Study of the destructive effect to inherent quality of Angelicae dahuricae radix (Baizhi) by sulfur-fumigated process using chromatographic fingerprinting analysis

The after-harvesting sun-dried process of Angelicae dahuricae radix (Chinese name: Baizhi) was previously the traditional treatment for commodity. Over recent decades the natural drying process for some fleshy roots or rhizomes of Chinese materia medica has been replaced by sulfur-fumigation for curtailing the drying duration and pest control. We used high performance liquid chromatography (HPLC) and high performance thin-layer chromatography (HPTLC) fingerprinting analysis to investigate the potential damaging effect of the sulfur-fumigating process. The experimental conditions were as follows. HPTLC analysis was carried out on pre-coated silica-gel 60 plate, twice development was performed with two solvent systems (mobile phase) A, chloroform-ethyl acetate (10:1) and B, hexane-chloroform-ether (4:1:2); the fluorescent images were observed under UV 365 nm. HPLC was preceeded on Zorbax SB-C18 column; the linear gradient elution was conducted with mobile phase prepared from methanol-0.5% acetic acid; column temperature was at 25 °C; the detection wavelength was 250 nm. We found serious degradation of the majority of coumarins in sulfur-fumigated Baizhi. The destructive effect was manifested by the defaced chromatographic profile and verified by imitating the sulfur dioxide reaction with the constituents in Baizhi in the laboratory. It is suggested that sulfur-fumigation process is an unacceptable approach for processing herbal drugs.