Berchemins A and B: Novel Enzyme‐Inhibiting Dimeric Lignan Glycosides from Berchemia pakistanica

Phytochemical investigation of Berchemia pakistanica by extensive bioassay‐guided fractionation resulted in the isolation of two novel dimeric lignan glycosides, berchemin A ( 1 ) and berchemin B ( 2 ), and of the four known compounds β ‐sitosterol, β ‐sitosterol 3‐ O ‐ β ‐ D ‐glucoside, vavain, and daphnetin 8‐ β ‐ D ‐glucoside. The structures of 1 and 2 were elucidated with the help of modern spectroscopic techniques, and the known compounds were identified by comparing their spectral data with those reported in the literature. Berchemins A and B were found to inhibit lipoxygenase and α ‐glucosidase enzymes in a concentration‐dependent fashion.