Synergistic effect of α-mangostin on antibacterial activity of tetracycline, erythromycin, and clindamycin against acne involved bacteria

Objective: To evaluate the synergistic effect of alpha-mangostin with tetracycline, erythromycin, and dindamycin against bacteria involved in acne production.Methods: A broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of alpha-mangostin and a range of antibiotics. Synergistic effects on antibacterial activity were determined based on their own MIC, and then using a checkerboard method and a time-kill assay at 37 degrees C for 24 h.Results: alpha-Mangostin exhibited antibacterial activity against Propionibacterium acnes, Staphylococcus aureus, S. epidermidis and S. pyogenes with MIC values of 0.78, 3.13, 0.78, and 6.25 mu g/mL, respectively. The results of the checkerboard assay showed that alpha-mangostin produced synergistic effects with tetracycline, erythromycin, and clindamycin against all tested bacteria, with a fractional inhibitory concentration index (FICI) between 0.09 and 0.32. Moreover, time-kill curve data indicated that alpha-mangostin increased the antibacterial activity of tetracycline, erythromycin, and clindamycin.Conclusion: These findings suggested that alpha-mangostin may be used to enhance the antibacterial activity of some antibiotics against bacteria involved in acne production. (C) 2019 Tianjin Press of Chinese Herbal Medicines. Published by Elsevier B.V. All rights reserved.