Dietary Inulin Increases Lactiplantibacillus plantarum Strain Lp900 Persistence in Rats Depending on the Dietary-Calcium Level.

Synbiotics are food supplements that combine probiotics and prebiotics to synergistically elicit health benefits in the consumer. Lactiplantibacillus plantarum strains display high survival during transit through the mammalian gastrointestinal tract and were shown to have health-promoting properties. Growth on the fructose polysaccharide inulin is relatively uncommon in L. plantarum, and in this study we describe FosE, a plasmid-encoded ß-fructosidase of L. plantarum strain Lp900 which has inulin-hydrolyzing properties. FosE contains an LPxTG-like motif involved in sortase-dependent cell wall anchoring but is also (partially) released in the culture supernatant. In addition, we examined the effect of diet supplementation with inulin on the intestinal persistence of Lp900 in adult male Wistar rats in diets with distinct calcium levels. Inulin supplementation in high-dietary-calcium diets significantly increased the intestinal persistence of L. plantarum Lp900, whereas this effect was not observed upon inulin supplementation of the low-calcium diet. Moreover, intestinal persistence of L. plantarum Lp900 was determined when provided as a probiotic (by itself) or as a synbiotic (i.e., in an inulin suspension) in rats that were fed unsupplemented diets containing the different calcium levels, revealing that the synbiotic administration increased bacterial survival and led to higher abundance of L. plantarum Lp900 in rats, particularly in a low-calcium-diet context. Our findings demonstrate that inulin supplementation can significantly enhance the intestinal delivery of L. plantarum Lp900 but that this effect strongly depends on calcium levels in the diet.IMPORTANCE Synbiotics combine probiotics with prebiotics to synergistically elicit a health benefit in the consumer. Previous studies have shown that prebiotics can selectively stimulate the growth in the intestine of specific bacterial strains. In synbiotic supplementations the prebiotics constituent could increase the intestinal persistence and survival of accompanying probiotic strain(s) and/or modulate the endogenous host microbiota to contribute to the synergistic enhancement of the health-promoting effects of the synbiotic constituents. Our study establishes a profound effect of dietary-calcium-dependent inulin supplementation on the intestinal persistence of inulin-utilizing L. plantarum Lp900 in rats. We also show that in rats on a low-dietary-calcium regime, the survival and intestinal abundance of L. plantarum Lp900 are significantly increased by administering it as an inulin-containing synbiotic. This study demonstrates that prebiotics can enhance the intestinal delivery of specific probiotics and that the prebiotic effect is profoundly influenced by the calcium content of the diet.

Preliminary study for the stimulation effect of plant-based meals on pure culture Lactobacillus plantarum growth and acidification in milk fermentation.

Fermented dairy products have been recognized as the best carriers for the administration of probiotics. Because one of the potential probiotic strains, Lactobacillus plantarum, has poor proteolytic ability and weak acidifying capacity in milk fermentation, the aim of this study was to preliminarily investigate the stimulation effect of plant-based meals on L. plantarum CCFM8661 growth in milk, and subsequently develop a yogurt or yogurt drinks containing probiotic strain L. plantarum CCFM8661. Milk supplemented with different concentrations (5 to 10%, wt/wt) of oat extract and malt extract, inoculated with 2.5 × 107 cfu/mL of L. plantarum CCFM8661, and then incubated at 35°C. The pH value, titration acidity, and viable cell counts during 48-h fermentation at 35°C and 25-d storage at 4°C, were determined at different intervals. The results showed that the promotion effects of oat extract and malt extract on L. plantarum CCFM8661 growth rate in milk were much stronger than almond, walnut, sweet corn, peanut, and soybean meals. In addition, the stimulation effect of oat extract was associated with its concentration, and was much stronger than that of malt extract. Furthermore, viable counts and titration acidity of yogurt were gradually increased in the oat extract group, whereas viable counts were gradually decreased and titration acidity were slightly increased in the malt extract group during the 25-d storage at 4°C.

Isolation of swine-derived Lactobacillus plantarum and its synergistic antimicrobial and health-promoting properties with ZnO nanoparticles.

