Isolation, Purification and Identification of Markers from medicinal plants  
     
  The efficacy and safety of any pharmaceutical product is determined by the compounds which it contains. The purpose of quality control is to ensure that each dosage unit of the drug product delivers the same amount of active ingredients and is, as far as possible, free of impurities. As herbal medicinal products are complex mixtures which originate from biological sources, great efforts are necessary to guarantee a constant and adequate quality. Biomarkers should be used at various stages of the development and manufacturing of an herbal medicine, such as authentication and differentiation of species, collecting and harvesting, quality evaluation and stability assessment, diagnosis of intoxication and discovery of lead compounds. Lack of biomarkers remains a major problem for the quality control of herbal medicines.