Abstract
This research sought to assess the anti-obesity potential of Enterococcus faecalis EF-1. An extensive and robust in vitro methodology confirmed EF-1's significant potential in combating obesity, probably due to its excellent gastrointestinal tract adaptability, cholesterol-lowering property, bile salt hydrolase activity, α-glucosidase inhibition, and fatty acid absorption ability. Moreover, EF-1 exhibited antimicrobial activity against several pathogenic strains, lacked hemolytic activity, and was sensitive to all antibiotics tested. To further investigate EF-1's anti-obesity properties in vivo, a high-fat diet (HFD) was used to induce obesity in C57BL/6J mice. Treatment with EF-1 (2 × 109 CFU/day) mitigated HFD-induced body weight gain, reduced adipose tissue weight, and preserved liver function. EF-1 also ameliorated obesity-associated microbiota imbalances, such as decreasing the Firmicutes/Bacteroidetes ratio and boosting the levels of bacteria (Faecalibacterium, Mucispirillum, Desulfovibrio, Bacteroides, and Lachnospiraceae_NK4A136_group), which are responsible for the generation of short-chain fatty acids (SCFAs). Concurrently, the levels of total SCFAs were elevated. Thus, following comprehensive safety and efficacy assessments in vitro and in vivo, our results demonstrate that E. faecalis EF-1 inhibits HFD-induced obesity through the regulation of gut microbiota and enhancing SCFA production. This strain appears to be a highly promising candidate for anti-obesity therapeutics or functional foods.