Rapid identification for the species discrimination of Curcumae Rhizoma using spectrophotometry and flash gas chromatography e-nose combined with chemometrics

Curcumae Rhizoma (CR) is a multi-origin herbal medicine from Cucurma kwangsiensis, Cucurma phaeocaulis, and Cucurma wenyujin. These three species are difficult to distinguish because of their similar morphological character-istics. In this study, a species discrimination strategy that combines spectrophotometry and flash gas chromatog-raphy (GC) e-nose was proposed. Principal component analysis (PCA) based on color parameters exhibited an overlap among the three species, which could be distinguished by color reference ranges and Bayes discriminant. Chemometric models were built based on odor information. The fingerprint revealed 18, 17, and 18 common peaks of C. kwangsiensis, C. phaeocaulis, and C. wenyujin, respectively. Heatmap and PCA visualized differences among the three varieties. With the accuracy of the validation set being 100%, linear discriminant analysis was used to identify different varieties rapidly and accurately. Meanwhile, 14 components, such as decanal, were determined to be chemical markers ( P < 0.05, VIP > 1) for the three species in partial least squares discriminant analysis. Finally, the Pearson test indicated that various components and color parameters were strongly related. In conclusion, spectrophotometry and flash GC e-nose combined with chemometrics can be used to identify CR from different species rapidly and accurately.