Masila Veronica M, Midiwo Jacob O, Zhang Jin, Gisacho Bonface M, Munayi Renee, Omosa Leonidah K, Wiggers Frank T, Jacob Melissa R, Walker Larry A, Muhammad Ilias
Nat Prod Commun. 2015 Apr;10(4):613-6.
The root extract of Thespesia garckeana yielded three known oxidatively coupled sesquiterpenoids, namely (-)-gossypol (1) and two of its derivatives (-)-6-methoxygossypol (2) and (+)-6,6'-dimethoxygossypol (3), and the stem bark afforded (E)-docosyl-3-(3,4-dihydroxyphenyl) acrylate (4), stigmasterol (5) and betulinic acid (6). The structures of the isolated compounds were determined on the basis of full spectral data (1D and 2D NMR and HRMS) and comparison with literature values. Compound 1 showed potent antibacterial activity against vancomycin-resistant Enterococcus faecium (VRE) with IC50/MIC/MBC values of 1.71/4.82/19.31 µM, respectively, whereas the reference standard vancomycin was found to be inactive. The mono- and di-methoxylated derivatives of this compound, (-)-6-methoxygossypol (2) and (+)-6,6'-dimethoxygossypol (3), were less active with respective IC50/MIC/MBC values of 2.73/4.70/9.40 µM and 6.14/18.32/18.32 µM against this microbe. Compound 2 was more potent than 1 against the low level VRE strain with I50/MIC/MBC values of 4.34/9.40/9.40 µM (vs 5.23/19.31/19.3 µM for 1). This compound also showed interesting activities against Candida glabrata with an I50 value of 2.97 µM, but was less active against methicillin-resistant S. aureus (MRSA) exhibiting an IC50 value of 17.33 µM. Compound 1 demonstrated modest activity against the
刺蒴麻的根提取物产生了三种已知的氧化偶联倍半萜类化合物，即（-）-棉酚（1）及其两种衍生物（-）-6-甲氧基棉酚（2）和（+）-6,6'-二甲氧基棉酚（3），其茎皮中含有（E）-二十二烷基-3-（3,4-二羟基苯基）丙烯酸酯（4）、豆甾醇（5）和桦木酸（6）。分离得到的化合物结构通过完整的光谱数据（一维和二维核磁共振以及高分辨质谱）并与文献值进行比较来确定。化合物1对耐万古霉素的屎肠球菌（VRE）显示出较强的抗菌活性，其IC50/MIC/MBC值分别为1.71/4.82/19.31 μM，而参考标准万古霉素无活性。该化合物的单甲氧基和二甲氧基衍生物，即（-）-6-甲氧基棉酚（2）和（+）-6,6'-二甲氧基棉酚（3），活性较低，对该微生物的IC50/MIC/MBC值分别为2.73/4.70/9.40 μM和6.14/18.32/18.32 μM。化合物2对低水平VRE菌株的活性比化合物1更强，其I50/MIC/MBC值为4.34/9.40/9.40 μM（化合物1为5.23/19.31/19.3 μM）。该化合物对光滑念珠菌也显示出有趣的活性，I50值为2.97 μM，但对耐甲氧西林金黄色葡萄球菌（MRSA）的活性较低，IC50值为17.33 μM。化合物1对……表现出适度的活性
