Investigation on Differences of Chemical Constituents between Sun-Dried and Sulfur-Fumigated Chuanxiong Rhizoma Based on UHPLC-Q-TOF MS and Chemometric Analysis

Sulfur-fumigation has been used around the world for centuries in the food industry to inhibit oxidation of the light-colored fruits or vegetables, and this sulfur-based preservative approach has also been employed in postharvest handling of the medicinal herbs to preserve color and freshness, and to protect against insects and molds over the last several decades in China. However, more and more recent reports about sulfur-fumigation show that it can cause the chemical transformations of the original bioactive components (the sulfur dioxide obtained from the heating of sulfur, as a strong reducing agent, may react with the ketonic group and hydroxyl radical-containing components of the medicinal herbs), affect the efficacies and the pharmacokinetics of the medicinal herbs and their extracts or preparations, and more seriously it can even lead to a toxic reaction in the liver and kidneys. Therefore, the influence on the intrinsic quality of Chuanxiong Rhizoma caused by sulfur-fumigation needs to be investigated systematically. In this paper, the differences of chemical constituents between sun-dried and sulfur fumigated Chuanxiong Rhizoma were investigated based on UHPLC-Q-TOF MS and chemometric analysis. The samples of 19 batches of sun-dried Chuanxiong Rhizoma, 11 batches of lab-prepared sulfur-fumigated Chuanxiong Rhizoma, and 9 batches of industrial sulfur-fumigated Chuanxiong Rhizoma were taken as the research objects. The sample solutions were prepared by the optimized extraction method. After injection of the prepared sample solutions, PeakView1.2 software was applied to analyze the mass spectrometric data and to identify the constituents based on the accurate m/z-values of Q-TOF MS and the fragments of Q-TOF MS². Meanwhile, MarkerView1.2.1 software was combined to develop the principal component analysis and t-test statistical analysis to identify as more common components and components with significant differences as possible. The results showed that the samples of sun-dried and sulfur-fumigated Chuanxiong Rhizoma could be classified clearly both in positive and negative ion modes by the means of principal component analysis, and there were obvious statistical differences existed among the principal components. What’s more, the results of t-test also demonstrated that there were a large number of constituents with statistical differences existed between sun-dried and sulfur-fumigated Chuanxiong Rhizoma, and parts of them were identified and their possible transformation pathways were further proposed. The study can provide the objective reference for the influence of sulfur-fumigation on the quality of Chuanxiong Rhizoma, and the theoretical basis for the control of excessive use of sulfur-fumigation in the processing of Chinese medicinal herbs and for the ensurance of safety and effectiveness of clinical medication in Chinese medicine.