The flop side of using heavy metal(oids)s in the traditional medicine: Toxic insults and injury to human health

Abstract

Traditional medicine is the earliest healthcare system of humanity, which relies on the revered traditional legacy of healing powers hidden in the natural objects like medicinal plants, animals, etc. It encompasses the Indian Ayurveda, traditional Chinese medicine, Arabic Unani medicine, and other forms of indigenous medicine. The Ayurveda is the most commonly practised system of traditional medicine in the Indian subcontinent and has been carving niche in the Western countries. It is based on the Vedic hypothesis that there are some common cardinal premises underlying the harmony and homeostasis maintained in the microcosm (individual body) and macrocosm (nature/universe). Both man and the universe are composed of the same basic elements, and disease manifests when the balance is destabilized. Some heavy metal(oid)s are added intentionally in Ayurvedic products as it is thought that the equilibrium of lead, copper, gold, iron, mercury, silver, tin, zinc thallium, and arsenic is essential for normal functioning of the human body. Similarly, traditional Chinese medicine believes that the human body has an organic unity based on the opposing and complementary relationships of yin and yang. Such medicine also contains heavy metals which come from contaminated soil source or are deliberately added as ingredients for specific curative cause. Traditional medicine focuses on causes, not the symptoms, heal the "whole", not the "part" by only correcting the symptoms, like the modern medicine. These low-cost medicines are thought of treating diseases and disorders without posing any risk of side effects. But it is wrong in reality, raising human health concerns and side effects due to their pharmaceutically non-validated nature and indiscriminate and irrational use. The quality, safety, and toxicity of herbal medicines have become a major concern for public health, health authorities, and pharmaceutical industries. Herbal medicines and products may contain highly active pharmacological components or contaminants including several toxic metals and metaloids. The metal(oid) contaminants or additives may be introduced during different phases such as cultivation, harvesting, collecting, cleaning, and drying of the medicinal plants in contaminated environment and/or during the processing and formulation of the herbal products. The objective of the present chapter is to show how through traditional medicine humans may be exposed to a cocktail of heavy metal(oid)s- the nonbiodegradable toxic group of environmental chemicals. Citing selected priority heavy metal(oid)s like lead, cadmium, chromium, arsenic, and mercury, it presents the spectra of vast array of toxic insults and injuries inflicted by them, ranging from cell to system levels, as well as the unique biochemical/molecular fingerprints the toxicants leave on human body.