Metabolomic profiling and antianginal activity of the bark of Sterculia setigera from Mali

Abstract

The present work focuses on the phytochemical characterization and evaluation of antianginal activity of the bark of Sterculia setigera. It was collected and authenticated in the African region of Mali, where the local population largely employs this plant for the treatment of several diseases. In the context of traditional or folk medicine and recent progresses in alternative medicine practices, it is essential to expand the knowledge about the chemical composition of such medicinal plants. In this research, a direct-Mass Spectrometry (MS) technique, known as Rapid Evaporative Ionization Mass Spectrometry (REIMS) was used for the identification of the main constituents of the Sterculia setigera bark. The REIMS source is here coupled with an electroknife as sampling device, so that the dried and pulverized bark was directly cut through the electroknife to generate a vapor, which was online transferred to the source via a Venture tube. In this way, an ambient MS approach was realized, which avoids any sample preparation procedure or pretreatment; the sample was analyzed in its native state according to a time-saving analytical process. A quadrupole-time of flight MS/MS analyzer was exploited for the identification process, based on mass accuracy data and MS/MS experiments for structure elucidation purposes. Lipids, including triterpenes, fatty acids, γ-sitosterol and α-tocopherol, and phenolic compounds were identified, some of them reported for the first time in a plant of the Sterculia genus and further confirmed through a gas chromatography-mass spectrometry analysis. The obtained metabolomic profile was successfully correlated to the antianginal activity of this plant.

Keywords: Coronary dilatator effect; Direct analysis; Rapid evaporative ionization; Shotgun mass spectrometry; Sterculia setigera; Traditional medicine.