Nitric oxide inhibitory coumarins from the roots and rhizomes of Notopterygium incisum

Phytochemical study on the roots and rhizomes of Notopterygium incisum resulted in the isolation of six new Coumarins, notoptetherins A - F (1-6), and 20 known analogues (7-26). Their structures were elucidated on the basis of extensive analyses of NMR and HRMS data, and the absolute configurations of 5 and 6 were established by Mo₂(AcO)₄-induced CD and exciton chirality, respectively. Moreover, a biomimetic synthesis of 6 from 21 was employed to confirm its absolute configuration. In a subsequent activity screening, compounds 12 and 17 exhibited potent inhibition against LPS-induced nitric oxide production in RAW 264.7 cells with IC₅₀ values of 12.7 and 10.2 μM, respectively.

Coumarins; Nitric oxide; Notopterygium incisum.