Research on the specifications and grades standard of the Paeoniae Radix Alba

Objective: Establish a standardized classification system for the Paeoniae Radix Alba that encompasses both appearance characteristics and internal quality. Methods: The diameter, sulfur dioxide residue, paeoniflorin content, and paeoniflorin sulfite content of 149 batches of paeony samples were measured by the 4-point method, acid-base titration, and HPLC, respectively. The obtained results were used for correlation analysis to study the association between extrinsic traits and intrinsic indicators of Paeoniae Radix Alba. Finally, according to the actual situation of the market, the classification standard of Paeoniae Radix Alba was established. Results: The diameter of 149 batches of Paeoniae Radix Alba ranged from 1.1 cm to 2 cm. Among them, 46 batches of Paeoniae Radix Alba were fumigated with sulfur, and the corresponding content of paeoniflorin sulfite was 0%–0.775%. The content of paeoniflorin in Paeoniae Radix Alba ranged from 1.6% to 4%. The results of correlation analysis showed that sulfur dioxide residue was positively correlated with paeoniflorin sulfite content, while other indexes were not significantly correlated. In conjunction with the stipulations outlined in the 2020 edition of the Chinese Pharmacopoeia and the current state of the medicinal materials market, the Paeoniae Radix Alba was classified into 3 grades based on their diameter, sulfur dioxide residue, paeoniflorin sulfite content, and paeoniflorin content: grade 1 Paeoniae Radix Alba, with a diameter of 1.5–2.5 cm, sulfur dioxide residue ≤30 mg/kg, paeoniflorin sulfite content ≤0.1%, and paeoniflorin content ≥2.2%; grade 2 Paeoniae Radix Alba, with a diameter of 1–1.5 cm, sulfur dioxide residue ≤400 mg/kg, paeoniflorin sulfite content ≤0.7%, and paeoniflorin content ≥1.9%; Standard Paeoniae Radix Alba, with a diameter of 1–2.5 cm, sulfur dioxide residue ≤400 mg/kg, paeoniflorin sulfite content ≤0.7%, and paeoniflorin content ≥1.6%. Conclusions: The classification system for the Paeoniae Radix Alba developed in this study is both scientific and rational, serving as a foundation for the market classification of commodities.