Bioactive triterpenoids from the caffeine-rich plants guayusa and maté

Abstract Unlike all other caffeinated plants, guayusa ( Ilex guayusa Loes.) and mate ( Ilex paraguariensis A. St. Hill) contain high amounts of pentacyclic triterpenoid acids and alcohols. A phytochemical investigation on these plants revealed a similar triterpenoid profile and a content of ursolic acid (0.7–1%) and amyrin esters (up to 0.5%), quite unusual for dietary plants. The major constituent of the amyrin complex from both plants is α-amyrin palmitate ( 2a ), accompanied by lower amounts of its corresponding palmitoleate ( 2b ) and by the corresponding constitutional isomers from the β-series ( 3a and 3b , respectively). Ursolic acid ( 1 ) was identified as the responsible for the activity of mate and guayusa extracts in the activation of TGR5, a nuclear receptor of relevance for the prevention and management of diabetes and metabolic syndrome because of its involvement in the regulation of energy expenditure and insulin sensitivity.