Quality assessment of crude and processed Leonuri Fructus by chemical and color analysis combined with chemometric method

Crude Leonuri Fructus (CLF), the fruits of the Leonurus japonicus Houtt, and processed Leonuri Fructus (PLF) by stir-baking as the important Chinese herbal medicines, have been used in China and other Asian countries for thousands of years. The objective of this research is to reveal the difference between CLF and PLF. The sensory technologies of the colorimetry, sensitive and validated HPLC-ELSD and GC combined with flame ionization detector (GC-FID) were employed to discriminate CLF and its processed product PLF. The color parameters of the samples were determined by colorimetric instrument CR-410. Moreover, the content of stachydrine and six fatty acids were determined by HPLC and GC. Subsequently, analysis of variance (ANOVA), principal components analysis (PCA), hierarchical cluster analysis (HCA), and Kendall's correlation test were performed for data analysis. The CLF and PLF were divided into two categories by PCA and HCA in terms of their component content and color. The results distinctly demonstrated significant changes in color and the content of indicative components between CLF and PLF. The study revealed that HPLC, GC, and colorimetric method in combination with chemometric method could be used as comprehensive quality evaluation for CLF and PLF.