Phytochemistry, Pharmacology and Toxicity of Medicinal Plants

Plants have been used for medicinal purposes from ancient times. The use of herbs is reported in ancient manuscripts of Egyptian papyrus, Unani, and Chinese writings. Some accounts are still commonly used by conventional systems of medicine. The population rise, insufficient medication, prohibitive treatment costs, side effects of many prescribed drugs, and the emergence of resistance to commonly used drugs. This resistance to drugs for infectious diseases has resulted in increased focus on the use of plant-based products as a source of medicinal products for a broad range of human diseases. Medicinal plants are good source of bioactive compounds or phytochemicals, which have been used to cure wide range of diseases such as diabetes, coronary heart disease, and cancer. The main groups of disease-preventing phytochemicals include dietary fiber, antioxidants, anticancer agents, detoxifiers, immune-potentiating agents, and neuropharmacological agents. Herbal remedies can function either as agonists or as antagonists that potentiate other drug therapies. Though globally, there is a common perception among consumers that herbal products are often safe because they are “natural,” but several studies report adverse effects on human beings. Therefore, it is prerequisite to study the photochemistry, pharmacology, and toxicity of herbal medicine to reflect their conventional usage in order to allow reasoned consideration to protect them for beneficial usage and conservation.