Compounds extracted from plants exposed to stressful conditions could be used to create a powerful new generation of functional foods, according to scientists.
A research team from the US Department of Agriculture said that these substances — known as phytoalexins — were naturally induced in plants as a defence mechanism against stress or fungal attack. They could also be prompted to appear using elicitor treatment and other stress inducing techniques.
In a paper published in the Journal of Agricultural and Food Chemistry, the scientists said that although phytoalexins had been investigated for their possible role in plant defence, until recently they had gone unexplored as nutritional components in human foods.
"These under-utilised plant compounds may possess key beneficial properties including antioxidant activity, anti-inflammation activity, cholesterol-lowering ability, and even anticancer activity," they said.
Modern farming techniques may have contributed in reducing the presence of phytoalexins in plants, the team suggested.
"Organically grown foods have been reported to contain higher levels of health promoting compounds due to exposure to 'naturally' occurring challenges from plant pests that induce defensive compounds (phytoalexins) that may have additional health benefits.
"It is tempting to speculate that in modern agriculture we are limiting at least to some extent the production of health-promoting compounds in our diets that may be present at higher levels in organically grown foods or have been at higher levels in foods grown before the advent of modern agricultural pest control."
Most functional foods relied on constitutive plant compounds to provide health-promoting benefits, they said, and specially-produced phytoalexins could potentially be used in this way.
"We propose a new area within functional food research called phytoalexin-enriched foods that utilise induced plant compounds or phytoalexins created either pre- or postharvest that have been traditionally viewed only as plant defensive compounds, but have beneficial health effects.
"Research from our laboratory and others has shown that many plants can produce higher levels of beneficial compounds under conditions of stress or elicitor treatment. By employing the plant's own enzyme factory, many of these compounds can be produced at increased levels and readily incorporated into food products."
Reference: Journal of Agricultural and Food Chemistry; "Phytoalexin-Enriched Functional Foods". Authors: S.M. Boue, T.E. Cleveland, C. Carter-Wientjes, B.Y. Shih, D. Bhatnagar, J.M. McLachlan, M.E. Burow
Access the paper in full at: http://pubs.acs.org/doi/abs/10.1021/jf8040403