Betulinic acid is a natural plant triterpenoid that is structurally related to mammalian bile acids. It is an agonist of the G protein-coupled bile acid receptor TGR5 (EC50 = 1 μM), which might be linked with its ability to alter gene expression and fatty liver development in cells and mice given ethanol. Betulinic acid also reduces NF-κB signaling and expression of microRNA-33 in LPS-treated macrophages, increasing levels of the ATP-binding cassette (ABC) cholesterol transporter ABCA1. It also inhibits replication of HIV-1 (IC50 = 1.4 μM) and has cytotoxic effects against cancer cells.
