Guaianolides from Ormenis Mixta: Structural Insights and Evaluation of Their Anti-inflammatory Profile

In this paper, the isolation of five new guaianolides (1:  - 5: ) and four (6:  - 9: ) known sesquiterpenes from aerial parts is reported. The structural determination of the guaianolides was obtained by NMR spectroscopic data, as well as MS experiments. Their relative configurations were assigned by a combined quantum mechanical/NMR approach, comparing the experimental C/H NMR chemical shift data and homonuclear coupling constants with the related predicted values. The isolates were assayed for their anti-inflammatory potential evaluating nitric oxide release and cyclooxygenase-2 expression in J774A.1 macrophages treated with lipopolysaccharide from . Our results indicated that, among the tested compounds, 1:  - 3: , and 7: were able to inhibit nitric oxide release, while all were able to inhibit cyclooxygenase-2 expression with different potencies.