|Ghazi, Irfan - Colorado State University|
|Zarei, Iman - Colorado State University|
|Mapesa, Job - Colorado State University|
|Wilburn, Jessie - Colorado State University|
|Leach, Jan - Colorado State University|
|Rao, Sangeeta - Colorado State University|
|Broeckling, Corey - Colorado State University|
|Ryan, Elizabeth - Colorado State University|
Submitted to: Journal of Applied Research on Medicinal and Aromatic Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2016
Publication Date: 10/28/2016
Citation: Ghazi, I.A., Zarei, I., Mapesa, J.O., Wilburn, J.R., Leach, J.E., Rao, S., Broeckling, C., McClung, A.M., Ryan, E.P. 2016. Rice bran extracts inhibit invasion and intracellular replication of Salmonella typhimurium in mouse and porcine intestinal epithelial cells. Journal of Applied Research on Medicinal and Aromatic Plants. doi:10.4172/2167-0412.1000271.
Interpretive Summary: It is estimated that some 21 million Salmonella infections, causing diarrhea, occur globally each year in humans that result in more than 200,000 deaths. Although there are some antibiotics that can be used in treatment, these may be limited in access to people in some parts of the world. Research has shown that consumption of rice bran, the outer layer of the rice grain that is removed during the milling of rice, promotes resistance to Salmonella infection in mice. In addition, bran of different rice varieties has shown differential protection against Salmonella. This study was conducted to compare the effects of rice bran on Salmonella infection using mouse and swine cell assays. Mouse and swine intestinal epithelia cells were cultured and provided with rice bran from two varieties, Lijiangxintuanheigu (LTH) (having red bran) and Sanhuangzhan-2 (SHZ-2) (having brown bran). Salmonella was then introduced to the cells and the degree of cellular infection and Salmonella proliferation was determined. Bran from LTH reduced Salmonella infection and replication. An analysis was performed to determine differences in metabolic compounds found in the two brans that may be related to the differential effect on Salmonella. LTH had higher total numbers of metabolites (429) versus SHZ-2 (407), and increased relative abundance of lipids and flavonoids as compared with SHZ-2. SHZ-2 had higher levels of dipeptide and phenylpropanoids. Future studies will focus on the role these potential bioactive rice bran metabolites may have on pathogen infection and other health related concerns.
Technical 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 serover 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 dipeptide 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.