In vitro Mutagen binding and antimutagenic activity of human Lactobacillus rhamnosus 231

The Anti- and Pro-Tumorigenic Role of Microbiota and Its Role in Anticancer Therapeutic Strategies

Human gut microbiota physiologically and actively participates as a symbiont to a wide number of fundamental biological processes, such as absorption and metabolism of nutrients, regulation of immune response and inflammation; gut microbiota plays also an antitumor role. However, dysbiosis, resulting from a number of different situations-dysmicrobism, infections, drug intake, age, diet-as well as from their multiple combinations, may lead to tumorigenesis and is associated with approximately 20% of all cancers. In a diagnostic, prognostic, therapeutic, and epidemiological perspective, it is clear that the bifaceted role of microbiota needs to be thoroughly studied and better understood. Here, we discuss the anti- and pro-tumorigenic potential of gut and other microbiota districts along with the causes that may change commensal bacteria from friend to foes.

Precise oral delivery systems for probiotics: A review

Probiotics have several health benefits to the host. However, low pH in the stomach, various digestive enzymes and bile salts in the intestine threaten their viability and function. Thus, probiotics need to be protected during gastric transit to address challenges associated with low viability and impaired function. At present, probiotic delivery systems with different trigger mechanisms have been constructed to successfully introduce numerous high-viability probiotics to the intestine. On this basis, the application of non-targeted/targeted probiotic delivery systems in different gut microenvironment and the adjuvant therapeutic effect of probiotic delivery systems on other disease were discussed in detail. It is important to also note that most of the current studies in this area focused on non-targeted probiotic delivery systems. Moreover, changes in intestinal microenvironment under disease state and discontinuous distribution of disease site limit their development. Thus, emphasis were made on the optimization of non-targeted probiotic delivery systems and the necessity of designing more precisely targeted ones.

Antimutagenic Activity as a Criterion of Potential Probiotic Properties

The antimutagenic activity of probiotic strains has been reported over several decades of studying the effects of probiotics. However, this activity is rarely considered an important criterion when choosing strains to produce probiotic preparations and functional food. Meanwhile, the association of antimutagenic activity with the prevention of oncological diseases, as well as with a decrease in the spread of resistant forms in the microbiota, indicates its importance for the selection of probiotics. Besides, an antimutagenic activity can be associated with probiotics' broader systemic effects, such as geroprotective activity. The main mechanisms of such effects are considered to be the binding of mutagens, the transformation of mutagens, and inhibition of the transformation of promutagens into antimutagens. Besides, we should consider the possibility of interaction of the microbiota with regulatory processes in eukaryotic cells, in particular, through the effect on mitochondria. This work aims to systematize data on the antimutagenic activity of probiotics and emphasize antimutagenic activity as a significant criterion for the selection of probiotic strains.

Antioxidant and antimutagenic properties of probiotic Lactobacilli determined using LUX-biosensors

The initial screening of probiotic strains in vitro, carried out by different methods, may omit strains that are promising from the point of view of biotechnology or, conversely, mark as promising strains those that will lose activity when transferred in vivo. It is known that the release of metabolites by probiotic bacteria, in particular, lactobacilli, is highly dependent on the biochemical context. In this work, we modified the method that was previously successfully used for the selection of probiotics for poultry, based on their antioxidant and DNA-protective properties. A comparison was made of this activity on standard media and on an artificial intestinal medium that mimics the intestines of a bird. As a result, three Lactobacillus strains were selected, which not only exhibit antioxidant and DNA-protective properties but also do not lose these activities in an artificial intestinal medium.

