基于指纹图谱与化学计量学的桑叶蜜炙前后差异性标志物研究

Study on the differential markers of Morus alba leaves before and after baked with honey based on fingerprint and chemometrics

目的比较桑叶蜜炙前后化学成分的变化,筛选差异性标志物并进行含量测定,为蜜炙桑叶的质量控制提供参考。方法采用高效液相色谱(HPLC)法建立桑叶蜜炙前后指纹图谱,标定共有峰并进行相似度评价;以生桑叶、蜜炙桑叶共有峰峰面积为指标,运用主成分分析和正交偏最小二乘-判别分析筛选桑叶蜜炙前后差异性标志物,并进行定量分析。结果从10批生桑叶、10批蜜炙桑叶HPLC指纹图谱中分别标定出23、24个共有峰,2类样品图谱的相似度均大于0.97;主成分分析结果显示,生桑叶和蜜炙桑叶分为2类,正交偏最小二乘-判别分析结果显示,峰2、峰H(5-羟甲基糠醛)、峰1、峰17(异绿原酸C)、峰16的变量重要性投影值均大于1;生桑叶、蜜炙桑叶中差异性标志物异绿原酸C的平均含量分别为0.0936、0.1278 mg/g,差异有统计学意义(P<0.05)。结论筛选得到异绿原酸C等5种差异性标志物;桑叶蜜炙后异绿原酸C含量显著升高。

OBJECTIVE To compare the changes of chemical components of Morus alba leaves,screen differential markers,and determine their contents,so as to provide reference for quality control of M.alba leaves before and after baked with honey.METHODS The fingerprints of M.alba leaves before and after baked with honey were established by high-performance liquid chromatography(HPLC).The common peaks of the fingerprints were identified and the similarity was evaluated.The differential markers of M.alba leaves before and after baked with honey were screened by principal component analysis(PCA)and orthogonal partial least squares-discriminant analysis(OPLS-DA)using common peak are of raw material and product baked with honey of M.alba leaves as index.The quantitative analysis was carried out.RESULTS Twenty-three and twenty-four common peaks were identified from the HPLC fingerprint spectra of ten batches of raw material and ten batches of product baked with honey of M.alba leaves,respectively.The similarities of HPLC fingerprints for raw material and product baked with honey of M.alba leaves were all greater than 0.97.The results of PCA showed that raw material and product baked with honey of M.alba leaves could be divided into two categories.The results of OPLS-DA showed that the variable importance in projection of peak 2,peak H(5-hydroxymethylfurfural),peak 1,peak 17(isochlorogenic acid C)and peak 16 were all greater than 1.The average contents of differential marker of isochlorogenic acid C in raw material and product baked with honey of M.alba leaves were 0.0936 and 0.1278 mg/g,respectively;there was statistical significance(P<0.05).CONCLUSIONS Five differential markers such as isochlorogenic acid C are obtained.The content of isochlorogenic acid C in M.alba leaves is significantly increased after baked with honey.