Background/Objectives: Lactiplantibacillus plantarum DSW3805 was isolated from Korean kimchi samples to examine its effect in a dextran sulfate sodium (DSS)-induced mouse model. Methods: To induce colitis, mice were treated with DSS for one week before sacrifice (n = 8 per group, total n = 40). Lacticaseibacillus rhamnosus GG (10⁹ CFU/day) or probiotics (L. plantarum DSW3805; 10⁸ or 10⁹ CFU/day) were administered for two weeks. To assess colitis damage, we evaluated the disease activity index, colon tissue, inflammatory factors, the microbiome, short-chain fatty acids, and intestine-related factors. Results: DSS induced colonic tissue damage (colon length, mucus thickness, and colonic crypts), and L. plantarum DSW3805 alleviated the tissue damage. Induced inflammation was reduced by inhibiting TNF-α, IFN-γ, IL-1β, IL-6, IgA, IgG, LTB4, PGE2, and NF-κB protein expression. The ratio of Firmicutes to Bacteroidetes in the PC group (DSS-treated control) was lower than that in the NC (DSS-nontreated control); L. plantarum DSW3805 increased the ratio. Higher concentrations of acetic, propionic, and butyric acids were detected in probiotic groups. In addition, harmful factors, such as calprotectin and β-glucuronidase, were reduced in the probiotic groups. Conclusions: L. plantarum DSW3805 alleviates gut damage by colitis; therefore, it can be used as a functional food to improve gut health.

Background: L-arginine is a conditionally essential amino acid that serves as a substrate for nitric oxide synthase and regulates energy metabolism. While its ergogenic effects have been proposed, the mechanisms underlying its anti-fatigue properties are not fully understood. Methods: Male ICR mice were orally administered L-arginine (300, 600, or 1200 mg/kg bw/day) for 28 days. Fatigue was chronically induced using twice-weekly forced swimming or treadmill running, and fatigue resistance was then assessed under these paradigms. Blood, skeletal muscle, and liver were analyzed for biomarkers including glucose, lactate, LDH, CPK, NEFA, ammonia, glycogen, nitric oxide, cortisol, and antioxidant enzymes. In parallel, C2C12 myoblasts were treated with L-arginine under proliferative and differentiated conditions to assess hexokinase (HK) activity, myogenin expression, and ROS generation. Results: In vivo, L-arginine decreased serum LDH, CPK, NEFA, ammonia, nitric oxide, and cortisol, while enhancing blood glucose and glycogen storage in both muscle and liver. Forced swimming reduced serum lactate, whereas treadmill exercise elevated intramuscular lactate, suggesting context-dependent lactate regulation. Importantly, L-arginine did not significantly improve forced-swimming immobility time, whereas treadmill time-to-exhaustion increased at the highest dose. Antioxidant responses were improved, as reflected by normalized hepatic catalase activity. In vitro, L-arginine increased HK activity, promoted myogenin expression, and reduced ROS levels, supporting improved glucose utilization, muscle differentiation, and oxidative stress resistance. Conclusions: These findings demonstrate that L-arginine supplementation under chronic fatigue-inducing paradigms improves endurance and alleviates fatigue by enhancing energy metabolism, preserving glycogen, reducing muscle injury, and attenuating oxidative stress. L-arginine shows potential as a functional ingredient for promoting exercise performance and recovery.

Background/Objectives: This research examined the anti-obesity potential of Lactiplantibacillus plantarum Ln4 in C57BL/6 mice fed a high-fat diet (HFD) for eight weeks. Methods: Forty male mice were randomly assigned (n = 8 per group) a normal diet (ND), HFD, HFD with orlistat (positive control), or HFD supplemented with Ln4 at 5 × 10⁸ or 5 × 10⁹ CFU/day (Ln4-8, Ln4-9). Ln4 was orally administered once daily throughout the study period. Results: Ln4 supplementation significantly attenuated body weight gain, visceral fat accumulation, and dyslipidemia, while improving lipid metabolism and hormonal balance. The Ln4-9 group exhibited effects comparable to those of orlistat, indicating potent anti-obesity activity. Ln4 also reduced serum triglyceride and total cholesterol concentrations and improved lipid and hormone profiles. At the molecular level, Ln4 downregulated adipogenic and lipogenic regulators (PPARγ, SREBP1c, and C/EBPα) while upregulating genes involved in lipolysis and fatty acid oxidation (PPARα, CPT1, and ACO) in the liver and adipose tissue. These changes were accompanied by lower insulin and leptin levels and restored adiponectin concentrations. Conclusions: Collectively, the results demonstrate that L. plantarum Ln4 mitigates HFD-induced obesity by improving lipid metabolism, suppressing adipogenesis, and balancing metabolic hormones, suggesting its potential as a functional probiotic for obesity management.