Effects of sesquiterpenes and amino acid–sesquiterpene conjugates from the roots of Saussurea lappa on inducible nitric oxide synthase and heat shock protein in lipopolysaccharide-activated macrophages Original Research Article

The methanolic extract of the roots of Saussurea lappa Clarke, a Chinese medicinal herb Saussureae Radix, was found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages. Among the constituents from the methanolic extract, two sesquiterpene lactones (costunolide and dehydrocostus lactone) and two amino acid-sesquiterpene conjugates (saussureamines A and B) potently inhibited LPS-induced NO production (IC50=1.2–2.8 μM). Saussureamines A and B in addition to costunolide and dehydrocostus lactone did not inhibit iNOS enzyme activity, but they inhibited both induction of inducible NO synthase and activation of nuclear factor-κB in accordance with induction of heat shock protein 72.