In Vitro and In Vivo Investigational Safety Evaluation of the Probiotic <i>Bacillus subtilis</i> BSP110 (MTCC 25471)

Probiotics are living microorganisms that, when given in sufficient quantities, boost the host's health. Probiotics have been used more often in recent years as dietary supplement to prevent illnesses, including diarrhea, obesity, and constipation. The probiotic strain <i>Bacillus subtilis</i> BSP110 is being developed as a dietary supplement. In this work, we assessed the in vivo safety of the probiotic strain <i>Bacillus subtilis</i> BSP110 in rats as per OECD-423 and 407 guidelines. Female rats were given a single oral (gavage) dosage of 2000 mg/kg (4 × 10¹¹ CFU/g) to assess the maximum tolerated dose (MTD). This was followed by a 28-day sub-acute toxicity study in which <i>Bacillus subtilis</i> BSP110 was given orally (gavage) once daily to male and female rats at dose levels of 250, 500, and 1000 mg/kg/day. No effects of <i>Bacillus subtilis</i> BSP110 were noted at any of the dosage levels given over the course of 28 days. Between the control and test groups, there was no discernible difference in body weight, clinical symptoms, urinalysis, hematological tests, clinical biochemistry, gross pathology, or histopathological evaluation. Additionally, in vitro cytotoxicity was evaluated using the MTT assay with the VERO cell line, and <i>Bacillus subtilis</i> BSP110 was found to be non-cytotoxic at 4 × 10¹¹ CFU/kg. The single dose MTD was ≥2000 mg/kg, and the NOAEL was 1000 mg/kg/day.