Chemical and Biocatalytic Synthesis of Capsaicinoids and Capsinoids: An Updated Review

Capsaicinoids have garnered significant attention due to their diverse bioactivities, including anti-inflammatory, antioxidant, and antitumor effects. However, their strong pungency severely limits their applications in food and pharmaceutical industries. In contrast, capsinoids retain similar biological activities without the irritating pungency, demonstrating much broader application potential. Nevertheless, both classes of compounds naturally occur in low concentrations in plants, rendering large-scale applications challenging. Therefore, the development of efficient and sustainable synthetic methods is urgently needed. Recent advances in novel catalytic technologies have opened new avenues for the green and efficient synthesis of capsaicinoids and capsinoids. This review systematically summarizes the current state of research on the synthesis of these compounds, with a focus on the characteristics of different synthetic methods and their impacts on the resulting bioactivities. Future directions for the development of synthetic approaches are also proposed, aiming to provide a theoretical foundation for further research and application expansion, thereby facilitating the maximal exploitation of their potential value.