RESUMEN
Objective: This study assessed the effects of alpha-mangostin (AM) and citronella oil (CO) working alone or in combination against Propionibacterium acnes (P. acnes) and Staphylococcus aureus (S. aureus). Methods: The screening for antibacterial activity of AM and CO against P. acnes and S. aureus was carried out using the disk diffusion method. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these two substances were determined using the broth microdilution method. The fractional inhibitory concentration indices (FICI) of a combination of AM and CO were obtained by checkerboard dilution assay. Results: The results showed that alpha-mangostin and citronella oil do indeed fight against P. acnes and S. aureus. The MICs and MBCs of AM against P. acnes and S. aureus were the same at 6.25 and 50 µg/ml, respectively. Both the MIC and the MBC of CO against P. acnes were 27.81µg/ml. The MIC and the MBC of CO against S. aureus were 112.13 and 224.25 µg/ml, respectively. The FICI of a combination of AM and CO against P. acnes and S. aureus were 2.00, indicating indifferent interaction with no additional inhibitory effect. Conclusion: AM and CO are very effective against P. acnes and S. aureus, nevertheless their effect when used together was indifferent from using alone. Further research may find that either or both of these substances combined with yet a different natural agent could provide synergy againstP. acnes and S. aureus.
RESUMEN
This study was performed to investigate the antibacterial, antioxidant, and termite repellent effects of citronella oil (CiO) and lemongrass oil (LO). When the antibacterial activity against Staphylococcus (S.) aureus with various levels of antibacterial resistance were tested, a 0.05% concentration of CiO and LO completely inhibited the growth of all tested S. aureus strains. Evaluation of the antioxidant effect demonstrated that the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of CiO was 2~3 times greater than that of LO. Among trial products made with various combinations of CiO and LO, a CiO : LO ratio of 6 : 4 had the most potent termite repellent effects. Assessment of acute toxicity of the trial product showed that the LD50 was more than 2,000 mg/kg. Based on the above results, CiO and LO have antibacterial, antioxidant, and termite repellent activities. Therefore, both compounds could be potential termites repellent reagents.