Strategies for the treatment of colorectal cancer caused by gut microbiota

Colorectal cancer (CRC), also named as colon and rectal or bowel cancer, is one of the leading neoplasia diagnosed in the world. Genetic sequencing studies of microorganisms from the intestinal microbiota of patients with CRC revealed that changes in its composition occur with the development of the disease, which can play a fundamental role in its development, being mediated by the production of metabolites and toxins that damage enterocytes. Some microorganisms are frequently reported in the literature as the main agents of this process, such as the bacteria Fusobacterium nucleatum, Escherichia coli and Bacteroides fragilis. Thus, understanding the mechanisms and function of each microorganism in CRC is essential for the development of treatment tools that focus on the gut microbiota. This review verifies current research aimed at evaluating the microorganisms present in the microbiota that can influence the development of CRC, as well as possible forms of treatment that can prevent the initiation and/or spread of this disease. Due to the incidence of CRC, alternatives have been launched considering factors beyond those already known in the disease development, such as diet, fecal microbiota transplantation, use of probiotics and antibiotics, which have been widely studied for this purpose. However, despite being promising, the studies that focus on the development of new therapeutic approaches targeting the microorganisms that cause CRC still need to be improved and better developed, involving new techniques to elucidate the effectiveness and safety of these new methods.

Screening of lactic acid bacteria for their capacity to bind cypermethrin in vitro and the binding characteristics and its application

In this study, the cypermethrin binding characteristics of lactic acid bacteria were investigated for the first time. Two strains, Lactobacillus plantarum RS60 and Pediococcus acidilactici D15, possessed the highest cypermethrin removal capacity and good tolerance to simulated digestive juices. They were employed for further studies on cypermethrin binding characteristics. 55.06% and 56.46% of cypermethrin were removed within 0.25 h by strains RS60 and D15, respectively. The effect of pH on binding capacity was negligible. Heat treatment enhanced cypermethrin binding rate. Moreover, inactive cells were capable of removing cypermethrin from fruit and vegetable juices, with over 60% cypermethrin reduction within 2 h. No adverse effect was found on the quality of juice during the biosorption process. Besides, these two strains also could bind other several pyrethroids and 3-phenoxybenzoic acid. These findings indicated that L. plantarum RS60 and P. acidilactici D15 may be useful to reduce cypermethrin in contaminated foods.

Postbiotics as Promising Tools for Cancer Adjuvant Therapy

As many investigations have reported, there is a complicated relation between fermented foods, lactic acid bacteria (LAB), and human health. It seems that bioactive components such as prebiotics, probiotics, and postbiotics are key mediators of the complex and direct association between these factors. LAB activity in the matrix of fermented foods and improving their growth by prebiotic compounds ultimately results in the production of bioactive molecules (postbiotics), which possess specific biological and physiological properties. The term "postbiotics" refers to a complex of biological micro- and macromolecules, if consumed in adequate amounts, provides the host with different health-promoting effects. Different reports have suggested that postbiotics possess the ability to moderate the effectiveness of cancer treatment and reduce the side-effects of conventional therapies in cancer patients due to their anti-proliferative, anti-inflammatory and anti-cancer properties. Consequently, postbiotics, for their unique characteristics, have gained great scientific attention and are considered as a novel approach for adjuvant therapy in patients with cancer.

Improved Gastric Acid Resistance and Adhesive Colonization of Probiotics by Mucoadhesive and Intestinal Targeted Konjac Glucomannan Microspheres

The low survival rate in harsh stomach conditions and short retention in intestine of probiotics greatly limit their health benefits. To solve this problem, thiolated oxidized konjac glucomannan (sOKGM) microspheres is designed with pH responsive and mucoadhesive properties. First, an increased survival rate of probiotics by sOKGM microspheres encapsulation in simulated gastric fluid (SGF) is discovered in contrast to the zero‐survival rate of naked probiotics. sOKGM/probiotics even show a higher survival rate in SGF compared with commercial Bb12 formulation. Further, an enhanced mucoadhesion of probiotics to intestinal mucus by mediated interactions with sOKGM is confirmed by isotherm titration calorimetry, rheology, and tensile measurements. The in vivo intestinal transition experiment indicates a prolonged retention of probiotics at intestine by sOKGM encapsulation. Moreover, in vivo evaluation of enhanced colonization and proliferation by sOKGM/probiotics is demonstrated by the fecal and intestinal bacteria copy number via quantitative polymerase chain reaction (qPCR) detection. Further investigation of the alleviation of constipation by sOKGM containing Bifidobacterium animalis subsp. lactis A6 suggests that sOKGM increases the abundance of Bifidobacterium, balanced intestinal flora, and alleviated constipation in mice compared with other formulations. sOKGM with both enhanced gastric acid resistance and adhesion colonization at intestine can effectively improve the function of probiotics.

