Rapid discovery of active ingredients from complex matrices is one of great challenges for modern drug development. Traditional methods often require many sample treatment steps, including an extraction step with exclusively dedicated solvents followed by repeated separation and activities assessment. This present work described an integrated analytical setup for natural antioxidants discovery in which the online extraction (OLE) of a solid sample is directly coupled to its analysis by high performance liquid chromatography-diode array detector-quadrupole time-of-flight tandem mass spectrometry and 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) antioxidant assay (OLE-HPLC-DAD-QTOF-MS/MS-ABTS). This developed approach makes sample extraction, chromatographic separation and chemical detection, and antioxidant assay integrated into a single HPLC injection and was successfully applied for the rapid discovery of natural antioxidant bioactives from Polygonum viviparum . A total of 21 secondary metabolites were characterized according to their retention times, ultraviolet (UV) spectra, exact mass and fragmentation ions in MS/MS spectra, and 18 of them displayed antioxidant activity (response as negative peaks in antioxidant assay). This work describes a simple, green and efficient approach to minimize the sample consumption (only 0.4 mg was required) and eliminate complex sample treatment procedures. The developed OLE-HPLC-DAD-QTOF-MS/MS-ABTS system offers new perspectives for rapid chemical profiling of natural products and their antioxidants discovery.
Given the safety of synthetic antioxidants, people are increasingly inclined to develop and use natural antioxidants. However, rapid screening and identification of active ingredients from the complex systems of natural products is one of the major challenges for the modernization of traditional Chinese medicine. In this study, online extraction-high performance liquid chromatography-diode array detection-quadrupole time-of-flight mass spectrometry coupled with ABTS antioxidant assay (OLE-HPLC-DAD-QTOF-MS/MS-ABTS), in which sample preparation, separation, detection and antioxidant assay were integrated in a single step, was used to rapidly identify antioxidant components from the different parts of Citrus reticulata , including its peels, leaves, vascular bundies and seeds. After method validation (system adaptability, extraction yield and repeatability), the four samples of different botanical parts were analyzed. As a result, among 49 found chromatographic peaks, 33 peaks displayed varying degrees of antioxidant activity and 39 peaks were tentatively or unambiguously identified based on their retention time, UV spectrum and mass spectrometry information and the comparison with reference substance and data in literature, including 10 phenolic acids, 9 polymethoxy flavonoids, 7 flavonoid- O -glycosides and 13 other ingredients. It is concluded that the established method is simple, fast, and reliable, which not only saves the materials and solvents as well as time, but also reduces the risk of degradation of chemical components during the extraction process, suitable for rapid screening and identification of antioxidant components of complex mixture.
危险品化学品经营许可证（带存储）