The Molecular Pharmacology of Genistein in Soy (Glycine max) and Its Relevance to Herbal Clinical Practice - A Selective Literature Review

By Elaine Aldred

Abstract

Pharmacology is now compulsory in any herb course accredited by the European Herbal and Traditional Practitioners Association (EHTPA). However, the principles of pharmacology often seem far removed from the everyday clinical situation. So ways have to be found to weave the seemingly disparate strands of both plant and orthodox medical pharmacology into the practical experiences of both students and practitioners. If this can be done then the results of experimental papers are a valuable resource for information relating to patient management.

The purpose of this research has been to examine experimental research papers to determine how it is possible to translate this complex knowledge into information herbal practitioners can incorporate into everyday clinical practice. In order to do this, genistein, a phytochemical found in soy (Glycine max.) is examined in detail as it is a commonly consumed food stuff that may have beneficial effects on inflammatory process associated with atherosclerosis. The phytochemical’s path from the growing plant to the physiologically active vascular endothelial cell was traced, examining all the relevant pharmacodynamics and pharmacokinetics encountered along the way.

The findings demonstrated that genistein’s actions occur largely through estrogen receptors (ER) as the concentration that could be achieved at the cellular level was easily sufficient to have an effect on ER. Other laboratory findings involving other receptors and pathways were found to be invalid clinically as the concentrations required for genistein’s intervention were not adequate. Ers, however, exert a considerable effect on these pathways enabling genistein to indirectly influence many cell mechanisms.

The findings also demonstrate that in vitro experiments are very different situations to that of in vivo, where a phytochemical must undergo complex processes before achieving its cellular targets. Hence the frequent inconsistencies between in vitro and in vivo studies particularly in the case of clinical trials. This understanding of molecular chemistry of a phytochemical should, therefore, empower a practitioner to utilise experimental and clinical data to make educated clinical management decisions. This type of secondary research is therefore relevant to clinical practice, but does possess limitations as only one active phytochemical was considered in isolation, when in fact the chemical composition of soy is more complicated. Nevertheless, this research is important as a template to show practitioners how to approach new knowledge, and in particular how to integrate the new knowledge into their practice.