Medicinal Chemistry: Through a Glass Darkly

The production of transgenic plants, whilst generating less immediate ethical attention, can prove of value to the generation of medicinal products of natural origin, such as scopolamine, through the introduction of the hyoscyamine hydroxylase gene into Atropa belladonna. Some 37 gene transfer trials have been approved worldwide and eighteen of these are designed to produce immediate therapeutic benefits. These include several trials, inserting the gene for adenosine deaminase to alleviate the absence of a natural immune system, and interleukin genes for several cancer types. The potential benefits of alleviating dopamine deficiency in the brains of Parkinson's patients by tissue implantation have been widely discussed from both clinical and ethical perspectives. It is clear that the issues of ethics raised by the rapid approach to the human genome are of increasing importance to definition of any new clinical interface. The concept of specific receptors and sites of drug action has many origins. The definition of receptors as specific sites for drug action owes much to the work of John Newton Langley and Paul Ehrlich. Their work on the autonomic nervous system, toxins, and chemotherapeutic agents led to the concept of a receptor, possessing both recognition and transduction components, and of drugs possessing discrete regions subserving specific functions. The emergence of both old and new diseases focuses continuing efforts on drug discovery and the central role of medicinal chemistry. These foci are switching increasingly from the empirical and intuitive discovery processes to structure- and mechanism-based discovery routes.