Isolation and characterization of secondary metabolites from Nyctanthes arbor-tristis L

Nyctanthes arbor-tristis L. has been used in Ayurvedic medicine to manage inflammatory diseases. It primarily contains iridoid glycosides and phenylethanoid glycosides. The objective of present studies was to identify anti-inflammatory constituent/s from N. arbor-tristis. The studies resulted in isolation of four compounds (1-4) including, an undescribed compound, a phenylethanoid glycoside named nyctanthesin B (1) and three known iridoid glycosides (2-4). The structure of the new compound (1) was elucidated as 3, 4-dihydroxy-β-phenylethyl-3'-O-benzoyl-β-D-glucopyranoside by analysing 1D, 2D NMR and HREI-MS. Compound 1 revealed potent anti-inflammatory activity by inhibiting ROS (reactive oxygen species) in both whole blood (WB) phagocytes (IC₅₀ = 8.5 ± 0.6 µg/mL) and isolated human polymorphonuclear leukocytes (PMNLs) (IC₅₀ = 2.2 ± 0.06 µg/mL). Ibuprofen was used as standard.