Safety and toxicity assessment of Lactobacillus salivarius AP-32 with Probiotic potential in vivo and in vitro

Lactobacillus salivarius AP-32 (namely Ligilactobacillus salivarius AP-32, L. salivarius AP-32), isolated from the human gut, has shown a favorable safety profile. In 14-day acute and 90-day subchronic toxicity studies in rodents, no adverse effects were observed. The maximum tolerated dose was 16 g/kg body weight in the acute study, and the no-observed-adverse-effect level in the 90-day study was 1.88 g/kg body weight. It showed no mutagenicity in vivo or in vitro, including no chromosomal aberrations in mouse spermatogonia, no bone marrow cytotoxicity, and no mutagenic response in the Ames test (5000 μg/mL). L. salivarius AP-32 exhibited γ-hemolysis and bile salt hydrolase activity. It was non-toxic to Caco-2 cells, did not induce cytotoxicity, and demonstrated strong acid and bile tolerance, intestinal adhesion, and antimicrobial activity against Helicobacter pylori, Salmonella enterica subsp. enterica, Escherichia coli, Listeria monocytogenes, and Vibrio parahaemolyticus, while inducing M2 macrophages. Prior research indicated milk and soybean fermentated L. salivarius AP-32 held potential in regulating blood glucose, alleviating neonatal jaundice, and suppressing vaginal and urinary tract pathogens. These findings supported its safety and potential as a probiotic.