Two-Generation Toxicity Study of the Antioxidant Compound Propyl-Propane Thiosulfonate (PTSO)

Propyl-propane thiosulfonate (PTSO), an antioxidant organosulfur compound present in the genus Allium, has become a potential natural additive for food and feed, as well as a possible biopesticide for pest control in plants. A toxicological assessment is necessary to verify its safety for livestock, consumers, and the environment. As part of the risk assessment of PTSO, this study was designed to explore its potential reproductive toxicity in mice following the OECD 416 guideline. The investigation spans two generations to comprehensively evaluate potential reproductive, teratogenic, and hereditary effects. A total of 80 CD1 mice per sex and generation were subjected to PTSO exposure during three phases (premating, gestation, and lactation). This evaluation encompassed three dose levels: 14, 28, and 55 mg PTSO/kg b.w./day, administered through the feed. No clinical changes or mortality attributed to the administration of PTSO were observed in the study. Some changes in the body weight and food consumption were observed, but not related to sex or in a dose-dependent manner. The two parental generations (F0, F1) exhibited normal reproductive performance, and the offspring (F1 and F2) were born without any abnormalities. The serum sexual hormone levels (progesterone -P-, testosterone -T-, estradiol -E2-, follicular stimulating hormone -FSH-, and luteinizing hormone -LH-) were in a normal range. Although significant changes were observed in the sperm analysis in the case of F0 group, no variation was found for F1 group, and no alterations in fertility were recorded either. The absolute organ weights and relative organ weight/body weight and organ weight/brain weight ratios, and the complete histopathological study, showed no significant alterations in males and females for all the generations considered. Considering all the results obtained, PTSO is not considered a reproductive or developmental toxicant in mice under the assayed conditions. These results support the good safety profile of PTSO for its potential application in the agrifood sector.