Major Capsaicinoids of Capsicum chinense: Botanical Aspects, Chemistry, Biosynthesis, and Insecticidal Potential

Capsicum chinense Jacq. is an economically important chili pepper species characterized by a high capsaicinoid content, which contributes to its growing relevance in the food, pharmaceutical, and agricultural sectors. Although the chemistry and biological properties of capsaicinoids have been extensively investigated, available information remains fragmented, and no review has comprehensively integrated their botanical aspects, chemistry, biosynthesis, and insecticidal potential. This review provides an integrated overview of the major capsaicinoids of C. chinense, particularly capsaicin, dihydrocapsaicin, and nordihydrocapsaicin, focusing on their chemical composition, biosynthetic pathways, structure–activity relationships, and insecticidal properties and mechanisms. Particular emphasis is placed on the relationship between chemical structure and biological activity, as well as on the role of capsaicinoids as natural defense compounds and their insecticidal potential. Current evidence indicates that capsaicinoids exhibit insecticidal, repellent, and antifeedant activities through multiple mechanisms, including membrane disruption, oxidative stress induction, and interference with ion transport and neuronal signaling. Despite these promising findings, further field validation, methodological standardization, and optimized formulations are required. Overall, this review integrates the currently dispersed evidence on C. chinense capsaicinoids and highlights their potential as bioactive compounds for the development of more sustainable botanical insecticides.