Secondary metabolites produced by plants are important for their survival and/or development. These metabolites include phenols, alkaloids and flavonoids among others. Their functions are to provide protection to the plant, be it by acting as UV sunscreens for the plants, anti-oxidants or acting as toxins against herbivores feeding on the plants .
These metabolites also benefit humans in a variety of ways. For example, they stimulate mechanisms in the human body that lead to production of anti-oxidative proteins and enzymes. Some have been found (for example,quercetin flavonoid) to help activate pathways that seek out and kill cancer cells . Another example, at a certain dose level of the aliphatic4-methylsulfinylbutyl glucosinolate (a secondary plant metabolite) upregulate some detoxification pathways and inhibit cell proliferation by inducing apoptosis, hence acting as an anti-carcigenic compound .
Recent studies have shown that low levels of UV-B (1 µmolm-2s-1) causes just enough stress in plants to upregulate production of these secondary compound without harming the plant to much . This technique can be used to grow fruits and vegetables in conditions with optimum UV-B levels to produce an adequate level of secondary metabolites that will be safe and beneficial to humans. However, such studies are relatively new and more experiments need to be performed to makes sure these are safe for humans and no harmful side effects are present.
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Mohammad Arshad Imrit