A New Essential Oil from the Native Andean Species Nectandra laurel Klotzsch ex Nees of Southern Ecuador: Chemical and Enantioselective Analyses

Abstract

The leaves of Nectandra laurel Klotzsch ex Nees, belonging to the family, Lauraceae, were collected in the province of Loja (Ecuador), dried, and analytically steam-distilled. An unprecedented essential oil was obtained, with a 0.03% yield by weight of dry plant material. The volatile fraction was submitted to qualitative (GC-MS) and quantitative (GC-FID) chemical analysis, on two orthogonal stationary phases. Seventy-eight compounds were detected and quantified on at least one column. The essential oil was dominated by sesquiterpene hydrocarbons (53.0–53.8% on the non-polar and polar stationary phase, respectively), followed by oxygenated sesquiterpenoids (18.9–19.0%). A third group was constituted by metabolites of other origins, mainly aliphatic compounds, apparently derived from the acetate pathway (11.7–8.5%). The major components of the EO (≥3.0% with at least one column) were δ-selinene (30.5–28.8%), δ-cadinene (5.4–6.4%), epi-α-cadinol (4.9–5.2%), an undetermined compound with a molecular weight of 204 (3.4–4.2%), α-pinene (3.3–2.9%), and α-cadinol (2.9–3.0%). Finally, the essential oil was submitted to enantioselective analysis, on two β-cyclodextrin-based chiral selectors, determining the enantiomeric distribution of seven chiral terpenes. Among them, (1R,5R)-(+)-α-pinene, (1R,5R)-(+)-β-pinene, and (R)-(−)-α-phellandrene were enantiomerically pure, whereas camphene, borneol, α-copaene, and α-terpineol were present as scalemic mixtures.