Separation, purification and quantification of verbascoside from Penstemon barbatus (Cav.) Roth.

Echinacoside and verbascoside possess a spectrum of significant beneficial bioactivities. A new method of preparative high-speed counter-current chromatography for rapid separation and purification of verbascoside from the leaves of Penstemon barbatus (Cav.) Roth was introduced. The solvent system employed here was n-butanol-water (1:1, v/v). The structure was confirmed by IR, (1)H NMR and (13)C NMR. According to the quantification results, echinacoside and verbascoside were found to be as much as 5.25 ± 0.13 mg/g and 11.21 ± 0.16 mg/g, respectively, in the leaves of P. barbatus. This indicates that P. barbatus might be an ideal alternative resource for large scale preparation of echinacoside and verbascoside.