A synergistic effect of artocarpanone from L. (Moraceae) on the antibacterial activity of selected antibiotics and cell membrane permeability.

AIM/BACKGROUNDS: Artocarpanone isolated from L. (Moraceae) exhibits antibacterial activity. The present study investigated synergistic activity between artocarpanone and tetracycline, ampicillin, and norfloxacin, respectively, against methicillin-resistant (MRSA), , and .

MATERIALS AND METHODS

A broth microdilution method was used for evaluating antibacterial susceptibility. Synergistic effects were identified using a checkerboard method, and a bacterial cell membrane disruption was investigated by assay of released 260 nm absorbing materials following bacteriolysis.

RESULTS AND DISCUSSION

Artocarpanone exhibited weak antibacterial activity against MRSA and with minimum inhibitory concentrations values of 125 and 500 μg/mL, respectively. However, the compound showed strong antibacterial activity against (7.8 μg/mL). The interaction between artocarpanone and all tested antibiotics revealed indifference and additive effects against and (fractional inhibitory concentration index [FICI] values of 0.75-1.25). The combination of artocarpanone (31.2 μg/mL) and norfloxacin (3.9 μg/mL) resulted in synergistic antibacterial activity against MRSA, with an FICI of 0.28, while the interaction between artocarpanone and tetracycline, and ampicillin showed an additive effect, with an FICI value of 0.5. A time-kill assay also indicated that artocarpanone had a synergistic effect on the antibacterial activity of norfloxacin. In addition, the combination of artocarpanone and norfloxacin altered the membrane permeability of MRSA.

CONCLUSION

These findings suggest that artocarpanone may be used to enhance the antibacterial activity of norfloxacin against MRSA.