Objective: To compare the chemical differences in 4 commercial specifications of Scutellaria Radix, research the affection of decayed central xylem part on the crude drug's chemical composition and provide scientific data for production, processing, sale and clinical applications of Scutellariae Radix.
Method: Macroscopical identification method was used for observation of different specifications of Scutellariae Radix, including Qinwang, Tiaoqin both in 1st class and 2nd class and inferior samples. HPLC fingerprint method was used to analyze chemically the decayed central xylem part and non-decayed part as well as complete sample, and the results were described by the relative peak area.
Result: The morphological characteristics of 4 specifications are greatly different from one another mainly in root diameters, root lengths and the proportions of decayed central xylem part in the root, and so the authors classified Qinwang and Tiaoqin in 1st class as Kuqin for all samples of them which have decayed central xylem; and classified Tiaoqin in 2nd class and the inferior samples as Ziqin, for having little decayed central xylem. The 4 specifications collected from the same producing area have similar HPLC fingerprint profile to one another, while they are different in relative peak area. The peak area ratios of aglycone to their glucuronide (baicalein/baicalin, wogonin/wogonoside, oroxylin A/oroxylin A-7-O-glucuronide) from Kuqin were significantly higher than those of Ziqin. The total area of the peaks in HPLC fingerprint chromatographs of decayed central xylem part were quite lower than that of non-decayed part, whereas peak areas of the characteristic peaks and the 3 peak area ratios of decayed central xylem were significantly higher than those of non-decayed part which could be used as characteristic parameters to distinguish Kuqin and Ziqin.
Conclusion: Four commercial specifications of Scutellariae Radix can be classified as Kuqin and Ziqin respectively according to morphological characteristics and the proportions of decayed central xylem part in the root. The chemical characteristics of Kuqin and Ziqin are different from each other, so it's worth clarifying the similarities and differences of Kuqin and Ziqin in future. The result in this research can be used as references for identification and quality control of Scutellariae Radix specifications, and investigation on effective components of Kuqin and Ziqin.