AIMS: The purpose of this study was to isolate Lactobacillus from gastrointestinal tract of healthy postweaning piglets and investigate its synergistic antimicrobial and probiotic effects with ZnO nanoparticles (nZnO). METHODS AND RESULTS: Of the 128 isolates, Lactobacillus plantarum BLPL03 was selected based on its excellent acid and bile salt tolerance properties. Lactobacillus plantarum BLPL03 was sensitive to ß-lactams, macrolides, amphenicols and cephalosporins, whereas it displayed the steady resistance to aminoglycosides, tetracyclines, quinolones and peptide antibiotics. In vitro analysis of antibacterial activities showed that L. plantarum BLPL03 inhibited the four common food-borne pathogenic bacteria including Escherichia coli O157:H7 CMCC 44828, Salmonella Typhimurium ATCC 13311, Staphylococcus aureus CMCC 26003 and Listeria monocytogenes CMCC 54007 in synergy with nZnO. Furthermore, the quantitative polymerase chain reaction test demonstrated that the combined administration of L. plantarum BLPL03 fermentation liquor (LFL) and nZnO synergistically elevated the faecal number of Bifidobacterium by 73·19-fold, and reduced the two potential enteropathogenic bacteria Enterobacteriaceae and Clostridium perfringens in mice challenged with Salm. Typhimurium. Finally, dietary supplementation with low dose of nZnO (20 mg kg-1 ) when combined with LFL administration enhanced final body weight, fur appearance and average daily gain, and decreased feed conversion ratio and diarrhoea incidence in weaned piglets. The faecal Bifidobacterium and Lactobacillus of piglets were dramatically enhanced by 81·96- and 3·15-fold, respectively, after administration of a mixture of nZnO and LFL. Meanwhile, combination of nZnO with LFL resulted in low levels of Bacteroides, Enterococcus, and Enterobacteriaceae. CONCLUSIONS: A combination of nZnO and LFL exhibits potential health-benefit properties for the control of gut microbial composition by their synergistic antimicrobial and probiotic effects. SIGNIFICANCE AND IMPACT OF THE STUDY: This study may provide a potential nutritional strategy to improve performance and gut health of animals with gut microbiota disorders caused by pathogen infections and weanling, and so on.

Effect of quality control on the proliferation of the extract from Taraxacum mongolicum Hand.-Mazz. in Lactobacillus plantarum.

In recent years, the fingerprint of high-performance liquid chromatography has been extensively applied in the identification and quality control of traditional Chinese medicine. It can be a potential protocol for assessing the authenticity, stability and consistency of traditional Chinese medicine and guaranteeing the expected biological activity. In this paper, a method using high-performance liquid chromatography to identify and control the quality of the extract of Taraxacum mongolicum Hand.-Mazz. (TME) was established. With this method, the correlation coefficients of the similarity of 10 batches were ≥0.994. The TME displayed a steady proliferative effect in Lactobacillus plantarum. In brief, this study successfully built a reliable, simple and efficient method to control and confirm the quality and the stability of biological activity of the TME.

Pectin-decorated magnetite nanoparticles as both iron delivery systems and protective matrices for probiotic bacteria.

The goal of this work was to investigate biophysical stability of iron-pectin nanoparticles and analyze the feasibility of using them as delivery systems for the probiotic strain Lactobacillus plantarum CIDCA 83114. Iron oxide (Fe3O4) nanoparticles were synthesized from 0.25M FeCl2/0.5 M FeCl3.6H2O, and coated with citrus pectins. Their physico-chemical properties [FTIR, X-ray diffraction (XRD), ζ-potential, particle size, SEM, TEM] and their effect on bacterial stabilization (viability after freeze-drying/storage, stability when exposed to simulated gastro-intestinal conditions) were assessed. XRD indicated the almost exclusive presence of magnetite crystalline phases. FTIR spectra confirmed the adsorption of pectin on magnetite nanoparticles surface. SEM and TEM images evidenced agglomerated nanoparticles, and a morphological surface change after adsorption of pectin. DLS and ζ-potential results proved the solvation of the ionizable groups in the hydrophilic network which induced chain expansion and agglomeration. Iron from nanoparticles demonstrated to be non-toxic for microorganisms up to 1.00 mg/mL. Simulated saliva and gastric solutions prevented nanoparticles from dissolution. The higher pH of the intestinal conditions (solvated -COO- and Fe-O- groups) facilitated the dispersion and partial dissolution of nanoparticles. Pectins adsorption on magnetite nanoparticles significantly enhanced electrostatic repulsion, which aided the solvation of ionized iron forms. The soluble species diffused out from the aggregates, being detected in the simulated intestinal fluid. Regarding bacterial viability, no decays were observed neither when pectin-decorated nanoparticles were exposed to simulated fluids nor when stored at 4 °C for 60 days. The composites engineered in this work appear as adequate delivery systems for probiotic bacteria, whose target is the gut.

