The gut–brain axis is a bidirectional relationship between the microbiota and the brain; genes related to the brain and gut synaptic formation are similar. Research on the causal effects of gut microbiota on human behavior, brain development, and function, as well as the underlying molecular processes, has emerged in recent decades. Probiotics have been shown in several trials to help reduce anxiety and depressive symptoms. Because of this, probiotic combinations have been tested in in vitro models to see whether they might modulate the gut and alleviate depression and anxiety. Therefore, we sought to determine whether a novel formulation might affect the pathways controlling anxiety and depression states and alter gut barrier activities in a 3D model without having harmful side effects. Our findings indicate that B. bifidum novaBBF7 10 mg/mL, B. longum novaBLG2 5 mg/mL, and L. paracasei TJB8 10 mg/mL may influence the intestinal barrier and enhance the synthesis of short-chain fatty acids. Additionally, the probiotics studied did not cause neuronal damage and, in combination, exert a protective effect against the condition of anxiety and depression triggered by L-Glutamate. All these findings show that probiotics can affect gut function to alter the pathways underlying anxiety and depression.

The gut-liver-adipose axis plays a pivotal role in metabolic regulation, and its dysregulation contributes to obesity and metabolic syndrome. Probiotics and polycosanol have shown potential in modulating gut barrier integrity, lipid metabolism, and inflammation. This study aimed to evaluate their combined effects using an in vitro model of the gut-liver-adipose axis. Transwell^® system was used to recreate the interaction between intestinal (CaCo-2), hepatic (HepG2), and adipose (3T3-L1) cells. Cells were treated with Bifidobacterium bifidum GM-25, Bifidobacterium infantis GM-21, Lacticaseibacillus rhamnosus GM-28, and polycosanols. The effects were assessed by analyzing intestinal barrier integrity (TEER, tight junction proteins), hepatic and adipose lipid accumulation (Oil Red O staining), oxidative stress (ROS production, lipid peroxidation), inflammation (TNF-α) and lipid metabolism (CD36, PPARγ, AMPK and SREBP-1 levels). Probiotics and polycosanols improved intestinal integrity, increased butyrate production, and reduced ROS levels. Hepatic lipid accumulation was significantly decreased, with enhanced PPARγ and AMPK activation. In adipocytes, probiotic-polycosanols treatment suppressed SREBP-1 expression, enhanced lipid oxidation, and promoted UCP1 and PGC-1α expression, suggesting activation of thermogenic pathways. These findings underline a possible biological relevance of probiotics and polycosanols in modulating metabolic pathways, improving gut barrier integrity, and reducing inflammation, supporting their role as functional ingredients for metabolic health.

Tremella fuciformis is high in polysaccharides, which have a structure made up of a straight chain of (1→3) α-D-mannan and side chains of glucuronic acid, xylose, and fucose. This study aimed to evaluate whether the non-animal hyaluronic acid extracted from Tremella fuciformis can maintain the chemical and physical characteristics of hyaluronic acid that ensure its biological functionality. Chemical and physical analyses such as hyaluronic content, screening of metals, purity, pH, nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (ATR/FTIR), and MALDI-TOF were performed. Chemical characterisation revealed that the most abundant polysaccharide in the extract was hyaluronic acid, accounting for ca. 87.76%, with a molecular weight above 2000 kDa. In addition, ATR/FTIR and NMR spectroscopy and MALDI-TOF analysis confirmed that Tremella fuciformis extract is a source of non-animal hyaluronic acid. In summary, every molecular attribute examined played a significant role in determining the functional qualities of the extract, indicating that a thoughtful choice of extraction technique can enhance its advantages.