A New Essential Oil from the Leaves of the Endemic Andean Species Gynoxys miniphylla Cuatrec. (Asteraceae): Chemical and Enantioselective Analyses

A previously uninvestigated essential oil (EO) was distilled from Gynoxys miniphylla Cuatrec. (Asteraceae) and submitted to chemical and enantioselective analyses. The qualitative and quantitative analyses were conducted by GC-MS and GC-FID, over two orthogonal columns (5%-phenyl-methylpolysiloxane and polyethylene glycol stationary phases). Major constituents (>= 2%) were, on both columns, respectively, as follows: alpha-phellandrene (16.1-17.2%), alpha-pinene (14.0-15.0%), germacrene D (13.3-14.8%), trans-myrtanol acetate (8.80%), delta-cadinene (4.2-4.6%), beta-phellandrene (3.3-2.8%), (E)-beta-caryophyllene (3.1-2.0%), o-cymene (2.4%), alpha-cadinol (2.3-2.6%), and alpha-humulene (1.7-2.0%). All the quantified compounds corresponded to 93.5-97.3% by weight of the whole essential oil, with monoterpenes counting for 53.8-55.6% of the total, and sesquiterpenes for 38.5-41.4%. For what concerns the enantioselective analyses, the chiral components were investigated through a beta-cyclodextrin-based enantioselective column (2,3-diethyl-6-tert-butyldimethylsilyl-beta-cyclodextrin). A total of six chiral metabolites were analysed and the respective enantiomeric excess calculated as follows: (1S,5S)-(-)-alpha-pinene (98.2%), (1S,5S)-(-)-beta-pinene (11.9%), (1R,5R)-(+)-sabinene (14.0%), (R)-(-)-alpha-phellandrene (100.0%), (R)-(-)-beta-phellandrene (100.0%), and (S)-(-)-germacrene D (95.5%). According to the chemical composition and enantiomeric distribution of major compounds, this EO can be considered promising as a cholinergic, antiviral and, probably, analgesic product.

Automated summary

In this study, the previously unexplored essential oil extracted from Gynoxys miniphylla Cuatrec. was subjected to chemical and enantioselective analyses. The results showed that the essential oil has potential medicinal value in cholinergic, antiviral, and analgesic therapies.