A Practical Protocol for a Comprehensive Evaluation of Sulfur Fumigation of Trichosanthis Radix Based on Both Non-Targeted and Widely Targeted Metabolomics.

Chuanzhi Kang,Wenjin Zhang,Lu-Qi Huang,Sheng Wang,Chaogeng Lv,Tielin Wang,Lanping Guo,Jian Yang,Jiahui Sun,Liping Kang,Wenqi Ma,Yang Ge

doi:10.3389/fpls.2020.578086

Abstract

Trichosanthis Radix (TR) is one of the most severely sulfur-fumigated herbs in the market, whose transformation mechanism of chemical compositions and sulfur-fumigation markers of TR have not been clarified. To excavate characteristic sulfur-fumigation markers of TR samples, this study brings up a practical protocol using both ultra-performance liquid chromatography/quadrupole time-of-flight-mass spectrum (UPLC-ESI-QTOF-MS/MS)-based non-targeted metabolomics and ultra-performance liquid chromatography/electrospray ionization/quadrupole multiple-stage linear ion-trap mass spectrum (UPLC-ESI-QTRAP-MS/MS)-based widely targeted metabolomics. The results of study demonstrated that five characteristic markers are sulfur-containing components, which were identified as p-Hydroxybenzyl hydrogen sulfite, cucurbitacin D sulfite I, cucurbitacin D sulfite II, cucurbitacin B sulfite I, and cucurbitacin B sulfite II, respectively. Additionally, cucurbitacin B and D were also filtered and identified as the characteristic sulfur-fumigation markers. Meanwhile, the different sulfur-fumigation extent of TR samples was tested by chemical transformations analysis and sulfur dioxide residues test. Further, 58.16% (139 of 239) of the differential metabolites content significantly reduced in sulfur-fumigated TR samples. Besides, 20 kinds of non-sulfur marker metabolites were tested to evaluate the quality of TR samples before and after sulfur fumigation, predominantly including phenolic acids, amino acids, lipids and nucleotides. Taking TR as an example, this work provides a comprehensive practical protocol for the quality supervision of sulfur-fumigation herbs.

Highlights

Sulfur fumigation has been used for more than 100 years as a common technology for the control of mold and insect in medicinal herbs (Jiang et al, 2013; Duan et al, 2016)
A UPLC-QTOF-MS/MS-based non-targeted metabolomics combined with UPLC-QTRAP-MS/MS-based targeted metabolomics method was developed to identify characteristic sulfur-fumigated markers in Trichosanthis Radix (TR) samples
The maker p-Hydroxybenzyl hydrogen sulfite was obviously correlated with p-Hydroxybenzyl alcohol, and this marker is present in sulfur-fumigated Gastrodia Rhizoma (Kang et al, 2017) which indicated that it has the potential to be developed as a relatively common sulfur-fumigation marker for other herbs

Summary

Introduction

Sulfur fumigation has been used for more than 100 years as a common technology for the control of mold and insect in medicinal herbs (Jiang et al, 2013; Duan et al, 2016). This method was initially only used in a few Chinese herbs which are rich in starch and polysaccharides, such as Dioscoreae Rhizoma. The critical steps in the quality control of medical materials include exploring the chemical transformation mechanism of sulfur-fumigated herbs and excavating the stable and reliable sulfur-fumigation markers

Methods

Results

Conclusion