Scanning Electron Microscopy and Liquid Chromatography for Physical and Chemical Inspection of Industrial Pharmaceutical Traditional Chinese Herbal Medicine

ACS Omega. 2020 May 11;5(20):11563-11569. doi: 10.1021/acsomega.0c00809. eCollection 2020 May 26.

Abstract

Multiherbal preparation of Coptidis rhizoma, Scutellariae radix, and Rhei rhizoma is a well-known herbal formula, which is widely used in the prescription for relieving heat toxicity, inflammation of the intestine, and eczema. However, little is known about the characteristics of the physical and chemical qualities of industrial pharmaceutical products. The aim of the study is to develop a liquid chromatography system to examine the quality and quantity of pharmaceutical products. Besides scanning electron microscopy, light microscopy photographs with Congo red staining and iodine-KI staining were used for physical examination of the quality of the pharmaceutical products. A reverse-phase C18 column was used to separate the analytes of baicalin, berberine, rhein, and p-hydroxybenzoate (internal standard) with a gradient eluent mobile phase of acetonitrile and 10 mM NaH2PO4 (pH 3.0, adjusted by orthophosphoric acid). The results demonstrated that a large variety of content range presents among the testing herbal pharmaceutical products. The contents of rhein, baicalin, and berberine were around 0.22-22.46, 0.44-50.79, and 0.41-2.48 mg/g, respectively. The physical examination data demonstrated that different brands of industrial pharmaceutical products have different shapes of granules or rods. In summary, to ensure the clinical efficacy of complicated herbal medicine, both quality and quantity controls are all very important. This study provides a reference standard operating procedure guide for the quality control (QC) with chemical and physical examination for the Chinese herbal pharmaceutical products of San-Huang-Xie-Xin-Tang (SHXXT).