Secondary metabolites of Cactaceae: current knowledge and perspectives

Secondary metabolites are crucial products from biosynthetic pathways in plants. The Cactaceae family, characterized by adaptations to arid environments, produces a diverse array of secondary metabolites, including phenolic compounds, flavonoids, and betalains, which are important for biotechnological applications. In this study, we conducted a systematic literature review to summarize advances in research on cactus secondary metabolites, highlighting their roles in plant defense, emphasizing their potential applications in pharmaceuticals, functional foods, and biotechnology, as well as their relevance for understanding ecological and evolutionary processes. After applying filters, we reviewed 63 papers, recording details on the identified metabolites, extraction methods, and the characteristics of the analyzed samples (taxon, tissue type, and growth condition). Overall, the genera Opuntia Mill. and Selenicereus (A. Berger) Britton & Rose are the most extensively studied due to their bioactive compounds with medicinal use, including antioxidant and antibacterial activities. Most studies have focused on cultivated species, leaving a significant gap in our understanding of the ecological and evolutionary roles of cactus secondary metabolites in wild populations. This review also discusses common techniques used in metabolomic studies, such as chromatography and spectroscopy, emphasizing the need for more integrative approaches combining metabolomics with genomics and transcriptomics. Future research should explore wild cactus species and overlooked tissues to deepen our understanding of their metabolic responses to environmental stress, offering new insights into plant adaptation and potential biotechnological innovations.