Anti-inflammatory of pyrrolizidine alkaloids from Heliotropium digynum

One new and six known pyrrolizidine alkaloids (1-7) were isolated from the 70% ethanol extract of the aerial parts of Heliotropium digynum (Forssk.) C. Chr. The chemical structure of the new compound, 7-Angeloylsincamidine N-Oxide (4) was determined by extensive 1D and 2D NMR spectroscopic analysis and HRESIMS. The absolute configuration of 4 was elucidated by comparing the experimental and electronic circular dichroism spectra. The anti-inflammatory activity of the ethanolic extract and compounds 1, 2, 4, and 6 were evaluated against the Nitric oxide production in lipopolysaccharide induced murine macrophages RAW 264.7 cells. The IC50 values of the tested compounds were 52.4, 85.1, 105.1, and 7.9 A mu M, respectively, while the % inhibition of the ethanolic extract at 25 A mu g/mL was 78.7%. A docking study was conducted to provide more explanation about the activity of the tested compounds.