Isatisindigoticanine A, a novel indole alkaloid with an unpresented carbon skeleton from the roots of Isatis tinctoria

Abstract

Isatisindigoticanine A (1), a new indole alkaloid with an unusual carbon skeleton of a benzofuran-3-one unit connected with a 1H-indole-3-yl unit and a 4-(1,2-dihydroxyethyl)-6-oxa-3-azabicyclo[3.1.0]hexan-2-one unit via a C-3－C-8'' bond and a C-4'－C-8'' bond, was obtained from the roots of Isatis tinctoria. Its structure was determined by physicochemical properties and spectroscopic methods including 1 D, 2 D NMR, IR, HRESIMS data. The absolutely configurations were deduced by comparison of its experimental CD and calculated ECD spectra. Nitric oxide (NO) inhibitory activities of isatisindigoticanine A was also evaluated in the LPS-stimulated RAW 264.7 cells, however, no inhibitory effect was presented.

Graphical Abstract

Key Words:

• Anti-inflammatory activity
• indole alkaloid
• Isatis tinctoria
• isatisindigoticanine A

Acknowledgments

The National Natural Science Foundation of China (81573571, 81673570), Excellent Academic Leaders Program of Shanghai (16XD1403500), the programs of High level University Innovation Team and Shanghai E-Research Institute of Bioactive Constituents in Traditional Chinese Medicine and Shanghai Scientific and Technological Innovation Program (18401931100) are acknowledged for supporting this study.

Disclosure statement

No competing financial interests were reported by the authors.