Climate Change and Environmental Stress-Driven Phytochemical Modulation in Medicinal Plants: Implications for Human Health and Disease Management

Abstract

Medicinal plants are an essential source of bioactive compounds for traditional and modern healthcare. However, climate change and environmental degradation increasingly influence plant physiology, secondary metabolism, and phytochemical composition, affecting the quality, safety, and therapeutic efficacy of herbal medicines. This review synthesizes current evidence on the effects of climatic factors, including elevated temperature, increased atmospheric CO₂, drought, salinity, altered precipitation, and ultraviolet radiation, together with environmental pollutants such as heavy metals and pesticide residues, on the biosynthesis of pharmacologically important secondary metabolites. Environmental stress modifies carbon allocation, redox homeostasis, oxidative signaling, and metabolic pathways, thereby regulating the accumulation of phenolics, flavonoids, alkaloids, terpenoids, and other specialized metabolites. While moderate stress can enhance the production of valuable phytochemicals, prolonged or severe stress often reduces medicinal quality, destabilizes metabolite profiles, promotes contaminant accumulation, and increases toxicological risks. These phytochemical alterations may influence the effectiveness of plant-derived therapies for cancer, diabetes mellitus, cardiovascular, neurodegenerative, inflammatory, and infectious diseases. The review emphasizes integrating plant stress biology, metabolomics, phytochemistry, pharmacology, toxicology, and quality-control strategies to develop climate-resilient cultivation systems and standardized production frameworks. Such interdisciplinary approaches are essential to ensure the safety, efficacy, sustainability, and global accessibility of medicinal plant-based therapeutics under rapidly changing environmental conditions.