A molecular biological basis for the nutritional and pharmacological benefits of dietary plants.

Individuals who regularly eat fruit and vegetables gain protection against a number of diseases. These advantages are usually ascribed to the rich vitamin, antioxidant and dietary fibre content of fruit and vegetables. However, clinical trials testing whether these nutrients are protective against specific diseases have been less consistent. The secondary metabolites of plant metabolism, particularly those from the terpenoid and phenolic families, could provide some of this health protection, through regulatory effects on the functional domains of ancient conserved proteins and DNA regions common to both plants and mammals. Small-molecular-mass molecules can regulate gene expression in a variety of ways, e.g. targeting DNA sequences, inducing gene expression and binding to protein-regulating sites. Secondary plant metabolites may also modulate the function of transmembrane channel receptors and enzymes.