Zhang Huaping, Tan Junjie, Vanderveer Don, Wang Xi, Wargovich Michael J, Chen Feng
Department of Food Science and Human Nutrition, Clemson University, Clemson, 29634 SC, USA.
Phytochemistry. 2009 Jan;70(2):294-9. doi: 10.1016/j.phytochem.2008.12.004. Epub 2009 Jan 10.
Five khayanolides (1-O-acetylkhayanolide B 1, khayanolide B 2, khayanolide E 3, 1-O-deacetylkhayanolide E 4, 6-dehydroxylkhayanolide E 5) were isolated from the stem bark of African mahogany Khaya senegalensis (Meliaceae). Their structures and absolute configurations were determined through extensive spectroscopic analyses including MS, NMR, and single-crystal X-ray diffraction experiments. The results established that two previously reported khayanolides, 1alpha-acetoxy-2beta,3alpha,6,8alpha,14beta-pentahydroxy-[4.2.1(10,30).1(1,4)]-tricyclomeliac-7-oate 6 and 1alpha,2beta,3alpha,6,8alpha,14beta-hexahydroxy-[4.2.1(10,30).1(1,4)]-tricyclomeliac-7-oate 7, were, in fact, 1-O-acetylkhayanolide B 1 and khayanolide B 2, and that the two reported phragmalin derivatives, methyl 1alpha-acetoxy-6,8alpha,14beta,30beta-tetrahydroxy-3-oxo-[3.3.1(10,2).1(1,4)]-tricyclomeliac-7-oate 8 and methyl 1alpha,6,8alpha,14beta,30beta-pentahydroxy-3-oxo-[3.3.1(10,2).1(1,4)]-tricyclomeliac-7-oate 9, were, in fact, khayanolide E 3 and 1-O-deacetylkhayanolide E 4, respectively. Based on the results from this study and consideration of the biogenetic pathway, the methyl 6-hydroxyangolensate in African mahogany K. senegalensis should have a C-6 S configuration while methyl 6-hydroxyangolensate in genuine mahogany Swietenia species should have a C-6 R configuration.
从非洲桃花心木（Khaya senegalensis，楝科）的茎皮中分离出了五种卡亚诺内酯（1 - O - 乙酰基卡亚诺内酯B 1、卡亚诺内酯B 2、卡亚诺内酯E 3、1 - O - 去乙酰基卡亚诺内酯E 4、6 - 脱羟基卡亚诺内酯E 5）。通过包括质谱（MS）、核磁共振（NMR）和单晶X射线衍射实验在内的广泛光谱分析确定了它们的结构和绝对构型。结果表明，之前报道的两种卡亚诺内酯，1α - 乙酰氧基 - 2β,3α,6,8α,14β - 五羟基 - [4.2.1(10,30).1(1,4)] - 三环楝 - 7 - 酸酯6和1α,2β,3α,6,8α,14β - 六羟基 - [4.2.1(10,30).1(1,4)] - 三环楝 - 7 - 酸酯7，实际上分别是1 - O - 乙酰基卡亚诺内酯B 1和卡亚诺内酯B 2；而报道的两种苦楝素衍生物，1α - 乙酰氧基 - 6,8α,14β,３０β - 四羟基 - 3 - 氧代 - [3.3.1(10,2).1(1,4)] - 三环楝 - 7 - 酸甲酯8和1α,6,8α,14β,３０β - 五羟基 - 3 - 氧代 - [3.3.1(10,２).1(1,4)] - 三环楝 - 7 - 酸甲酯9，实际上分别是卡亚诺内酯E 3和1 - O - 去乙酰基卡亚诺内酯E 4。基于本研究结果并考虑生物合成途径，非洲桃花心木K. senegalensis中的6 - 羟基安哥拉酸甲酯应具有C - 6 S构型，而真正桃花心木Swietenia属植物中的6 - 羟基安哥拉酸甲酯应具有C - 6 R构型。
