ABSTRACT
Objective To evaluate the in vitro antifungal activity of Cinnamaldehyde in combination with Voriconazole (VRC) against clinically isolated Aspergillus fumigatus strains. Methods According to the Clinical and Laboratory Stan?dards Institute (CLSI) M38-A2 document,the minimal inhibitory concentrations (MIC) of Cinnamaldehyde and VRC alone or in combination against 42 clinical Aspergillus fumigatus isolates were determined by both microdillution method and check?board method respectively. The MIC50, MIC90, MICG and MICs distribution were compared between single drug and both in combination. The concentration-accumulative curve was drawn and fractional inhibitory concentration index (FICI) was cal?culated to evaluate the interaction between two test agents. Results The values of MIC50, MIC90 and MICG were significant?ly decreased (P<0.001) when combination of the two drugs than those of their single use, with their MIC distribution concen?tration-accumulative curves shifted to the left. The value of FICI of Cinnamaldehye-VRC combination ranged from 0.187 5 to 1.5. Sixteen strains (38.10%) of them showed the synergistic effect, 19 strains (45.23%) showed additive effect, and 7 strains (16.67%) showed an unrelated effect, and no antagonist effect on tested Aspergillus fumigatus strains in vitro. Conclu?sion Cinnamaldehye in combination with VRC mainly shows a combined synergic and additive inhibitory effect on Asper?gillus fumigatus isolates, and this combination appears to be more active against the test strains, which are less susceptible to voriconazole.