In vivo investigation of antimicrobial effects of cinnamaldehyde using immunosuppressed ICR mice with invasive pulmonary aspergillosis

Objective Invasive pulmonary Aspergillus infection has the characteristics of high morbidity, difficult to be treated, poor prognosis and high mortality. This study aims to investigate the effects of cinnamaldehyde on 1,3-β- D -glucans in the pulmonary Aspergillus fumigatus cell wall to provide a basis for developing novel antifungal drugs. Methods Immunosuppressed ICR mice were intranasally inoculated with 50 µL of A. fumigatus suspension (1 × 107 CFU/mL) and then separated into two groups, for the experimental group cinnamaldehyde was orally administered at 240 mg/kg/d consecutively for 14 d. While for the control group, voriconazole was used to treat the fungus infection. Pulmonary tissues were then extracted for 1,3-β- D -glucans assay and electron microscopy. Results The concentration of 1,3-β- D -glucans was significantly different between the cinnamaldehyde and voriconazole groups, which was (1160.89 ± 364.96) pg/mL and (3885.94 ± 845.45) pg/mL, respectively (P D -glucan layer) of A. fumigatus cell wall were damaged and fell off, resulting in serious defect of the cell wall, but the cell membrane was clear and intact. Conclusion Cinnamaldehyde has a significant influence on the integrity of 1,3-β- D -glucans in the pulmonary A. fumigatus cell wall, but the cell membrane is unaffected, suggesting that cinnamaldehyde has unique antifungal properties depending on its action against the 1,3-β- D -glucans on the pulmonary A. fumigatus cell wall.