Kinetic Profile of Urine Metabolites after Acute Intake of a Phenolic Compounds-Rich Juice of Juçara (Euterpe edulis Mart.) and Antioxidant Capacity in Serum and Erythrocytes: A Human Study

Abstract

The juçara palm tree produces a small spherical and black-purple fruit similar to açaí. It is rich in phenolic compounds, especially anthocyanins. A clinical trial evaluated the absorption and excretion of the main bioactive compounds in urine and the antioxidant capacity in serum and erythrocytes of 10 healthy subjects after juçara juice intake. Blood samples were collected before (0.0 h) and 0.5 h, 1 h, 2 h, and 4 h after a single dose (400 mL) of juçara juice, while urine was collected at baseline and 0-3 and 3-6 h after juice intake. Seven phenolic acids and conjugated phenolic acids were identified in urine deriving from the degradation of anthocyanins: protocatechuic acid, vanillic acid, vanillic acid glucuronide, hippuric acid, hydroxybenzoic acid, hydroxyphenylacetic acid, and ferulic acid derivative. In addition, kaempferol glucuronide was also found in urine as a metabolite of the parent compound in juçara juice. Juçara juice caused a decrease in the total oxidant status of serum after 0.5 h in comparison to baseline values (p < 0.05) and increased the phenolic acid metabolites excretion. This study shows the relationship between the production of metabolites of juçara juice and the total antioxidant status in human serum, indicating evidence of its antioxidant capacity.

Keywords: Euterpe edulis; anthocyanins; antioxidant activity; phenolic compounds; urine metabolites.

Figure 1

Concentration of phenolic compounds quantified in the urine of ten subjects after consumption of the juçara juice: hydroxybenzoic acid (A), protocatechuic acid (B), hippuric acid (C), vanillic acid glucuronide (D), vanillic acid (E), hydroxyphenylacetic acid (F), and kaempferol glucuronide (G). No significant differences were detected between the tests carried out 0–3 h and 3–6 h after the intake. Data expressed as the means and standard error of the mean (SEM). Note: * p-values < 0.05 compared to the baseline (n = 8–10); one-way ANOVA and Tukey’s post hoc test.

Figure 2

Relative changes in the serum and erythrocyte antioxidant parameters catalase (CAT) (A), superoxide dismutase (SOD) (B), glutathione peroxidase (GPx) (C), uric acid (D), total antioxidant status (TAS) (E), total oxidant status (TOS) (F) after the juçara juice consumption. Data are expressed as the means and SEM. Note: * p-values < 0.05 compared to the baseline (n = 8–10); one-way ANOVA and Tukey’s test.