Emerging interest towards the understanding of xenobiotics metabolism by gut microbes

From the last few years, researchers started thinking in this direction also. As all of the xenobiotics, we took daily either directly (pharmaceutical drugs) or indirectly (from our regular diet) first encountered by microbes residing in our gut. In our gut, microbes are present in larger number in comparison to our own cells so it is obvious that they might have key enzymes also for the metabolism of xenobiotics. This early stage metabolism (before reaching into blood circulation) might affect overall metabolism by the host. Researcher in this field Carmody and Turnbaugh described in detail that microbial enzymes are involved in the metabolism of xenobiotics compounds either directly or indirectly (active or deactivate host enzyme via microbial metabolite). You can read this paper from the following link http://www.jci.org/articles/view/72335. They highlighted till now known examples of xenobiotics metabolism by gut microbes and effect of this metabolism on overall efficacy and toxicity of the compounds. In 1998 around two decades ago first time Okuda et al discussed probable mechanism responsible for the deaths of eighteen patients treated with soravudine and oral 5-fluorouracil prodrugs. You can read this paper from the following link http://www.ncbi.nlm.nih.gov/pubmed/9808711. They addressed how the metabolite produced by the gut microbes involved in the inhibition of key enzyme (hepatic dihydropyrimidine dehydrogenase) that are responsible for maintaining the level of 5-FU. This is the only one example which I have mentioned here, there could be several others, we have a very limited information of microbial metabolism of xenobiotics. But, now, because of next generation sequencing  and metagenomics, the understanding towards the microbial world is increasing day by day. Now a days this microbial metabolism part is important to study in order to develop better pharmaceuticals (increased efficacy and/or decrease toxicity). Hopefully, Recently completed project like Human microbiome project (http://hmpdacc.org/) could provide new directions to this field.
Here I am sharing a recently published note on “Why xenobiotics, foreign chemicals to our bodies, are the next frontier in health and disease.”

http://www.theglobeandmail.com/life/health-and-fitness/health-advisor/why-xenobiotics-foreign-chemicals-to-our-bodies-are-the-next-frontier-in-health-and-disease/article24302600/