions by adding the bacterium Salmonella typhimurium to the growing medium in order to provide biotic stress. S. typhimurium was added alive or after inactivation by autoclave or microwave irradiation in different stages of fungal growth. Extracts were prepared by liquid-liquid extraction using ethyl acetate, a medium polarity solvent in order to avoid extracting culturing media components. Production of fatty acids of relevance for the pharmaceutical and food industries was enhanced by the modified fermentative conditions and they were identified and quantified. The extracts were evaluated for acetylcholinesterase inhibition and the more active extract (91±2.91% inhibition) was prepared in large scale. From this active P. lilacinus extract, a novel pyridone alkaloid, named Paecilomide, was isolated and its structure was elucidated by modern nuclear magnetic resonance techniques and mass spectrometric analyses. Paecilomide (1) was also evaluated for acetylcholinesterase inhibition, presenting 57.5±5.50% of acetylcholinesterase inhibition.
真菌是产生生物活性次生代谢物的最重要的生物之一。这种成功与生物技术的进步有关，也与使用“OSMAC”（一种菌株多种化合物）等技术的可能性有关，通过改变培养条件可以获得不同的真菌次生代谢产物谱。采用这种方法，在马铃薯葡萄糖肉汤中培养了真菌物种拟青霉（Paecilomyces lilacinus），通过向生长培养基中添加沙门氏菌（Salmonella typhimurium），在 14 种不同的发酵条件下进行培养，从而提供生物胁迫。沙门氏菌以活菌或经高压灭菌或微波辐射失活的形式，在真菌生长的不同阶段加入。通过液-液萃取用乙酸乙酯（一种中等极性溶剂）提取，以避免提取培养介质成分。通过修改发酵条件增强了与制药和食品行业相关的脂肪酸的产生，并对其进行了鉴定和定量。评估了提取物对乙酰胆碱酯酶的抑制作用，并对活性更高的提取物（91±2.91%抑制率）进行了大规模制备。从这种活性较强的拟青霉提取物中，分离出了一种新型的吡啶酮生物碱，命名为 Paecilomide，并通过现代核磁共振技术和质谱分析阐明了其结构。Paecilomide（1）也对乙酰胆碱酯酶抑制作用进行了评估，表现出 57.5±5.50%的乙酰胆碱酯酶抑制作用。
