Nature's Sedative: Isolation and Structural Elucidation of Valtrate from Centranthus ruber

The importance of natural plant products and how they can be used as learning aids at senior undergraduate level are highlighted in this experiment. The experiment involves the isolation and structural determination of valtrate, a valepotriate occurring naturally in the roots and aerial parts of the medicinal plant, Valeriana officinalis, and its related species, Centranthus ruber. Valerian root extracts have been employed in both traditional and conventional medicine as sedating and antispasmolytic agents and appear to be nature's answer to modern benzodiazepine tranquillizers. We present various isolation and structural elucidation methodologies, including thin layer and flash column chromatography, and detailed spectroscopic analysis by NMR, IR, and mass spectra. The students isolated valtrate with an average recovery of 4.1% and subsequently managed to unravel the structure of valtrate using the various spectra provided, all within a six-hour laboratory (two week) session.