There are more than 1000 species of microbes reside in the human gut, umbering∼1014 microbes. As the invisible organ of human beings, gut microbiota can usually participate in drug metabolism by producing specific enzymes, such as reductase and hydrolytic enzyme, thus affecting the efficacy, toxicity, and bioavailability of drugs. At least 30 commercially available drugs have been shown to be substrates of gut microbes-derived enzymes, and an increasing number of drugs may have the potential to contact with the distal gut with the help of improved release systems or poor solubility/permeability, more drugs are expected to be found to be metabolized through the gut flora. By collecting examples of intestinal flora participating in the metabolism of synthetic drugs and traditional Chinese medicine components, this article provides a comprehensive reference for future researchers to study drug metabolism by intestinal flora. Noticeably, the composition and quantity of intestinal flora varies among individuals, and can be affected by some drug administration (such as antibiotics) or environmental changes (acute plateau hypoxia). This seems to suggest that intestinal flora could have the potential to be a new drug target to affect the efficacy of drugs which can be metabolized by Intestinal flora. Accordingly, understanding the impact of intestinal flora on drug metabolism and clarifying the drug transformation process is of great significance for guiding rational clinical use, individualized use, toxicological evaluation, and promoting drug discovery and development.
Keywords: Gut microbiota; drug metabolism; enzymes; therapeutic effect; toxicity.