Search Results (30)

The present study described, for the first time, the chemical and enantiomeric composition of an essential oil, distilled from the cupules of Aiouea montana (Sw.) R. Rohde. On the one hand, chemical analyses were carried out through GC-MS (qualitative) and GC-FID (quantitative), on two stationary phases of different polarity. Major components (≥3.0%) were S-methyl-O-2-phenylethyl carbonothioate (23.1%), α-copaene (20.3%), α-phellandrene (18.7%), (E)-β-caryophyllene (6.1%), and α-pinene (4.5%). On the other hand, enantioselective analyses were conducted, through GC-MS, on two columns with different chiral selectors, based on derivatised β-cyclodextrins. A total of 12 chiral components were analysed, of which (1S,5S)-(−)-α-pinene and (1R,2S,6S,7S,8S)-(−)-α-copaene were found to be enantiomerically pure. All the other chiral components were present as scalemic mixtures. Finally, both chemical and enantiomeric profiles were compared to the ones previously described in the literature for the leaf essential oil of A. montana. In conclusion, cupules of A. montana produced an essential oil with a higher yield in comparison with leaves but with a lower content of S-methyl-O-2-phenylethyl carbonothioate. On the other hand, to some extent, the enantiomeric compositions of these volatile fractions were somewhat different. To the best of the authors’ knowledge, the cupule essential oil of A. montana could be the second main natural source of (−)-α-copaene so far described in the literature. Full article

The present study is the first report on the chemical and enantiomeric compositions of essential oils from the Ecuadorian species Gynoxys hallii Hieron., Gynoxys calyculisolvens Hieron., and Gynoxys azuayensis Cuatrec. All the volatile fractions presented a sesquiterpene-based chemical profile, typical of other volatile fractions from this genus. Both qualitative (GC-MS) and quantitative (GC-FID) chemical analyses were carried out on two stationary phases of different polarity (non-polar and polar). The main constituents of G. hallii essential oil on the two columns, respectively, were α-pinene (33.6–31.5%), (E)-β-caryophyllene (6.2–6.4%), germacrene D (35.7–38.3%), and bicyclogermacrene (3.8–4.0%). In G. calyculisolvens, the major compounds were α-pinene (11.2–11.0%), p-cymene (4.0–3.7%), α-copaene (3.6–3.7%), (E)-β-caryophyllene (8.1–8.3%), germacrene D (20.8–22.0%), and germacrene D-4-ol (8.4–8.6%). Finally, the main components of G. azuayensis were α-pinene (4.5–4.1%), germacrene D (14.1–12.4%), bicyclogermacrene (2.6–3.0%), tridecanal (6.4–6.2%), and spathulenol (7.8–7.1%). Furthermore, enantioselective analyses were conducted on the three volatile fractions, using two stationary phases based on β-cyclodextrins. As a result, twelve chiral components were investigated, detecting both enantiomerically pure compounds and scalemic mixtures with various enantiomeric excess. Full article

Tea tree oil (TTO), acquired from Melaleuca alternifolia (Maiden & Betche) Cheel, Myrtaceae, is a widely utilized essential oil (EO) due to its bioactive properties. The identification and quantification of TTO ingredients is generally performed by GC-MS, which provides the most accurate results. However, in some instances, the cost and time of analysis may pose a challenge. Thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) offer a simpler, faster, cost-effective alternative capable of simultaneously analyzing and quantifying multiple samples. In addition, for more complex oils, two-dimensional (2D) or multigradient development (MGD) TLC provide better separation. Nevertheless, further development is sometimes necessary for the isolation of comigrating components. This study showcases a combined 2D-MGD TLC/HPTLC method for the successful separation of TTO components of interest. While human error, limited separation, and the partial evaporation of volatile components may still present a challenge during the process, considerable recovery of mono- and sesquiterpenes was achieved. This protocol also resulted in the successful isolation of target oxygenated monoterpenes (OMs) producing highly pure terpinen-4-ol (100%) and α-terpineol (≥94%), confirmed by GC-MS. The accurate enantiomeric distribution of these major OMs was verified by GC-FID through the use of a chiral cyclodextrin-based stationary phase. The observed positive enantiomer range (area percent) as well as (+)/(−) ratio for each terpinen-4-ol and α-terpineol were within acceptable ISO criteria. Full article

