四倍体桦树树皮中三萜化合物的测定与评价

白桦脂酸、齐墩果酸和白桦脂醇是桦树树皮中含量较高的3种三萜类化合物,具有重要的药用价值。本实验以超声波辅助提取法提取桦树树皮中的三萜化合物,并利用高效液相色谱法分离检测3种三萜化合物,进而构建小提琴图和星相图等研究2种四倍体桦树树皮中3种三萜化合物的含量差异,并通过因子分析法,筛选出综合性状优良的四倍体桦树单株。结果表明:三萜化合物分离、检测的色谱条件为以十八烷基硅烷键合硅胶为填充剂的C18色谱柱(4.6 mm250 mm5 m),以乙腈-水(含0.1%磷酸)为流动相,梯度洗脱,柱温30 ℃,流速0.5 mL/min,检测波长为195 nm;在0.05的显著性水平下,2种四倍体桦树树皮中齐墩果酸的含量存在显著差异,在0.10的显著性水平下,2种四倍体桦树树皮中白桦脂酸和白桦脂醇的含量存在显著差异,其中杂种白桦中3种三萜化合物含量普遍高于白桦;3种三萜化合物间存在极显著的正相关关系,其中白桦脂酸和白桦脂醇间的相关系数最高,为0.911,而白桦脂醇和齐墩果酸间的相关系数最低,为0.631;利用因子分析法构建了F=48.620%F1+21.080%F2+21.075%F3桦树三萜综合评价公式,并筛选出了综合性状相对优良的桦树单株,其中白桦中综合得分最高的前3个单株依次为4126、4123、4125,杂种白桦中得分最高的前3个单株依次为4202、4204、4208。 

Analysis and evaluation of triterpenoids in tetraploid birch ( Betula)

Betulinic acid, oleanolic acid and betulin are three pentacyclic triterpenoids in birch bark with high contents and a variety of medicinal values. In this study, we used ultrasonic-assistant measure to extract triterpenoids from birch bark rapidly with high efficiency. Using HPLC, we separated and detected the three kinds of triterpenoids. Then, we examined the differences in contents of three triterpenoids between two kinds of birches by building violin plots and star plots. Finally, we applied factor analysis method to screen the tetraploid birches with excellent comprehensive traits. The HPLC assay was performed using a reversed-phase C18 column (4. 6 mm × 250 mm × 5 μm) with a column temperature of 30 ℃. The mobile phase was composed of acetonitrile and 0. 1% aqueous phosphoric acid with a flow rate of 0. 5 mL/min and detection wavelength of 195 nm. There were significant differences in contents of betulinic acid and betulin between the two kinds of tetraploid birches at the confidence level of 0. 10 , and also a significant difference in oleanolic acid content at the confidence level of 0. 05 . The contents of three triterpenoids in B. platyphylla × B. pendula were always higher than that in B. platyphylla. The results indicated that there was a significantly positive correlation among contents of three triterpenoids. Analysis revealed that the correlation coefficient was the highest ( 0. 911 ) between betulinic acid and betulin and the lowest (0. 631) between oleanolic acid and betulin. With factor analysis we obtained the following comprehensive evaluation formula for individual birch plants: F = 48. 620% F1 + 21. 080% F2 +21. 075%F3 , and screened out the individual plants with excellent comprehensive characters. The three top-scorer individuals of B. platyphylla were Nos. 4126, 4123 and 4125, and those of B. platyphylla × B. pendula were Nos. 4202, 4204 and 4208.