In Vitro Studies on Therapeutic Potential of Probiotic Yeasts Isolated from Various Sources

The present study investigates the therapeutic properties of probiotic yeasts viz. Yarrowia lipolytica VIT-MN01, Kluyveromyces lactis VIT-MN02, Lipomyces starkeyi VIT-MN03, Saccharomycopsis fibuligera VIT-MN04 and Brettanomyces custersianus VIT-MN05. The antimutagenic activity of probiotic yeasts against the mutagens viz. Benzo[a]pyrene (B[a]P), and Sodium azide (SA) was tested. S. fibuligera VIT-MN04 showed highest antimutagenicity (75%). Binding ability on the mutagen acridine orange (AO) was tested and L. starkeyi VIT-MN03 was able to bind AO effectively (88%). The probiotic yeasts were treated with the genotoxins viz. 4-Nitroquinoline 1-Oxide (NQO) and Methylnitronitrosoguanidine (MNNG). The prominent changes in UV shift confirmed the reduction in genotoxic activity of S. fibuligera VIT-MN04 and L. starkeyi VIT-MN03, respectively. Significant viability of probiotic yeasts was noted after being exposed to mutagens and genotoxins. The adhesion capacity and anticancer activity were also assessed using Caco-2 and IEC-6 cell lines. Adhesion ability was found to be more in IEC-6 cells and remarkable antiproliferative activity was noted in Caco-2 cells compared to normal cells. Further, antagonistic activity of probiotic yeasts was investigated against S. typhimurium which was found to be more in S. fibuligera VIT-MN04 and L. starkeyi VIT-MN03. The inhibition of α-glucosidase and α-amylase activity confirmed the antidiabetic activity of probiotic yeasts. Antioxidant activity was also tested using standard assays. Therefore, based on the results, it can be concluded that probiotic yeasts can serve as potential therapeutic agents for the prevention and treatment of colon cancer, type 2 diabetes and gastrointestinal infections.

Molecular mechanisms of postbiotics in colorectal cancer prevention and treatment

The occurrence of colorectal cancer (CRC) has been rising expeditiously and anticipated that 2.4 million new occasions of CRC will be detected yearly around the world until the year 2035. Due to some side-effects and complications of conventional CRC therapies, bioactive components such as microbial-derived biomolecules (postbiotics) have been attaining great significance by researchers for adjuvant therapy in CRC patients. The term 'postbiotics' encompasses an extensive range of complex micro- and macro-molecules (<50, 50-100, and 100< kDa) such as inactivated microbial cells, cell fractions or metabolites, which confer various physiological health benefits to the host when administered in adequate amounts. Postbiotics modulate the composition of the gut microbiota and the functionality of the immune system, as well as promote the CRC treatment effectiveness and reduces its side-effects in CRC patients due to possessing anti-oxidant, anti-proliferative, anti-inflammatory, and anti-cancer activities. Presently scientific literature confirms that postbiotics with their unique characteristics in terms of clinical (safe origin), technological (stability), and economic (low production costs) aspects can be used as promising tools for both prevent and adjuvant treat strategies in CRC patients without any serious undesirable side-effects. This review provides an overview of the concept and safety issues regarding postbiotics, with emphasis on their biological role in the prevention and treatment of CRC.

