ABSTRACT
Exopolysaccharide (EPS)-producing Bifidobacterium bifidum EPS DA-LAIM was isolated from healthy human feces, the structure of purified EPS from the strain was analyzed, and its prebiotic activity was evaluated. The EPS from B. bifidum EPS DA-LAIM is a glucomannan-type heteropolysaccharide with a molecular weight of 407-1007 kDa, and its structure comprises 2-mannosyl, 6-mannosyl, and 2,6-mannosyl residues. The purified EPS promoted the growth of representative lactic acid bacteria and bifidobacterial strains. Bifidobacterium bifidum EPS DA-LAIM increased nitric oxide production in RAW 264.7 macrophage cells, indicating its immunostimulatory activity. Bifidobacterium bifidum EPS DA-LAIM also exhibited high gastrointestinal tract tolerance, gut adhesion ability, and antioxidant activity. These results suggest that EPS from B. bifidum EPS DA-LAIM is a potentially useful prebiotic material, and B. bifidum EPS DA-LAIM could be applied as a probiotic candidate. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01213-w.
ABSTRACT
Exopolysaccharide (EPS)-producing Lacticaseibacillus paracasei EPS DA-BACS was isolated from healthy human feces and its probiotic properties, as well as the structure and prebiotic activity of the EPS from this strain were examined. EPS from L. paracasei EPS DA-BACS had a ropy phenotype, which is known to have potential health benefits and is identified as loosely cell-bounded glucomannan-type EPS with a molecular size of 3.7 × 106 Da. EPS promoted the acid tolerance of L. paracasei EPS DA-BACS and provided cells with tolerance to gastrointestinal stress. The purified EPS showed growth inhibitory activity against Clostridium difficile. L. paracasei EPS DA-BACS cells completely inhibited the growth of Bacillus subtilis, Pseudomonas aeruginosa, and Aspergillus brasiliensis, as well as showed high growth inhibitory activity against Staphylococcus aureus and Escherichia coli. Treatment of lipopolysaccharide-stimulated RAW 264.7 cells with heat-killed L. paracasei EPS DA-BACS cells led to a decrease in the production of nitric oxide, indicating the anti-inflammatory activity of L. paracasei EPS DA-BACS. Purified EPS promoted the growth of Lactobacillus gasseri, Bifidobacterium bifidum, B. animalis, and B. faecale which showed high prebiotic activity. L. paracasei EPS DA-BACS harbors no antibiotic resistance genes or virulence factors. Therefore, L. paracasei EPS DA-BACS exhibits anti-inflammatory and antimicrobial activities with high gut adhesion ability and gastrointestinal tolerance and can be used as a potential probiotic.
ABSTRACT
Black tea has been reported to have anti-obesity effects in both rodents and humans. Gallic acid, an active component of black tea, decomposes quickly into pyrogallol in high-temperature solutions. This study introduced a new, aqueous ethanol extraction of black tea, which resulted in extracts with higher concentrations of gallic acid than conventional black tea extracts prepared by hot-water extraction or hot-ethanol extraction. We confirmed that, compared with the hot-water extract of black tea, the cold-ethanol extract of black tea (CE-BTE) had greater effects on reducing body weight and body fat, improving fatty liver, regulating blood glucose, and reducing blood cholesterol in the high-fat diet-induced obese mouse model. Nonetheless, although CE-BTE significantly reduced fat content, it did not reduce peroxisome proliferator-activated receptor (PPARγ) protein in epididymal fat tissue of HFD mice. We also showed that CE-BTE did not inhibit the function of PPARγ protein to drive adipogenesis of mouse 3T3-L1 preadipocytes. Considering that PPARγ is a master transcription factor not only for adipocyte differentiation, but also for adipose tissue function, such as glucose and lipid metabolism and insulin sensitivity, these results suggest that CE-BTE reduced fat mass and body weight without dampening fat cell homeostasis and insulin sensitivity.
