黄芩素的分离纯化与结构表征

以聚酰胺为柱层析吸附剂，以乙醇-氯仿混合溶剂梯度洗脱，从中药黄芩的甲醇提取液中分离出有效成分黄芩素的粗品。 通过对有效成分进行重结晶等纯化处理，得到了一种黄色短棱柱晶状产物。 利用红外光谱(FTIR)、紫外-可见光谱(UV-Vis)、质谱(MS)、氢谱(1H-NMR)及碳谱(13C-NMR)等分析测试手段，对产物的组成和结构进行了表征。 红外光谱测定结果表明，产物的结构中含有共轭芳香体系和单取代苯；紫外-可见光谱和质谱表明，产物为黄酮而非黄酮苷化合物，A环上含有三个酚羟基， B环无羟基和其他基团取代；核磁共振氢谱及碳谱表明，产物的结构中含15个碳原子， 三组羟基质子。 同时，文章还对所有1H-NMR和13C-NMR信号进行了归属，对FTIR光谱特征吸收峰所对应的官能团及其振动形式进行了指认，给出了化合物及碎片离子在质谱中的裂解方式，最终将黄色短棱柱晶状产物鉴定为5,6,7-三羟基黄酮，即黄芩素，分子式为C₁₅H₁₀O₅。

Separation and Purification and Structural Characterization of Baicalein

The root of scutellaria baicalensis georgi that contains a variety of flavonoids is a very old and well-known drug in traditional Chinese medicine, which is widely used for treatment of bronchitis, tumors and inflammatory diseases.The baicalein is the main active component from traditional Chinese medicine-scutellaria baicalensis georgi.It is a very significance research work that the baicalein was separated and purified, and its composition and molecular structure are analyzed and determined for the pharmacology study of Chinese medicine-scutellaria baicalensis georgi.The main works in this paper are as follows.Powdered roots (100 g) were extracted with methanol by three times, each time for 48 hours.The crude extracts were purified by poly-amide column chromatography and CH₃Cl-C₂H₅OH gradient desorption.A short yellow prismatic crystal was acquired by re-crystallizing technique and its composition and molecular structure were characterized by color reactions and spectral analysis methods as FTIR, UV-Vis, MS and 1H NMR, 13C-NMR.The FTIR spectrum appears the absorption bands for hydroxyls, pyrone carbonyl, aromatic C=C bond and singly substituted phenyl.The characteristic absorption peaks and the vibration modes in FTIR spectrum were identified as corresponding groups.The UV-Vis spectrum in methanol solution and the mix solution of methanol with 5 diagnostic reagents, NaOMe, NaOAc, NaOAc/H₃BO₃, AlCl₃, AlCl₃/HCl, respectively indicate that the yellow prismatic crystal is flavone with 5-hydroxyl, 4-carbonyl and 5,6,7- or 5,7,8-trihydroxyls on ring A.The structure of the crystal was characterized by three different MS.The results of FAB-, ESI- and EI-MS show that it is not a flavone glocuside but the flavone with three phenyl hydroxyls on ring A, and no OH group and other substituted groups on ring B.The molecular ion and fragment ions are identified by MS, which include such as m/z 270 M+, m/z 242 M-CO]+, m/z 168 A, m/z 140 A₁-CO]+, m/z 105 B, m/z 102 B, m/z 77 B₂-CO]+, respectively.13C-NMR(DMSO-d6)exhibits the signals of the fifteen carbon atoms, nine oxygenous aromatic C, five non-oxygenous aromatic C and a carbonyl C.1H-NMR(DMSO-d6+D₂O，DMSO-d₆)indicates the presence of C-5, C-6, C-7 hydroxyl protons, which is consistent with the results of UV spectrum.The signals for C-2′,6′ hydroxyls appear at δ=8.055 as a doublet peak with spin-spin coupling constant 6.0 Hz.The other signals were ascribed to the corresponding H or C atoms in the compound.The results of FTIR, UV-Vis, MS, 1H NMR, 13C-NMR spectroscopy characterization show that crystal is the 5,6,7-trihydroxy-flavone, that is baicalein, and the molecular formula is C₁₅H₁₀O₅.