An integration of UPLC-Q-TOF/MS and chemometrics analysis for the holistic quality evaluation of different geographical Paederia scandens

Quality by design-based capillary electrophoresis method development for the quantitative analysis of four iridoid compounds in Gentiana macrophylla Radix

In this study, the capillary electrophoresis-photodiode array detector was employed for the analysis of four iridoid compounds in Gentiana macrophylla Radix (RGM), and the method was optimized based on the concept of analytical quality by design (AQbD). The peak areas relative standard deviation (n = 3) and resolution of the four analytes were selected as critical method attributes. Fractional factorial design test combined with Pareto analysis were employed to screen critical method parameters (buffer concentration, pH, sodium dodecyl sulfate [SDS] micelle concentration, temperature, and voltage). Subsequently, three main factors (buffer concentration, buffer pH, and SDS concentration) were selected by central composite design test for constructing the design space. The optimal separation conditions as follows: capillary column (50.2 cm ×m50 µm, detection length 40 cm). Working background electrolyte consisted of 51 mmol/L borax solution (pH = 9.47) and 40 mmol/L SDS. The samples were injected by pressure (5 s at 0.5 psi) and the detection was performed at 254 nm. Applied voltage was 20 kV and column temperature was 23°C. The developed method is rapid and reliable for the quantitative analysis of four iridoid compounds in RGM, providing a reference for the application of AQbD concept in the analysis of natural products.

Characterization and Discrimination of Ophiopogonis Radix with Different Levels of Sulfur Fumigation Based on UPLC-QTOF-MS Combined Molecular Networking with Multivariate Statistical Analysis

Ophiopogonis Radix, also known as "Maidong" (MD) in China, is frequently sulfur-fumigated (SF) in the pretreatment process of MD to improve the appearance and facilitate preservation. However, the process leads to changes in chemical composition, so it is essential to develop an approach to identify the chemical characteristics between nonfumigated and sulfur-fumigated products. This paper provided a practical method based on UPLC-QTOF-MS combined Global Natural Products Social Molecular Networking (GNPS) with multivariate statistical analysis for the characterization and discrimination of MD with different levels of sulfur fumigation, high concentration sulfur fumigation (HS), low concentration sulfur fumigation (LS) and without sulfur fumigation (WS). First, a number of 98 compounds were identified in those MD samples. Additionally, the results of Principal component analysis (PCA) and Orthogonal partial least-squares-discriminant analysis (OPLS-DA) demonstrated that there were significant chemical differences in the chemical composition of MD with different degrees of SF. Finally, fourteen and sixteen chemical markers were identified upon the comparison between HS and WS, LS and WS, respectively. Overall, these results can be able to discriminate MD with different levels of SF as well as establish a solid foundation for further quality control and pharmacological research.