Antidiabetic flavonol glycosides from Eryngium caeruleum

Phytochemical investigation of the aerial parts of Eryngium caeruleum led to the isolation of two new source flavone glycosides (1 and 2). The structures of these compounds were determined with the help of one- and two-dimensional (1D- and 2D-) NMR techniques including 1H-NMR, 13C-NMR, HMQC, HMBC, 1H-1H COSY, and NOESY experiments. The compounds were studied for their in vitro aldose reductase (ALR1 and ALR2) and glucosidase (α and β) inhibitory activities, and antiglycation potential. Both the compounds showed higher inhibition potential against ALR1 than ALR2. Compound 2 showed three fold higher potency against ALR2 than the reference drug Sorbinil. In silico studies were performed to understand the binding mechanism of these compounds to aldose reductase.