Analysis of Polyphenols, Anthocyanins and Toxic Elements in Açaí Juice (Euterpe oleracea Mart.): Quantification and In Vivo Assessment of the Antioxidant Capacity of Clarified Açaí Juice

This study aims to measure the concentration of total polyphenols, anthocyanins and inorganic contaminants (Al, Pb and Ni) in samples of açaí juice collected in the municipalities of Pará and evaluate the in vivo antioxidant capacity of purified açaí juice. Total polyphenols and anthocyanins were determined by UV/Vis spectrophotometry, while inorganic contaminants were measured using Graphite Furnace Atomization Atomic Absorption Spectrometry (GF-AAS) and Flame Atomic Absorption Spectrometry (F-AAS) after microwave-assisted digestion. The in vivo study lasted five days and involved 16 rats divided into four groups. The antioxidant capacity was evaluated through the formation of peroxyl free radicals (ACAP) in rat liver tissue. The average concentrations (mg GAE/DE) of total phenolic compounds averaged 27.34, with individual values ranging from 13.28 to 56.58. The average concentration (mg ANTO/g) of anthocyanins was 7.6, with individual concentrations ranging from 5.52 to 9.75. Contaminant concentrations (mg/kg) ranged from 1.82 to 11.74 for Al, 0.04 to 0.53 for Pb and 0.18 to 0.78 for Ni. The levels of Pb found in the samples may represent a concern to health. Al and Pb induced oxidative stress in the liver tissue, but Euterpe oleracea clarified juice (EOCJ) led to significant antioxidant protection. Animals treated with the highest dose of EOCJ (2.07g/kg body weight) experienced an approximately five-fold reduction in ACAP compared to the group exposed to the metals (Al and Pb). The findings suggest the need to monitor inorganic contaminants in açaí products as well as the potential benefits of antioxidant compounds against the liver toxicity of Al and Pb.