Bioactive properties of probiotic set-yogurt supplemented with Siraitia grosvenorii fruit extract.

Siraitia grosvenorii fruit (SGF) has been used as a natural sweetener and traditional medicine in China for more than two centuries. This study evaluated the effect of SGF extract supplementation (0.5%, 1%, and 2%) on the chemical, microbial and sensory properties of probiotic yogurt. The antioxidant, angiotensin-converting-enzyme inhibitory (ACE-I) and antibacterial bioactivities were determined. SGF extract supplementation improved some of the chemical and physicochemical characteristics. Probiotic yogurt with the fruit extract had significantly more Lactobacillus casei and Lactobacillus bulgaricus, whereas there was no significant effect on the number of Streptococcus thermophiles. The bioactivities were significantly increased by SGF extract supplementation. Probiotic yogurt with 2% SGF extract showed the highest antioxidant, ACE-I, and antibacterial activities, whereas the one with 1% SGF extract conferred the highest sensory attributes score. Overall, SGF extract offers a promising option as a dietary supplement to produce novel dairy products that have high nutritional and bioactivity values.

A High Throughput Isolation Method for Phosphate-Accumulating Organisms.

Hyperphosphatemia is a secondary issue associated with chronic kidney disorder. Use of phosphate binders and dialysis are the treatments for hyperphosphatemia, albeit with harmful side effects and high cost, respectively. A safer and healthier approach is attempted to administer phosphate-accumulating organisms (PAOs) from probiotics to prevent hyperphosphatemia. However, screening and isolation of PAOs are limited by inefficient enrichment of relevant metabolism and contamination. Therefore, we devised a novel strategy to isolate elite PAOs from Lactobacillus casei JCM 1134 and Bifidobacterium adolescentis JCM 1275 (previously reported PAOs). PAOs were first enriched for phosphate uptake and incubated in low-pH phosphate-free media to dormant non-PAOs, and then purified using Percoll density gradient centrifugation. Subsequently, elite PAOs were isolated from centrifuged pellet on a toluidine blue O-supplemented agar-based media. Using this technique, elite PAOs could not only be isolated, but also semi-quantitatively scored for their phosphate accumulation capabilities. Additionally, these scores correlated well with their accumulated phosphate values. The elite PAOs isolated from L. casei and B. adolescentis showed 0.81 and 0.70 [mg-phosphate/mg-dry cell], respectively (23- and 4.34-fold increase, respectively). Thus, our method can be used to successfully isolate elite PAOs, which might be of use to prevent hyperphosphatemia at early stages.

Copaifera reticulata oleoresin: Chemical characterization and antibacterial properties against oral pathogens.

Oral infections such as periodontitis and tooth decay are the most common diseases of humankind. Oleoresins from different copaifera species display antimicrobial and anti-inflammatory activities. Copaifera reticulata is the commonest tree of this genus and grows abundantly in several Brazilian states, such as Pará, Amazonas, and Ceará. The present study has evaluated the chemical composition and antimicrobial potential of the Copaifera reticulata oleoresin (CRO) against the causative agents of tooth decay and periodontitis and has assessed the CRO cytotoxic potential. Cutting edge analytical techniques (GC-MS and LC-MS) aided the chemical characterization of CRO. Antimicrobial assays included determination of the Minimum Inhibitory Concentration (MIC), determination of the Minimum Bactericidal Concentration (MBC), determination of the Minimum Inhibitory Concentration of Biofilm (MICB50), Time Kill Assay, and Checkerboard Dilution. Conduction of XTT assays on human lung fibroblasts (GM07492-A cells) helped to examine the CRO cytotoxic potential. Chromatographic analyses revealed that the major constituents of CRO were ß-bisabolene, trans-α-bergamotene, ß-selinene, α-selinene, and the terpene acids ent-agathic-15-methyl ester, ent-copalic acid, and ent-polyalthic acid. MIC and MBC results ranged from 6.25 to 200 µg/mL against the tested bacteria. The time-kill assay conducted with CRO at concentrations between 50 and 100 µg/mL showed bactericidal activity against Fusobacterium nucleatum (ATCC 25586) and Streptococcus mitis (ATCC 49456) after 4 h, Prevotella nigrescens (ATCC 33563) after 6 h, Porphyromonas gingivalis (ATCC 33277) and Lactobacillus casei (clinical isolate) after 12 h, and Streptococcus salivarius (ATCC 25975) and Streptococcus mutans (ATCC 25175) after 18 h. The fractional inhibitory concentration indexes (FICIs) revealed antagonistic interaction for Lactobacillus casei (clinical isolate), indifferent effect for Porphyromonas gingivalis (ATCC 33277), Fusobacterium nucleatum (ATCC 25586), Prevotella nigrescens (ATCC 33563), and Streptococcus salivarius (ATCC 25975), and additive effect for Streptococcus mutans (ATCC 25175) and Streptococcus mitis (ATCC 49456). Treatment of GM07492-A cells with CRO demonstrated that concentrations up to 39 µg/mL significantly reduced cell viability as compared to the negative control, being IC50 equal to 51.85 ± 5.4 µg/mL. These results indicated that CRO plays an important part in the search for novel sources of agents that can act against oral pathogens.

