Bacterial vaginosis (BV) is caused by a microbial imbalance in the vaginal ecosystem, which causes genital discomfort and a variety of potential complications in women. This study validated the potential of Lactobacillus helveticus HY7801 as a probiotic to benefit vaginal health. In vivo, HY7801 reduced the number of Gardnerella vaginalis (GV) and pro-inflammatory cytokines in the vagina of GV-induced BV mice and ameliorated vaginal histological changes. In vitro, HY7801 exhibited positive resistance to simulated gastrointestinal conditions, showed excellent adherence ability to the female genital epithelium, and had high lactic acid and H₂O₂ production capacity. Furthermore, it was found that HY7801 can alleviate BV because it can suppress the expression of virulence factor genes of GV involved in epithelial cell adhesion and biofilm formation along with antibacterial activity against GV. These results indicate that HY7801 can be used as a promising probiotic strain for the maintenance of a healthy vaginal physiological state.

Here, we show that Lactiplantibacillus plantarum LP158 (LP158), Lactobacillus helveticus HY7804 (HY7804), and Lacticaseibacillus paracasei LPC226 (LPC226) isolated from raw milk alleviate non-alcoholic fatty acid disease (NAFLD) in a C57BL/6 mouse model. Lactic acid bacteria (LAB) were screened for their ability to inhibit fatty acid accumulation in palmitic acid (PA)-treated HepG2 cells, and three strains were selected based on the results. We also investigated hemolytic activity and antibiotic resistance of the three strains. LP158, HY7804, and LPC226 suppressed expression of mRNA encoding genes related to lipogenesis, and increased expression of genes related to β-oxidation, in a PA-induced HepG2 cell model. Moreover, when LP158, HY7804, and LPC226 were administered at 10⁹ CFU/kg/day for 8 weeks to mice with dietary-induced NAFLD, they all modulated blood biochemistry markers and reduced steatosis in liver tissue. Also, all three strains significantly reduced expression of mRNA encoding lipogenesis genes (Fasn, Acaca, and Srebp-1c) and inflammatory factors (Tnfα and Ccl-2) and fibrosis factors, and increased expression of a β-oxidation gene (Acox1) in the liver. In particular, HY7804 showed the strongest effects both in vitro and in vivo. Therefore, HY7804, LP158, and LPC226 can be proposed as potential supplements that can improve NAFLD through anti-steatosis, anti-inflammatory, and anti-fibrotic effects.

People on vegan diets are at risk of being deficient in varied nutrients such as vitamin B₁₂ and certain amino acids. In this study, we investigated vitamin B₁₂-producing lactic acid bacteria (LAB) as well as the probiotic and antioxidant properties. Lactiplantibacillus plantarum HY7720 was screened from 22 strains of LAB that were isolated from different plant foods, and its growth ability and extracellular vitamin B₁₂-producing capacity in vitamin B₁₂-deficient medium were investigated. To determine whether HY7720 functions as a probiotic, survival rate in the simulated gastrointestinal tract and adhesion property to human intestinal epithelial cells of HY7720 were compared with positive control, Lacticaseibacillus rhamnosus GG (LGG). Moreover, the results showed that HY7720 recovered the gene expression levels of tight junction-associated proteins (TJPs), including TJP1, TJP2, occludin (OCLN), and claudin-1 (CLDN1) and inhibited the secretion levels of pro-inflammatory cytokines, including interleukin (IL)-6 and IL-8, in tumor necrosis factor (TNF)-α-stimulated Caco-2 cells. Furthermore, we verified that HY7720 exhibit the antioxidant potential, by showing its intracellular reactive oxygen species (ROS) scavenging ability in hydrogen peroxide (H₂O₂)-stimulated Caco-2 cells. The ability of HY7720 to ameliorate H₂O₂-induced cytotoxicity in Caco-2 cells was inhibited by mitogen-activated protein kinase (MAPK) inhibitors, indicating that its antioxidant responses are related to extracellular signal-regulated kinase (ERK) and c-JUN N-terminal kinase (JNK). This study also investigated the nutritional qualities of three plant-based materials (brown rice, white rice, and soy milk) fermented using HY7720. Collectively, HY7720 could be used as a promising probiotic strain for the prevention of nutritional deficiencies among people on vegetarian diets.

Inflammatory bowel disease (IBD) involves chronic inflammation and disruption of the intestinal barrier, often accompanied by alterations in gut microbiota composition. This study examined the protective potential of a prebiotic mixture extract (PME) prepared from Vigna radiata (mung bean), Vigna angularis (red bean), and Foeniculum vulgare (fennel) using the HT-29 cell and colitis animal model. PME exhibited concentration-dependent antioxidant activity, with greater radical-scavenging capacity in the ABTS assay than in the DPPH assay. In LPS-stimulated HT-29 epithelial cells, PME reduced the mRNA expression of inflammation-associated genes (TNF-α, IL-1β, NF-κB) and upregulated tight junction markers (CLDN1 and OCLN), demonstrating its anti-inflammatory and supportive effects on the intestinal barrier. Vitexin, a C-glycosylated flavonoid, was detected in PME and is expected to mediate these protective effects. In a DSS-induced colitis mouse model, PME administration alleviated disease severity by increasing colon length, reducing serum levels of inflammatory cytokines and COX-2/PGE2, and restoring intestinal permeability. Furthermore, PME modulated the gut microbiota by enhancing beneficial bacteria such as Bifidobacterium and Faecalibaculum while suppressing inflammation-associated taxa, including Escherichia, Bacteroides, and Mucispirillum. These improvements collectively suggest that PME reinforces epithelial barrier integrity and promotes intestinal homeostasis through both anti-inflammatory and microbiota-regulating actions.