Anti-inflammatory diterpene from Thyrsanthera suborbicularis

Bioactivity-guided isolation on a n-hexane-soluble fraction of Thyrsanthera suborbicularis led to the isolation of a new rosane-type diterpene, 19-hydroxy-1(10), 15-rosadiene (1), along with three known compounds, taraxerol, acetyl aleuritolic acid, and spathulenol. The structures of isolated compounds were determined by interpretation of NMR spectroscopic data and mass spectrometry. Compound 1 demonstrated significantly inhibitory activity on nitric oxide production in RAW264.7 lipopolysaccharide (LPS)-activated mouse macrophages with an IC(50) value of 2.91 μg/ml via the suppression of inducible nitric oxide synthase (iNOS) mRNA expression.