Sub-acute Cinnamaldehyde rectal administration induces non-toxic effects in neurological and physiological responses in C57BL/6 mice

Trans-Cinnamaldehyde, the main component of cinnamon essential oil, is widely used in food and traditional herbal medicine. The objective of this study was to investigate the subacute toxic effects of trans-Cinnamaldehyde (Cinn; 2000 mg/kg/day) administered intrarectally for 15 consecutive days in male C57BL/6 mice, a route of administration not previously evaluated in this model. Mice were monitored for survival, preclinical signs, and behavior. Neurotoxic potential was assessed using a functional observational battery (FOB), ambulatory activity, and spontaneous locomotion. Physiological parameters included sperm motility, liver function, relative liver weight, and macroscopic and microscopic liver morphology. Food and water intake were recorded and considered in the analysis. Subacute intrarectal administration of Cinn did not produce neurotoxic, hepatotoxic, or reproductive adverse effects. The treatment was well tolerated and associated with reduced body weight gain without changes in food or water intake. In conclusion, these results support the safety of Cinn and suggest potential applications in metabolic research, particularly in the context of obesity.