Leptospermum scoparium 추출물 중 케톤체 분획물의 항균력 및 항생제와의 병용효과

Activities of Ketonic Fraction from Leptospermum scoparium alone and Synergism in Combination with Some Antibiotics Against Various Bacterial Strains and Fungi

Whole oil and ketonic fraction (KF) of Leptospermum scoparium have been tested for their antimicrobial activity and combination effect with several antibiotics against various bacterial strains and fungi by using microbiological assay methods. Antibacterial activities of KF against a number of test strains were 2-3 fold stronger than those of whole oil. MICs of the KF were 65-125mcg/ml agaist several gram positive bacterial strains, 65-250mcg/ml against 19 methicillin resistance Staphylococcus aureus strains, and 65-50mcg/ml against 14 quinolone resistance strains. However, KF showed little or no activity against gram negative bacteria. MICs of the KF were 16-250mcg/ml against more than 50% of the anaerobic bacterial strains of Bacteroides thetaiotamicron, or three strains of Bacteroides ovatus, and the more active than ciprofloxacin against one strain of Bacteroides thetaiotamicron and three strains of Bacteroides ovatus. The MICs of KF was 63 and 250mcg/ml agaisnt Aspergilus niger and Candida albicans, respectively. Antibacterial activities of KF in combination with 19 antibiotics against 14 strains and with four antifungal agent against one fungal strain were determined by paper strip diffusion method. While most of combination showed additivity, KF showed synergism with bactracin, cefadroxil, cephradin, and meropenem for 29-57% of the strains tested. However, ofloxacin, enoxacin, sparfloxacin showed antagonism with KF for 43-71% of the strains. KF alone and in combination with bacteitracin, gentamycin, neomycin, itraconazole, fluconazole, terfinafine and ketoconazole against five bacterial strains or one fungus strain synergistic effect was demonstrated against 33% of strains examined with FIC index value below 0.5 by checkerboard study. Synergistic effect of KF with gentamicin against Staphylococcus epidermidis 329 (QRS) was found by time-kill study.