UV-B-Induced Secondary Plant Metabolites - Potential Benefits for Plant and Human Health

Epidemiological studies have revealed an inverse association between the consumption of fruit, vegetables, and herbs and the risk of both cancer and cardiovascular disease. This protective effect is mostly due to secondary metabolites present in plant tissues. During the last decade, it has become increasingly clear that UV-B radiation is an important regulator of plant secondary metabolism. Low, ecologically-relevant UV-B levels trigger distinct changes in the accumulation of, among others, phenolic compounds, carotenoids and glucosinolates. Fundamental understanding of plant UV-B perception and responses opens up new opportunities for crop manipulation. Thus, targeted low dosage UV-B radiation treatments as emerging technology may be used to generate fruit, vegetables, and herbs enriched with secondary plant metabolites for either fresh consumption or as a source for functional foods and nutraceuticals, resulting in increased ingestion of these health-promoting substances. The UV-B induced accumulation of secondary plant metabolites is likely to have evolved as a plant defense response against harmful UV-B radiation. However, UV-B induced secondary metabolites also alter other trophic interactions, for example by altering plant herbivore resistance. Thus, UV-B driven metabolic changes in the plant's secondary metabolism have benefits for both ends of the bio-based food chain, i.e., for plants themselves as well as for humans.