TY - JOUR AB - The objective of the present study was to investigate the antibacterial activity of a single constituent, ursolic acid 3-O-α-L-arabinopyranoside (URS), isolated from the leaves of Acanthopanax henryi (Oliv.) Harms, alone and in combination with oxacillin (OXA) against methicillin-resistant Staphylococcus aureus (MRSA). A broth microdilution assay was used to determine the minimal inhibitory concentration (MIC). The synergistic effects of URS and OXA were determined using a checkerboard dilution test and time-kill curve assay. The mechanism of action of URS against MRSA was analyzed using a viability assay in the presence of a detergent and an ATPase inhibitor. Morphological changes in the URS-treated MRSA strains were evaluated via transmission electron microscopy (TEM). In addition, the producing penicillin-binding protein 2a (PBP2a) protein level was analyzed using western blotting. The MIC value of URS against MRSA was found to be 6.25 µg/ml and there was a partial synergistic effect between OXA and URS. The time-kill growth curves were suppressed by OXA combined with URS at a sub-inhibitory level. Compared to the optical density at 600 nm (OD600) value of URS alone (0.09 µg/ml), the OD600 values of the suspension in the presence of 0.09 µg/ml URS and 0.00001% Triton X-100 or 250 µg/ml N,N'-dicyclohexylcarbodiimide reduced by 56.6 and 85.9%, respectively. The TEM images of MRSA indicated damage to the cell wall, broken cell membranes and cell lysis following treatment with URS and OXA. Finally, an inhibitory effect on the expression of PBP2a protein was observed when cells were treated with URS and OXA compared with untreated controls. The present study suggested that URS was significantly active against MRSA infections and revealed the potential of URS as an effective natural antibiotic. AD - Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Institute of Biotechnology, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea School of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410-208, P.R. China Department of Oriental Medicine Resources, College of Bio Industry Science, Sunchon National University, Sunchon, Jeonnam 540-742, Republic of Korea AU - Zhou,Tian AU - Li,Zhi AU - Kang,Ok‑Hwa AU - Mun,Su‑Hyun AU - Seo,Yun‑Soo AU - Kong,Ryong AU - Shin,Dong-Won AU - Liu,Xiang‑Qian AU - Kwon,Dong‑Yeul DA - 2017/10/01 DO - 10.3892/ijmm.2017.3099 EP - 1293 IS - 4 JO - Int J Mol Med KW - ursolic acid 3-O-α-L-arabinopyranoside oxacillin methicillin-resistant Staphylococcus aureus synergism detergent ATPase inhibitor producing penicillin-binding protein 2a PY - 2017 SN - 1107-3756 1791-244X SP - 1285 ST - Antimicrobial activity and synergism of ursolic acid 3-O-α-L-arabinopyranoside with oxacillin against methicillin-resistant Staphylococcus aureus T2 - International Journal of Molecular Medicine TI - Antimicrobial activity and synergism of ursolic acid 3-O-α-L-arabinopyranoside with oxacillin against methicillin-resistant Staphylococcus aureus UR - https://doi.org/10.3892/ijmm.2017.3099 VL - 40 ER -