Presentation on probiotics and their mode of action.pptx

Probiotics and their mode of action

1. Introduction to Probiotics & their mode of action Trainer- Dr. Kusum Dua Chaudhary

2. INTRODUCTION Probiotics are live microbes that can be formulated into many different types of product , including foods, drugs, and dietary supplements. Probiotics are defined as ‘live microorganisms which when administered in adequate amount confer health benefits to the host’ (FAO/WHO, 2002). Species of Lactobacillus and Bifidobacterium are most commonly used as probiotics , but the yeast Saccharomyces cerevisiae and some E. coli and Bacillus species are also used as probiotics . Lactic acid bacteria, including Lactobacillus species, which have been used for preservation of food by fermentation for thousands of years, can serve a dual function by acting as agents for food fermentation and, in addition, potentially imparting health benefits .

3. History of Probiotics

4. History Of Probiotics Elie Metchnikoff, postulated that lactic acid bacteria (LAB) offered health benefits capable of promoting longevity. He suggested that “intestinal autointoxication” and the resultant aging could be suppressed by modifying the gut microbiota and replacing proteolytic microbes such as Clostridium. He developed a diet with milk fermented with the bacterium he called “Bulgarian bacillus .” A Bifidobacterium was first isolated by Henry Tissier from a mother-fed infant, and he named the bacterium Bacillus bifidus communis . Tissier claimed that bifidobacteria would displace the proteolytic bacteria that cause diarrhea and recommended the administration of bifidobacteria to infants suffering from this symptom .

5. Common probiotic microorganisms The most commonly used are bacteria belonging to the genera Lactobacillus, the first and largest group of microorganisms to be regarded as probiotics and Bifidobacterium . These bacteria are indigenous to the human GIT . They are known to have no harmful effects , which is in contrast to other gut bacteria. Species of Lactobacilli include L. acidophilus, L.rhamnosus , L. casei , L. delbrueckii ssp. bulgaricus , L. johnsonii , L. reuteri , L. brevis , L. cellobiosus , L. curvatus , L. fermentum , L. gasseri and L. plantarum . The most recognized bifidobacteria species used are Bifidobacterium breve , B. animalis subsp lactis formerly B. lactis and B. longum biotypes infantis and longum .

6. Probiotics now include other lactic acid bacteria (LAB) from genera such as Streptococcus, Lactococcus , Enterococcus , Leuconostoc , Propionibacterium , and Pediococcus . Other non-related microbes used include bacteria such as non pathogenic E. coli Nissle 1917 and Clostridium butyricum , yeasts ( Saccharomyces cereviciae , Saccharomyces boulardii ), filamentous fungi ( Aspergillus oryzae ), and some spore forming bacilli also.

7. Prebiotics and Synbiotics Prebiotics are dietary substances that nurture a selected group of microorganisms living in the gut . They favor the growth of beneficial bacteria over that of harmful ones. most prebiotics are used as foods like biscuits, cereals, chocolate, spreads, and dairy products. Commonly known prebiotics are: · Oligofructose - found in wheat, onions, bananas, honey, garlic, and leeks. · Inulin · Galacto -oligosaccharides · Lactulose - synthetic disaccharide used as a drug for the treatment of constipation and hepatic encephalopathy · Breast milk oligosaccharides

8. Fermentation of oligofructose in the colon results in a large number of physiologic effects, including: · Increasing the numbers of bifidobacteria in the colon · Increasing calcium absorption · Increasing fecal weight · Shortening gastrointestinal transit time · Possibly, lowering blood lipid levels Synbiotics are appropriate combinations of prebiotics and probiotics . A synbiotic product exerts both a prebiotic and probiotic effect.

9. NOMENCLATURE A probiotic strain is identified by the genus, species, and an alphanumeric designation. In the scientific community, there is an agreed nomenclature for microorganisms—for example, Lactobacillus casei DN-114 001 or Lactobacillus rhamnosus GG

10. Probiotic Strains in Products

11. Properties essential for effective and successful probiotics The probiotic strain should survive in the site where it is presumed to be active. For maximum activity, the strain should be able to proliferate and colonize at this specific location. should also be tolerated by the immune system . should not be pathogenic, allergic, or mutagenic/carcinogenic . Probiotics for human should have ‘ generally regarded as safe ’ status, with a proven low risk of inducing or being associated with the disease. The probiotic organisms should preferably be of human origin , must be able to survive and grow in the in vivo conditions of the desired site of administration, and thus must be able to tolerate low pH and high concentration of bile acids. For successful application in foods, the probiotic used should also be technologically compatible with the food manufacturing process. In addition to that, the foods containing the probiotic bacteria must maintain the characteristic sensory attributes of the traditional food.

