RESUMEN
Eugenia involucrata DC. (Myrtaceae) is a native tree species from Brazil that has been scarcely studied. We investigated the phenolic composition, the antioxidant capacity and the antitumoral activity of ethanolic extracts from fruits (FE) and seeds (SE) of E. involucrata. Six anthocyanins were identified by UPLC-PDA/MS/MS in FE, being four derived from cyanidin, and the other ones derived from delphinidin and pelargonidin. Using HPLC-PDA, FE presented a larger number of phenolic compounds (epicatechin, catechin, rutin, ellagic acid, myricetin and quercetin) than SE, which did not show myricetin and quercetin. However, SE showed higher total phenolic content and generally stronger in vitro antioxidant capacity than FE, except that only FE exhibited superoxide radical scavenging activity, which may be attributed to the anthocyanins present in fruits. Additionally, only SE exhibited antitumoral activity in a pancreatic cancer cell line (PANC-1). The antitumoral mechanisms involved imbalance of antioxidant status, alteration of mitochondrial membrane potential, cytoskeleton disassembly and induction of cell death by apoptosis and necrosis. Compared to the standard antitumoral drug gemcitabine, SE exhibited higher antitumoral efficacy and selectivity index. The highest concentration of total phenolics and of specific phenolic compounds bearing antitumoral properties may be related to the antitumoral activity of SE. Our results corroborate previous data of E. involucrata as an important source of bioactive compounds and provide, for the first time, evidences of in vitro antitumoral potential of its seeds on pancreatic cancer cell line.