Characterization of some potentially probiotic Lactobacillus strains of human origin

Lacticaseibacillus paracasei LB12, a Potential Probiotic Isolated from Traditional Iranian Fermented Milk (Doogh)

In Iran, dairy-based fermented foods, like yogurt, cheese, fermented milk, buttermilk, kashk, butter, and Doogh are essential dietary components. Doogh is typically made using fermented yogurt or buttermilk. However, a literature review revealed a lack of research on extracting probiotics from Doogh during processing. As dairy products contain lactic acid bacteria, the aim was to isolate and identify them using culture and PCR-sequencing techniques. Samples of traditional Doogh were collected throughout the Chaharmahal Bakhtiari province of Iran. A specific number of strains have been isolated and among them, the strain LB12 was selected for further characterization based on its probiotic properties. Probiotic properties like adhesion capability, antagonistic activity, resistance to the simulated stomach and intestinal fluids, pH, and bile salt were assessed according to National Standard ISO 19459 of Iran. The LB12 strain was identified as Lacticaseibacillus paracasei by partial 16 rDNA sequence analysis. This L. paracasei strain demonstrated its in vitro resilience to stomach conditions with 58.04% survival at pH 3 and more than 50% resistance to different bile salt concentrations. L. paracasei LB12 showed a cell surface hydrophobicity of 38.18% and a 6.2 log CFU/ml resistance to simulated gastric and intestinal fluids, and a rate of auto- and co-aggregation of 15% and 22%, respectively. L. parasei LB12 showed also a moderate adhesion to HT-29 cell line. In conclusion, L. paracasei LB12 is considered a promising potential probiotic suitable for the development of food supplement and pharmaceutical products.

Anti-Inflammatory Response in TNFα/IFNγ-Induced HaCaT Keratinocytes and Probiotic Properties of Lacticaseibacillus rhamnosus MG4644, Lacticaseibacillus paracasei MG4693, and Lactococcus lactis MG5474

Atopic dermatitis (AD) is a chronic inflammatory disease caused by immune dysregulation. Meanwhile, the supernatant of lactic acid bacteria (SL) was recently reported to have anti-inflammatory effects. In addition, HaCaT keratinocytes stimulated by tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) are widely used for studying AD-like responses. In this study, we evaluated the anti-inflammatory effects of SL from lactic acid bacteria (LAB) on TNF-α/IFN-γ-induced HaCaT keratinocytes, and then we investigated the strains' probiotic properties. SL was noncytotoxic and regulated chemokines (macrophage-derived chemokine (MDC) and thymus and activation-regulated chemokine (TARC)) and cytokines (interleukin (IL)-4, IL-5, IL-25, and IL-33) in TNF-α/IFN-γ-induced HaCaT keratinocytes. SL from Lacticaseibacillus rhamnosus MG4644, Lacticaseibacillus paracasei MG4693, and Lactococcus lactis MG5474 decreased the phosphorylation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK). Furthermore, the safety of the three strains was demonstrated via hemolysis, bile salt hydrolase (BSH) activity, and toxicity tests, and the stability was confirmed under simulated gastrointestinal conditions. Therefore, L. rhamnosus MG4644, L. paracasei MG4693, and Lc. lactis MG5474 have potential applications in functional food as they are stable and safe for intestinal epithelial cells and could improve atopic inflammation.

Evaluation of probiotic properties of Levilactobacillus brevis isolated from hawthorn vinegar

Probiotic microorganisms are increasing their interest today due to the benefits they provide to humans. Vinegar is the process of processing foods containing carbohydrates that can be fermented by acetic acid bacteria and yeasts. Hawthorn vinegar is also important in terms of amino acids, aromatic compounds, organic acids, vitamins and minerals it contains. Depending on the variety of microorganisms in it, the content of hawthorn vinegar changes, especially its biological activity. Bacteria were isolated from handmade hawthorn vinegar obtained in this study. After performing its genotypic characterization, it has been tested that it can grow in low pH environment, survive in artificial gastric and small intestinal fluid, survive against bile acids, surface adhesion characteristics, antibiotic susceptibility, adhesion, and degrade various cholesterol precursors. According to the results obtained, the studied isolate is Levilactobacillus brevis, it can reproduce best at pH 6.3, survives 72.22% in simulated gastric juice, 69.59% in small intestinal fluid, and 97% adhesion to HTC-116. Partially reproduces even in the presence of 2% ox-bile, surface hydrophobicity is 46.29% for n-hexadecane. It has been determined that it can degrade 4 different cholesterol precursors except for Sodium thioglycolate and is generally resistant to antibiotics except for CN30 and N30. Considering the experimental findings of Levilactobacillus brevis isolated from hawthorn vinegar for the first time, it can be said that Levilactobacillus brevis has probiotic properties.