Selection, characterisation and evaluation of potential probiotic Lactobacillus spp. isolated from poultry droppings.

Aim of the present study was to characterise and evaluate probiotic potential of lactobacilli isolated from indigenous poultry. Lactobacilli were isolated from poultry droppings and identified by genus specific polymerase chain reaction and 16S rRNA gene sequencing. Isolates were characterised in vitro by their ability to tolerate low pH and bile salts, phytase activity, antimicrobial activity, antibiotic susceptibility profile, and autoaggregation and coaggregation with poultry gut pathogens. In vivo evaluation of selected isolates was done by their effect on the body weight gain and immune response of broiler chicks. Total of 90, one-day old chicks, were randomly divided in 9 groups and given selected lactobacilli alone and in combinations (108 cfu/bird, daily) from day 7 to day 35. Body weight gain and humoral immune response to New Castle Disease Virus (NDV) vaccine were determined weekly. Three lactobacilli isolates (SMP52, SMP64 and SMP70) were selected as potentially probiotic bacteria on the basis of in vitro characterisation and identified as Lactobacillus crispatus, Lactobacillus casei and L. crispatus, respectively. Chicks supplemented with 'SMP52', 'SMP64', 'SMP70' and 'SMP64+SMP70' and a commercial probiotic product (Protexin) showed significantly higher mean weight gain per bird (1,584±35.2, 1,629±30.6, 1,668±34.7, 1,619±29.5 and 1,576±31.7 g/bird, respectively) as compared to negative control group (1,394±26.7 g/bird), on day 35. SMP 70 also showed significantly higher geometric mean titre against NDV vaccine at day 21 as compared to negative control. It is concluded that L. crispatus SMP52, L. casei SMP64 and L. crispatus SMP70 are potential probiotic candidates which alone or in different combinations may increase body weight of broilers.

Lactobacillus strains belonging to Casei group display various adherence to enterocytes and mucus.

BACKGROUND: The ability of lactobacilli to adhere to the surface of the intestine is an important functional characteristic which can largely determine the effective colonization of the intestinal tract by probiotics. The following study compares the adhesion efficiency of the twenty strains of Lactobacillus genus belonging to Casei group to the Caco-2 cells and gastrointestinal mucus. METHODS: Twenty isolates of lactobacilli belonging to Casei group were tested. The ability of bacterial cells to adhere to mucus was examined using adhesion assay to gastrointestinal mucus. Obtained results were compared with adhesion efficiency to Caco-2 cells. Phylogenetic relationship between isolates was analysed by rep-PCR. RESULTS: The results showed large differences in adhesion efficiency between strains, as well as differences in the efficiency of adhesion to the intestinal epithelial cells and mucus. Group similarity highlighted by a rep-PCR technique does not correspond with groups of similarity in terms of the characteristics of the ability to adhere to mucus or the epithelial cells of intestinal tract. CONCLUSIONS: Strains having a high adhesion efficiency to enterocytes do not always show a high adhesion efficiency to the mucus. This may indicate the presence of different and multiple factors responsible for adhesion efficiency of Lactobacillus group Casei strains to epithelial cells and mucus.

Estimation of the antioxidant activity of the commercially available fermented milks.

BACKGROUND: Free radicals are connected with the increased risk of certain diseases, especially cancers. There is some scientific evidence that antioxidant-rich diet may inhibit the negative impact of free radicals. The aim of the present study was to analyse the antioxidant capacity of the selected commercial natural and flavoured fermented milks offered in Poland, derived from different producers. METHODS: The following commercially available natural fermented milks: 12 yoghurts, 12 kefirs, 2 butter milks, 2 cultured milks, Turkish yoghurt drink (ayran) and the following flavoured fermented milks: 22 yoghurts, 2 acidophillus milks, 2 kefirs, butter milk and vegetable flavoured fermented milk were analysed for their antioxidant potential. The antioxidant capacity was assessed, in two replicates and twice for each product, by means of ferric reducing antioxidant power (FRAP) and DPPH radical scavenging ability (expressed as ARP - anti radical power) methods. RESULTS: Among all analysed plain products, yoghurts and kefirs were characterised by the highest antioxidant activity. The presence of probiotic Lactobacillus casei strains in the product positively affected both FRAP and ARP values. Antioxidant capacity of the flavoured fermented milks was primarily affected by the type and quality (e.g. fruit concentration) of the added flavouring preparation. The most valuable regarding the estimated parameters were chocolate, coffee, grapefruit with green tea extract as well as bilberry, forest fruits, strawberry and cherry with blackcurrant fillings. CONCLUSIONS: Protein content, inclusion of probiotic microflora as well as type and quality of flavouring preparations are the main factors affecting antioxidant properties of fermented milks.

