Phytochemicals as Sources of Drugs

Medicinal plants are known to contain substances which could be useful for the treatment of diseases or for the production of drugs. These substances occur naturally in plants (leaves, stems, barks, and root) and are referred to as secondary metabolites because they are synthesized to protect the plant other than for growth just like the primary metabolites. Fortunately for humans, most of these secondary metabolites possess medicinal potentials which are active against many diseases. Before the advent of modern analytical techniques for the screening of plant actives, the traditional plants have been used primitively to alleviate symptoms of illnesses such as stomach ache, toothache, body pain and inflammation, diarrhea, malaria, typhoid, diabetes etc. This chapter presents an overview of the usefulness of medicinal plants as sources of drugs, the drug discovery process, the efficacy and safety of phytochemicals, current uses, advances in screening tools, problems and the way forward.