Alkaloids from Acorus gramineus rhizomes and their biological activity

As part of our ongoing search for bioactive constituents from natural Korean medicinal resources, a bioassay-guided fractionation and chemical investigation of the MeOH extract from the rhizomes of Acorus gramineus resulted in the isolation and identification of two alkaloids, including a new aporphine-type alkaloid (1), named gramichunosin, and a known pyrrole alkaloid (2). Their structures were determined by a combination of 1D and 2D NMR spectroscopic analysis and HRMS. This is the first report of alkaloids from A. gramineus. Compounds 1 and 2 showed antiproliferative activities against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines with IC₅₀ values in the range of 7.46 – 45.23µM. Moreover, the anti-neuroinflammatory activities of these compounds were determined by measuring the nitric oxide (NO) levels in the medium using murine microglia BV-2 cells. Compound 1 inhibited NO production in lipopolysaccharide-stimulated BV-2 with IC₅₀ values of 7.83µM.