Exopolysaccharides (EPS) have attracted a great interest due to their potential health-promoting properties and industrial applications. This study aimed to investigate the physicochemical, rheological, and biological properties of an EPS produced by a potential probiotic strain Enterococcus faecalis 84B. The results show that the extracted EPS, designated EPS-84B, had an average molecular weight of 604.8 kDa, particles size diameter of 322.0 nm, and mainly composed of arabinose and glucose with a molar ratio of 1:2. Furthermore, EPS-84B exhibited a shear-thinning behavior and had a high melting point. The rheological properties of EPS-84B were strongly influenced by the type of salt than by the pH value. EPS-84B displayed ideal viscoelastic properties, with both viscous and storage moduli increasing with frequency. The antioxidant activity of EPS-84B at a concentration of 5 mg/mL was 81.1 % against DPPH and 35.2 % against ABTS. At 5 mg/mL, the antitumor activity of EPS-84B against Caco-2 and MCF-7 cell lines was 74.6 and 38.6 %, respectively. In addition, the antidiabetic activity of EPS-84B towards α-amylase and α-glucosidase was 89.6 and 90.0 %, respectively at 100 μg/mL. The inhibition of foodborne pathogens by EPS-84B was up to 32.6 %. Overall, EPS-84B has promising properties that could be utilized in food and pharmaceutical industries.

NMR, cytotoxicity, antimicrobial, FTIR, Antidiabetic, SEM

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
2,4,6	aDGlcp	98.91	70.91	81.51	70.67	72.41	61.45
2,4	aDGlcp	100.63	72.60	74.05	70.40	72.12	66.85
2	bDGlcp	104.70	74.22	76.79	77.96	75.68	61.55
	aDGlcp	99.16	81.70	72.71	70.45	72.54	61.47


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
2,4,6	aDGlcp	4.97	3.70	3.91	3.72	3.75	3.77-3.85
2,4	aDGlcp	5.36	3.60	3.69	3.52	3.90	3.77-3.99
2	bDGlcp	4.67	3.41	3.80	3.64	3.60	3.79-3.94
	aDGlcp	5.54	3.71	3.91	3.50	3.98	3.76-3.86


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
2,4,6	aDGlcp	98.91/4.97	70.91/3.70	81.51/3.91	70.67/3.72	72.41/3.75	61.45/3.77-3.85
2,4	aDGlcp	100.63/5.36	72.60/3.60	74.05/3.69	70.40/3.52	72.12/3.90	66.85/3.77-3.99
2	bDGlcp	104.70/4.67	74.22/3.41	76.79/3.80	77.96/3.64	75.68/3.60	61.55/3.79-3.94
	aDGlcp	99.16/5.54	81.70/3.71	72.71/3.91	70.45/3.50	72.54/3.98	61.47/3.76-3.86

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*O[C@H]1[C@H](O)[C@@H](CO)O[C@H](OC[C@H]2O[C@H](O[C@@H]3[C@@H](CO)O[C@@H](O[C@@H]4[C@@H](O)[C@H](O)[C@@H](CO)O[C@@H]4*)[C@H](O)[C@H]3O)[C@H](O)[C@@H](O)[C@@H]2O)[C@@H]1O

648.564 g/mol (C₂₄H₄₀R₂O₂₀, R = next and previous repeats, not counted in mol weight)