Effect of Aloe vera (Aloe barbadensis Miller) on survivability, extent of proteolysis and ACE inhibition of potential probiotic cultures in fermented milk.

BACKGROUND: In the present investigation, the effect of Aloe vera gel powder on angiotensin-converting enzyme (ACE) inhibitory activity, extent of proteolysis during fermentation and survival of Lactobacillus casei NCDC19 during storage of fermented milk was studied. RESULTS: Among the different cultures screened for ACE inhibitory activity, Lactobacillus casei NCDC 19 exhibited the highest ACE inhibition (approx. 40%) as well as extent of proteolysis (0.37, Abs340). In the presence of Aloe vera (0.5% and 1% w/v) an increase in extent of proteolysis (0.460 ± 0.047 and 0.480 ± 0.027) and percent ACE inhibitory activity (44.32 ± 2.83 and 47.52 ± 1.83) was observed in comparison to control. Aloe vera powder addition also led to an increase in viable counts (>11 log cfu mL⁻¹) of L. casei NCDC 19 in fermented milk during storage for 7 days and the counts were maintained in sufficiently higher numbers. CONCLUSION: The study suggests Aloe vera to be a good functional ingredient which can be further explored for different health attributes.

Immunological evaluation of Lactobacillus casei Zhang: a newly isolated strain from koumiss in Inner Mongolia, China.

BACKGROUND: There is increasing evidence to suggest an immunomodulation function both within the intestines and systemically upon consuming probiotic species. We recently isolated a novel LAB, Lactobacillus caseiZhang (LcZhang) from koumiss. LcZhang exhibited favorable probiotic properties, such as acid resistance, bile resistance, gastrointestinal (GI) colonization ability, etc. In order to examine the immunomodulatory qualities of LcZhang, we administered LcZhang to healthy mice with varying doses of either live or heat-killed LcZhang and measured various parameters of the host immune response. RESULTS: The study was performed in four separate experiments via oral administration of live and heat-killed LcZhang to BALB/c mice for several consecutive days. We investigated the immunomodulating capacity of LcZhang in vivo by analyzing the profile of cytokines, T cell subpopulations, and immunoglobulin concentrations induced in blood serum and intestinal fluid in BALB/c mice. Only live bacteria elicited a wide range of immune responses, which include the increased production of interferon-gamma (IFN-gamma), and depression of tumor necrosis factor-alpha (TNF-alpha) levels. In addition, interleukin-2 (IL-2) and IL-2 receptor gene transcription increased significantly, but the proportion of T cell subsets appeared to be unaffected. We also observed that LcZhang was capable of inducing gut mucosal responses by enhancing the production of secretory Immunoglobulin A (sIgA) as well influencing the systemic immunity via the cytokines released to the circulating blood. CONCLUSION: The present work shows that the dose-dependent administration of LcZhang is capable of influencing immune responses, implying that it may be a valuable strain for probiotic use in humans.

Lactobacillus casei improves resistance to pneumococcal respiratory infection in malnourished mice.

We studied the effect of Lactobacillus casei CRL 431 used as a supplement in a repletion diet on the resistance to Streptococcus pneumoniae respiratory infection in malnourished mice. Weaned mice were malnourished after they consumed a protein-free diet (PFD) for 21 d. Malnourished mice were fed a balanced conventional diet (BCD) with or without supplemental L. casei for 7, 14, or 21 consecutive days, or BCD for 7 d with L. casei supplementation on d 6 and 7 (7dBCD+2dLc). The malnourished control (MNC) group was fed only the PFD, whereas well-nourished control (WNC) mice consumed the BCD ad libitum. Mice were challenged with S. pneumoniae at the end of each dietary treatment. Lung colonization and bacteremia were significantly greater in MNC than in WNC. Normalization of the immune response occurred in malnourished mice fed the BCD for 21 d. L. casei supplementation reduced the time required for a normal response from 21 to 7 d. Mice administered the 7dBCD+2dLc repletion treatment had a more effective pathogen clearance from blood and significantly lower lung damage than MNC. This treatment improved both the number of leukocytes and neutrophils in blood and bronchoalveolar lavages (BAL) and the bactericidal function of phagocytic cells to levels that did not differ from those of WNC. In the 7dBCD+2dLc mice, antipneumococcal IgA in BAL was higher than in WNC, whereas antipneumococcal IgG in serum and BAL did not differ. This study suggests that the addition of L. casei to the repletion diet has a beneficial effect because it accelerates the recovery of the innate immune response and improves the specific immune mechanisms against an S. pneumoniae respiratory infection in malnourished mice.