Pseudoguaianelactones A-C: three unusual sesquiterpenoids from Lindera glauca with anti-inflammatory activities by inhibiting the LPS-induced expression of iNOS and COX-2.

The pseudoguaianelactones A (1) and B (2), two novel sesquiterpene lactones with an unprecedented [5,7,7] ring system featuring an α-methylene-γ-lactone moiety, together with a new pseudoguaianelactone C (3) were isolated from the roots of Lindera glauca. Pseudoguaianelactones A-C (1-3) inhibited nitric oxide (NO) production, with IC50 values ranging from 1.38 to 4.00 μM. Moreover, all compounds significantly suppressed the production of pro-inflammatory mediators (TNF-α, IL-6, IL-1β and PGE2) and the protein expression of the enzymes iNOS and COX-2.