The impact of distillation process on the chemical composition and potential prebiotic activity of different oligosaccharidic fractions extracted from grape seeds.

The study was designed to evaluate how the distillation process is able to affect the composition and bioactivity of oligosaccharides contained in the grape seeds. Different oligosaccharidic fractions have been extracted both before and after grape pomace distillation in order to valorize this by-product. A multistep solid-phase extraction approach (C-18 and carbograph cartridges) has been applied to purify and fractionate the oligosaccharidic compounds. Chemical characterization of the fractions was performed using a UPLC-ESI-MSn method. Complex oligosaccharides consist principally of neutral oligosaccharides rich in arabinose and glucose. Then, the oligosaccharides contained in the different fractions as potential functional ingredients with prebiotic activity toward well-known probiotic bacteria, such as Lactobacillus acidophilus and Lactobacillus plantarum, were evaluated. Data showed how, in some combination, oligosaccharidic fractions obtained may be considered a novel "functional ingredient" with potential prebiotic activity mainly towards L. acidophilus.

Bacteriocin production by Lactobacillus plantarum ST16Pa in supplemented whey powder formulations.

Whey, the main by-product of the dairy industry, is frequently disposed of in the environment without any treatment due to the high cost of this process. Alternatively, whey can be used as a medium to culture lactic acid bacteria and produce value-added products such as bacteriocins. In this work, we attempted to improve bacteriocin production by Lactobacillus plantarum ST16Pa in a whey powder formulation supplemented with additional sources of carbon, nitrogen, and vitamin B12 at different levels and varying the agitation intensity according to a Plackett-Burman experimental design. Only the addition of tryptone positively influenced the production of this bacteriocin. The results allowed us to identify a supplemented whey formulation, comprising 150 g/L of whey total solids plus 10 g/L of tryptone and soybean extract, whose fermentation by Lb. plantarum ST16Pa in shake flasks under agitation at 150 rpm led to a cell-free supernatant with an antimicrobial activity against Listeria innocua 6a CLIST 2865 (inhibition zone of 13.23 mm) close to that previously obtained in de Man, Rogosa and Sharpe medium by other authors. These results are significant considering that the same strain cultured in cheese whey did not previously display any antimicrobial activity.

Interrelation between Tween and the membrane properties and high pressure tolerance of Lactobacillus plantarum.

Tween® 80 is a frequently used supplement of media for the cultivation of lactic acid bacteria. We investigated its effect on the cell physiology and stress tolerance of Lactobacillus (L.) plantarum. Data on the transcriptomic response to Tween 80 supplementation and its effects on cellular fatty acid profiles and growth characteristics are compared with data characterizing the effect of Tween 80, other Tween types and free fatty acids on the high hydrostatic pressure (HHP) tolerance of L. plantarum strain TMW 1.708. These include effects on cell viability, sub-lethal injury, metabolic activity, protein release and propidium iodide uptake. Tween 80 caused the downregulation of fatty acid biosynthesis and an increase in oleic acid and cyclopropane fatty acid levels in the cell membrane. Tween 20, Tween 80 and free oleic acid, but not Tween 40, Tween 60 and other free fatty acids, conferred resistance against HHP. Tween 80 diminished pressure-induced loss of metabolic activity, protein release and uptake of propidium iodide. However, loss of cell viability exceeded by far membrane permeabilization, suggesting that membrane permeabilization, which has frequently been postulated as a major factor in HHP inactivation of microbes, is not necessarily required for HHP-induced cell death of Lactobacillus plantarum.

