Chemical correlation between Shuanghuanglian injection and its three raw herbs by LC fingerprint

Shuanghuanglian injection, a famous composite formula in China, is a combination of Flos lonicerae japonicae, Radix scutellariae and Fructus forsythiae. To develop a method to overall evaluate the correlation between the formula and its three raw herbs, the representative LC fingerprint of Shuanghuanglian injection was established from 12 batches of samples. Ten peaks were selected as the common peaks to evaluate the similarities of different samples from different manufacturers. Hierarchical clustering analysis was used as a powerful pattern recognition tool to identify and classify Shuanghuanglian injection from different factories. In addition, chemical correlation between the formula and the three raw herbs was evaluated qualitatively through comparison of their chromatograms under the same HPLC conditions. The results showed that peak 1, 2, 3 and 9 in the formula fingerprint were characteristic components of Flos lonicerae japonicae, peaks 5, 6 and 8 were that of F. forsythiae, peak 10 was that of R. scutellariae, while peak 7 was the common component of Flos lonicerae japonicae and F. forsythiae, peak 4 was addressed to F. forsythiae and it was also the product of the manufacturing procedure.