Discovery of Three New Monoterpenoid Indole Alkaloids from the Leaves of Gardneria multiflora and Their Vasorelaxant and AChE Inhibitory Activities

Abstract

Three novel monoterpenoid indole alkaloids gardflorine A (1), gardflorine B (2), and gardflorine C (3) were isolated from the leaves of Gardneria multiflora. Their structures, including absolute configurations, were established on the basis of spectroscopic methods (MS, UV, IR, 1D and 2D NMR) and circular dichroism experiments. All the compounds were evaluated for their vasorelaxant and acetylcholinesterase (AChE) inhibitory activities. Compound 1 exhibited potent vasorelaxant activity, with an EC50 value of 8.7 μM, and compounds 2 and 3 showed moderate acetylcholinesterase (AChE) inhibitory activities, with IC50 values of 26.8 and 29.2 μM, respectively.