A complex and diverse microbial ecosystem associated with the several parts of human body plays an important role in the maintenance of human health. The large number (~trillion) of microbes resides within the gastrointestinal tract and they are significantly related with various metabolic disorders. It has been reported that the gut microbial community consists of ~1000 microbial species, from the bacterial and archaeal domains. Genomes of gut microbiota collectively encode for millions of genes that is more than 100 times of genes found in the human genome and hence, adding up to the increased metabolic variability of the human body. The unique protein-coding genes from the gut microbes can participate in the various metabolic functions. Several studies had proved that these symbiotic metabolic functions are crucial in deciding upon the actual metabolism of xenobiotics including drugs. This is the very important aspect in the field of pharmaceuticals as most of the drugs, administered via oral route are first encountered by gut microbes. These gut microbes can alter the overall activity and toxicity of a drug molecule via metabolizing it in the gastrointestinal tract. For example, A recent study revealed that the activity of a cardiovascular drug is dependent on the gut microbial composition of the individual. Until today, the complete understanding of the gut microbial metabolic potential towards the xeno-metabolism is very limited and seek for the advancement.
