Flavonoids rather than alkaloids as the diagnostic constituents to distinguish Sophorae Flavescentis Radix from Sophorae Tonkinensis Radix et Rhizoma: an HPLC fingerprint study.

Sophorae Flavescentis Radix (Sophora flavescens Ait., SFR) and Sophorae Tonkinensis Radix et Rhizoma (S. tonkinensis Gapnep., STR) are two commonly used traditional Chinese medicines from Sophora (Leguminosae) plants, which are believed to possess similar bioactive components with entirely different clinical applications. In order to find out the characteristic chemical constituents potentially leading to the unique medicinal properties claimed for each of the two closely related TCMs, an HPLC fingerprint method was developed for analyses of the alkaloid and flavonoid constituents of SFR and STR, respectively, which were further evaluated and compared through similarity calculation and hierarchical clustering analysis (HCA). The results from the present study showed that the alkaloid fingerprints of the two herbs were similar, with many components co-existing in both drugs and various batches of samples from different species being mixed together in the HCA dendrogram. However, their flavonoid constituents were totally different with specific fingerprints being yielded for each herb, and further HCA analysis showed that the tested samples could almost be clearly divided into two groups based on their origins of species. The results from the present study indicated that the flavonoid constituents could serve as the differentially diagnostic constituents of SFR and STR and might potentially attributed to their distinct therapeutic effects.

Qualitative and quantitative analysis of flavonoids in Sophora tonkinensis by LC/MS and HPLC.

AIM: To develop analytical methods for the identification and determination of the flavonoids in Sophora tonkinensis for comprehensive quality evaluation. METHODS: An HPLC-DAD-ESI-MS method was used for the separation and characterization of the flavonoids in S. tonkinensis, and a liquid chromatographic method was employed to simultaneously determine five major active flavonoids in this crude drug. RESULTS: Seventeen flavonoids were identified, among which, seven were unambiguously identified as trifolirhizin, quercetin, formononetin, macckiain, kurarinone, sophoranone, and sophoranochromene by comparing their retention times, and UV and MS spectra with those of the authentic compounds, and the other ten flavonoids were tentatively identified by comparing their UV and MS/MS spectra with those of literature data. Furthermore, five major active flavonoids, including trifolirhizin, quercetin, maackiain, sophoranone, and sophoranochromene were determined in S. tonkinensis. All calibration curves expressed good linearity (r > 0.999 8) within the test ranges, and the recovery from this method was 96.40%-104.43%. The developed HPLC method was successfully applied to quantitatively determine the five flavonoids in seventeen samples of S. tonkinensis. CONCLUSION: The developed method rapidly characterized the bioactive flavonoids of S. tonkinensis, and could be readily utilized to enhance the quality assurance approaches for this traditional Chinese medicine.

Genetic characterization and phytochemical analysis of wild and cultivated populations of Scutellaria baicalensis.

Scutellaria baicalensis was collected from four wild and four cultivated populations from different locations in China. Forty-two samples were analyzed using random amplification of polymorphic DNA (RAPD) techniques for genetic profiling, and high performance liquid chromatography (HPLC) techniques to determine the flavonoid content. The selected 23 RAPD primers yielded a total of 838 clear and reproducible bands of which 237 were found to be polymorphic. The wild population exhibited higher polymorphism than that of the cultivated population. The dendrogram generated by the UPGMA method via Nei's genetic distance revealed three distinct genotypes from the cultivated populations and several branches from the wild populations. The contents of baicalin and wogonoside in dried roots of the samples ranged from (w/w) 8.63 to 17.84%, and from 1.99 to 4.21%, respectively, whereas their aglycones, baicalein and wogonin, were within the range of only 0.04-0.23%. The total content of the four flavonoids varied from 9.45 to 26.24%. Comparatively, the cultivated populations contained much higher levels of baicalin and total flavonoids than those in the wild populations. The results from genetic characterization and phytochemical analysis demonstrated that the quality variation of this drug was mainly determined by extrinsic environmental or agricultural factors, rather than by genetic differences. Our findings can be used for the commercial production and germplasm management of this medicinal plant.