Supercritical CO 2 Extract of Cinnamomum zeylanicum: Chemical Characterization and Antityrosinase Activity BRUNO MARONGIU, † ALESSANDRA PIRAS, † SILVIA PORCEDDA, † ENRICA TUVERI, † ENRICO SANJUST, § MASSIMO MELI, § FRANCESCA SOLLAI, § PAOLO ZUCCA, § AND ANTONIO RESCIGNO* ,§ Dipartimento di Scienze Chimiche and Dipartimento di Scienze e Tecnologie Biomediche, Università di Cagliari Cittadella Universitaria, I-09042 Monserrato (CA), Italy The volatile oil of the bark of Cinnamomum zeylanicum was extracted by means of supercritical CO 2 fluid extraction in different conditions of pressure and temperature. Its chemical composition was characterized by GC-MS analysis. Nineteen compounds, which in the supercritical extract represented >95% of the oil, were identified. (E)-Cinnamaldehyde (77.1%), (E)--caryophyllene (6.0%), R-terpineol (4.4%), and eugenol (3.0%) were found to be the major constituents. The SFE oil of cinnamon was screened for its biological activity about the formation of melanin in vitro. The extract showed antityrosinase activity and was able to reduce the formation of insoluble flakes of melanin from tyrosine. The oil also delayed the browning effect in apple homogenate. (E)-Cinnamaldehyde and eugenol were found to be mainly responsible of this inhibition effect. KEYWORDS: Supercritical CO 2 extraction; volatile oil; Cinnamomum zeylanicum; tyrosinase; melanin; inhibition INTRODUCTION Cinnamon (Cinnamomum zeylanicum Blume syn. C. Verum J.S. Presl, Lauraceae) is a medium-sized tree native to Sri Lanka and tropical Asia. It is also known as Ceylon cinnamon, true cinnamon, Ceylon-Zimtbaum, and cannelle de Ceylan (1). The term cinnamon is also used to indicate other species: Cinna- momum loureirii Nees syn. C. obtusifolium Nees var. loureirii Perr et Eb. and C. burmanii (Nees & T. Nees) Blume syn. C. pedunculata J. S. Presl. Trees of C. zeylanicum are cultivated in Sri Lanka and India to obtain leaves, bark, and roots. The essential oils, obtained by steam distillation from different parts of this species, are dissimilar, and the oil obtained from the bark, called oil of cinnamon Ceylon, is considered to be superior for its aroma. Essential oils obtained from twigs, pedicels, buds, flowers, and fruits are characterized by a very low content (<4.0%) of (E)- cinnamaldehyde and larger and variable amounts of (E)- cinnamyl acetate, (E)--caryophyllene, and linalool (2). Cin- namon leaf oil has been reported to show a notable antifungal activity against Botrytis cinerea (3). The chemical composition of the volatile oil has been also determined in fruits of C. zeylanicum (4). Simic et al. reported that a commercial oil, chiefly constituted by (E)-cinnamaldehyde (62.79%), limonene (8.31%), and linalool (7.09%), showed a very strong antifungal activity against 17 different micromycetes (5). Pawar and Thaker, who tested 75 essential oils against the fungus As- pergillus niger, found that the highest inhibitory effect was exhibited by the oil obtained from the bark of cinnamon (6). The antioxidant activity of this oil is also known (7, 8). Hydrodistillation or steam distillation, even when it does not induce extensive phenomena of hydrolysis and thermal degrada- tion, gives in any case a product with a characteristic off-odor (9). Solvent extraction can give oil, but due to a high content of waxes and/or other high molecular mass compounds, often gives rise to a concrete with a scent very similar to the material from which it was derived. However, small amounts of organic solvents can pollute the extraction product. Supercritical fluid extraction (SFE) is a good technique for the production of flavors and fragrances from natural materials and can constitute a valid alternative to both of the above- mentioned processes. In fact, compressed carbon dioxide, CO 2 , is able to solubilize hydrocarbons and oxygenated mono- and sesquiterpenes (10), the main essential oil constituents. The separation of the extractant is easy, hydrolysis and thermal degradation are practically absent, and the extract retains the organoleptic features of the starting material. Possible residues do not cause a risk for human health. Indeed, CO 2 , besides being * Address correspondence to this author at the Department of Biomedical Sciences and Technologies, University of Cagliari, Citta- della Universitaria, I-09042 Monserrato (CA), Italy (e-mail rescigno@ unica.it; fax +39 070 6754527; telephone +39 070 6754516). † Dipartimento di Scienze Chimiche. § Dipartimento di Scienze e Tecnologie Biomediche. 10022 J. Agric. Food Chem. 2007, 55, 10022–10027 10.1021/jf071938f CCC: $37.00  2007 American Chemical Society Published on Web 10/30/2007