Isolated Compounds and Semi-Synthetic Derivatives from Miconia ferruginata as Inhibitors of Cathepsins K and B and their Cytotoxic Evaluation

Miconia genus, belonging to Melastomataceae family, is widely distributed in tropical America. Isolated compounds and semi-synthetic derivatives from Miconia ferruginata leaves were evaluated both for their cytotoxicity on tumor cell lines and against important proteolytic enzymes such as cathepsins B and K. Among the evaluated compounds, the mixture of methyl ursolate ( 2a ) and oleanate ( 3a ) showed considerable cytotoxicity against melanoma (MDA-MB435) and colon cancer (HCT-8) cell lines. In addition, it was also demonstrated that the mixture of ursolic ( 2 ) and oleanolic ( 3 ) acids inhibited of the cathepsin B, with IC 50 value of 13.02 μM. On the other hand, mixture of compounds 2a and 3a showed considerable activity against cathepsin K, with IC 50 value of 1.42 μM. The compound 5,6,7-trihydroxy 4’-methoxyflavone ( 1) showed no activity.