An integrated approach to assessing the bio-activity of nutrients in vitro: The anti-oxidant effects of catechin and chlorogenic acid as an example

To explore how screening for potential nutrient bio-activity could be improved by integrating biological and chemical markers of cellular responses, we assessed the effect of the known anti-oxidants, catechin and chlorogenic acid, on anti-oxidant activity in vitro. We determined an active concentration (25 μM) of each compound and then measured its effects on anti-oxidant gene expression and regulation, enzyme activity, and cellular anti-oxidant activity. We found that only catechin retained biological anti-oxidant effects in vitro, although catechin and chlorogenic acid are chemical anti-oxidants. A limited role for microRNA regulation of anti-oxidant was found, however it cannot be excluded as a possible mechanism because other microRNAs and/or epigenetic factors may be involved. Our approach found that screening for bio-activity of nutrients, in this example anti-oxidant activity, is more appropriate using an integrated approach and highlights the importance of using a range of techniques, such as those used in this study, to properly characterise the effects of dietary ingredients.