Qualitative and quantitative analysis of four species of Curcuma rhizomes using twice development thin layer chromatography

The rhizomes of Curcuma phaeocaulis, Curcuma kwangsiensis, Curcuma wenyujin and Curcuma longa are used as Ezhu or Jianghuang in traditional Chinese medicine for a long time. Due to their similar morphological characters, it is difficult to distinguish their origins of raw materials used in clinic. In this study, a simple, rapid and reliable twice development TLC method was developed for qualitative and quantitative analysis of the four species of Curcuma rhizomes. The chromatography was performed on silica gel 60F254 plate with chloroform–methanol–formic acid (80:4:0.8, v/v/v) and petroleum ether–ethyl acetate (90:10, v/v) as mobile phase for twice development. The TLC markers were colorized with 1% vanillin–H2SO4 solution. The four species of Curcuma were easily discriminated based on their characteristic TLC profiles, and simultaneous quantification of eight compounds, including bisdemethoxycurcumin, demethoxycurcumin, curcumine, curcumenol, curcumol, curdione, furanodienone and curzerene, in Curcuma were also performed densitometrically at λscan = 518 nm and λreference = 800 nm. The investigated compounds had good linearity (r2 > 0.9905) within test ranges. Therefore, the developed TLC method can be used for quality control of Curcuma rhizomes.