Antioxidant, antibacterial, and anti-inflammatory activity of lactic acid bacteria-bioconversioned highbush blueberry (Vaccinium corymbosum L.) extract

This study investigated the antioxidant, antibacterial, and anti-inflammatory activity of highbush blueberry (Vaccinium corymbosum L.) extract fermented using three lactic acid bacteria (LAB). Lactic acid was the major organic acid in the extract. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and total phenolic content of the non-bioconversion blueberry extract (BE) (control) were 225.03 μg Trolox Equivalent Antioxidant Capacity (TEAC)/ml and 369.98 μg gallic acid equivalent/ml, respectively, and increased up to 25.56% and 18.80% compared to control after bioconversion. Antibacterial activity was confirmed based on the inhibition of biofilm formation and growth of three pathogenic bacteria (Salmonella typhimurium, Escherichia coli, and Staphylococcus aureus). To verify anti-inflammatory activity, the mRNA expression levels of pro-inflammatory chemokines and cytokines in lipopolysaccharide-induced RAW 264.7 cells were analysed via real-time polymerase chain reaction analysis. In total, 22 volatile compounds, including 2 acids, 8 alcohols, 6 aldehydes, 2 ketones, and 4 terpenes, were detected. This study provides valuable information on the applicability of LAB-bioconversion in enhancing the antioxidant, antibacterial, and anti-inflammatory activities and volatile compound content of highbush BE.