LAUSR

Abstract The leaves of Laurus nobilis, commonly called as bay leaves, have been traditionally used for the treatment of inflammatory symptoms. As a part of the research on the characterization of bioactive constituents from natural products, twenty one sesquiterpene lactones were isolated from the leaves of L. nobilis. Among them, laurenoperoxylides A (1) and B (2) were first reported in nature and sivosinolide (11), altissin (12), maroniolid (13) and 4α-hydroxy-guaia-10(14), 11(13)-diene-12,6α-olide (20) were first isolated from this plant. The anti-inflammatory activity of isolated compounds was evaluated by measuring their effects on the NF-κB transcriptional activity induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages cells. Among twenty one sesquiterpenes, 11-exo-methylenesantonin (9) exerted the most potent inhibition with an IC50 value of 4.0 μM. Santamarine (4), magnolialide (5) and zaluzanin D (18) also significantly inhibited NF-κB activity with IC50 values of