Re-examining the role of the gut microbiota in the conversion of the lipid-lowering statin monacolin K (lovastatin) into its active ß-hydroxy acid metabolite.

Monacolin K (MK, lovastatin), a naturally occurring statin, only exerts lipid-lowering effects in its active ß-hydroxy acid form (MKA). This activation was thought to be mediated by the gut microbiota (GM). We report here for the first time that the GM does not convert MK into MKA (a spontaneous pH-dependent conversion) but catabolises MKA. The GM might hamper the lipid-lowering effects by degrading the active metabolite MKA.