Transcriptomic response to GABA-producing Lactobacillus plantarum CGMCC 1.2437T induced by L-MSG.

Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter found in the central nervous system of mammals. A range of bacterial species can synthesize GABA, including Lactobacillus plantarum of which L-monosodium glutamate (L-MSG) is an inducer of its production. In order to synthesize GABA in high concentrations, L-MSG was utilized as the single inducing factor, a chemically defined medium (CDM) was used as the fermentation substrate, with L. plantarum CGMCC 1.2437T cultured in medium supplemented with or without L-MSG. High-throughput transcriptome sequencing was used to explore the differential genes expression of bacterial cells at 36 h of fermentation, where the GABA concentration of CDM with L-MSG reached the peak value and was 7.7 times higher than that of medium without L-MSG at the same timepoint. A total of 87 genes showed significant differential expression induced by L-MSG: of these, 69 were up-regulated genes and 18 were down-regulated. The up-regulated genes were assigned to biological processes and molecular function, while the down-regulated genes covered biological process, cellular process and molecular function. Interrogation of results using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, indicated carbohydrate metabolism, fatty acid synthesis and amino acid metabolism were closely associated with GABA synthesis induced by L-MSG. This study provides insights into L. plantarum-mediated GABA fermentation at the molecular level and will provide a new approach for further studies related to GABA production by the other Lactic acid bacteria.

Rapid Screening of Natural Plant Extracts with Calcium Diacetate for Differential Effects Against Foodborne Pathogens and a Probiotic Bacterium.

This study focused on advancing a rapid turbidimetric bioassay to screen antimicrobials using specific cocktails of targeted foodborne bacterial pathogens. Specifically, to show the relevance of this rapid screening tool, the antimicrobial potential of generally recognized as safe calcium diacetate (DAX) and blends with cranberry (NC) and oregano (OX) natural extracts was evaluated. Furthermore, the same extracts were evaluated against beneficial lactic acid bacteria. The targeted foodborne pathogens evaluated were Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus using optimized initial cocktails (∼108 colony-forming unit/mL) containing strains isolated from human food outbreaks. Of all extracts evaluated, 0.51% (w/v) DAX in ethanol was the most effective against all four pathogens. However, DAX when reduced to 0.26% and with added blends from ethanol extractions consisting of DAX:OX (3:1), slightly outperformed or was equal to same levels of DAX alone. Subculture of wells in which no growth occurred after 1 week indicated that all water and ethanol extracts were bacteriostatic against the pathogens tested. All the targeted antimicrobials had no effect on the probiotic organism Lactobacillus plantarum. The use of such rapid screening methods combined with the use of multistrain cocktails of targeted foodborne pathogens from outbreaks will allow rapid large-scale screening of antimicrobials and enable further detailed studies in targeted model food systems.

Investigation of pectin/starch hydrogel as a carrier for oral delivery of probiotic bacteria.

The present study highlights the fabrication of novel food-grade hydrogel particles based on pectin and starch for probiotic colon delivery. Lactobacillus plantarum ATCC:13643 (L. plantarum) cells were encapsulated in pectin/starch hydrogels by extrusion method. Four batches were formulated with different ratios of starch/pectin solutions. Optical and scanning electron microscopy obviously showed the random distribution of L. plantarum throughout the hydrogel network. The viability of encapsulated cells in simulated gastric fluid (SGF) and bile salt solution was significantly higher when compared to nonencapsulated cells. Results demonstrated that encapsulated cells in pectin/starch hydrogels were resistant against adverse conditions of the gastro-intestinal tract and bile salt solution compared to non-encapsulated cells. After sequential exposure to simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) for 2h almost complete death of free cells was observed however the numbers of surviving cells were 5.15 and 6.67 Log CFU/g for pectin and pectin/starch hydrogel, respectively.

Antimicrobial effect of the extracts from Hypericum perforatum against oral bacteria and biofilm formation.

