Abstract
The mechanical extraction of oils from Brazilian açaí (Euterpe oleracea Mart) produces significant amounts of a byproduct known as "meal", which is frequently discarded in the environment as waste material. Nevertheless, plant byproducts, especially those from oil extraction, may contain residual polyphenols in their composition and be a rich source of natural bioactive compounds. In this study, the phenolic composition and in vitro biological properties of a hydroethanolic açaí meal extract were elucidated. The major compounds tentatively identified in the extract by high-resolution mass spectrometry were anthocyanins, flavones, and flavonoids. Furthermore, rhamnocitrin is reported in an açaí byproduct for the first time. The extract showed reducing power and was effective in scavenging the ABTS radical cation (820.0 µmol Trolox equivalent∙g-1) and peroxyl radical (975.7 µmol Trolox equivalent∙g-1). NF-κB activation was inhibited at 10 or 100 µg∙mL-1 and TNF-α levels were reduced at 100 µg∙mL-1. However, the antibacterial effects against ESKAPE pathogens was not promising due to the high concentration needed (1250 or 2500 µg∙mL-1). These findings can be related to the diverse polyphenol-rich extract composition. To conclude, the polyphenol-rich extract obtained from açaí meal showed relevant biological activities that may have great applicability in the food and nutraceutical industries.