Gelderblom Wentzel C A, Sewram Vikash, Shephard Gordon S, Snijman Petra W, Tenza Kenny, van der Westhuizen Liana, Vleggaar Robert
Programme on Mycotoxins and Experimental Carcinogenesis, Medical Research Council, Tygerberg 7505, South Africa.
J Agric Food Chem. 2007 May 30;55(11):4388-94. doi: 10.1021/jf070061h. Epub 2007 May 1.
1H and 13C NMR spectroscopy of both fumonisin B3 and B4, as well as high-performance liquid chromatography (HPLC) analysis of samples of fumonisin B3 used as standards, showed in each case the presence of two stereoisomers, which could not be separated by preparative chromatography. The 2,3-anti relative configuration for the two minor stereoisomers of fumonisin B3 and B4 was deduced from the NMR data, and their 2S,3R absolute configurations were established by application of Mosher's method using the fumonisin B3 sample. Samples of fumonisin B3 and B4 can contain between 10 and 40% of fumonisin B compounds of the 3-epi series. The 3-epi-FB3, determined by HPLC with fluorescence detection of the o-phthaldialdehyde derivative and confirmed by liquid chromatography-tandem mass spectrometry, was found to occur naturally in a range of maize samples at levels much lower than FB3 (< 20%). The identification of members of the 3-epi-fumonisin B series provides insight into the order and selectivity of steps in fumonisin biosynthesis.
伏马毒素B3和B4的1H和13C核磁共振光谱，以及用作标准品的伏马毒素B3样品的高效液相色谱（HPLC）分析，在每种情况下均显示存在两种立体异构体，这两种异构体无法通过制备色谱法分离。根据核磁共振数据推断出伏马毒素B3和B4的两种次要立体异构体的2,3-反式相对构型，并通过使用伏马毒素B3样品应用莫舍尔方法确定了它们的2S,3R绝对构型。伏马毒素B3和B4样品中3-表异构体系列的伏马毒素B化合物含量可能在10%至40%之间。通过对邻苯二甲醛衍生物进行荧光检测的HPLC测定并经液相色谱-串联质谱确证的3-表-伏马毒素B3，发现在一系列玉米样品中天然存在，其含量远低于伏马毒素B3（<20%）。3-表伏马毒素B系列成员的鉴定为伏马毒素生物合成步骤的顺序和选择性提供了见解。
