Institute of Molecular Biology and Pathology-CNR P.le Aldo Moro 5, 00185 Rome, Italy.
Department of Chemistry, Sapienza University, P.le A Moro 5, I-00185 Rome, Italy.
Molecules. 2019 Jul 13;24(14):2553. doi: 10.3390/molecules24142553.
Ochratoxin A (OTA) is a mycotoxin with a serious impact on human health. In Mediterranean countries, the black Aspergilli group, in particular , causes the highest OTA contamination. Here we describe the synthesis of three polyphenolic flavonoids: 5-hydroxy-6,7-dimethoxy-flavone (MOS), 5,6-dihydroxy-7-methoxy-flavone (NEG), and 5,6 dihydroxy-flavone (DHF), as well as their effect on the prevention of OTA biosynthesis and lipoxygenase (LOX) activity in cultured in a conducive liquid medium. The best control effect on OTA biosynthesis was achieved using NEG and DHF. In fungal cultures treated with these compounds at 5, 25, and 50 μg/mL, OTA biosynthesis significantly decreased throughout the 8-day experiment. NEG and DHF appear to have an inhibiting effect also on the activity of LOX, whereas MOS, which did not significantly inhibit OTA production, had no effect on LOX activity. The presence of free hydroxyls in catecholic position in the molecule appears to be a determining factor for significantly inhibiting OTA biosynthesis. However, the presence of a methoxy group in C-7 in NEG could slightly lower the molecule's reactivity increasing OTA inhibition by this molecule at 5 μg/mL. Polyphenolic flavonoids present in edible plants may be easily synthesized and used to control OTA biosynthesis.
赭曲霉毒素 A（OTA）是一种对人类健康有严重影响的真菌毒素。在地中海国家，黑曲霉属（ Aspergillus ）尤其会导致最高水平的 OTA 污染。在这里，我们描述了三种多酚类黄酮的合成：5-羟基-6,7-二甲氧基黄酮（MOS）、5,6-二羟基-7-甲氧基黄酮（NEG）和 5,6-二羟基黄酮（DHF），以及它们对在有利液体培养基中培养的 OTA 生物合成和脂氧合酶（LOX）活性的抑制作用。在浓度为 5、25 和 50 μg/mL 的处理组中，NEG 和 DHF 对 OTA 生物合成的抑制作用最佳。在真菌培养物中，这两种化合物在整个 8 天的实验中均显著降低了 OTA 的生物合成。NEG 和 DHF 似乎对 LOX 的活性也有抑制作用，而 MOS 虽然没有显著抑制 OTA 的产生，但对 LOX 的活性没有影响。在分子的邻苯二酚位置存在游离的羟基似乎是显著抑制 OTA 生物合成的决定因素。然而，NEG 中 C-7 位上的甲氧基的存在可能会略微降低分子的反应性，从而使该分子在 5 μg/mL 时对 OTA 的抑制作用增强。存在于食用植物中的多酚类黄酮可能很容易被合成并用于控制 OTA 的生物合成。