CONTEXT: One traditional medicines, Hypericum perforatum L. (Hypericaceae), possesses several beneficial effects against depression, ulcers, dyspepsia, abdominal pains, burns, bacterial infections, migraine headaches, and sciatica. OBJECTIVE: The present study investigates the antimicrobial activity of the ethanol extract (HP-EtOH) of H. perforatum and its sub-extracts, namely n-hexane (HP-hexane), chloroform (HP-CHCl3), ethyl acetate (HP-EtOAc), n-butanol (HP-n-BuOH), and water (HP-H2O) extracts, against Streptococcus mutans, S. sobrinus, Lactobacillus plantarum, and Enterococcus faecalis. MATERIALS AND METHODS: For the evaluation of the antimicrobial activity, flowering aerial parts of H. perforatum were extracted with EtOH and then this extract was fractionated to obtain five sub-extracts in different polarities. Antimicrobial activities of HP-EtOH and its sub-extracts against Streptococcus mutans, S. sobrinus, L. plantarum, and E. faecalis were assessed by using colorimetric micro-well dilution at concentration ranges of 64-0.5 µg/ml as well as resazurin microplate and modified microtiter-plate assays between the ranges of 100 and 0.78125 µg/ml. RESULTS: According to the results of the present study, HP-H2O sub-extract displayed strong antibacterial activity (MIC values 8 µg/mL) against S. sobrinus and L. plantarum, and exerted moderate activity against S. mutans and E. faecalis at 32 and 16 µg/mL concentrations, respectively. Other sub-extracts also demonstrated antimicrobial activity against S. sobrinus at a concentration of 16 µg/mL. HP-EtOAc and HP-n-BuOH showed antimicrobial activity against L. plantarum and HP-EtOAc and HP-H2O were also active against E. faecalis at the same concentrations (16 µg/mL). CONCLUSION: According to the results, we suggest that H. perforatum could be employed as a natural antibacterial agent in oral care products.

Characterisation of biofilms formed by Lactobacillus plantarum WCFS1 and food spoilage isolates.

Lactobacillus plantarum has been associated with food spoilage in a wide range of products and the biofilm growth mode has been implicated as a possible source of contamination. In this study we analysed the biofilm forming capacity of L. plantarum WCFS1 and six food spoilage isolates. Biofilm formation as quantified by crystal violet staining and colony forming units was largely affected by the medium composition, growth temperature and maturation time and by strain specific features. All strains showed highest biofilm formation in Brain Heart Infusion medium supplemented with manganese and glucose. For L. plantarum biofilms the crystal violet (CV) assay, that is routinely used to quantify total biofilm formation, correlates poorly with the number of culturable cells in the biofilm. This can in part be explained by cell death and lysis resulting in CV stainable material, conceivably extracellular DNA (eDNA), contributing to the extracellular matrix. The strain to strain variation may in part be explained by differences in levels of eDNA, likely as result of differences in lysis behaviour. In line with this, biofilms of all strains tested, except for one spoilage isolate, were sensitive to DNase treatment. In addition, biofilms were highly sensitive to treatment with Proteinase K suggesting a role for proteins and/or proteinaceous material in surface colonisation. This study shows the impact of a range of environmental factors and enzyme treatments on biofilm formation capacity for selected L. plantarum isolates associated with food spoilage, and may provide clues for disinfection strategies in food industry.

Performance of stress resistant variants of Listeria monocytogenes in mixed species biofilms with Lactobacillus plantarum.

Population diversity and the ability to adapt to changing environments allow Listeria monocytogenes to grow and survive under a wide range of environmental conditions. In this study, we aimed to evaluate the performance of a set of acid resistant L. monocytogenes variants in mixed-species biofilms with Lactobacillus plantarum as well as their benzalkonium chloride (BAC) resistance in these biofilms. L. monocytogenes LO28 wild type and acid resistant variants were capable of forming mixed biofilms with L. plantarum at 20°C and 30°C in BHI supplemented with manganese and glucose. Homolactic fermentation of glucose by L. plantarum created an acidic environment with pH values below the growth boundary of L. monocytogenes. Some of the variants were able to withstand the low pH in the mixed biofilms for a longer time than the WT and there were clear differences in survival between the variants which could not be correlated to (lactic) acid resistance alone. Adaptation to mild pH of liquid cultures during growth to stationary phase increased the acid resistance of some variants to a greater extent than of others, indicating differences in adaptive behaviour between the variants. Two variants that showed a high level of acid adaptation when grown in liquid cultures, showed also better performance in mixed species biofilms. There were no clear differences in BAC resistance between the wild type and variants in mixed biofilms. It can be concluded that acid resistant variants of L. monocytogenes show diversity in their adaptation to acidic conditions and their capacity to survive in mixed cultures and biofilms with L. plantarum.

