Betalain-containing foods and their antitumoral potential: A comprehensive review of in vitro and in vivo evidence

Background The plant pigments betalains have emerged as a family of compounds with nutraceutical potential due to the growing scientific evidence demonstrating their antitumoral capacity. Scope and approach The present work aims to analyze decades of studies in this field, summarizing and critically reviewing these investigations, and examining their limitations and areas for improvement. Key findings and conclusions After compiling the information, beetroot ( Beta vulgaris ) was highlighted as the most widely used source of betalains , followed by prickly pear ( Opuntia ficus-indica ). The most studied tumors were those of the colon and breast, investigated using both in vitro (cell lines) and in vivo (rodents) models. Pure betanin was used in vitro at concentrations ranging from 1 to 80 μM in the studies, and the overall results showed a reduction in malignant cells of up to 65 %. Betalains can modulate apoptosis by activating caspases , enhancing their antitumoral potential. However, the excessive use of extracts with a low degree of reported purity makes it difficult to identify the effects attributed to specific betalains. Future studies should prioritize the use of pure, structurally characterized betalains to identify their individual contributions to anticancer effects. Nevertheless, the numerous pieces of current evidence of the antitumoral potential of betalains collected in this work support the possible application of these compounds for the prevention and/or treatment of cancer.