A New Phenylethanoid Glycoside From the Leaves of Rosmarinus officinalis With Nitric Oxide Inhibitory Activity

Abstract

A new phenylethanoid glycoside, named rosmacinalis (1), and 6x known compounds {2-phenylethyl O-α-L-rhamnopyranosyl-(1‴→6″)- O-β-D-glucopyranoside (2), clinopodiolide C (3), rosmanol (4), 7 α-methoxyrosmanol (5) 7 β-methoxyrosmanol (6) and carnosol (7)} were isolated from the leaves of Rosmarinus officinalis. Their structures were determined by extensive analysis of high-resolution electron spray ionization mass spectrum and nuclear magnetic resonance spectral data, as well as by comparison of the spectral data with those reported in the literature. Anti-inflammatory activity of compounds 1‐7 was evaluated by their inhibition of NO production in lipopolysaccharide-stimulated RAW 264.7 cells. At a concentration of 100 µM, compounds 1 and 2 exhibited inhibitory rates of 47.1% ± 2.2% and 44.5% ± 1.3%, respectively, while compounds 3‐7 showed a cytotoxic effect. After dilution to a concentration of 20 µM, except compound 7, compounds 1‐6 did not show a cytotoxic effect. Their NO inhibitory rates ranged from 14.2% ± 1.3% to 31.1% ± 1.9%.