The biosynthetic pathways of phytochemicals in Catharanthus involve complex, multistep processes responsible for producing diverse bioactive compounds, including TIAs, flavonoids, and phenolic acids. These pathways integrate primary and secondary metabolism, with key enzymes orchestrating the synthesis of compounds like vinblastine and vincristine. Evolutionary adaptations have shaped these pathways, enabling tissue-specific expression and metabolite diversity. Functional studies reveal their roles in plant defense, development, and ecological interactions. Understanding the evolution and regulation of these pathways provides insights into plant metabolic networks and supports metabolic engineering strategies for enhanced phytochemical production in medicinal and biotechnological applications.