Glycyrrhetic acid 3-O-mono-β-d-glucuronide (GAMG) is an important derivative of glycyrrhizin (GL) and has attracted considerable attention, especially in the food and pharmaceutical industries, due to its natural high sweetness and strong biological activities. The biotransformation process is becoming an efficient route for GAMG production with the advantages of mild reaction conditions, environmentally friendly process, and high production efficiency. Recent studies showed that several β-glucuronidases (β-GUS) are key GAMG-producing enzymes, displaying a high potential to convert GL directly into the more valuable GAMG and providing new insights into the generation of high-value compounds. This review provides details of the structural properties, health benefits, and potential applications of GAMG. The progress in the development of the biotransformation processes and fermentation strategies to improve the yield of GAMG is also discussed. This work further summarizes recent advances in the enzymatic synthesis of GAMG using β-GUS with emphasis on the physicochemical and biological properties, molecular modifications, and enzymatic strategies to improve β-GUS biocatalytic efficiencies. This information contributes to a better framework to explore production and application of bioactive GAMG.

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Nitrogen-containing heterocycles are especially considered “privileged” structural scaffolds for the development of new drugs. However, traditional methods of organic synthesis are mainly based on thermal cycloaddition reaction; thus, the exploration of new strategies for the rapid assembly of N-heterocycles under mild conditions is highly desirable. Here, we developed a new method that visible light along with 1 mol % cercosporin, which is one of the perylenequinonoid pigments with excellent properties of photosensitization and can be easily produced by a new isolated endophytic fungus Cercospora sp. JNU001 strain with high yield through microbial fermentation, catalyzes the synthesis of 1,2,3-thiadiazoles and 1,4,5,6-tetrahydropyridazines by a photocatalytic process with good regioselectivity and broad functional-group compatibility under mild conditions. Thus, a bridge between microbial fermentation and organic photocatalysis for the construction of nitrogen-containing heterocycles was set up in a sustainable, environmentally friendly manner.

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A cercosporin-catalyzed photo-mediated oxidation for the rapid and efficient synthesis of kynurenine (Kyn) derivatives as well as Kyn-contained peptides under mild conditions was developed, exhibiting great functional group tolerance and...