Combination of molecular network and centrifugal partition chromatography fractionation for targeting and identifying Artemisia annua L. antioxidant compounds

Abstract

Artemisia annua L. is an annual weedy herb belonging to the Asteraceae family. As a traditional Chinese herb, Artemisia annua is a major source of artemisinin, an antimalarial drug. In addition to artemisinin, this plant contains several other molecular families presenting a wide range of biological properties. To facilitate the screening and the identification of active compounds, the present study describes their targeting by combining the dereplication information obtained by means of Molecular Networks and a crude extract fractionation by Centrifugal Partition Chromatography to obtain and test simplified fractions. This simple and fast approach was developed focused on the antioxidant activity of Artemisia annua with the aim of screening and identifying the antioxidant molecules for further cosmetic uses. Firstly, the aerial parts of Artemisia annua were extracted and their antioxidant activity was evaluated by DPPH, ABTS, CUPRAC, FRAP and iron (II) chelating assays. Extract with a positive response was subjected to UHPLC-HRMS with autoMS/MS experiments in order to build a Molecular Network using the GNPS (Global Natural Products Social Molecular Networking) platform. Secondly, the crude extract was fractionated using CPC with an adapted Arizona solvent system. The fractions obtained were evaluated for antioxidant activity to focus on active compounds, which were located on the Molecular Network and identified thanks to their MS/MS spectra. Using this approach, the major phenolic compound contributing to the antioxidant activity of Artemisia annua extract was identified.

Keywords: Antioxidant activity; Artemisia Annua; Centrifugal partition chromatography; Molecular network.