Anti-bacterial and anti-inflammatory activities of lactic acid bacteria-bioconversioned indica rice (Oryza sativa L.) extract

Abstract

Abstract Background In this study, indica rice (Oryza sativa L.) was bioconversioned using Lactobacillus plantarum ATCC14917 and Lactobacillus rhamnosus GG KCTC5033. Results Compared to the control treatment (RE), rice extract fermented with Lactobacillus plantarum ATCC14917 (LP-RE) and Lactobacillus rhamnosus GG KCTC5033 (LR-RE) inhibited the growth of pathogenic bacteria significantly except for E. coli O157:H7 (p < 0.05). The LR-RE treatment had the strongest inhibitory effect on Staphylococcus aureus biofilm formation (10.81 ± 1.98%). Additionally, real-time PCR analyses confirmed that LP-RE inhibited S. aureus-induced IL-8 expression in Caco-2 cells by 60%. HPLC-orbitrap analysis indicated that this treatment increased the levels of key metabolites with therapeutic properties such as acetophenone, 9-oxo-10(E), 12(E)-octadecadienoic acid, nicotinic acid, and indol-3-lactic acid. Conclusions This study demonstrated that the secondary metabolites were linked to antibacterial and anti-inflammatory effects, suggesting that bioconversion is a promising means to produce dietary supplements with therapeutic properties. Graphical Abstract

Keywords

• Indica rice
• Bioconversion
• Lactic acid bacteria
• Anti-bacterial
• Anti-inflammatory
• Secondary metabolite