Exploring the bioactive compounds from berry biowaste: Eugenia involucrata DC. as a study case

Aiming at valorising the Eugenia involucrata residue, the present work aimed in investigating the chemical profile and in vitro bioactivities of the residue (EIR) and its individual parts, i.e., seeds (EIS) and peels (EIP). Chromatographic analyses showed that EIP had the highest content of organic acids, tocopherols, and anthocyanins, whereas EIS was the richest in hydrolysable tannins. bis-HHDP-glucoside isomers and cyanidin-3-O-galactoside were the main detected phenolic compounds. By the cellular antioxidant activity (CAA) assay, the samples showed similar. antioxidant potential with 71%, 77%, and 80% inhibition for EIP, EIR, and EIS, respectively, while EIS demonstrated the best antioxidant activity by thiobarbituric acid reactive substances (TBARS, IC50 = 4.96 μg/mL) and oxidative inhibition assay (OxHLIA, IC50 = 40 μg/mL). The samples were able to inhibit the growth of seven bacteria and two fungi. Between the microorganisms tested, all samples showed a strong antibacterial activity (MIC = 0.156 mg/mL) against Yersinia enterocolitica and Pseudomonas aeruginosa (MIC = 0.156–0.625 mg/mL). Moreover, they also display a high antifungal activity against Arpergillus brasiliensis (MIC = 0.625 mg/mL). Furthermore, only EIR and EIS had anti-inflammatory effect via NO production inhibition (IC50 = 168–259 μg/mL, respectively) and anti-proliferative activity towards four tumour and one non-tumour cell lines. These findings suggest that the biowaste generated during the processing of E. involucrata fruit has potential as a source of bioactive compounds.