This study presents the first chemical and enantioselective analyses of essential oils (EOs) derived from the leaves of two endemic species, Gynoxys reinaldii Cuatrec. and Gynoxys pulchella (Kunth) Cass., from Loja, Ecuador. The distillation yields, by weight of dry plant material, were 0.04 ± 0.007% for G. reinaldii and 0.03 ± 0.002% for G. pulchella. For both plants, the chemical analyses were conducted by GC-MS (qualitative) and GC-FID (quantitative), on two stationary phases of different polarity (5% phenyl-methylpolysiloxane and polyethylene glycol). The major components of G. reinaldii EO included germacrene D (22.3–22.1%), α-pinene (14.2–14.1%), and (E)-β-caryophyllene (13.6–14.5%). Similarly, G. pulchella EO was characterized by germacrene D (9.5–12.9%), caryophyllene oxide (7.2–6.7%), and n-tricosane (4.9% in both columns). The enantioselective analyses were carried out with two columns, based on 2,3-diacetyl-6-tert-butyldimethylsilyl-β-cyclodextrin and 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin, detecting nine chiral terpenes and terpenoids. In G. reinaldii EO, (1S,5S)-(−)-α-pinene, (1S,5S)-(−)-β-pinene, (1S,5S)-(−)-sabinene, (R)-(−)-α-phellandrene, and (R)-(−)-β-phellandrene were enantiomerically pure, whereas cis-linalool oxide, linalool, terpinene-4-ol, and germacrene D were non-racemic mixtures of enantiomers. In G. pulchella, only (R)-(−)-α-phellandrene was enantiomerically pure. The detection of enantiomerically pure compounds may provide insights into the biosynthetic pathways and potential bioactivities of these EOs. Full article

The essential oil was obtained by steam distillation, using a Clevenger apparatus, from the pericarp of the fruit of Zanthoxylum lepidopteriphilum from Ecuador. The qualitative and quantitative analyses were performed by gas chromatography coupled with mass spectrometry (GC-MS) and flame ionization detection (GC-FID) on two capillary columns with non-polar DB-5ms and a polar HP-INNOWax stationary phase. Thirty-three components were identified, accounting for 99.62% and 99.30% total essential oil. The essential oil was dominated by oxygenated monoterpenes (90.21–89.21%), respectively. The main constituents of the essential oil were α-thujone (70.26–70.38%), β-thujone (10.78–10.90%), terpinen-4-ol (4.15–4.06%), and sabinene (3.60–4.02%). Enantioselective analysis by GC was realized on a β-cyclodextrin-based chiral column (2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin) in this analysis, determining three couples of enantiomers, which exhibited the compound (1R,4S,5S)-(+)-α-thujone with an enantiomeric excess of 84.40%. Full article

A complete and comprehensive chemical and biological study of Drimys granadensis, a native Ecuadorian aromatic plant, was conducted. By conventional steam distillation from dried leaves, a yellowish, translucent essential oil (EO) with a density of 0.95 and a refractive index of 1.5090 was obtained. The EO was analyzed by gas chromatography coupled to a mass spectrometer (GC/MS) and an FID detector (GC/FID), respectively. Enantiomeric distribution was also carried out by GC/MS using a chiral selective column (diethyl tert-butylsilyl-BETA-cyclodextrin). The microdilution broth method was employed to assess the antibacterial and antifungal activity of the EO against a panel of opportunistic microorganisms. Antioxidant capacity was measured using diphenyl picryl hydrazyl (DPPH) and azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals. Finally, the inhibitory potential of the EO against acetylcholinesterase was also valued. Sixty-four chemical compounds, constituting 93.27% of the total composition, were identified, with major components including γ-muurolene (10.63%), spathulenol (10.13%), sabinene (5.52%), and δ-cadinene (4.22%). The characteristic taxonomic marker of the Drimys genus, Drimenol, was detected at very low percentages (<2%). Two pairs of enantiomers ((1S,5R)-(+)-α-pinene/(1S,5S)-(–)-α-pinene; (1S,5R)-(+)-β-pinene/(1S,5S)-(–)-β-pinene) and one pure enantiomer (1R,4S)-(–)-camphene were identified. Regarding antimicrobial potency, the EO exhibited a significant moderate effect on Listeria monocytogenes with a minimal inhibitory concentration (MIC) value of 250 µg/mL, while with the remaining microorganisms, it exerted less potency, ranging from 500 to 2000 µg/mL. The EO displayed moderate effects against the ABTS radical with a half scavenging capacity of 210.48 µg/mL and no effect against the DPPH radical. The most notable effect was noticed for acetylcholinesterase, with a half inhibition concentration (IC₅₀) of 63.88 ± 1.03 µg/mL. These antiradical and anticholinesterase effects hint at potential pharmacological applications in Alzheimer’s disease treatment, although the presence of safrole, albeit in low content (ca. 2%), could limit this opportunity. Further in vivo studies are necessary to fully understand their potential applications. Full article

