Dipartimento di Biochimica, Biofisica e Patologia Generale, Università degli Studi della Campania "Luigi Vanvitelli", Via L. De Crecchio 7, 80138 Napoli, Italy.
Dipartimento di Biochimica, Biofisica e Patologia Generale, Università degli Studi della Campania "Luigi Vanvitelli", Via L. De Crecchio 7, 80138 Napoli, Italy.
Food Chem. 2018 Sep 15;260:193-199. doi: 10.1016/j.foodchem.2018.03.114. Epub 2018 Apr 5.
Quaternary ammonium compounds containing N-trimethylamino moiety, such as choline derivatives and carnitine, abundant in meat and dairy products, are metabolic precursors of trimethylamine (TMA). A similar fate is reported for N-trimethyllysine and γ-butyrobetaine. With the aim at investigating the metabolic profile of such metabolites in most employed animal dietary sources, HPLC-ESI-MS/MS analyses on ruminant and non-ruminant milk and meat were performed. Results demonstrate, for the first time, the presence of δ-valerobetaine, occurring at levels higher than γ-butyrobetaine in all ruminant samples compared to non-ruminants. Demonstration of δ-valerobetaine metabolic origin, surprisingly, showed that it originates from rumen through the transformation of dietary N-trimethyllysine. These results highlight our previous findings showing the ubiquity of free N-trimethyllysine in vegetable kingdom. Furthermore, δ-valerobetaine, similarly to γ-butyrobetaine, can be degraded by host gut microbiota producing TMA, precursor of the proatherogenic trimethylamine N-oxide (TMAO), unveiling its possible role in the biosynthetic route of TMAO.
季铵化合物含有 N-三甲基氨基部分，如胆碱衍生物和肉碱，在肉类和奶制品中含量丰富，是三甲胺（TMA）的代谢前体。N-三甲基赖氨酸和γ-丁基甜菜碱也有类似的命运。为了研究这些代谢物在大多数动物饲料来源中的代谢特征，对反刍动物和非反刍动物的牛奶和肉类进行了 HPLC-ESI-MS/MS 分析。结果首次证明了δ-缬草酸的存在，与非反刍动物相比，所有反刍动物样本中的δ-缬草酸水平均高于γ-丁基甜菜碱。令人惊讶的是，δ-缬草酸代谢来源的证明表明，它是通过饮食中 N-三甲基赖氨酸的转化从瘤胃中产生的。这些结果突出了我们之前的发现，即游离 N-三甲基赖氨酸在植物界中普遍存在。此外，δ-缬草酸与γ-丁基甜菜碱类似，可以被宿主肠道微生物群降解，产生 TMA，TMA 的前体是动脉粥样硬化前体三甲胺 N-氧化物（TMAO），揭示了其在 TMAO 生物合成途径中的可能作用。
