NO inhibitory guaianolide-derived terpenoids from Artemisia argyi.

An unusual dimeric guaianolide, artemilinin A (1) and a sesquiterpene-monoterpene lactone, isoartemisolide (2), were isolated from the leaves of Artemisia argyi. Their structures were elucidated on the basis of extensive spectroscopic analysis (IR, HR-ESIMS, 1D- and 2D-NMR), and the absolute configurations were determined by CD spectra and quantum chemical ECD calculation. Furthermore, in in vitro assay, compound 2 exhibited pronounced inhibition on the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 microglial cells with an IC50 value of 4.00μM.