Phytochemicals and callus suspension culture as cancer therapeutics

Cancer remains a formidable health crisis in the world, driving an urgent need for effective, less toxic, and affordable therapeutic alternatives to conventional treatments. Herbal medicines and phyto-derived natural products represent a promising avenue. The bioactive compounds have varied modes of action, inducing apoptosis, inhibiting angiogenesis, and targeting important signaling pathways such as PI3K-AKT-mTOR and p53, with low toxicity to normal cells. Callus suspension culture is emerging as an innovative and superior alternative for producing these therapeutic compounds, providing a consistent, scalable, pathogen-free, and new metabolites that are not produced in the native plant. This review summarizes the anticancer properties and mechanisms of action of the bioactive compounds from the selected medicinal plants and discusses the concept of callus suspension culture-derived metabolites as highly efficacious anticancer agents. In vitro studies found that compounds from callus are more effective than those from whole-plant extracts and chemotherapeutics. They induce apoptosis by upregulating p53, altering the Bcl-2/Bax ratio, activating caspases, and arresting cancer cells in G2/M. Even though the suspension culture of callus is a promising technology, there are challenges such as bioavailability, lack of preclinical/clinical data, quality control issues for large-scale production and regulatory challenges.