Hypoglycemic, Antioxidant Activities, and Probiotic Characteristics of Lacticaseibacillus rhamnosus LBUX2302 Isolated from Stool Samples of Neonates

Abstract

Lacticaseibacillus species have shown potential in managing hyperglycemia, hypercholesterolemia, and oxidative stress, depending on the strain and species. This study aimed to isolate a novel Lacticaseibacillus rhamnosus strain from healthy newborns and assess its hypoglycemic and antioxidative activity, along with other probiotic properties. A non-hemolytic L. rhamnosus LBUX2302 was isolated, and it exhibited survival rates of 2.7%, 22%, and 27.5% at pH 2, 3, and 5 for 120 min. It metabolized various carbon sources and showed resistance to gentamicin, dicloxacillin, and penicillin; coaggregated with Salmonella typhi ATCC14028, Staphylococcus aureus STCC6538, and Escherichia coli O157:H7. L. rhamnosus LBUX2302 showed hydrophobicity, autoaggregation, and adhesion to HaCat, HeLa, MCF-7, SK-LU-1, and SW620 cell lines. It also exhibited extracellular activity of bile salt hydrolase. Enzymatic inhibition assays revealed 66% and 24% inhibitions of α-amylase and α-glucosidase, respectively. Its cell-free supernatant inhibited DPPH (89%), hydroxyl (81%), and superoxide anion radicals (61%). Also, antioxidant activity was observed in whole cells and cell fragments. Finally, the presence of ferulic acid activity was detected. The results highlight L. rhamnosus LBUX2302 as a promising probiotic with hypoglycemic and antioxidant effects, warranting further in vivo evaluation for its possible inclusion in functional food and health formulations.

Keywords: Lacticaseibacillus rhamnosus; adhesion; antioxidant effect; bile salt hydrolase activity; probiotics.

Figure 1

Phylogeny analysis based on 16S rRNA gene sequences from 7 bacteria including species of Lacticaseibacillus, Lactobacillus and Escherichia. The percent numbers at the nodes indicate the levels of bootstrap support based on Maximum Likelihood analyses of 1000 replicates.

Figure 2

Growth kinetics of L. rhamnosus LBUX2302 by using different carbon sources. ● glucose, ♦ saccharose, ■ FOS, ▲ lactose, ○ raffinose, ◊ lactulose, □ xylan, and Δ xylose. Markers in each curve of growth kinetics represents the average of three independent trials. The error bars above the markers indicate the standard deviation.

Figure 3

BSH activity of ■ L. rhamnosus LBUX2302 and ■ L. casei. * in black indicates significant differences p ≤ 0.05 between bile salts to L. rhamnosus LBUX2302, * in blue to L. casei and in red between both strains in the same bile salt. Each bar represents the average of three independent trials. Two bars that share the same number of asterisks of the same color indicate that there is no statistically significant differences between them. In contrast, bars with a different number of asterisks of the same color indicate a statistically significant difference. Error bars indicate the standard deviation.

Figure 4

Percentage of survival under different pH 1.5 (●), 2 (♦), 3 (■), 5 (▲) of L. rhamnosus LBUX2302 and L. casei. Markers in each curve of viability curve represents the average of three independent trials. Error bars above the markers indicate the standard deviation.

Figure 5

Antioxidant activity of ■ L. rhamnosus LBUX2302 and ■ L. casei (a) % of DPPH inhibition, (b) Hydroxyl anion inhibition, (c) Superoxide anion inhibition. Each bar represents the average of three independent trials. Error bars indicate the standard deviation. * in black means differences between different evaluations in the same strain. * in blue means differences among the strains between the treatments (p ≤ 0.05). Two bars that share the same number of asterisks of the same color indicate that there is no statistically significant differences between them. In contrast, bars with a different number of asterisks of the same color indicate a statistically significant difference.

Figure 5

Antioxidant activity of ■ L. rhamnosus LBUX2302 and ■ L. casei (a) % of DPPH inhibition, (b) Hydroxyl anion inhibition, (c) Superoxide anion inhibition. Each bar represents the average of three independent trials. Error bars indicate the standard deviation. * in black means differences between different evaluations in the same strain. * in blue means differences among the strains between the treatments (p ≤ 0.05). Two bars that share the same number of asterisks of the same color indicate that there is no statistically significant differences between them. In contrast, bars with a different number of asterisks of the same color indicate a statistically significant difference.

Figure 6

α-amylase and α-glucosidase activity inhibition of ■ L. rhamnosus LBUX2302 and ■ L. casei. Each bar represents the average of three independent trials. Error bars indicate the standard deviation. No significant differences were found.

Figure 7

Cell adhesion ability of L. rhamnosus LBUX2302 to different cellular lines. * Indicates significant differences (p ≤ 0.05). Each bar represents the average of three independent experiments. Error bars indicate the standard deviation. Two bars that share the same number of asterisks indicate that there is no statistically significant differences between them. In contrast, bars with a different number of asterisks indicate a statistically significant difference.