Efficient enzymatic synthesis of theaflavin and its production mechanism

• Published in: Journal of food science 2024-03, Vol.89 (3), p.1531-1539
• Main Authors: Jian, Jinjin, Gao, Zhijiang, Ding, Yangping
• Format: Article
• Language: English
• Subjects: Cryonics; dark reaction solution; Enzymatic synthesis; Hypotheses; Ice; ice bath; Mathematical analysis; Oxidation; production mechanism; Quantum mechanics; Quinones; Synthesis; theaflavin
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/1750-3841.16947

In this study, a novel preparation method of theaflavin (TF) has been established. Our findings indicated that the formation of TF was significantly enhanced by using an ice bath (2–3°C). Additionally, increasing the ratio of (−)‐epigallocatechin (EGC) under the ice bath could further improve its yield. This approach prevented the appearance of a dark solution within 3 h, effectively protecting TF from oxidation. Our study on the generation mechanism of TF suggested that EGC‐quinone I (EGC‐Q‐I) with two carbanions could potentially serve as one of synthons based on the retrosynthetic analysis of the bicyclo[3.2.1]octane‐type intermediate. Subsequently, quantum mechanical calculations further supported this hypothesis. Practical Application: In this study, we have developed a novel method for the synthesis of theaflavin (TF), demonstrating that the use of ice bath significantly enhanced its yield. Increasing the ratio of (−)‐epigallocatechin (EGC) under the ice bath further improved TF yields and prevented darkening of the solution for at least 3 h, thereby protecting TF from oxidation. Our study suggested that EGC‐quinone I is a potential synthon based on the retrosynthetic analysis of the bicyclo[3.2.1]octane‐type intermediate (BOI). This hypothesis is supported by QM calculations.