The structural elucidation and antimicrobial activities of two isoflavane glycosides from Astragalus membranaceus (Fisch) Bge. var. mongholicus (Bge) Hsiao

Two isoflavane glycoside had been isolated from the EtOAc-soluble fraction of the roots of Astragalus membranaceus (Fisch) Bge. var. mongholicus (Bge) Hsiao. This is the first report on the structure elucidation of 2′,5′-dicarbonyl-3′,4′-dimethoxyisoflavanequinone-7-O-β-d-glucoside (1) based on spectroscopic methods including UV (Ultraviolet Spectrophotometry), IR (Infrared Absorption Spectroscopy), ESI-MS (Electrospray Ionization Mass Spectrometry), 1D NMR (Nuclear Magnetic Resonance Spectroscopy) and 2D NMR techniques. At the same time, antimicrobial activity of the two compounds was evaluated against various bacteria and fungi.