VOLATILE CONSTITUENTS OF TAHEEBO 287 Copyright © 2004 John Wiley & Sons, Ltd. Flavour Fragr. J. 2004; 19: 287–292 FLAVOUR AND FRAGRANCE JOURNAL Flavour Fragr. J. 2004; 19: 287–292 Published online 29 March 2004 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ffj.1345 Comparison of three sample preparation methods on the recovery of volatiles from taheebo (Tabebuia impetiginosa Martius ex DC) Byeoung-Soo Park, 1# Kwang-Geun Lee 2## and Gary R. Takeoka* 1 Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA 94710, USA 2 Department of Environmental Toxicology, University of California, Davis, CA 95616 USA Received 1 April 2003; Revised 14 April 2003; Accepted 29 April 2003 ABSTRACT: The volatile constituents of taheebo (the dried inner bark of Tabebuia impetiginosa Martius ex DC) were isolated by three methods: solvent-assisted flavour evaporation (SAFE); steam distillation under reduced pres- sure, followed by continuous liquid–liquid extraction (DRP-LLE); and high-flow dynamic headspace sampling (including closed-loop stripping) (DHS). The extracts were analysed qualitatively and quantitatively by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The masses of total volatile components recovered from 50 g taheebo by SAFE, DRP-LLE and DHS were 26.3 ± 2.0, 19.4 ± 1.0 and 1.2 ± 0.2 mg, respectively. The major constitu- ents isolated with the SAFE method were 4-methoxyphenol (121.65 μg/g), 4-methoxybenzyl alcohol (96.49 μg/g), 1,2- propanediol (92.95 μg/g) and 4-methoxybenzaldehyde (31.33 μg/g). The DRP-LLC method yielded 4-methoxybenzaldehyde (64.54 μg/g), 4-methoxyphenol (42.30 μg/g), 5-(2-propenyl)-1,2,3-trimethoxybenzene (elemicin; 41.22 μg/g), and 1-methoxy- 4-(1E)-1-propenylbenzene (trans-anethole; 39.16 μg/g) as major volatiles, while the main compounds recovered with the DHS method were 4-methoxybenzaldehyde (2.61 μg/g), 4-methoxyphenol (2.10 μg/g), 2-methyl-5-(1-methylethenyl)-2- cyclohexen-1-one (carvone; 1.71 μg/g) and 3,7-dimethyl-1,6-octadien-3-ol (linalool; 1.64 μg/g). Copyright © 2004 John Wiley & Sons, Ltd. KEY WORDS: volatile components; solvent-assisted flavour evaporation (SAFE); dynamic headspace sampling (DHS); pau d’arco * Correspondence to: G. R. Takeoka, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, 800 Buchanan Street, Albany, CA 94710, USA. E-mail: grt@pw.usda.gov # Current address: School of Agricultural Biotechnology, Seoul National University, San 56-1, Shillim-dong, Gwanak-gu, Seoul 151-742, Korea. ## Current address: Department of Food Science and Technology, Dongguk University, 26, 3 Pil-Dong, Chung-gu, Seoul 100-715, Korea. Introduction The bark of various South and Central American Tabebuia species is sold under the name of ‘taheebo’, ‘pau d’arco’ or ‘lapacho’. The material is reported to possess astringent, antiinflammatory, antibacterial, anti- fungal, diuretic and laxative properties. Major constituents in methanol extracts of Tabebuia spp. have been reported several times. They included furanonaphthoquinones, 1–3 quinones, 4 naphthoquinones, 5 benzoic acid, benzaldehyde derivatives, 6 cyclopentene dialdehydes 7 and flavonoids. 8 Many studies have investigated the biological and pharmacological effects of Tabebuia spp. extracts and their isolated compounds. 9–14 To our knowledge, the only volatile constituents of taheebo that have been reported to date are 3,4-dimethoxybenzaldehyde, 4- hydroxy-3-methoxybenzaldehyde (vanillin) and 4-meth- oxybenzaldehyde. 6 The volatile chemical composition of the extracts isolated from plants depends on the type of sample preparation technique employed. Chemical trans- formations such as hydrolysis can occur during steam distillation. Chaintreau reviewed the development of simultaneous distillation–extraction and compared this technique with other sample preparation methods to illus- trate its capabilities and limitations. 15 Practical guidelines for its use, along with ways to minimize artifact forma- tion, were also discussed. Solvent-assisted flavour evapo- ration (SAFE) is the one of the most versatile methods used for the isolation of food and plant volatile constitu- ents. 16 This technique allows the fast and careful isolation of volatiles from complex food matrices under very mild conditions. High-flow dynamic headspace sampling, when combined with the addition of excess sodium sulphate, leads to the identification of highly water-soluble volatiles that are not effectively isolated by conventional sample preparation methods. 17 Advantages and disadvan- tages of dynamic headspace sampling and simultaneous distillation–extraction as methods for isolating food volatiles were reported by Buttery and Ling. 18 Mayer et al. 19 compared the recovery of important tomato flavour constituents using three sample preparation methods. The dynamic headspace method (combined with the addition of saturated calcium chloride solution to the tomato sample) gave good recovery of most of the compounds and performed better than the SAFE method for constituents such as phenylacetaldehyde (64%