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/

Role of Gut Microbiome in the Regulation of Host Metabolism

Microbes are integral part of our routine life as they live in a constant association with the host to regulate the metabolism. Collection of microbes present at the epithelial surface and cavities of our body such as stomach are known as human associated microbiome/microflora. Bacteria are the predominant part of the microflora, however, some amount of virus, fungi and protozoans also present. The most complex community ever studied is the human distal gut microbiome, which contained 1,000 different microbial species across human populations. These microbes contain millions of different genes, largely more than the total number of host genes. Now a days, several research groups are working on how gut dysbiosis is related with the various metabolic disorders such as obesity, diabetes, IBD, cancer etc. This is quite interesting filed to know how microbes are interacting with each other or with the host in order to attain healthy or diseased phenotype. Since, the microflora is very complex and dynamic, and it is known to have a profound influence on the human metabolism. This vast diversity of the human-associated microbes poses a big challenge in the field of medical science. 

Recently, an interesting report published on the following topic "Modern Life Depletes Your Gut Microbes in a Number of Different Ways". 

http://articles.mercola.com/sites/articles/archive/2015/05/06/modern-life-depletes-gut-microbes.aspx