Detoxification of Heterocyclic Aromatic Amines by Probiotic to Inhibit Medical Hazards

Cancer is the second leading factor of human death in the world. Long-term consumption of cooked red meat brings about various types of cancers like colorectal cancer due to the formation of Heterocyclic Aromatic Amines (HAAs) during the heating process of meat. There are various solutions for the reduction of these toxicants. The aim of this article is to describe probiotic as one of the possible strategies for bioremoval of these carcinogenic and mutagenic substances and change food to functional one as well. The mechanism of biodetoxification is binding by probiotics, which depends on some variables including the probiotic characteristics, kind and content of the mutagens, as well as some properties of media. In this article, after introducing detoxification ability of probiotics and listing of all reported probiotics in this field, the influencing variables are surveyed and finally, opportunities and problems of HAA bioremoval by probiotics are described.

Probiotics, prebiotics and colorectal cancer prevention

Colorectal cancer (CRC), the third major cause of mortality among various cancer types in United States, has been increasing in developing countries due to varying diet and dietary habits and occupational hazards. Recent evidences showed that composition of gut microbiota could be associated with the development of CRC and other gut dysbiosis. Modulation of gut microbiota by probiotics and prebiotics, either alone or in combination could positively influence the cross-talk between immune system and microbiota, would be beneficial in preventing inflammation and CRC. In this review, role of probiotics and prebiotics in the prevention of CRC has been discussed. Various epidemiological and experimental studies, specifically gut microbiome research has effectively improved the understanding about the role of probiotics and microbial treatment as anticarcinogenic agents. A few human studies support the beneficial effect of probiotics and prebiotics; hence, comprehensive understanding is urgent to realize the clinical applications of probiotics and prebiotics in CRC prevention.

Antigenotoxic and Antimutagenic Activities of Probiotic Lactobacillus rhamnosus Vc against N-Methyl-N'-Nitro-N-Nitrosoguanidine

The present study provides experimental evidence of in vivo reduction of genotoxic and mutagenic activities of potent carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) by the strain Lactobacillus rhamnosus Vc. In vitro studies revealed that coincubation of MNNG with viable cells of L. rhamnosus Vc resulted in the detoxification of the parent compound accompanied with reduction in genotoxicity (69%) and mutagenicity (61%) as evaluated by SOS-Chromotest and Ames test, respectively. Oral feeding of probiotic bacteria L. rhamnosus Vc (10(9) cfu) to Gallus gallus (chicks) for 30 days provided protection against MNNG-induced damage as evidenced from the significant decrease (P = 0.009) in glutathione S-transferase activity in the L. rhamnosus Vc+MNNG-treated chicks in comparison to the MNNG-treated chicks. Histopathology of colon and liver showed intact cells and mild inflammation in the L. rhamnosus Vc+MNNG-treated chicks, whereas heavy inflammation and degenerative changes were observed in MNNG-treated chicks. The results indicate that the probiotic L. rhamnosus Vc provided in vivo protection against MNNG-induced colon damage by detoxification of MNNG to less toxic metabolites.

Safety evaluation of multiple strains of Lactobacillus plantarum and Pediococcus pentosaceus in Wistar rats based on the Ames test and a 28-day feeding study

Three lactic acid bacterial strains, Lactobacillus plantarum, HK006, and HK109, and Pediococcus pentosaceus PP31 exhibit probiotic potential as antiallergy agents, both in vitro and in vivo. However, the safety of these new strains requires evaluation when isolated from infant faeces or pickled cabbage. Multiple strains (HK006, HK109, and PP31) were subject to a bacterial reverse mutation assay and a short-term oral toxicity study. The powder product exhibited mutagenic potential in Salmonella Typhimurium strains TA98 and TA1535 (with or without metabolic activation). In the short-term oral toxicity study, rats received a normal dosage of 390 mg/kg/d (approximately 9 × 10⁹ CFU/kg/d) or a high dosage of 1950 mg/kg/d (approximately 4.5 × 10¹⁰ CFU/kg/d) for 28 d. No adverse effects were observed regarding the general condition, behaviour, growth, feed and water consumption, haematology, clinical chemistry indices, organ weights, or histopathologic analysis of the rats. These studies have demonstrated that the consumption of multiple bacterial strains is not associated with any signs of mutagenicity of S. Typhimurium or toxicity in Wistar rats, even after consuming large quantities of bacteria.

