[Botanical origin identification of Rhei Radix et Rhizoma based on color digitalization]

The color characteristic information of Rhei Radix et Rhizoma powder was obtained by spectrophotometer, the feasibility of rapid identification of Rhei Radix et Rhizoma origin based on chromaticity value was studied by statistical analysis. The results of rank correlation analysis showed that a~*(P<0.01), b~*(P<0.01) had significantly correlation with the origin of medicinal herbs, which could be used as two important parameters to distinguish the origin of Rhei Radix et Rhizoma, the larger the a~* value, the more red the powder color,and the greater the b~* value, the more yellow the powder color. Meanwhile, through Fisher discriminant analysis, the linear discriminant functions of different genus Rhei Radix et Rhizoma were established, which was Rheum tanguticum=40.666a~*+0.019b~*-213.303, Rh. palmatum=34.121a~*+0.061b~*-151.770, Rh. officinale=28.071a~*+0.113b~*-104.604 3, the coincidence rate of cross-validation was over 95%, among them, the discriminant rate of Rh. tanguticum and Rh. officinale reached 100%;In addition, using the percentile method to analyze the 90% reference value range of three different origin of Rhei Radix et Rhizoma, as a result, Rh. tanguticum a~*(10.236 5-10.604 7), b~*(32.294 8-34.841 7); Rh. palmatum a~*(8.602 7-8.770 0), b~*(27.534 8-28.968 6), and Rh. officinale a~*(6.825 7-7.464 3),b~*(21.001 6-27.716 4). According to this study, rank correlation analysis and Fisher discriminant analysis are feasible to distinguish the base of Rhei Radix et Rhizoma in a certain range, and provide some theoretical basis for the identification of Rhei Radix et Rhizoma. It also provides a new method and idea for the identification of other multi-base Chinese medicine.