Hui Wang , Fangzhou Lu , Xin Feng , Yuchen Zhang , Wenxuan Di , Ming Chen , Ruiyun Wu , Man Rao , Pengbin Yin , Yanling Hao , Zhengyuan Zhai
{"title":"Characterization of a novel antioxidant exopolysaccharide from an intestinal-originated bacteria Bifidobacterium pseudocatenulatum Bi-OTA128","authors":"Hui Wang , Fangzhou Lu , Xin Feng , Yuchen Zhang , Wenxuan Di , Ming Chen , Ruiyun Wu , Man Rao , Pengbin Yin , Yanling Hao , Zhengyuan Zhai","doi":"10.1016/j.micres.2024.127914","DOIUrl":null,"url":null,"abstract":"<div><div>Microbial exopolysaccharides (EPSs) have attracted extensive attention for their biological functions in antioxidant activities. In this study, we characterized a novel EPS produced by <em>Bifidobacterium pseudocatenulatum</em> Bi-OTA128 which exhibited the highest antioxidant capacity compared to nine other ropy bacterial strains, achieving 76.50 % and 93.84 % in DPPH· and ABTS·<sup>+</sup> scavenging activity, and ferric reducing power of 134.34 μM Fe<sup>2+</sup>. Complete genomic analysis identified an <em>eps</em> gene cluster involved in the EPS biosynthesis of Bi-OTA128 strain, which might be responsible for its ropy phenotype. The EPS was then isolated and purified by a DEAE-Sepharose Fast Flow column. A single elution part EPS<sub>128</sub> was obtained with a recovery rate of 43.5 ± 1.78 % and a total carbohydrate content of 93.6 ± 0.76 %. Structural characterization showed that EPS<sub>128</sub> comprised glucose, galactose, and rhamnose (molar ratio 4.0:1.2:1.1), featuring a putative complex backbone structure with four branched chains and an unusual acetyl group at <em>O</em>-2 of terminal rhamnose. Antioxidant assay <em>in vitro</em> indicated that EPS<sub>128</sub> exhibited antioxidant potential with 50.52 % DPPH· and 65.40 % ABTS·<sup>+</sup> scavenging activities, reaching 54.3 % and 70.44 % of the efficacy of standard Vitamin C at 2.0 mg/L. Furthermore, EPS<sub>128</sub> showed protective effects against H<sub>2</sub>O<sub>2</sub>-induced oxidative stress in HepG2 cells by reducing cellular reactive oxygen species (ROS) and increasing cell viability. These findings present the first comprehensive report of an antioxidant EPS from <em>B. pseudocatenulatum</em>, highlighting its potential as a natural antioxidant for applications in the food industry and clinical settings.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":null,"pages":null},"PeriodicalIF":6.1000,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microbiological research","FirstCategoryId":"99","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S094450132400315X","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Microbial exopolysaccharides (EPSs) have attracted extensive attention for their biological functions in antioxidant activities. In this study, we characterized a novel EPS produced by Bifidobacterium pseudocatenulatum Bi-OTA128 which exhibited the highest antioxidant capacity compared to nine other ropy bacterial strains, achieving 76.50 % and 93.84 % in DPPH· and ABTS·+ scavenging activity, and ferric reducing power of 134.34 μM Fe2+. Complete genomic analysis identified an eps gene cluster involved in the EPS biosynthesis of Bi-OTA128 strain, which might be responsible for its ropy phenotype. The EPS was then isolated and purified by a DEAE-Sepharose Fast Flow column. A single elution part EPS128 was obtained with a recovery rate of 43.5 ± 1.78 % and a total carbohydrate content of 93.6 ± 0.76 %. Structural characterization showed that EPS128 comprised glucose, galactose, and rhamnose (molar ratio 4.0:1.2:1.1), featuring a putative complex backbone structure with four branched chains and an unusual acetyl group at O-2 of terminal rhamnose. Antioxidant assay in vitro indicated that EPS128 exhibited antioxidant potential with 50.52 % DPPH· and 65.40 % ABTS·+ scavenging activities, reaching 54.3 % and 70.44 % of the efficacy of standard Vitamin C at 2.0 mg/L. Furthermore, EPS128 showed protective effects against H2O2-induced oxidative stress in HepG2 cells by reducing cellular reactive oxygen species (ROS) and increasing cell viability. These findings present the first comprehensive report of an antioxidant EPS from B. pseudocatenulatum, highlighting its potential as a natural antioxidant for applications in the food industry and clinical settings.
期刊介绍:
Microbiological Research is devoted to publishing reports on prokaryotic and eukaryotic microorganisms such as yeasts, fungi, bacteria, archaea, and protozoa. Research on interactions between pathogenic microorganisms and their environment or hosts are also covered.