3‐Alkyl‐2‐Methoxypyrazines: Overview of Their Occurrence, Biosynthesis and Distribution in Edible Plants

Abstract

Pyrazines are ubiquitous in nature – biosynthesized by microorganisms, insects, and plants. Due to their great structural diversity, they own manifold biological functions. Alkyl‐ and alkoxypyrazines for instance play a key role as semiochemicals, but also as important aroma compounds in foods. Especially 3‐alkyl‐2‐methoxypyrazines (MPs) have been of great research interest. MPs are associated with green and earthy attributes. They are responsible for the distinctive aroma properties of numerous vegetables. Moreover, they have a strong influence on the aroma of wines, in which they are primarily grape‐derived. Over the years various methods have been developed and implemented to analyse the distribution of MPs in plants. In addition, the biosynthetic pathway of MPs has always been of particular interest. Different pathways and precursors have been proposed and controversially discussed in the literature. While the identification of genes encoding O‐methyltransferases gave important insights into the last step of MP‐biosynthesis, earlier biosynthetic steps and precursors remained unknown. It was not until 2022 that in vivo feeding experiments with stable isotope labeled compounds revealed l‐leucine and l‐serine as important precursors for IBMP. This discovery gave evidence for a metabolic interface between the MP‐biosynthesis and photorespiration.

Interaction and Binding Kinetics of Different Substituted Pyrazines with HSA: Based on Multispectral, Physiological Activity, and Molecular Dynamics Simulations

“…2,3-Dimethylpyrazine (2,3-DMTP), 2,5-dimethylpyrazine (2,5-DMTP), 2,3,5-trimethylpyrazine (TMTP), and 2,3,5,6tetramethylpyrazine (TTMP) are pyrazine compounds with diferent position substituents (Figure 1(b)). Tese pyrazines have a pleasant nutty and barbecue favour that produces a unique aroma [10], which is widely used in the food industry [11][12][13]. At the same time, these pyrazines are also important favour substances in liquor, which can be detected in fermented grains by GC-MS [14,15] (Figure 1(a)).…”