Fingerprint of Vinegar Processed Genkwa Flos Based on Improving Euclidean Distance

To improve the traditional fingerprint method to distinguish vinegar processed Genkwa Flos from raw Genkwa Flos.Ten batches of Genkwa Flos were collected, processed with vinegar through a standard method, and then analyzed under the optimum HPLC condition. Based on the chromatographic data obtained, a common model of vinegar processed Genkwa Flos fingerprints, including 11 common peaks and the components genkwanin, hydroxygenkwanin, luteolin, apigenin and yuanhuacin were identified, was established. The peak of baicalein, an exogenous component added quantitatively to the samples as an internal standard, was served as the reference peak. The similarity between the test samples and the common model was computed using the improved Euclidean distance method developed in this paper.The similarities between vinegar processed Genkwa Flos samples and the common model were higher than 0.9, whereas those between raw Genkwa Flos and the common model were lower than 0.9.The proposed method thus effectively provides a clear distinction between vinegar processed and raw Genkwa Flos samples. The result is helpful to ensure the safe clinical use of the plant and expand the application field of fingerprinting technology.