Tanaka H, Sato M, Fujiwara S, Hirata M, Etoh H, Takeuchi H
Department of Natural Product Chemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan.
Lett Appl Microbiol. 2002;35(6):494-8. doi: 10.1046/j.1472-765x.2002.01222.x.
To screen 16 isoflavonoids isolated from Erythrina variegata (Leguminosae) for their antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).
The roots of E. variegata were macerated with acetone. The chloroform-soluble fraction of the residue was subjected to repeated silica gel column chromatography followed by elution with various solvents. Structures of the isolated compounds were determined by extensive spectroscopic studies. Each compound was dissolved in dimethyl sulphoxide and added to agar plates (final concentration 1.56-100 microg ml(-1) and suspensions of MRSA spotted onto the agar plates to determine the minimum inhibitory concentration (MIC). Repeated silica gel chromatography yielded 16 compounds and spectroscopic studies revealed that all were isoflavonoids. Whilst 14 compounds showed antibacterial activity in this concentration range, the MIC values varied significantly among them. Of the active compounds, 3,9-dihydroxy-2,10-di(gamma,gamma-dimethylallyl)-6a,11a-dehydropterocarpan (erycristagallin) and 9-hydroxy-3-methoxy-2-gamma,gamma-dimethylallylpterocarpan (orientanol B) exhibited the highest activity with MIC values of 3.13-6.25 microg ml(-1).
Erycristagallin and orientanol B showed the highest anti-MRSA activity (3.13-6.25 microg ml(-1).
Erycristagallin and orientanol B could be leading compounds for phytotherapeutic agents against MRSA infections.
筛选从刺桐（豆科）中分离出的16种异黄酮对耐甲氧西林金黄色葡萄球菌（MRSA）的抗菌活性。
刺桐根用丙酮浸渍。残渣的氯仿可溶部分经反复硅胶柱色谱，然后用各种溶剂洗脱。通过广泛的光谱研究确定分离出的化合物的结构。将每种化合物溶解于二甲基亚砜中，并添加到琼脂平板中（终浓度为1.56 - 100μg ml⁻¹），将MRSA菌悬液点种到琼脂平板上以测定最低抑菌浓度（MIC）。反复硅胶色谱得到16种化合物，光谱研究表明所有化合物均为异黄酮。虽然14种化合物在此浓度范围内显示出抗菌活性，但它们的MIC值差异显著。在活性化合物中，3,9 - 二羟基 - 2,10 - 二（γ,γ - 二甲基烯丙基）- 6a,11a - 脱氢紫檀素（刺桐晶）和9 - 羟基 - 3 - 甲氧基 - 2 - γ,γ - 二甲基烯丙基紫檀素（东方醇B）表现出最高活性，MIC值为3.13 - 6.25μg ml⁻¹。
刺桐晶和东方醇B显示出最高的抗MRSA活性（3.13 - 6.25μg ml⁻¹）。
刺桐晶和东方醇B可能成为抗MRSA感染植物治疗剂的先导化合物。
