Journal of Chromatography A, 1054 (2004) 227–233 Tocopherol measurement in edible products of vegetable origin Diego J.M. G´ omez-Coronado a , Elena Iba ˜ nez b , F. Javier Rup´ erez a , Coral Barbas a,∗ a FacultadC.C.ExperimentalesydelaSalud,UniversidadSanPablo-CEU,28668BoadilladelMonte,Madrid,Spain b DepartamentodeCaracterizaci´ ondeAlimentos,InstitutodeFermentacionesIndustriales(CSIC),JuandelaCierva3,28006Madrid,Spain Available online 15 September 2004 Abstract Since natural antioxidants present increasing interest for food industry due to their beneficial effect on health, new potential sources have been screened among edible aromatic plants and a microalgae, Spirulina platensis. The determination was performed after optimising a previously validated method, because important differences have been found among values described in literature for tocopherol content in products of vegetable origin. Values obtained ranged from 3.42 mg -tocopherol/100 g of dill to 132.2 mg/100 g of fresh bay and from 0.14 mg -tocopherol/100 g of spearmint to 3.45 mg/100 g of parsley. In all cases results were calculated from fresh leaves. Preliminary experiments were developed with bay (Laurusnobilis) plant to devise the supercritical fluid extraction of tocopherols, generating environmentally friendly processes to selectively extract fractions enriched with antioxidant compounds while removing fractions corresponding to essential oils, that is, those that correspond to the characteristic aroma of the plants. Another striking result has been the tocopherol content in the microalgae, 1.3 mg -tocopherol/100 g of dried commercial spirulina, which do not justify the supposed source of antioxidant vitamins. Results suggest the need of more reliable determinations of tocopherols in vegetable sources to be included in databases. © 2004 Elsevier B.V. All rights reserved. Keywords: Vitamin E; Screening; Supercritical fluid extraction; Spirulina; Microalgae 1. Introduction Tocopherols (vitamin E) are lipid-soluble antioxidants synthesized only by photosynthetic organisms [1,2]. These are present as constituents of unsaponifiable matter and may occur together with phospholipids, carotenoids, chlorophylls and triterpenyl alcohols. The subject of natural antioxidants continues to captivate the interest of food and biomedical scientists, because of the reports that diets rich in plant antioxidants derived from fruits and vegetables are associated with lower risks of coronary heart disease and cancer [3,4]. Owing to the emerging evidence of the physiological im- portance concerning the balance of the different tocopherols in biological systems, the possible benefits of using natural tocopherol mixtures from plant origin as vitamin supplements in human nutrition should be considered when such medica- tion seems necessary [5]. Furthermore, synthetic tocopherols ∗ Corresponding author. Fax: +34 913510 475. E-mailaddress: cbarbas@ceu.es (C. Barbas). are not as biologically active as natural, due to non-active stereoisomers [6], not present in natural sources. Therefore, the importance of finding out vegetable compounds able to take effectively the role of conventional antioxidants, and their investigation and economical verification, is greatly in- creasing. Many medicinal and aromatic plants, spices and herbs have traditionally been used in foods to improve or modify their flavour. However, their protective effect for in- hibiting oxidation plays an important role unknown for years and it could be related to their tocopherol content. On the other hand, Spirulina platensis is a microalgae, which is said to be a recent re-discovery to the modern world as it shows several health effects [7]. As for its composition, S.platensis can be considered a natural source of therapeutical compounds since it has been described as containing significant amounts of -carotene [8], inositol, niacin, -tocopherol and polyunsaturated fatty acids (PUFA) such as gamma-linolenic acid [9] and eicosapentaenoic acid [10], among others. Data for the development of a database for tocopherol val- ues for plants are derived from a wide variety of methods and 0021-9673/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2004.08.072 ELSEVIER Available online at www.sciencedirect.com SCIENCE@DIRECT" JOURNAL OF CHROMATOGRAPHY A www.elsevier.com/locate/ chroma