Correlation study of color of Curcuma longa in Sichuan and content of main composition based on theory of “distinguish quality by appearance of medicine” / 中草药

ABSTRACT

Objective The research is about the correlation of the color values of Curcuma longa in Sichuan and the content of the main composition (curcumin, demethoxycurcumin, bisdemethoxycurcumin, and curcuminoids). Methods Based on the theory of “distinguish quality by the appearance of medicine”, CM-5 spectro-colorimeter was used to measure the color values of slices and powders of C. longa in Sichuan, and combining to the content of the main composition of these medicines to analyze the correlation between them. Results It showed that there was a significant negative correlation between the color values of powders of C. longa in Sichuan (L*, b*, and ΔE*ab) and the content of the main component of medicines. The correlation coefficients were all around 0.4; Meanwhile, there was a significant positive correlation between the color value a* of C. longa in Sichuan and its main composition content, and the correlation coefficients were all around 0.7. Conclusion The color value a* of C. longa powders produced in Sichuan has higher correlation than other color values. It prompted that we can predict and judge the quality of C. longa in Sichuan by color value a* of C. longa powders, thereby verifying the scientificity of “distinguish quality by the appearance of medicine” in the identification of C. longa. The research can lay the foundation of establishing the evaluation system of C. longa, which can rapidly identify the quality of C. longa.