The MIC90 values of
the ethanol extract and rhodomyrtone were 32 and 0.5 mg/mL, respectively. The numbers of the bacterial
cells were reduced at least 99% after treatment with the ethanol extract and rhodomyrtone within 72 and
24 h, respectively. Cytotoxicity test of the extract and rhodomyrtone was performed on human normal
fibroblast. The IC50 values of the ethanol extract and rhodomyrtone were 476 and more than 200 mg/mL,
approximately 15 and 400 folds higher than the MIC90 values indicating that both substances were very
low cytotoxic which could be applied as topical therapeutic anti-acne agents