Propionibacterium acnes have been recognized as one of the main causative agents in pathogenesis of
acne. Twenty one isolates of P. acnes isolated from
acne lesions were screened for
lipase and
protease activity which are reported to be associated in
acne and
inflammation. Interestingly, all P. acnes isolates demonstrated
lipase activity. Similarly, 90% of test P. acnes produced
protease enzyme. Antibacterial activity of the
ethanol extract of Rhodomyrtus tomentosa (Aiton) Hassk. leaves and
rhodomyrtone, its principle compound were tested against P. acnes using broth macrodilution method. The MIC(90) values of the
ethanol extract and
rhodomyrtone were 32 and 0.5 μg/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 IC(50) values of the
ethanol extract and
rhodomyrtone were 476 and more than 200 μg/mL, approximately 15 and 400 folds higher than the MIC(90) values indicating that both substances were very low cytotoxic which could be applied as topical therapeutic anti-
acne agents.