<i>Lactobacillus plantarum</i> fermented barley extract attenuates obesity in <scp>HFD</scp>‐induced obese rats by regulating gut microbiota

Lactobacillus plantarum fermented barley extract (LFBE) has a potent anti-obesity effect on high-fat-diet fed (HFD) obese rats. However, the underlying mechanism remains unclear. Herein, we investigated the anti-obesity effect and mechanism of LFBE in 3 T3-L1 preadipocytes and HFD-induced obese rats. LFBE significantly inhibited lipid accumulation by decreasing the expression of adipogenesis-related transcription factors, including peroxisome proliferator-activated receptor (PPAR-γ) and CCAAT/enhancer binding protein (C/EBP-α) in differentiated 3 T3-L1 cells. The expression levels of adiponectin, acetyl CoA carboxylase (ACC), and fatty acid synthase (FAS) were also suppressed in differentiated three T3-L1 cells. Administration of LFBE significantly reduced insulin resistance, blood lipid profiles, and improved metabolic hormones in HFD-induced obese rats. Furthermore, the serum pro-inflammatory cytokines including CRP, IL-6, TNFα, and INFγ in HFD-induced obese rats were significantly decreased after LFBE administration. LFBE treatment also attenuated oxidative stress in HFD-induced obese rats by decreasing MDA production and restoring SOD and catalase enzymatic activity. Administration of LFBE could modulate gut microbiota imbalance by increasing the abundance of Lactobacillus and Ruminococcaceae UCG-014 and decreasing Prevotella-9 at the genus level and restoring intestinal barrier dysfunction in HFD-induced obesity rats. Taken together, our study indicated that LFBE is a promising candidate for treating obesity through multiple mechanisms.