Berberine pharmacology and the gut microbiota: A hidden therapeutic link.

Berberine is a natural pentacyclic isoquinoline alkaloid that has been isolated as the principal component of many popular medicinal plants such as the genus Berberis, Coptis and Hydrastis. The multifunctional nature of berberine as a therapeutic agent is an attribute of its diverse effects on enzymes, receptors and cell signalling pathways. Through specific and general antioxidant and anti-inflammatory mechanisms, its polypharmacology has been established. Intriguingly, this is despite the poor bioavailability of berberine in animal models and hence begging the question how it induces its reputed effects in vivo. A growing evidence now suggest the role of the gut microbiota, the so-called the hidden organ, as targets for the multifunctional role of berberine. Evidences are herein scrutinised to show that the structural and numerical changes in the gut microbiota under pathological conditions are reversed by berberine. Examples in the pharmacokinetics field, obesity, hyperlipidaemia, diabetes, cancer, inflammatory disease conditions, etc. are used to show the link between the gut microbiota and the polypharmacology of berberine.