College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Wonkwang University, Iksan, Jeonbuk, Republic of Korea.
Pharm Biol. 2010 Nov;48(11):1285-90. doi: 10.3109/13880201003770150. Epub 2010 Oct 7.
Methicillin-resistant Staphylococcus aureus (MRSA) is a substantial contributor to morbidity and mortality. In search of a natural products capable of inhibiting this multidrug resistant bacteria, we have investigated the antimicrobial activity of emodin (EM) isolated from Rheum palmatum L. (Polygonaceae) against 17 different strains of the bacterium. New antimicrobial activity was found using the paper disc diffusion method, agar dilution as well as checkerboard method. Against the 17 strains, the disc diffusion test was in the range of 18-30 mm, and the minimum inhibitory concentrations (MICs) of EM were in the range of 1.5-25 μg/mL. From those results we performed the checkerboard test to determine the synergism of EM in combination with ampicillin (AM) or oxacillin (OX) against all strains. The combined activity of EM and two antimicrobial agents (AM, OX) against all strains resulted in a fractional inhibitory concentrations index (FICI) ranging from 0.37-0.5 and from 0.37-0.75, respectively. The effect of EM with AM and OX was found to be synergistic or partially synergistic. We found that EM reduced the MICs of AM and OX. EM and in combination with AM or OX could lead to the development of new combination antibiotics against MRSA infection.
耐甲氧西林金黄色葡萄球菌（MRSA）是发病率和死亡率的主要原因。为了寻找能够抑制这种多药耐药细菌的天然产物，我们研究了从大黄（Polygonaceae）中分离出的大黄素（EM）对 17 种不同细菌菌株的抗菌活性。使用纸片扩散法、琼脂稀释法和棋盘法发现了新的抗菌活性。在 17 株菌株中，纸片扩散试验范围为 18-30mm，EM 的最小抑菌浓度（MIC）范围为 1.5-25μg/ml。根据这些结果，我们进行了棋盘试验，以确定 EM 与氨苄西林（AM）或苯唑西林（OX）联合使用对所有菌株的协同作用。EM 与两种抗菌药物（AM、OX）联合使用对所有菌株的联合活性的部分抑菌浓度指数（FICI）范围分别为 0.37-0.5 和 0.37-0.75。发现 EM 与 AM 和 OX 具有协同或部分协同作用。我们发现 EM 降低了 AM 和 OX 的 MIC。EM 与 AM 或 OX 联合使用可能会导致针对 MRSA 感染的新联合抗生素的开发。
