From Traditional Medicine to Modern Oncology: Mechanistic Insights into Plant-Derived Anticancer Agents

Abstract

The plant kingdom has been the single most productive source of clinically useful anticancer drugs, contributing an estimated 50–60% of the modern chemotherapeutic arsenal. What began as ethnomedical practice—the empirical use of medicinal plants across Ayurvedic, Chinese, and other traditional systems—was transformed, through mid-twentieth-century screening programmes, into four cornerstone drug classes: the vinca alkaloids (from Catharanthus roseus), the taxanes (from Taxus spp.), the camptothecin derivatives (from Camptotheca acuminata), and the epipodophyllotoxins (from Podophyllum spp.). This review traces that translational arc and dissects the molecular mechanisms that underpin it. The established agents act through precisely defined targets—vinca alkaloids destabilise and taxanes stabilise microtubules to arrest mitosis, while camptothecins and epipodophyllotoxins inhibit topoisomerases I and II, respectively, to trigger lethal DNA damage. A second, expanding wave of investigational phytochemicals—curcumin, resveratrol, EGCG, genistein, sulforaphane, withaferin A and others—acts pleiotropically across the hallmarks of cancer, inducing apoptosis (frequently p53-dependent), arresting the cell cycle, and simultaneously modulating the PI3K/AKT/mTOR, NF-κB, JAK/STAT3, Wnt/β-catenin and MAPK pathways, suppressing angiogenesis, metastasis and cancer-stem-cell survival.
These compounds show micromolar in-vitro potency (representative IC₅₀ values of ~2–50 µM) and multitarget action with comparatively low toxicity, but their clinical translation is constrained by poor bioavailability and rapid metabolism. Modern strategies—nanoformulation (exemplified by nab-paclitaxel), semisynthesis, network pharmacology and rational combinations—are being deployed to close this gap. The review concludes that plant-derived agents remain central to oncology, and that integrating traditional knowledge with modern mechanistic and delivery science is the most promising route to the next generation of anticancer drugs.