PharmacoMicrobiomics or how bugs modulate drugs: an educational initiative to explore the effects of human microbiome on drugs
© Aziz et al; licensee BioMed Central Ltd. 2011
Published: 5 August 2011
Pharmacogenomics investigates how variations within the human genome affect the action and disposition of drugs as well as drug tolerance . Yet, variations within the human genome do not fully account for the tremendous phenotypic variations observed between individuals. Human-associated microbes, which exceed the human cells in number, significantly contribute to the effective human gene pool, and their combined genomes (known as the human microbiome) have not gained attention until recently. The Human Microbiome Project was launched in 2007 to catalogue the tremendous diversity of cultured and uncultured human-associated microbial communities residing in different human tissues, and to study the effect of microbial genes and genomes on human health and disease [2, 3]. However, the effect of these microbes on drugs remains largely unexplored. Since microbes have complex metabolism, including an extraordinary ability to metabolize xenobiotics [4–6], they are expected to play a pivotal role in modulating the action, disposition, and toxicity of drugs with which they interact in different sub-ecosystems within the human body .
Materials and methods
Examples of effects of gut microbes on drugs
Baicalin [Potential antioxidant, anti-inflammatory and liver tonic]
Gut microbes hydrolyze baicalin and enhance its absorption. Absence of gut microbiota resulted in lower levels of baicalin in plasma following oral administration .
Digoxin [Cardiac glycoside]
Eubacterium lentum is responsible for the difference in metabolite concentration of digoxin between North Americans and Southern Indians 
Chlorogenic acid [Antioxidant]
Variation in gut microbiome alters chlorogenic acid metabolism .
Acetaminophen [Analgesic and antipyretic]
Acetaminophen toxicity is associated with elevated levels of p-cresol produced by some bacterial communities .
(+)- catechin and (-)-epichatechins [Anti-oxidants]
In germ-free rats, (+)-catechins and (-)-epicatechins resulted in increase in the levels of liver CYP450 2C11, and (+) catechins caused elevation in the specific activity of liver UGT-Chloramphenicol .
Gut microbiota reduce zonisamide into 2-sulfomoyacetylphenol. Levels of 2-sulfomoyacetylphenol reportedly increased upon re-inoculation of germ-free rats with gut microbiota 
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