Functional Mechanisms of Probiotics

Abstract

Probiotics are the live microorganisms which when ingested in adequate amounts confer health benefits. The strains most frequently used as probiotics include Lactic acid bacteria, bifidobacteria and yeast Saccharomyces boulardii. However, several other bacterial strains are being investigated for potential probiotic value viz. Enterococcus, Streptococcus, Bacillus, among others. Significant therapeutic potential of probiotics has been demonstrated in several in vitro studies and that involving animal models and humans. Despite intense focus on probiotics research the mechanisms responsible for health benefits are not yet completely understood. Several important mechanisms have been proposed such as improvement of gut epithelial barrier function, Immunomodulatory effects, degradation of toxin receptors, competition for nutrients, production of inhibitory substances, antiproliferative effects, blocking of adhesion sites and modulation of gut microbiota. Bacterial cell components such as DNA or peptidoglycan may also be involved in functional mechanism of probiotics. Effectiveness of a probiotic for potential application as prophylactic or treatment agent for certain ailment is determined by its ability to possess all or most of these characteristic features. The current article describes the general functional mechanisms of probiotics.

New Progress Regarding the Use of Lactic Acid Bacteria as Live Delivery Vectors, Treatment of Diseases and Induction of Immune Responses in Different Host Species Focusing on Lactobacillus Species

“…This demonstrates that probiotic strains of Lactobacillus exert early immunostimulatory effects that may be directly linked to the initial inflammation of the response of human macrophages [98,153]. Lactobacillus species such as Lactobacillus plantarum, and Lactobacillu scasei have been shown to increase the expression of proteins involved in tight junction barrier function which induces several protective mechanisms that restore tissue damage, such as modulation of the stability of tight junctions of the gastrointestinal lining because when become compromised and permeability increases, it allows toxins and other forms of waste to leak into the bloodstream then endotoxins trigger immune activation through Toll-like receptor 4 (TLR4) [94,154].…”

Phytase-Producing Potential and Other Functional Attributes of Lactic Acid Bacteria Isolates for Prospective Probiotic Applications

“…Health benefits of probiotics are multifaceted and include prevention and treatment of various types of diarrhea, alleviation of lactose intolerance, modulation of gut microbiota, immunomodulation, and/or alleviation of allergies and atopic diseases [1]. However, probiotics differ widely with respect to their health benefitting effects on the host.…”

“…Several lactic acid bacteria (LAB) species viz. Lactobacillus spp., Bifidobacterium spp., and the yeast Saccharomyces boulardii are the most commonly used probiotic organisms; however, Bacillus, Enterococcus, Escherichia, Propionibacterium, among several others are also been investigated as promising probiotics [1][2][3]. Certain illnesses developed due to dysbiosis of the intestinal ecosystem can be reversed by favorable alterations by probiotics [5].…”

“…Several of the LAB enjoy 'generally recognized as safe' status, and no serious adverse effects have been reported except some rare and isolated reports of systemic infections such as sepsis or endocarditis, fungemia, liver abscess. [1,2]; however, some LAB may have pathological history as opportunistic pathogens, thus, before commercial application of LAB as probiotics exhaustive safety studies based on animal models/human volunteers is needed [12].…”

“…Furthermore, probiotics should possess desired functional attributes viz. high hydrophobicity, coaggregation and autoaggregation (AAg), antimicrobial activity against pathogens, sensitivity to antibiotics, among several others [1,2,6]. Furthermore, should probiotics not survive in sufficient numbers while transiting through the hostile GIT [14], they may be subjected to microencapsulation to enhance their viability [15].…”