Enhancement of bile resistance in Lactobacillus plantarum strains by soy lecithin.

UNLABELLED: This study evaluated the effect of soy lecithin on the bile resistance of Lactobacillus plantarum. Six strains were cultured in MRS broth supplemented with soy lecithin at different concentrations. The strains incubated in MRS broth with 1·0% soy lecithin showed no inhibitory effect on cell growth. After culturing in MRS broth with 0·2-1·0% soy lecithin, the survival rate of harvested cells increased significantly (P < 0·05) in the 0·3% bile challenge compared with the no added soy lecithin group. The cells incubated with 0·6% soy lecithin were able to grow in an MRS broth with a higher bile salt content. The surface hydrophobicity and cell leakage in the bile challenge were assessed to reveal the physical changes caused by the addition of soy lecithin. The cell surface hydrophobicity was enhanced and the membrane integrity in the bile challenge increased after culturing with soy lecithin. A shift in the fatty acid composition was also observed, illustrating the cell membrane change in the soy lecithin culture. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we report for the first time the beneficial effect of adding soy lecithin to an MRS broth on subsequent bile tolerance of Lactobacillus plantarum. Soy lecithin had no inhibitory effect on strain viability but significantly enhanced bile resistance. Surface hydrophobicity and cell integrity increased in strains cultured with soy lecithin. The observed shift in the cell fatty acid composition indicated changes to the cell membrane. As soy lecithin is safe for use in the food industry, its protective effects can be harnessed for the development of bile-sensitive strains with health-benefit functions for use in probiotic products.

Bioactivity of proteins isolated from Lactobacillus plantarum L67 treated with Zanthoxylum piperitum DC glycoprotein.

Lactobacilli in the human gastrointestinal tract have beneficial effects on the health of their host. To enhance these effects, the bioactivity of lactobacilli can be fortified through exogenous dietary or pharmacological agents, such as glycoproteins. To elucidate the inductive effect of Zanthoxylum piperitum DC (ZPDC) glycoprotein on Lactobacillus plantarum L67, we evaluated the radical-scavenging activity, anti-oxidative enzymes (SOD, GPx and CAT), growth rate, ATPase activity and ß-galactosidase activity of this strain. When Lact. plantarum L67 was treated with ZPDC glycoprotein at different concentrations, the intensities of a few SDS-PAGE bands were slightly changed. The amount of a 23 kDa protein was increased upon treatment with increasing concentrations of ZPDC glycoprotein. The results of this study indicate that the radical-scavenging activity for O2(-) and OH¯, but not for the DPPH radical, increased in a concentration-dependent manner after treatment with ZPDC glycoprotein. The activation of anti-oxidative enzymes (SOD, GPx and CAT), growth rate and ß-galactosidase activity also increased in a concentration-dependent manner in response to ZPDC glycoprotein treatment, whereas ATPase activity was decreased. In summary, ZPDC glycoprotein stimulated an increase in the bioactivity of Lact. plantarum L67. Significance and impact of the study: This study demonstrated that Lactobacillus plantarum L67 possesses anti-oxidative activity. This strain of lactic bacteria has been known to have various probiotic uses, such as yogurt starters and dietary additional supplements. We found, through this experiment, that the protein has a strong anti-oxidative character, and the activity can be enhanced by treatment with Zanthoxylum piperitum DC (ZPDC) glycoprotein. This study may be application of Lact. plantarum L67 treated by ZPDC glycoprotein in yogurt fermentation. It could be one of the avenues of minimizing yogurt postacidification during storage. In addition, it can be manufactured and incorporated in food products without losing viability and functionality of Lact. plantarum L67.

Plectranthus amboinicus leaves stimulate growth of probiotic L. plantarum: evidence for ethnobotanical use in diarrhea.

