Dietary Phytochemicals and Herbal Medicines Re-Program Cellular Networks by Targeting Key Transcription Factors

Through the intake of dietary phytochemicals and herbal drugs, humans are exposed to a great number of natural products that can be either beneficial or detrimental to health outcomes. Phytochemicals from foods and medicinal plants, often referred to as secondary metabolites to emphasize their difference from metabolites produced by primary metabolism, contribute not just to occasional but long term or life-long exposure. While pharmacological actions of synthetic drugs are closely tied to changes in gene expression, the same holds true for foods and herbal drugs, but the wealth of research data is heterogeneous. This original review article attempts to clarify the exact mechanisms of gene regulation or expression by natural products through direct or indirect effects on transcription factors or epigenetic changes, with a focus on frequently occurring pathways and phytochemical classes. This review points at recent pharmaceutical drug development that arose from the investigation of natural products in food ingredients and herbal medicines and carefully evaluates negative effects on gene expression, which can lead to disease or reduced life expectancy. This article reviews seven relevant natural substance classes according to their approximate frequency in common foods and medicinal plants, and discusses general or more discrete effects on gene expression according to structure-activity relationships (SARs).