Influence of catechins and their methylated metabolites on lifespan and resistance to oxidative and thermal stress of Caenorhabditis elegans and epicatechin uptake

Catechins are major polyphenols in many plant foods that have been related to health promotion. In the human organism they are largely metabolized to different conjugates such as methylated derivatives, which may contribute to the effects associated to the intake of the parent compounds. In this study the effects of catechin, epicatechin, 3'-O-methylepicatechin and 4'-O-methylepicatechin have been evaluated using C. elegans as a model organism. It was found that the methylated epicatechin derivatives (200μM) increased the mean lifespan of the nematode by 6-12%, whereas catechin and epicatechin did not have influence on its life duration. All the assayed catechins enhanced the resistance of the worm against thermal and oxidative stress, producing an increase in the survival rates up to 44% in relation to untreated animals. However, no significant effects of these compounds were observed in the reproductive output or size of the worms. The uptake of epicatechin by C. elegans and its complete biotransformation to different metabolites, namely glycoside conjugates, was confirmed by LC-MS analyses. Nevertheless, the extent of epicatechin uptake was very low as suggested by the low levels of metabolites determined.