12. Health attributes of probiotics

13. Mechanism of Action of Probiotics Probiotics have numerous advantageous functions in human organisms. 1. Their main advantage is the development of proper balance between pathogens and the bacteria that are necessary for a normal function of the organism. 2. Counteracting the activity of pathogenic intestinal microbiota , introduced from contaminated food and environment. 3. Probiotic microorganisms such as Lactobacillus plantarum are natural producers of B group vitamins (B1, B2, B3, B6, B8, B9, B12). They also increase the efficiency of the immunological system, enhance the absorption of vitamins and mineral compounds, and stimulate the generation of organic acids and amino acids 4 . Probiotic microorganisms may also be able to produce enzymes, such as esterase, lipase, and co-enzymes A, Q, NAD, and NADP. Some products of probiotics ’ metabolism may also show antibiotic ( acidophiline , bacitracin , lactacin ), anti- cancerogenic , and immunosuppressive properties

14. The basics of the beneficial effect of probiotics , involve four mechanisms: (1) Antagonism through the production of antimicrobial substances (2) Competition with pathogens for adhesion to the epithelium and for nutrients (3) Immunomodulation of the host (4) Inhibition of bacterial toxin production

15. 1. Antagonism through the production of antimicrobial substances In vitro studies indicate the role of low-molecular-weight substances produced by probiotic microorganisms (e.g., hydroperoxide and short-chain fatty acids) in inhibiting the replication of pathogens. For example, Lactobacillus genus bacteria may be able to produce bacteriocins , including low-molecular-weight substances (LMWB—antibacterial peptides), as well as high-molecular-weight ones (class III bacteriocins ), and some antibiotics. Probiotic bacteria (e.g., Lactobacillus and Bifidobacterium ) may produce the so-called de-conjugated bile acids (derivatives of bile acids), demonstrating stronger antibacterial effect than the bile salts produced by their host. The nutrient essential for nearly all bacteria, except for lactic acid bacteria, is iron. Lactobacillus bacteria do not need iron in their natural environment, which may be their crucial advantage over other microorganisms. Lactobacillus delbrueckii affects the function of other microbes by binding iron hydroxide to its cellular surface, thus making it unavailable to other microbes

16. 2. Competition with pathogens for adhesion to the epithelium and for nutrients The ability of probiotic strains to co-aggregate, as one of their mechanisms of action, may lead to the formation of a protective barrier preventing pathogenic bacteria from the colonisation of the epithelium. Probiotic bacteria may be able to adhere to epithelial cells, thus blocking pathogens. The adhesion of probiotic microorganisms to epithelial cells may trigger a signalling cascade, leading to immunological modulation. The release of some soluble components may cause a direct or indirect (through epithelial cells) activation of immunological cells. This effect plays an important role in the prevention and treatment of contagious diseases, as well as in chronic inflammation of the alimentary tract

17. 3. Immunomodulation of the host The immunomodulatory effect of the intestinal microbiota , including probiotic bacteria, is based on three phenomena: (1) Induction of immunological tolerance to environmental antigens; (2) Induction and control of immunological reactions against pathogens; (3) Inhibition of auto-aggressive and allergic reactions. Probiotic -induced immunological stimulation is also manifested by the increased production of immunoglobulins , enhanced activity of macrophages and lymphocytes, and stimulation of interferon production. Probiotics may influence the congenital and acquired immunological system through metabolites, components of the cellular wall, and DNA, recognised by specialised cells of the host (e.g., those equipped with receptors). The principal host cells that are important in the context of the immune response are intestinal epithelial cells and intestinal immune cells.

18. Components of the cellular wall of lactic acid bacteria stimulate the activity of macrophages which in turn destroy microbes rapidly by the increased production of free oxygen radicals and lysosomal enzymes. The immunological activity of yeast is associated with the presence of glucans in their cellular wall which stimulate the response of the reticuloendothelial system

19. 4. Inhibition of bacterial toxin production It is based on actions leading to toxin inactivation and help with the removal of toxins from the body. Detoxification from the body can take place by adsorption (some specific strains can bind toxins to their cell wall and reduce the intestinal absorption of toxins), but can also result from the metabolism of mycotoxins (e.g., aflatoxin ) by microorganisms. The effectiveness of some probiotics in combating diarrhoea is probably associated with their ability to protect the host from toxins. An important role in the action of probiotics is played by species- and strain specific traits, such as: cellular structure, cell surface, size, metabolic properties, and substances secreted by microorganisms. The use of a combination of probiotics demonstrating various mechanisms of action may provide enhanced protection offered by a bio-therapeutic product.

20. Conclusion Probiotic organisms are crucial for the maintenance of balance of human intestinal microbiota . Probiotic microorganisms are attributed a high therapeutic potential in, e.g., obesity, insulin resistance syndrome, type 2 diabetes, and non-alcohol hepatic steatosis , irritable bowel syndrome, enteritis, bacterial infections, and various gastrointestinal disorders and diarrhoeas . Prebiotics may be used as an alternative to probiotics , or as an additional support for them. The development of bio-therapeutic formulas containing both appropriate microbial strains and synergistic prebiotics may lead to the enhancement of the probiotic effect in the small intestine and the colon.