In vivo investigation of antimicrobial effects of cinnamaldehyde using immunosuppressed ICR mice with invasive pulmonary aspergillosis / 中草药·英文版

ABSTRACT

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 < 0.01). Electron microscopy showed that 2−3 outer layers (1,3-β-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.