Coumarins from Seseli petraeum M. Bieb. (Apiaceae) and their α-glucosidase inhibitory activity

Abstract Seseli L. species from the Apiaceae family are well-known medicinal plants with rich bioactive components. In the present study, the phytochemical investigation of the n-hexane extract of the aerial parts from Seseli petraeum M. Bieb., a fairly narrow growing plant on the northern side of Turkey, led to the isolation of one new pyranocoumarin called 3′-isovaleryl-4′-oxo-lomatin (petracoumarin, (1) along with 12 known coumarins octanoyllomatin (2), selinidin (3), anomalin (4), 3′-isobutryl-lomatin (5), 3′-angeloyl-4′-isovaleryl-cis-khellactone (6), 3′-isovaleryl-4′-angeloyl-cis-khellactone (7), calipteryxin (8), samidin (9), 4′-senecioyl-cis-khellactone (10), 3′-senecioyl-cis-khellactone (11), cis-khellactone (12) and angelicin (13), and six plant sterols (campesterol, stigmasterol, β-sitosterol, stigmastanol, stigma-7-en-3-ol and γ-ergosterol, 14–19). The structures of the coumarins were elucidated by spectroscopic methods, including extensive 1D/2D NMR, and MS techniques. In addition, several coumarins have been tested for their inhibitory activity against α-amylase and α-glucosidase enzymes. The coumarins exhibited notable inhibitory activity against the α-glucosidase enzyme and low inhibitory potential against α-amylase. Among the tested compounds, octanoyllomatin (2) was found to be the best inhibitor of α-glucosidase with IC50 = 69.00 ± 0.43 µg/mL. The promising results will guide our future studies and suggest that more detailed studies can be done on in vivo models.