Variations in yield and composition of leaf essential oil from Syzygium aromaticum at various phases of development

Abstract

<p>The changes in the essential oil yield and composition from <em>Syzygium aromaticum</em> leaf harvested at different phases of development from young leaves to mature leaves were studied. Separation of the essential oils was conducted by steam distillation in a Clevenger apparatus for about 4h. Essential oils analyses were performed by GC/MS. The yield of essential oil (ml per 100 g of DM) of the leaf following the four phases of development was in order of: young leaves (5.1%) > expanded leaves 1 (4.5%) > expanded leaves 2 (4.1%) > mature leaves (3.8%). Sixteen compounds were detected by GC/MS. Eugenol and eugenyl acetate were the dominant components. Eugenol and eugenyl acetate amount had a divergent evolution during the four expansions of leaves. When eugenol reached its highest percentages at expanded leaves 2 (84.00 - 90.48%) and mature leaves stage (88.32 - 90.22%), eugenyl acetate reached the lowest ones with, respectively, 0.96 - 7.16% and 0.36 - 1.64%, but when the eugenyl acetate reached a maximum percentage at young leaves stage with 61.44 - 65.52%, eugenol reached a minimum of 25.43 - 30.38%. It is judicious to collect and extract <em>S. aromaticum</em> leaf in expended leaves 2 (pale green leaves) and mature leaves stage (dark green leaves) in order to obtain the optimal yield and maximum percentage of eugenol.</p>