Megastigmane and phenolic components from Laurus nobilis L. leaves and their inhibitory effects on nitric oxide production.

Laurus nobilis L. leaves are widely used in cooking and in folk medicine. Five new megastigmane glucosides (2-4, 7, and 9) named laurosides A-E and a new phenolic glucoside 12 were isolated from the methanolic extract of L. nobilis L. leaves, along with 10 known components: megastigmane (5), megastigmane glucosides (1, 6, 8, 10, and 11), aromatic compounds (13 and 14), and flavonoids (15 and 16). The structures and relative stereochemistry have been elucidated by one- and two-dimensional nuclear magnetic resonance experiments ((1)H and (13)C NMR, DEPT, correlation spectroscopy, heteronuclear multiple quantum correlation, heteronuclear multiple bond correlation, and nuclear Overhauser enhancement spectroscopy) and by chemical derivatization. The effect of isolated compounds on nitric oxide production in lipopolysaccharide-activated murine macrophages were examined.