High quality standard of Scutellariae Radix based on plant metabolomics and index components

Abstract

Scutellariae Radix(SR), derived from the dried root of Scutellaria baicalensis in the family Lamiaceae, commonly serves as Chinese medicinal material. Affected by producing areas, growing years, and harvesting periods, the quality of SR fluctuates in the market. However, baicalin≥9% in SR required in the Chinese Pharmacopoeia(2020 edition) can only determine the qualified SR but cannot identify high-quality SR. To improve the quality control methods of SR, the present study analyzed the accumulation of metabolites in SR of different growth years by plant metabolomics, and identified 28 metabolites increasing with growth years(1-3 years). Subsequently, 14 main metabolites were quantitatively analyzed by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry(UPLC-QQQ-MS). Among them, baicalin, wogonoside, baicalein, and wogonin with high content and good activity were selected as the index components of SR for quality evaluation. A high-performance liquid chromatography(HPLC) method was established to determine the content of four index components in 32 batches of SR from different producing areas, harvesting perio-ds, and growth years. The results showed that the growth years could greatly affect the content of index components. The total content of four index components in 2-year SR was the highest, followed by the 3-/4-year SR and 1-year SR. Based on HPLC data and verification results by enterprises, baicalin ≥12.0%, wogonoside ≥2.3%, baicalein ≥0.1%, and wogonin ≥0.03% were proposed as the evaluation criteria for the high-quality SR. The findings of this study are expected to provide a basis for improving the quality of SR.