Quantitative determination of the major constituents of Verbena officinalis using high performance thin layer chromatography and high pressure liquid chromatography

A pentacyclic triterpenoid, ursolic acid (1), two iridoid glucosides, verbenalin (2) and hastatoside (3), and a phenylpropanoid glycoside, verbascoside (4), were isolated from Verbena officinalis Linn. (Verbenaceae), a plant listed in the Chinese Pharmacopoeia and the British Herbal Pharmacopoeia. A procedure for the optimised extraction of these constituents for quantitative estimations has been established. An HPTLC method was employed for the determination of 1 using Liebermann Burchard reagent. A reversed-phase HPLC system with photodiode array detector was used to resolve compounds 2, 3 and 4 in the methanol extracts of different parts of the plant. Tender parts of the plant were rich in all of these constituents (0.24–0.34%, w/w) while the roots, which are not official in the Pharmacopoeias, contained a maximum amount (0.32%, w/w) of the bioactive verbascoside (4). The assay methods described are simple, rapid and accurate, and may form part of future drug authentication protocols. Copyright © 2000 John Wiley & Sons, Ltd.