Chemical Composition, Enantiomeric Analysis, AEDA Sensorial Evaluation and Antifungal Activity of the Essential Oil from the Ecuadorian Plant Lepechinia mutica Benth (Lamiaceae)

Abstract

This study describes the GC-FID, GC/MS, GC-O, and enantioselective GC analysis of the essential oil hydrodistilled from leaves of Lepechinica mutica (Lamiaceae), collected in Ecuador. GC-FID and GC/MS analyses allowed the characterization and quantification of 79 components, representing 97.3% of the total sample. Sesquiterpene hydrocarbons (38.50%) and monoterpene hydrocarbons (30.59%) were found to be the most abundant volatiles, while oxygenated sesquiterpenes (16.20%) and oxygenated monoterpenes (2.10%) were the minor components. In order to better characterize the oil aroma, the most important odorants, from the sensorial point of view, were identified by Aroma Extract Dilution Analysis (AEDA) GC-O. They were α-Pinene, β-Phellandrene, and Dauca-5,8-diene, exhibiting the characteristic woody, herbaceus, and earthy odors, respectively. Enantioselective GC analysis of L. mutica essential oil revealed the presence of twelve couples and two enantiomerically pure chiral monoterpenoids. Their enantiomeric excesses were from a few percent units to 100%. Moreover, the essential oil exhibited moderate in vitro activity against five fungal strains, being especially effective against M. canis, which is a severe zoophilic dermatophyte causal agent of pet and human infections.

Phytochemical Study of the Ecuadorian Species Lepechinia mutica (Benth.) Epling and High Antifungal Activity of Carnosol against Pyricularia oryzae

“…Fresh leaves and flowers were both steam distilled to obtain the essential oils. A quite complete study of the essential oil from leaves has recently been published [ 17 ].…”

“…In order to accomplish this task, the dermatophyte Microsporum canis and the phytopatogen P. oryzae were selected as targets for the in vitro antifungal assay of our samples. Up to now, the antifungal activity of this plant has been described only for the essential oil distilled from leaves [ 17 , 18 ]. To the best of the authors’ knowledge, the phytochemistry and the biological activity of L. mutica non-volatile fraction have not been described so far.…”

Essential Oils of Lamiaceae Family Plants as Antifungals

“…Carene (8.69-24.23%), Thujopsan-2-α-ol (0.0-11.9%), Shyobunol (0.0-10.8%), β-Pinene (3.78-7.96%), δ-Cadinene (0.0-6.96%), Globulol (0.0-5.91%), Valerianol (0.0-5.19%), epi-Cubebol (0.0-4.62%), β-Caryophyllene (0.0-4.55%), Limonene (3.79-4.47%), α-Eudesmol (0.0-4.47%), α-Phellandrene (0.34-3.8%), β-Phellandrene (3.79%), γ-Cadinene (0.0-2.86%), α-Pinene (1.23-2.68%), o-Cymene (0.0-2.04%), Isobornyl acetate (0.0-2.2%)[56,57] …”

The Flower Essential Oil of Dalea mutisii Kunth (Fabaceae) from Ecuador: Chemical, Enantioselective, and Olfactometric Analyses

“…The following thermal program was used: 50 °C, held for 5 min, rising to 220 °C at a rate of 2 °C/min, and kept at this temperature for 5 min. The elution order was established according to literature, where enantiomerically pure standards were injected in the same column and conditions [ 3 , 10 ].…”

“…Among natural products, a special interest exists in essential oils (EOs) [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ], whose main property is their aroma. In fact, they are defined in the European Pharmacopoeia as “odorous products, usually of complex composition, obtained from a botanically defined plant raw material by steam distillation, dry distillation, or a suitable mechanical process without heating.…”