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

A pentacyclic triterpenoid, ursolic acid (1), two iridoid glucosides, verbe nalin (2) and hastatoside (3), and a phenylpropanoid glycoside, verbascosid e (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 quantitat ive 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 a nd 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) whil e the roots, which are not official in the Pharmacopoeias, contained a maxi mum amount (0.32%, w/w) of the bioactive verbascoside (4), The assay method s described are simple, rapid and accurate, and may form part of future dru g authentication protocols. Copyright (C) 2000 John Wiley & Sons, Ltd.