Quality Assessment of Herbal Drugs and Medicinal Plant Products

Abstract

Abstract The herbal drugs and medicinal plant products have been widely used for thousands of years in many parts of the world. Medicinal plants constitute a source of raw material for both traditional and modern systems of medicine. In recent few decades, growth and popularity of herbal medicine and plant products have taken a significant share of the healthcare. Various systems of traditional medicines have been recognized in many countries such as India, Japan, Korea, China, USA, and some European countries. Each country has its own set of guidelines to assess the quality control of the herbal medicine depending on the system they adapt to prepare herbal medicine. The importance of quality control and standardization of botanical products is of utmost concern for global acceptability of these drugs in the modern system of medicine. These assessments are needed at different levels of drug‐manufacturing processes and post‐manufacturing stages. As herbal medicinal products are complex mixtures that originate from biological sources, great efforts are necessary to guarantee a constant and adequate quality. The morphological and microscopic identifications are utilized to determine the authenticity of herbal medicines, and the physical and chemical characters are used to evaluate the quality of herbs in the existing quality standards. The fingerprint analyses have been internationally accepted as one of the efficient methods to control the quality of herbal medicines. In addition to fingerprinting, other parameters such as microbiological and chemical contaminations, adulterants, and toxicity including genotoxicity are to be assessed. In this chapter, the current scenario of the quality control assessment of herbal medicine and medicinal plant products is reviewed. Botanical parameters such as sensory or organoleptic evaluation, histological observations and measurements are discussed. An overview covering various techniques employed in quantitative characterization of herbal medicines such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC), gas chromatography (GC), mass spectrometry (MS), and infrared (IR) spectroscopy is reported. Potential of metabolomics in the developments of improved phytotherapeutic agents, and DNA‐based molecular markers in adulterants, is described. Pharmacological and toxicological parameters such as pesticide residue, heavy metals, aflatoxins, and microbial and radioactive contaminations are also addressed.