Phytochemistry and bioactivity of Pedicularis sibthorpii growing in Iran

Abstract

The methanol extract of the aerial parts of the medicinal plant Pedicularis sibthorpii Boiss., Scrophulariaceae, growing in the Azerbaijan province of Iran, was found to be active in the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and the antibacterial agar well diffusion assays, but no general toxicity was observed in the brine shrimp lethality assay. A combination of solid-phase extraction (SPE) and preparative reversed-phase high-performance liquid chromatography (prep-RP-HPLC) analyses of the methanolic extract afforded three phenylethanoids (verbascoside, martynoside and isomartynoside), an iridoid (aucubin), a flavonoid (luteolin 7-O-beta-D-glucopyranoside) and mannitol, and the structures of these compounds were elucidated unambiguously by spectroscopic means. The distribution of the isolated compounds within the genus Pedicularis has also been discussed.