Abstract
Plants are a source of many drugs such as antispasmodics, emetics, antimicrobials, antipyretics, antidiarrheals, antioxidants, and antitumor agents. A large number of the plants are claimed to possess valuable properties in traditional medicine and are also used extensively by tribal people worldwide. Research has emphasized the evaluation and characterization of various plants and plant constituents against a number of diseases. Detection, estimation and extraction of the bioactive plant constituents have always been a challenging task. This review will provide an overview of the simple and reliable methods of qualitative and quantitative determination of the most common classes of medicinal compounds. It gives a valuable guide to biologically active constituents and methods to investigate the importance of a plant as a source of biologically active compounds.