Purpose: In this study, we characterized the antimicrobial and antioxidant activities of Peumo and Arrayan leaves and fruits.
Methods: The disk diffusion and a modified micro dilution methods were used to determine the antimicrobial activity, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against different strains of Salmonella, Escherichia coli, Listeria, and Staphylococcus aureus bacteria. The antioxidant activity was characterized by the determination of total polyphenol content (TPC) and the samples antioxidant capacity (AC). Methanol extracts were analyzed at two ripening stages (unripe and ripe), and the antioxidant activity was compared to commercial blueberries.
Results: Overall, fruit extracts were effective in inhibiting both gram positive and gram negative foodborne bacteria. While leave extracts were only efficient in inhibiting one Staphylococcus aureus strain. Arrayan extracts showed a higher antimicrobial activity as compared to Peumo extracts (P < 0.05). Fruit extracts MIC ranged between 143 and 250 mg/ml for Arrayan and Peumo extracts, respectively. While MIC for leaves extracts were 153 and 150 mg/ml for Arrayan and Peumo, respectively. Antioxidant activity for both native species were greater than commercial blueberries (P < 0.05). The TPC and AC were higher for ripe than unripe fruits, with ripe Arrayan fruit having the highest AC (83.6 g AG/100 g and 19.2 µM, TPC and DPPH, respectively).
Significance: Our results suggest a potential application for the use of these traditional berries as natural antimicrobial agents to control foodborne pathogens in foods, while the high antioxidant content adds the value of the use of the fruits as alternative food ingredients.