Insight into the Draft Genome Sequence of Human Isolate Lactobacillus rhamnosus LR231, a Bacterium with Probiotic Potential

Lactobacillus rhamnosus strain LR231 was isolated from the feces of healthy human subjects. It is observed to be a potential probiotic strain, having a broad spectrum of antimicrobial activity against a wide range of human pathogens and food pathogens. Here, we provide the 2.59-Mb draft genome sequence of L. rhamnosus LR231.

Genotoxicity assessment of multispecies probiotics using reverse mutation, mammalian chromosomal aberration, and rodent micronucleus tests

Genotoxicity assessment is carried out on freeze dried powder of cultured probiotics containing Lactobacillus rhamnosus LCR177, Bifidobacterium adolescentis BA286, and Pediococcus acidilactici PA318. Ames tests, in vitro mammalian chromosome aberration assay, and micronucleus tests in mouse peripheral blood are performed. For 5 strains of Salmonella Typhimurium, the Ames tests show no increased reverse mutation upon exposure to the test substance. In CHO cells, the frequency of chromosome aberration does not increase in responding to the treatment of probiotics. Likewise, the frequency of micronucleated reticulocytes in probiotics-fed mice is indistinguishable from that in the negative control group. Taken together, the toxicity assessment studies suggest that the multispecies probiotic mixture does not have mutagenic effects on various organisms.

Potential of probiotics, prebiotics and synbiotics for management of colorectal cancer

Colorectal Cancer (CRC) is the second leading cause of cancer-related mortality and is the fourth most common malignant neoplasm in USA. Escaping apoptosis and cell mutation are the prime hallmarks of cancer. It is apparent that balancing the network between DNA damage and DNA repair is critical in preventing carcinogenesis. One-third of cancers might be prevented by nutritious healthy diet, maintaining healthy weight and physical activity. In this review, an attempt is made to abridge the role of carcinogen in colorectal cancer establishment and prognosis, where special attention has been paid to food-borne mutagens and functional role of beneficial human gut microbiome in evading cancer. Further the significance of tailor-made prebiotics, probiotics and synbiotics in cancer management by bio-antimutagenic and desmutagenic activity has been elaborated. Probiotic bacteria are live microorganisms that, when administered in adequate amounts, confer a healthy benefit on the host. Prebiotics are a selectively fermentable non-digestible oligosaccharide or ingredient that brings specific changes, both in the composition and/or activity of the gastrointestinal microflora, conferring health benefits. Synbiotics are a combination of probiotic bacteria and the growth promoting prebiotic ingredients that purport "synergism."

Protective effect of Lactobacillus rhamnosus 231 against N-Methyl-N'-nitro-N-nitrosoguanidine in animal model

The protective effect of Lactobacillus rhamnosus 231 (Lr 231) against potent carcinogen N-Methyl-N'-Nitro-N-Nitrosoguanidine (MNNG) in the rat model is studied. Daily feeding with Lr 231 improved the body weight of male Wistar rats compared with control groups. Fecal azoreductase (p < 0.001) and nitroreductase (p < 0.01) enzyme activity decreased significantly in Lr 231 group in comparison with control groups that received only phosphate buffer or MNNG. Oral administration of MNNG led to a significant increase in Glutathione transferase (GST) while Glutathione reductase (GSH) showed decreased activity. Conversely, feeding Lr 231 showed significantly increased GSH and decreased GST activity in comparison to the MNNG group, emphasizing the protection provided by Lr 231 against MNNG. Histopathological analysis of liver, spleen and colon showed decreased signs of inflammation in the Lr 231 group. The present study highlights that inclusion of active Lr 231 in regular diets could be used to prevent MNNG induced colon carcinoma.