Stachaegyptin A-C: Neo-clerodane diterpenes from Stachys aegyptiaca

Abstract Phytochemical investigation of Stachys aegyptiaca resulted in the characterization of three new diterpenes ( 1 - 3 ) together with eleven known compounds including four neo -clerodane diterpenes and seven flavonoid aglycones. Structure elucidation was performed by spectroscopic analysis by HRFABMS, 1D and 2D NMR and X-ray. Isolated compounds were screened for anti-inflammatory activity using a lipopolysaccharide-induced nitric oxide inhibition assay employing murine macrophage cells. Among the assayed compounds, 13 (calycopterin) showed a concentration-dependent inhibition of LPS-induced nitric oxide release with a IC 50 of 62.5 μM.