Heavy Metal Stress in Medicinal Plants: Detoxification Mechanisms, Antioxidants, and Implications for Human Health

The aromatic and medicinal plants that are used for flavoring, cooking, and medicine make up more than 10% of all vascular plants. Approximately 80% of individuals globally rely on herbal remedies for their medical needs. Heavy metals (HMs) toxicity are mostly caused by anthropogenic activities, although they are also released into the atmosphere and accumulate in soil as a result of natural processes. Metal leaching from landfills, industrial effluent, animal and poultry manure, fertilizer, and pesticide industries, and human activities are among them. Volcanic eruptions and metal smelting are the main sources of numerous HMs. As, Cd, Pb, Cr, and Hg are the most dangerous HMs among those that are released into the environment in terms of their potential toxicity and exposure to living things. HMs accumulation in the environment, such as soil and the atmosphere, is primarily caused by anthropogenic sources. HMs are most effectively transported by particulate matter (PM), which also transports them into plant cuticles through foliar absorption via stomata. It is crucial to detoxify HMs from medicinal plants using both enzymatic and non-enzymatic methods. If HM levels in the plants stay above the recommended threshold during detoxification, it will have an adverse effect on human organs and their functions. A suitable system and procedure should be developed to control the entire process, from the manufacturing of HM-free raw materials to the final consumer good.