Structural Characterization of an Exopolysaccharide Isolated from Enterococcus faecalis, and Study on its Antioxidant Activity, and Cytotoxicity Against HeLa Cells

Production and Characterization of Exopolysaccharide From Newly Isolated Marine Probiotic Lactiplantibacillus plantarum EI6 With in vitro Wound Healing Activity

“…The NMR spectroscopic technique was used to get structural information on the EI6-EPS, such as monosaccharide composition, configurations, and linkage types (Li et al, 2011 ). The acquired 1 H NMR spectrum of EI6-EPS ( Figure 3C ) revealed a similar signature to other reported polysaccharides (Amer et al, 2020 ; Choudhuri et al, 2020 ). The ring protons at the positions C2–C6 belong to the sugar moieties and appeared in the range of δ = 2.96–4.19 ppm, while the anomeric protons displayed in the range of δ = 4.45–5.16 ppm.…”

“…In this study, the carbohydrate content was estimated as glucose, accounting for ~91.5% of the EI6-EPS. The sugar content was higher than that reported for the marine strain of Rhodobacter johrii CDR-SL 7Cii (86.82%) (Sran et al, 2019 ) but lower than the carbohydrate content of the exopolysaccharide from Enterococcus faecalis (94.7%) (Choudhuri et al, 2020 ).…”

“…The IR spectrum revealed characteristic signatures and distinctive functional groups of carbohydrates ( Figure 3A ). Therefore, the assignments of the IR bands were mainly based on the previously reported polysaccharide spectra (Amer et al, 2020 ; Choudhuri et al, 2020 ). The broadband at 3,289 cm −1 in the region (3,150–3,490 cm −1 ) denoted the stretching vibration of a large number of hydroxyl (O-H) groups belonging to the sugar moieties of carbohydrates (Abid et al, 2018 ; Amer et al, 2020 ; Choudhuri et al, 2020 ; Sirin and Aslim, 2020 ).…”

“…Therefore, the assignments of the IR bands were mainly based on the previously reported polysaccharide spectra (Amer et al, 2020 ; Choudhuri et al, 2020 ). The broadband at 3,289 cm −1 in the region (3,150–3,490 cm −1 ) denoted the stretching vibration of a large number of hydroxyl (O-H) groups belonging to the sugar moieties of carbohydrates (Abid et al, 2018 ; Amer et al, 2020 ; Choudhuri et al, 2020 ; Sirin and Aslim, 2020 ). The absorption band at 2,970–2,850 cm −1 was assigned to the stretching vibration of the aliphatic C-H of the methyl or methylene groups in hexoses (e.g., galactose and glucose) and deoxyhexoses (e.g., rhamnose and fucose), which is characteristic of polysaccharides (Abid et al, 2018 ; Choudhuri et al, 2020 ; Sirin and Aslim, 2020 ).…”

“…The broadband at 3,289 cm −1 in the region (3,150–3,490 cm −1 ) denoted the stretching vibration of a large number of hydroxyl (O-H) groups belonging to the sugar moieties of carbohydrates (Abid et al, 2018 ; Amer et al, 2020 ; Choudhuri et al, 2020 ; Sirin and Aslim, 2020 ). The absorption band at 2,970–2,850 cm −1 was assigned to the stretching vibration of the aliphatic C-H of the methyl or methylene groups in hexoses (e.g., galactose and glucose) and deoxyhexoses (e.g., rhamnose and fucose), which is characteristic of polysaccharides (Abid et al, 2018 ; Choudhuri et al, 2020 ; Sirin and Aslim, 2020 ). The absorption peaks at 1,724 and 1,656 cm −1 may relate to the stretching vibration of the C=O group in free and bonded states, respectively (Zhou et al, 2016 ; Abid et al, 2018 ; Sirin and Aslim, 2020 ).…”