Oligosaccharides from Palm Kernel Cake Enhances Adherence Inhibition and Intracellular Clearance of Salmonella enterica Serovar Enteritidis In Vitro

Abstract

Salmonella enterica serovar (ser.) Enteritidis (S. Enteritidis) is a foodborne pathogen often associated with contaminated poultry products. This study evaluated the anti-adherence and intracellular clearance capability of oligosaccharides extracted from palm kernel cake (PKC), a by-product of the palm oil industry, and compared its efficacy with commercial prebioticsfructooligosaccharide (FOS) and mannanoligosaccharide (MOS)-against S. Enteritidis in vitro. Based on the degree of polymerization (DP), PKC oligosaccharides were further divided into 'Small' (DP ≤ 6) and 'Big' (DP > 6) fractions. Results showed that the Small and Big PKC fractions were able to reduce (p < 0.05) S. Enteritidis adherence to Cancer coli-2 (Caco-2) cells at 0.1 mg/ mL while MOS and FOS showed significant reduction at 1.0 mg/mL and 10.0 mg/mL, respectively. In terms of S. Enteritidis clearance, oligosaccharide-treated macrophages showed better S. Enteritidis clearance over time at 50 µg/mL for Small, Big and MOS, while FOS required a concentration of 500 µg/mL for a similar effect. This data highlights that oligosaccharides from PKC, particularly those of lower DP, were more effective than MOS and FOS at reducing S. Enteritidis adherence and enhancing S. Enteritidis clearance in a cell culture model.

Palm Kernel Cake Oligosaccharides Acute Toxicity and Effects on Nitric Oxide Levels Using a Zebrafish Larvae Model

“…For OligoPKC, the fraction at 500 µg/ml and above exhibited both acute toxicity and teratogenicity effects on the zebrafish embryos involved. HPLC analysis from our laboratory and literature reported that mannose makes up a large portion of the oligosaccharides extracted from PKC and it is the low degree of polymerization (DP) molecule portion, such as those found in the OligoPKC used in this study that exerts its bioactive properties (Ibuki et al, 2011;Jahromi et al, 2016;Foo et al, 2020). However the more potent the biological effect, the higher the toxicity.…”

“…The difference in toxicity and teratogenicity observed in OligoPKC when compared to MOS could be due to the oligosaccharide composition as well as structure. In terms of oligosaccharide composition, the saccharides present in the OligoPKC used in this study were up to 6 DP while the DP of the purchased MOS was not specified by the manufacturer (Henanjunda, 2017;Foo et al, 2020). Molecular weight determination of MOS using Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (LC-QTOF/MS) indicates that the saccharides present in MOS may be larger than 10 DP or that these saccharides may exist as oligosaccharide derivatives (Lesage and Bussey, 2006;Foo et al, 2020).…”

“…In terms of oligosaccharide composition, the saccharides present in the OligoPKC used in this study were up to 6 DP while the DP of the purchased MOS was not specified by the manufacturer ( Henanjunda, 2017 ; Foo et al, 2020 ). Molecular weight determination of MOS using Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (LC-QTOF/MS) indicates that the saccharides present in MOS may be larger than 10 DP or that these saccharides may exist as oligosaccharide derivatives ( Lesage and Bussey, 2006 ; Foo et al, 2020 ). In terms of chemical structure, the mannan oligosaccharide extracted from PKC is of the β-configuration while the chemical structure of the MOS extracted from the yeast cell wall is of the α-configuration ( Jones and Ballou, 1969 ; Jahromi et al, 2016 ).…”

“…The preparation of OligoPKC is based on the method reported by Foo et al (2020) and Jahromi et al (2016) . Commercial oligosaccharides MOS (Henan Junda Biological Technology Co., Ltd., China) and FOS (Quantum Hi-Tech (China) Biological Co., Ltd., China) were used as comparison to OligoPKC in this study.…”

“…One of the NDOs used will be oligosaccharides extracted from palm kernel cake (PKC) as these PKC oligosaccharides (OligoPKC), particularly those of the lower degree of polymerization, has been shown to exhibit prebiotic properties ( Rezaei et al, 2015 ; Jahromi et al, 2016 ; Foo et al, 2020 ). In addition to that, Jahromi Faseleh et al (2017) has also reported that oligosaccharides from PKC were able to improve the antioxidant capacity of the liver in rats.…”