Impact of sulfur fumigation on quality of Scutellariae Radix

Abstract

Sulfur fumigation usually causes transformation of chemical components of traditional Chinese medicine (TCM). As for the process and storage of TCM, the sulfur fumigation has been no longer recommended by the government. This study is to explore the impact of the sulfur fumigation on the quality of Scutellariae Radix. Distillation combined with ion-chromatography was used to evaluate the residue of sulfur dioxide in 180 batches of Scutellariae Radix decoction pieces and 26 batches of Scutellariae Radix herbs. In addition, LC-MS combined with principal component analysis (PCA) was used to compare the changes in chemical components and flavonoid content in radix scutellariae before and after sulfur fumigation. As a result, 74 batches of Scutellariae Radix decoction pieces were determined to be unqualified on the basis of the residue limit of sulfur dioxide in Chinese Pharmacopoeia 2015 Vol. Ⅳ (≤150 mg•kg⁻¹), with a qualification rate of 35.9%. All of the unqualified samples were decoction pieces. The fingerprint and PCA indicates that flavonoid content of Scutellariae Radix had no change before and after sulfur fumigation, but flavonoid glycosides decreased after sulfur fumigation and baicalin decreased sharply. The flavonoid glycoside was hydrolyzed to flavone aglycone in the process of sulfur fumigation, which caused the decrease in content of falvonoid glycosides and had an impact on the quality of Scutellariae Radix. The decoction pieces of Scutellariae Radix were seriously fumigated with sulfur in the processing, suggesting the key regulatory point is the decoction pieces production process.