Rice Bran Extracts Inhibit Invasion and Intracellular Replication of Salmonella typhimurium in Mouse and Porcine Intestinal Epithelial Cells

Abstract

Dietary rice bran supplementation has been shown to inhibit Salmonella fecal shedding in animals. The aim of this study was to determine if bran extracts from two distinct rice varieties, Lijiangxintuanheigu (LTH) and Sanhuangzhan-2 (SHZ-2), differentially inhibit Salmonella enterica serovar Typhimurium invasion and intracellular replication. Rice bran extracts were tested in vitro using mouse small intestine epithelial (MSIE) and intestinal porcine epithelial cells (IPEC-J2). Fluorescent labeled Salmonella was detected using fluorescence microscopy and culture based methods. Non-targeted metabolomics using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was performed on LTH and SHZ-2 rice bran extracts. LTH bran extract dose-dependently reduced entry and intracellular replication of Salmonella in both MSIE and IPEC-J2 cells when compared with SHZ-2. The rice bran metabolite profiling revealed significant variations between LTH and SHZ-2. LTH had higher total numbers of metabolites (429) versus SHZ-2 (407), with increased relative abundance of lipids (i.e., galactolipids and phospholipids) and flavonoids compared with SHZ-2. SHZ-2 had higher levels of dipeptides and phenylpropanoids. Distinct metabolite differences between LTH and SHZ-2 revealed rice bran components that may be responsible for blocking Salmonella invasion and intracellular replication. Metabolomics is a powerful phenotyping tool for identifying rice bran compounds with protective effects against pathogens. Future studies may identify the rice genes responsible for these bioactive rice bran metabolites distinguishing LTH from SHZ-2, and enable genetic selection for compounds as traits that offer important health and disease fighting benefits.

Differential effects of rice bran cultivars to limit Salmonella Typhimurium in chicken cecal in vitro incubations and impact on the cecal microbiome and metabolome

“…Typhimurium by rice bran was previously investigated across rice varieties in mice [ 9 , 18 ], and these findings are relevant to the present study for chickens as the previous studies compared three different cultivars of rice: Jasmine, Red Wells, and Calrose that were examined as treatment candidates in the current study. The previous studies confirmed variation in secondary metabolite components such as total phenolics, γ-oryzanol, fatty acids and vitamin E isoforms [ 9 , 18 , 19 ]. Jasmine rice has a brown bran layer and has significantly less total phenolic content compared to Red Wells, but is relatively rich compared to other varieties in γ-tocotrienol, a vitamin E isoform with anti-proliferative activity on Caco-2 cells, a human colon cancer cell line [ 19 ].…”

Phytochemical content, antioxidant capacity, and in vitro antibacterial activity of bran extracts of Philippine rice (Oryza sativa) cultivars

“…and Escherichia coli with minimum inhibitory concentrations as high as 0.976 mg/mL for the V. cholerae strain (Kondo et al 2011). In another study by Ghazi et al (2016), Salmonella enterica subsp. serovar Typhimurium is dose-dependently inhibited by red rice bran extracts in the small intestine epithelial (MSIE) and intestinal porcine epithelial cells (IPEC-J2) in mice.…”