Lee Shoei-Sheng, Lin Hsiao-Ching, Chen Chien-Kuang
School of Pharmacy, College of Medicine, National Taiwan University, 1, Sec. 1, Jen-Ai Road, Taipei 10051, Taiwan, ROC.
Phytochemistry. 2008 Sep;69(12):2347-53. doi: 10.1016/j.phytochem.2008.06.006. Epub 2008 Jul 17.
Bioassay-guided fractionation and isolation of the active constituents from the leaf extract of Machilusphilippinense Merr. yielded two active compounds, kaempferol-3-O-alpha-L-rhamnopyranoside 3'',4''-di-E-P-coumaroic acid ester (1) and 3''-E,4''-Z-di-p-coumaroic acid ester (2) when tested against a Bacillus stearothermophilus, a alpha-glucosidase type IV. The IC50 values of 1 and 2 were 6.10 and 1.00microM, respectively. Further application of the HPLC-SPE-NMR hyphenated technique in the on-line characterization of other active ingredients present in the CH2Cl2 - soluble fraction led to identification of luteolin (3) and seven additional 3-O-(coumaroyl-rhamnopyranosyl)-flavonols (4-10). Their structures were determined mainly by 1H NMR spectroscopic analyses. Among the compounds identified, compounds 2, 4, 5, and 7 were hitherto unknown natural products.
采用生物测定导向的分离方法，从菲律宾楠木叶提取物中分离出活性成分。当用嗜热脂肪芽孢杆菌IV型α-葡萄糖苷酶进行测试时，得到了两种活性化合物，山奈酚-3-O-α-L-鼠李糖苷3'',4''-二-E-p-香豆酸酯（1）和3''-E,4''-Z-二-p-香豆酸酯（2）。化合物1和2的IC50值分别为6.10和1.00μM。进一步应用HPLC-SPE-NMR联用技术对二氯甲烷可溶部分中存在的其他活性成分进行在线表征，鉴定出木犀草素（3）和另外七种3-O-（香豆酰-鼠李糖基）黄酮醇（4-10）。它们的结构主要通过1H NMR光谱分析确定。在所鉴定的化合物中，化合物2、4、5和7是迄今未知的天然产物。
