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

Abstract

Background: In this study, indica rice (Oryza sativa L.) was bioconversioned using Lactobacillus plantarum ATCC14917 and Lactobacillus rhamnosus GC KCTC5033. Results: Compared to the control treatment (RE), rice extract fermented with Lactobacillus plantarum ATCC14917 (LP-RE) and Lactobacillus rhamnosus GC 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. [GRAPHICS] .