Essential oil of wild Ocotea quixos (Lam.) Kosterm. (Lauraceae) leaves from Amazonian Ecuador: chemical characterization and biological properties

Ocotea quixos is a medium sized tree native to Amazonian Ecuador and neighbouring countries, which is reputed to have known aromatic properties since the period of the Incas but is not well known outside Ecuador. Flower calyces and leaves are used by the Amazonian indigenous people as appetizer spices appreciated for their cinnamon-like perfume, but also for eupeptic, disinfectant and local anesthetic activities. The essential oil extracted by steam distillation from the leaves of wild Ocotea quixos, Lauraceae was analyzed by GC and GC-MS. Sixty-one compounds were identified, representing 93.6% of the total detected. The main components were β-caryophyllene (15.1%), cinnamylacetate (11.4%), sabinene (7.6%), geranial (5.6%) and trans-cinnamaldehyde (5.1%), α-pinene (4.4%). Remarkable differences were noted with respect to the flower calyces essential oil of the same plant which reflect a weaker cinnamon-like smell and a pungent woody tone of leaves essential oil. In vitro antioxidant properties of the essential oil, obtained by DPPH (1,1-diphenyl-2-picrylhydrazyl) and β-carotene bleaching assays, were also evaluated with respect to synthetic antioxidants (trolox® and BHA: buthylhydroxyanisole) and Thymus vulgaris essential oil taken as natural reference. The results evidenced a weak activity of the O. quixos leaves essential oil (13.6% DPPH inhibition) both in comparison to the synthetic compounds - 28.2% and 86.9% for trolox® and BHA respectively - and thyme essential oil (75.6%). Antimicrobial activity tests are in progress, but preliminary data pointed out weak activity with respect to the flower calyces essential oil both against gram negative and positive bacteria, and yeasts. Finally, the O. quixos leaves essential oil showed potential applicative perspectives mainly linked to its delicate scent, and composition, moreover evidenced by the absence of potentially toxic compounds as safrole. Therefore, these data taken as a whole could suggest that the essential oil could find possible practical employ in flavour and cosmetic industry