Liver metabolic changes induced by conjugated linoleic acid in calorie-restricted rats

Exploring the Potential Probiotic Properties of Bifidobacterium breve DSM 32583-A Novel Strain Isolated from Human Milk

Human milk is the best nutrition for infants, providing optimal support for the developing immune system and gut microbiota. Hence, it has been used as source for probiotic strain isolation, including members of the genus Bifidobacterium, in an effort to provide beneficial effects to infants who cannot be exclusively breastfed. However, not all supplemented bifidobacteria can effectively colonise the infant gut, nor confer health benefits to the individual infant host; therefore, new isolates are needed to develop a range of dietary products for this specific age group. Here, we investigated the beneficial potential of Bifidobacterium breve DSM 32583 isolated from human milk. We show that in vitro B. breve DSM 32583 exhibited several characteristics considered fundamental for beneficial bacteria, including survival in conditions simulating those present in the digestive tract, adherence to human epithelial cell lines, and inhibition of growth of potentially pathogenic microorganisms. Its antibiotic resistance patterns were comparable to those of known beneficial bifidobacterial strains, and its genome did not contain plasmids nor virulence-associated genes. These results suggest that B. breve DSM 32583 is a potential probiotic candidate.

Conjugated linoleic acid alleviates glycolipid metabolic disorders by modulating intestinal microbiota and short-chain fatty acids in obese rats

Although conjugated linoleic acid (CLA) has been shown to have anti-obesity properties, the effect and mechanism of CLA in alleviating glycolipid metabolism disorders remains unclear. In this work, it was observed that rats fed a high-fat diet (HFD) had lower body weight and body fat levels after 9 weeks of low-dose and high-dose CLA interventions. The results of blood biochemical indices showed that CLA significantly reduced the levels of total cholesterol, triglycerides, fasting blood glucose and insulin. Additionally, high-dose CLA could restore the intestinal microbiota composition, including increasing the relative abundances of short-chain fatty acid (SCFA)-producing microbiota, such as Dubosiella, Faecalibaculum and Bifidobacterium; decreasing the relative abundances of Enterococcus and Ruminococcus_2; and increasing the content of SCFAs in feces and serum. Further analysis showed that high-dose CLA could increase the expression levels of Insr, Irs-2, Akt and Glut4 in the liver tissue of HFD-induced obese rats. Consistently, high dose of CLA could reversibly improve the downregulation of INSR, AKT, PI3K and GLUT4 protein expression caused by HFD and reverse the decline in AKT phosphorylation levels. Correlation clustering analysis with a heatmap showed that the changes in specific microbiota induced by high-dose CLA were correlated with changes in obesity-related indices and gene expression. The molecular docking analysis showed that the molecular docking of SCFAs with the IRS-2, AKT and GLUT4 proteins had high linking activity. The results supported that CLA can alleviate glycolipid metabolic imbalances associated with obesity by altering the intestinal microbiota to induce the production of SCFAs and thereby activate the INSR/IRS-2/AKT/GLUT4 pathway. This study supports CLA may be preferentially used by the intestinal microbiota of the host to promote its health.

Enhancing the Recovery of Bioactive Compounds of Soybean Fermented with Rhizopus oligosporus Using Supercritical CO2: Antioxidant, Anti-Inflammatory, and Oxidative Proprieties of the Resulting Extract

The aim of the present study was to evaluate the use of supercritical CO₂ combined with cosolvent for the recovery of bioactive compounds of soybean fermented with Rhizopus oligosporus NRRL 2710. Soxhlet extractions using seven different organic solvents (n-hexane, petroleum ether, ethyl acetate, acetone, ethanol, methanol, and water) were initially performed for comparative purposes. The extracts obtained were characterized by physicochemical, antioxidant, total phenolic, and oxidative proprieties. For the Soxhlet extractions, the highest and lowest yields obtained were 45.24% and 15.56%, using methanol and hexane, respectively. The extraction using supercritical CO₂ combined with ethanol as a static modifier (scCO₂ + EtOH) presented, at a high pressure (25 MPa) and temperature (80 °C), a phenolic compound content of 1391.9 μg GAE g⁻¹ and scavenging of 0.17 g, reaching a 42.87% yield. The extracts obtained by sCO₂ + EtOH were characterized by high contents of essential fatty acids (linoleic acid and oleic acid) and bioactive compounds (gallic acid, trans-cinnamic acid, daidzein, and genistein). These extracts also showed a great potential for inhibiting hyaluronidase enzymes (i.e., anti-inflammatory activity). Thermogravimetric analyses of the samples showed similar profiles, with oil degradation values in the range from 145 to 540 °C, indicating progressive oil decomposition with a mass loss ranging from 93 to 98.7%. In summary, this study demonstrated the flexibility of scCO₂ + EtOH as a green technology that can be used to obtain high-value-added products from fermented soybean.

Bacterial conjugated linoleic acid production and their applications

Conjugated linoleic acid (CLA) has been shown to exert various potential physiological properties including anti-carcinogenic, anti-obesity, anti-cardiovascular and anti-diabetic activities, and consequently has been considered as a promising food supplement. Bacterial biosynthesis of CLA is an attractive approach for commercial production due to its high isomer-selectivity and convenient purification process. Many bacterial species have been reported to convert free linoleic acid (LA) to CLA, hitherto only the precise CLA-producing mechanisms in Propionibacterium acnes and Lactobacillus plantarum have been illustrated completely, prompting the development of recombinant technology used in CLA production. The purpose of the article is to review the bacterial CLA producers as well as the recent progress on describing the mechanism of microbial CLA-production. Furthermore, the advances and potential in the heterologous expression of CLA genetic determinants will be presented.