Isolation and Characterization of Rare Flavone Tetraglycosides from the Seeds of the Bioactive Plant: Peganum harmala L.

The phytochemical investigation of Peganum harmala L. seeds yielded two rare flavone tetraglycosides following isolation, purification, and analyses. The compound determined to be diosmetin-7-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (1) was first isolated from the species while the other compound characterized to be acacetin-7-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (2) was isolated from the genus Peganum for the first time. Their structures were primarily elucidated by one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) (¹H, ¹³C NMR, DEPT, COSY, HSQC and HMBC) and supported by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and MALDI-TOF-MS/MS analyses.