Metabolomics of endemic six Astragalus species by combined NMR and GC-MS analysis

Abstract

Introduction: Astragalus anthylloides, A. dipsaceus, A. karamasicus, A. lycius, A. sigmoideus and A. xylobasis var. angustus are an endemic and generally grow in the Irano-Turanian phytogeographic region of Turkey. Astragalus species contain saponins, polysaccharides, and phenolics, while the toxic compounds include imidazoline alkaloids, nitro toxins, and selenium derivatives.

Objectives: To apply a combined metabolomic fingerprinting approach by nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS) of endemic six Astragalus species extract.

Methodology: The whole plant collected in Turkey of six endemic Astragalus subsp. were dried and then extracted with hexane, chloroform, ethylacetate, n-butanol and methanol solvents, respectively. The hexane extracts were analyzed by GC-MS. Carbon-13 (¹³ C)-NMR analyzes of all extracts were performed. In both analyses, a biomarker was obtained.

Results: The hexane extracts were determined as palmitic acid, arachidic acid, behenic acid, and linolenic acid as the main components. As a result of ¹³ C-NMR analyzes, in hexane, chloroform, and ethylacetate the extracts detected were palmitic acid, arachidic acid, behenic acid, and linolenic acid. d-Pinitol was obtained using ¹³ C-NMR analyzes with n-butanol and methanol extracts.

Conclusion: This study demonstrated that d-pinitol is a biomarker for the endemic six Astragalus subsp.

Keywords: Astragalus subsp; biomarker; d-pinitol; endemic; metabolomics.