Acute oral toxicity evaluation of <i>p</i>-propoxybenzoic acid in Sprague-Dawley rats according to OECD guideline 425 – Up and down method

Objectives: The purpose of this study was to assess the acute oral toxicity of p-propoxybenzoic acid (p-PBA) following the Organisation for Economic Co-operation and Development Guideline 425. Materials and Methods: Then animals were equally divided into two groups: p-PBA and normal control (NC). The standardised up-and-down procedure involved a limit test, starting with a 2000 mg/kg dose of p-PBA in one animal of the p-PBA group. On confirming the absence of toxicity in one animal, the remaining four animals of p-PBA and five animals of NC group were treated with the same dose of p-PBA and vehicle (1 mL, 0.1% carboxymethyl cellulose), respectively. Monitoring extended over a 14-day period, encompassing observations of body weight, behavioural patterns, blood serum parameters and histopathological examinations. Results: The study revealed no significant difference in the body weight of the p-PBA and NC groups over the 14-day observation period. Behavioural patterns, including respiration, sleep tendencies and itching, showed transient alterations in the p-PBA group, returning to baseline within the study period. Blood parameters, serum renal and lipid profile displayed no statistically significant differences between the groups. Histopathological analysis demonstrated no hypertrophy or abnormalities in the heart, kidney and liver. Minor muscular damage was observed in the heart and a loose network of neurons in the cerebellum. Conclusion: The absence of significant adverse effects on body weight, behavioural patterns and vital organs suggests a favourable safety profile. Minor histopathological findings indicate a nuanced impact on cardiac and neurological tissues, warranting further investigation. The study revealed the acute oral toxicity of p-PBA supporting its potential therapeutic applications.