A New Essential Oil from the Leaves of Gynoxys rugulosa Muschl. (Asteraceae) Growing in Southern Ecuador: Chemical and Enantioselective Analyses

Abstract

An essential oil, distilled from the leaves of the Andean species Gynoxys rugulosa Muschl., is described in the present study for the first time. The chemical composition was qualitatively and quantitatively determined by GC–MS and GC–FID, respectively. On the one hand, the qualitative composition was obtained by comparing the mass spectrum and the linear retention index of each component with data from literature. On the other hand, the quantitative composition was determined by calculating the relative response factor of each constituent, according to its combustion enthalpy. Both analyses were carried out with two orthogonal columns of nonpolar and polar stationary phases. A total of 112 compounds were detected and quantified with at least one column, corresponding to 87.3–93.0% of the whole oil mass. Among the 112 detected components, 103 were identified. The main constituents were α-pinene (5.3–6.0%), (E)-β-caryophyllene (2.4–2.8%), α-humulene (3.0–3.2%), germacrene D (4.9–6.5%), δ-cadinene (2.2–2.3%), caryophyllene oxide (1.6–2.2%), α-cadinol (3.8–4.4%), 1-nonadecanol (1.7–1.9%), 1-eicosanol (0.9–1.2%), n-tricosane (3.3–3.4%), 1-heneicosanol (4.5–5.8%), n-pentacosane (5.8–7.1%), 1-tricosanol (4.0–4.5%), and n-heptacosane (3.0–3.5%). Furthermore, an enantioselective analysis was carried out on the essential oil, by means of two cyclodextrin-based capillary columns. The enantiomers of α-pinene, β-pinene, sabinene, α-phellandrene, β-phellandrene, linalool, α-copaene, terpinen-4-ol, α-terpineol, and germacrene D were detected, and the respective enantiomeric excess was calculated.

The Leaf Essential Oil of Gynoxys buxifolia (Kunth) Cass. (Asteraceae): A Good Source of Furanoeremophilane and Bakkenolide A

“…Finally, the chemical description of this EO could not be considered exhaustive without the enantioselective analysis of at least some chiral components. To the best of the authors’ knowledge, there are only two EOs from the genus Gynoxys whose enantioselective analyses are currently available in literature: G. miniphylla and the volatile fraction from G. rugulosa [ 12 , 13 ]. From the comparison between the three volatile fractions, a great difference in the enantiomeric composition emerged.…”

“…Therefore, this work is part of an unfunded project, whose aim is the description of the EOs, obtained from the species of the genus Gynoxys growing in the province of Loja (Ecuador). This systematic research began with the recent publications about the volatile fractions in the leaves of G. miniphylla and G. rugulosa and continues with the description of EOs from other species currently under investigation [ 12 , 13 ].…”

Gynoxys revolutifolia (Senecioneae, Asteraceae): A new species from southern Ecuador

“…Phenology:-Specimens in bloom have been collected between September and November. Chemical composition:-The distilled leaf essential oil from samples collected at El Tiro (N. Cumbicus 1986, HUTPL-14664) were previously analyzed by Maldonado et al (2023) using GC-MS & GC-FID techniques, reporting a low yield (0.02% ± 0.004% dry weight); the main components were: α-pinene (5.3-6.0%), germacrene D (4.9-6.5%), α-cadinol (3.8-4.4%), α-humulene (3.0-3.2%), (E)-β-caryophyllene (2.4-2.8%), δ-cadinene (2.2-2.3%), and caryophyllene oxide (1.6-2.2%). Ocampo 34851 (LOJA); Cantón: Loja, parroquia Yangana, borde del camino Yangana-Cerro Toledo, 4°23'7.52" S, 79°7'12.56" W, 2960 m, 11 November 2023 (fl.…”

A New Leaf Essential Oil from Endemic Gynoxys laurifolia (Kunth) Cass. of Southern Ecuador: Chemical and Enantioselective Analyses

“…In Ecuador, 33 species are reported, of which 23 are endemics [15]. So far, according to the literature, only five species have been studied for their EOs, three of which (G. miniphylla, G. rugulosa, and G. buxifolia) are a part of this project [16][17][18]. The object of the present study is the EO distilled from the leaves of Gynoxys laurifolia (Kunth.)…”