ETHNOPHARMACOLOGICAL RELEVANCE: Leaves of Plectranthus amboinicus are consumed in India along with buttermilk (a probiotic source) during pathogen induced diarrhea. This treatment is known to reduce the number of episodes as well as duration of diarrhea. AIM OF THE STUDY: In the background of its ethnobotanical use, the present investigation was carried out to determine whether, apart from having an antimicrobial activity on pathogens, the leaves could possibly also have a positive effect on the beneficial microflora of the gut resulting in accelerated microbial ecological balance. MATERIALS AND METHODS: The growth stimulating activity of the hot water extract (HWE) of P. amboinicus leaves on probiotic Lactobacillus plantarum was determined by microbroth dilution technique and viable plate count method in selective medium (MRS) as well as in fermented milk. The ability of the bacteria to utilize the phytoconstituents of HWE primarily phenolic acids and sugars was determined by assaying for phenolic acid decarboxylase by SDS-PAGE and ß-galactosidase activity by ß-gal ONPG assay. RESULTS: HWE of P. amboinicus leaves inhibited growth of pathogens (Escherichia coli and Salmonella typhimurium) while stimulated the growth of L. plantarum. SDS-PAGE gel showed the presence of phenolic acid decarboxylase enzyme induced in the presence of HWE in L. plantarum indicating the utilization of polyphenols by the bacteria. Cells grown on HWE also showed ß-galactosidase activity indicating their ability to utilize sugars present in HWE. CONCLUSION: Indian borage leaves have a prebiotic effect on the probiotic bacteria (L. plantarum) which utilizes the phytoconstituents of the leaves by producing necessary metabolic enzymes. This work provides evidence in the traditional use of the leaves in the alleviation of diarrhea by accelerating microbial gut balance during infection.

Fermentation of soy milk via Lactobacillus plantarum improves dysregulated lipid metabolism in rats on a high cholesterol diet.

We aimed to investigate whether in vitro fermentation of soy with L. plantarum could promote its beneficial effects on lipids at the molecular and physiological levels. Rats were fed an AIN76A diet containing 50% sucrose (w/w) (CTRL), a modified AIN76A diet supplemented with 1% (w/w) cholesterol (CHOL), or a CHOL diet where 20% casein was replaced with soy milk (SOY) or fermented soy milk (FSOY). Dietary isoflavone profiles, serum lipids, hepatic and fecal cholesterol, and tissue gene expression were examined. The FSOY diet had more aglycones than did the SOY diet. Both the SOY and FSOY groups had lower hepatic cholesterol and serum triglyceride (TG) than did the CHOL group. Only FSOY reduced hepatic TG and serum free fatty acids and increased serum HDL-CHOL and fecal cholesterol. Compared to CHOL, FSOY lowered levels of the nuclear forms of SREBP-1c and SREBP-2 and expression of their target genes, including FAS, SCD1, LDLR, and HMGCR. On the other hand, FSOY elevated adipose expression levels of genes involved in TG-rich lipoprotein uptake (ApoE, VLDLR, and Lrp1), fatty acid oxidation (PPARα, CPT1α, LCAD, CYP4A1, UCP2, and UCP3), HDL-biogenesis (ABCA1, ApoA1, and LXRα), and adiponectin signaling (AdipoQ, AdipoR1, and AdipoR2), as well as levels of phosphorylated AMPK and ACC. SOY conferred a similar expression profile in both liver and adipose tissues but failed to reach statistical significance in many of the genes tested, unlike FSOY. Our data indicate that fermentation may be a way to enhance the beneficial effects of soy on lipid metabolism, in part via promoting a reduction of SREBP-dependent cholesterol and TG synthesis in the liver, and enhancing adiponectin signaling and PPARα-induced expression of genes involved in TG-rich lipoprotein clearance, fatty acid oxidation, and reverse cholesterol transport in adipose tissues.

Vitamin C inhibits staphylococcus aureus growth and enhances the inhibitory effect of quercetin on growth of Escherichia coli in vitro.

