New insights into immunomodulatory properties of lactic acid bacteria fermented herbal medicines

Abstract

The COVID-19 pandemic has brought more attention to the immune system, the body’s defense against infectious diseases. The immunomodulatory ability of traditional herbal medicine has been confirmed through clinical trial research, and has obvious advantages over prescription drugs due to its high number of potential targets and low toxicity. The active compounds of herbal drugs primarily include polysaccharides, saponins, flavonoids, and phenolics and can be modified to produce new active compounds after lactic acid bacteria (LAB) fermentation. LAB, primary source of probiotics, can produce additional immunomodulatory metabolites such as exopolysaccharides, short-chain fatty acids, and bacteriocins. Moreover, several compounds from herbal medicines can promote the growth and production of LAB-based immune active metabolites. Thus, LAB-mediated fermentation of herbal medicines has become a novel strategy for regulating human immune responses. The current review discusses the immunomodulatory properties and active compounds of LAB fermented herbal drugs, the interaction between LAB and herbal medicines, and changes in immunoregulatory components that occur during fermentation. This study also discusses the mechanisms by which LAB-fermented herbal medicines regulate the immune response, including activation of the innate or adaptive immune system and the maintenance of intestinal immune homeostasis.

Effect of Lactic Acid Bacteria Fermentation on Plant-Based Products

“…The fermentation of herbs by lactic acid bacteria can increase the bioavailability and release of immune-active substances, such as polysaccharides, saponins, and polyphenols, which possess strong immunomodulatory activity. The oral intake of lactic-acid-bacteriafermented herbs can promote intestinal secretion of immunomodulatory-active metabolites, such as EPS, short-chain fatty acids, and bacteriocins [114]. It was found that mice that ingested lychee juice fermented by L. casei could have an enhanced immunomodulatory activity.…”

“…This process is mainly due to the increase in flora diversity and the relative abundance of Bacteroidetes, the reduction in the Firmicutes/Bacteroidetes ratio, as well as the enrichment of some intestinal probiotics, such as Ackermania [20]. This fermentation process also promoted the secretion of mucosal SIgA, a critical mediator in the regulation of intestinal homeostasis, thereby protecting the mouse intestine and modulating the composition of the intestinal microbiota [114]. Additionally, short-chain fatty acids, which are non-direct nutrients produced by the gut microbiota, play important physiological regulatory roles.…”

Interaction between plants and epiphytic lactic acid bacteria that affect plant silage fermentation

“…Catechin has a positive effect on the growth of oxygen-sensitive probiotics (such as Lactobacillus helveticus ) ( Gaudreau et al, 2012 ). Zhu H. et al (2022) pointed out that polyphenols, polysaccharides, and saponins in plants can promote the growth and metabolism of LAB. The phenolic compounds in olive fruits can decrease bacterial growth ( Rodríguez et al, 2009 ).…”

Impact of Lactic Acid Bacteria Fermentation on (Poly)Phenolic Profile and In Vitro Antioxidant and Anti-Inflammatory Properties of Herbal Infusions

“…Most of the functional foodstuffs are produced by species and (or) strains belonging to lactic acid bacteria (LAB), which are generally recognized as safe (GRAS) and confer a multitude of functional and sensory properties [6,7]. In this regard, for outside plant-based fermented foods or drinks which are currently widely studied, the LAB starter cultures are directed towards the fermentation of novel substrates from plant foods, herbs, or spices in order to improve their health-promoting effects by stimulating the release or production of bioactive metabolites [8][9][10].…”