Quantitative fingerprinting based on the limited-ratio quantified fingerprint method for an overall quality consistency assessment and antioxidant activity determination of Lianqiao Baidu pills using HPLC with a diode array detector combined with chemometric methods

Lianqiao Baidu pills are widely used herbal medicinal preparation that were analyzed to develop a quality consistency technique. The characteristic fingerprints of 28 batches of Lianqiao Baidu pill samples were established at five wavelengths and simultaneously assessed by using a limited-ratio quantified fingerprint method using 15 marker compounds. The principal component analysis and fingerprinting results were compared, and the qualitative classification of the samples by principal component analysis agreed with their quantitative evaluation by the limited-ratio quantified fingerprint method. Furthermore, the antioxidant activities of the samples were surveyed and determined using a 2,2-diphenyl-1-picrylhydrazyl radical-scavenging approach. A relationship between the common peaks in the fingerprints and the antioxidant activities was established using a partial least squares model. The relationship can be used both to determine the antioxidant activities of the Lianqiao Baidu pill preparations in vitro and as a reference for the selection of active constituents for sample quality classification. The classification results for the samples based on principal component analysis agreed with the quantitative evaluation by the limited-ratio quantified fingerprint method, which demonstrated that the method can be applied to the holistic quality control of traditional Chinese medicine and herbal preparations.