Quercetin is a natural flavonoid possessing a number of health beneficial effects. Its bioactivity is restricted by low solubility and sensitivity to oxidative degradation, factors that are often ignored in laboratory studies. We studied the antimicrobial effects of quercetin on Staphylococcus aureus, Escherichia coli and Lactobacillus plantarum at concentrations at which it is soluble and investigated how the antioxidant vitamin C modulates these activities. S. aureus was the most sensitive of the studied bacteria. After 12 hours of culturing, 90 µM quercetin decreased the growth of S. aureus to 75 % of the value for a control culture. 1 mM vitamin C combined with 90 µM quercetin diminished the growth of S. aureus drastically to 3 % of that of the control culture supplemented with vitamin C only. Interestingly, vitamin C by itself inhibited the growth of S. aureus as well, and 5 mM vitamin C inhibited growth completely. The growth inhibition of E. coli was slightly but significantly better in the presence of both quercetin and vitamin C than in the presence of quercetin alone. Probiotic L. plantarum was resistant to quercetin in the presence and absence of vitamin C. Enhancement of quercetin's antimicrobial activity by vitamin C is partly explained by the stabilizing effect of vitamin C on quercetin. Even though the acidity of vitamin C contributes to the inhibition of S. aureus growth, neutralized vitamin C also inhibits the growth efficiently even without quercetin. Our results suggest that vitamin C affects the metabolism of S. aureus and that these changes are likely to result in the observed growth inhibition. Although vitamin C itself is a powerful antioxidant, its aerobic metabolism increases oxidative stress on bacterial cells. Vitamin C may therefore be a safe and natural alternative for restricting the growth of S. aureus when non-toxicity is required.

Effects of lactobacillus plantarum ZJ316 on pig growth and pork quality.

BACKGROUND: Lactobacillus plantarum is a plant-associated bacterial species but it has also been found in human, mouse and porcine gastrointestinal tracts. It can ferment a broad spectrum of plant carbohydrates; it is tolerant of bile salts and low pH, and it has antagonistic potential against intestinal pathogens. However, experiments reporting the use of L. plantarum as a probiotic are limited. In this study, the effects of L. plantarum ZJ316 isolated from infant fecal samples on pig growth and pork quality were investigated. RESULTS: One hundred and fifty newly weaned pigs were selected randomly and divided into five groups. Group 1 was fed a diet supplemented with the antibiotic mequindox; Groups 2, 3 and 4 were fed a diet supplemented with L. plantarum and no antibiotic; and Group 5 was fed a mixture of mequindox and L. plantarum. After a 60 days initial treatment, samples were collected for evaluation. The results showed that, the L. plantarum ZJ316 has probiotic effects on pig growth and that these effects are dose dependent. The effects of a dose of 1 × 109 CFU/d were more pronounced than those of a dose of 5 × 109 CFU/d or 1 × 1010 CFU/d. In Group 2 (1 × 109 CFU/d), the diarrhea (p = 0.000) and mortality rates (p = 0.448) were lower than in antibiotic-treated pigs (Group 1), and the daily weight gain (p = 0.001) and food conversion ratios were better (p = 0.005). Improved pork quality was associated with Lactobacillus treatment. pH (45 min, p = 0.020), hardness (p = 0.000), stickiness (p = 0.044), chewiness (p = 0.000), gumminess (p = 0.000) and restoring force (p = 0.004) were all significantly improved in Lactobacillus-treated pigs (Group 2). Although we found that L. plantarum exerted probiotic effects on pig growth and pork quality, the mechanisms underlying its action require further study. Polymerase chain reaction-denaturing gradient gel electrophoresis results showed that the gut bacterial communities in Lactobacillus- and antibiotic-treated pigs were very similar and the quantity of L. plantarum ZJ316 was below the detection limits of DGGE-band sequencing. The concentration of short-chain fatty acids in Lactobacillus- and antibiotic-treated fecal samples were not significantly different (p = 0.086). However, the villus height of ilea (p = 0.003), jejuna (p = 0.000) and duodena (p = 0.036) were found to be significantly improved by Lactobacillus treatment. CONCLUSION: L. plantarum ZJ316 was found to have probiotic effects, improving pig growth and pork quality. The probiotic mechanism might not involve L. plantarum colonization and alteration of the gut bacterial community. Rather, it might be related to the inhibition of the growth of opportunistic pathogens and promotion of increased villus height.