Phenotypic Assessment of Probiotic and Bacteriocinogenic Efficacy of Indigenous LAB Strains from Human Breast Milk

Breast milk is the combination of bioactive compounds and microflora that promote newborn’s proper growth, gut flora, and immunity. Thus, it is always considered the perfect food for newborns. Amongst their bioactives, probiotic communities—especially lactic acid bacteria (LAB)—are characterized from breast milk over the first month of parturition. In this study, seven LAB were characterized phenotypically and genotypically as Levilactobacillus brevis BDUMBT08 (MT673657), L. gastricus BDUMBT09 (MT774596), L. paracasei BDUMBT10 (MT775430), L. brevis BDUMBT11 (MW785062), L. casei BDUMBT12 (MW785063), L. casei BDUMBT13 (MW785178), and Brevibacillus brevis M2403 (MK371781) from human breast milk. Their tolerance to lysozyme, acid, bile, gastric juice, pancreatic juice, and NaCl and potential for mucoadhesion, auto-aggregation, and co-aggregation with pathogens are of great prominence in forecasting their gut colonizing ability. They proved their safety aspects as they were negative for virulence determinants such as hemolysis and biofilm production. Antibiogram of LAB showed their sensitivity to more than 90% of the antibiotics tested. Amongst seven LAB, three isolates (L. brevis BDUMBT08 and BDUMBT11, and L. gatricus BDUMBT09) proved their bacteriocin producing propensity. Although the seven LAB isolates differed in their behavior, their substantial probiotic properties with safety could be taken as promising probiotics for further studies to prove their in vivo effects, such as health benefits, in humans.

The effect of kefir consumption on the lipid profile for individuals with normal and dyslipidemic properties: a randomized controlled trial

ABSTRACT Objective This research was conducted as a prospective, self-controlled, eight-week clinical trial to investigate the effect of kefir consumption on the lipid profile of individuals with normal and dyslipidemic properties. Methods Kefir microorganisms given to volunteer subjects were determined using classical microbial count methods and qReal-Time Polymerase Chain Reaction. The study was carried out with 23 volunteer hospital health personnel between the ages of 20 and 55 who met the research criteria and did not have any health problems. The volunteers regularly consumed kefir on an empty stomach for four weeks. In the last stage, the eight-week study was completed by making blood and anthropometric measurements of the subjects, who continued to be studied without kefir consumption for four more weeks. Results Considering the changes in the serum lipid profiles of 13 individuals with dyslipidemic symptoms during the 4-week period they consumed kefir, Total Cholesterol values decreased by 9.15% compared to initial values, LDL-Cholesterol values decreased by 10.64%, HDL-Cholesterol values decreased by 6.9%, and triglyceride values decreased by 2.46%. The changes in the serum lipid profiles of 13 individuals with dyslipidemic findings at the end of an eight-week study were a 5.71% decrease in total cholesterol values (p<0.018) considered statistically significant, as well as a 5.31% decrease in LDL-Cholesterol values (p<0.021); the HDL-Cholesterol results were found to be significant with an 8.58% decrease in the values (p<0.035) and insignificant with a 17.21% increase in the triglyceride values (p<0.926). We concluded that regular kefir consumption was effective in both women and men in lowering total cholesterol and LDL-Cholesterol from blood lipid profiles, especially in individuals with dyslipidemic symptoms, while this effect was not observed in normal individuals. Conclusion Kefir can positively affect the total cholesterol and LDL-Cholesterol blood parameters of dyslipidemic individuals with high serum lipid values.

Adhesion and anti-inflammatory potential of Lactobacillus rhamnosus GG in a sea buckthorn based beverage matrix

A seabuckthorn based beverage matrix retains the functionality of L. rhamnosus GG and exhibits enhanced anti-inflammatory effects against LPS-induced inflammation in zebrafish.

Evaluation of probiotic potential and anti-hyperglycemic properties of a novel Lactobacillus strain isolated from water kefir grains

A total of eight strains of lactic acid bacteria were isolated from water kefir grains and assessed for their in vitro α-glucosidase inhibitory activity. Lactobacillus mali K8 demonstrated significantly higher inhibition as compared to the other strains, thus was selected for in vitro probiotic potential characterization, antibiotic resistance, hemolytic activity and adaptation to pumpkin fruit puree. L. mali K8 demonstrated tolerance to pH 2.5 and resisted the damaging effects of bile salts, pepsin and pancreatin, comparable to that of Lactobacillus rhamnosus GG ATCC 53103 (reference strain). Lack of hemolytic activity and susceptibility to the five standard antibiotics indicated the safety of the K8 strain. This strain showed singular properties to be used as starters in the pumpkin fruit puree fermentation. These preliminary in vitro tests indicated the safety and functionality of the K8 strain and its potential as a probiotic candidate.