South African Medical Research Council, TB Epidemiology and Intervention Research Unit, South African National Blood Service, Pretoria, South Africa.
J Nat Prod. 2009 Dec;72(12):2169-71. doi: 10.1021/np800778b.
The bioassay-guided fractionation of the EtOH extract of the leaves of Galenia africana led to the isolation of three known flavonoids, (2S)-5,7,2'-trihydroxyflavanone (1), (E)-3,2',4'-trihydroxychalcone (2), and (E)-2',4'-dihydroxychalcone (3), and the new (E)-3,2',4'-trihydroxy-3'-methoxychalcone (4). Compounds 1 and 3 exhibited moderate antituberculosis activity. During synergistic studies, a combination of compound 4 and an existing antituberculosis drug, isoniazid, reduced their original MICs 4-fold, resulting in a fractional inhibitory concentration of 0.50. The most pronounced effect was demonstrated by compound 1 and isoniazid reducing their MICs 16-fold and resulting in an FIC of 0.12. Both EtOH extract and isolated compounds failed to exhibit any NADPH oxidase activity at 800.0 muM concentrations, indicating that mycothiol disulfide reductase is not the target for their antituberculosis activity.
基于生物活性的导向分离，从非洲山黧豆叶的乙醇提取物中分离得到了三种已知的黄酮类化合物，（2S）-5,7,2'-三羟基黄烷酮（1）、（E）-3,2',4'-三羟基查尔酮（2）和（E）-2',4'-二羟基查尔酮（3），以及新的（E）-3,2',4'-三羟基-3'-甲氧基查尔酮（4）。化合物 1 和 3 表现出中等的抗结核活性。在协同研究中，化合物 4 与现有的抗结核药物异烟肼的组合将它们的原始 MIC 降低了 4 倍，导致分数抑制浓度为 0.50。最显著的效果是化合物 1 和异烟肼将它们的 MIC 降低了 16 倍，导致 FIC 为 0.12。乙醇提取物和分离得到的化合物在 800.0 μM 浓度下均未表现出任何 NADPH 氧化酶活性，表明它们的抗结核活性不是针对巯基二硫化物还原酶的。