As part of our interest in the volatile phytoconstituents of aromatic plants of the Great Basin, we have obtained essential oils of Ambrosia acanthicarpa (three samples), Artemisia ludoviciana (12 samples), and Gutierrezia sarothrae (six samples) from the Owyhee Mountains of southwestern Idaho. Gas chromatographic analyses (GC-MS, GC-FID, and chiral GC-MS) were carried out on each essential oil sample. The essential oils of A. acanthicarpa were dominated by monoterpene hydrocarbons, including α-pinene (36.7–45.1%), myrcene (21.6–25.5%), and β-phellandrene (4.9–7.0%). Monoterpene hydrocarbons also dominated the essential oils of G. sarothrae, with β-pinene (0.5–18.4%), α-phellandrene (2.2–11.8%), limonene (1.4–25.4%), and (Z)-β-ocimene (18.8–39.4%) as major components. The essential oils of A. ludoviciana showed wide variation in composition, but the relatively abundant compounds were camphor (0.1–61.9%, average 14.1%), 1,8-cineole (0.1–50.8%, average 11.1%), (E)-nerolidol (0.0–41.0%, average 6.8%), and artemisia ketone (0.0–46.1%, average 5.1%). This is the first report on the essential oil composition of A. acanthicarpa and the first report on the enantiomeric distribution in an Ambrosia species. The essential oil compositions of A. ludoviciana and G. sarothrae showed wide variation in composition in this study and compared with previous studies, likely due to subspecies variation. Full article

Alzheimer’s disease is a global health problem due to the scarcity of acetylcholinesterase inhibitors, the basis for symptomatic treatment of this disease; this requires new approaches to drug discovery. In this study, we investigated the chemical composition and anticholinesterase activity of Eugenia valvata McVaugt (Myrtaceae) collected in southern Ecuador, which was obtained as an essential oil (EO) with a yield of 0.124 ± 0.03% (w/w); as a result of the chemical composition analysis, a total of 58 organic compounds were identified—representing 95.91% of the total volatile compounds—using a stationary phase based on 5% phenyl-methylpolysiloxane, as analyzed via gas chromatography coupled to mass spectrometry (GC-MS) and flame ionization detection (GC-FID). The main groups were hydrocarbon sesquiterpenes (37.43%), oxygenated sesquiterpenes (31.08%), hydrocarbon monoterpenes (24.14%), oxygenated monoterpenes (0.20%), and other compounds (3.058%). Samples were characterized by the following compounds: α-pinene (22.70%), α-humulene (17.20%), (E)-caryophyllene (6.02%), citronellyl pentanoate (5.76%), 7-epi-α-eudesmol (4.34%) and 5-iso-cedranol (3.64%); this research was complemented with an enantioselective analysis carried out using 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin as a stationary phase chiral selector. As a result, α-pinene, limonene, and α-cadinene enantiomers were identified; finally, in the search for new active principles, the EO reported strong anticholinesterase activity with an IC₅₀ of 53.08 ± 1.13 µg/mL, making it a promising candidate for future studies of Alzheimer’s disease. Full article

Echinacea purpurea (L.) Moench is a medicinal plant commonly used for the treatment of upper respiratory tract infections, the common cold, sore throat, migraine, colic, stomach cramps, and toothaches and the promotion of wound healing. Based on the known pharmacological properties of essential oils (EOs), we hypothesized that E. purpurea EOs may contribute to these medicinal properties. In this work, EOs from the flowers of E. purpurea were steam-distilled and analyzed by gas chromatography–mass spectrometry (GC–MS), GC with flame-ionization detection (GC–FID), and chiral GC–MS. The EOs were also evaluated for in vitro antimicrobial and innate immunomodulatory activity. About 87 compounds were identified in five samples of the steam-distilled E. purpurea EO. The major components of the E. purpurea EO were germacrene D (42.0 ± 4.61%), α-phellandrene (10.09 ± 1.59%), β-caryophyllene (5.75 ± 1.72%), γ-curcumene (5.03 ± 1.96%), α-pinene (4.44 ± 1.78%), δ-cadinene (3.31 ± 0.61%), and β-pinene (2.43 ± 0.98%). Eleven chiral compounds were identified in the E. purpurea EO, including α-pinene, sabinene, β-pinene, α-phellandrene, limonene, β-phellandrene, α-copaene, β-elemene, β-caryophyllene, germacrene D, and δ-cadinene. Analysis of E. purpurea EO antimicrobial activity showed that they inhibited the growth of several bacterial species, although the EO did not seem to be effective for Staphylococcus aureus. The E. purpurea EO and its major components induced intracellular calcium mobilization in human neutrophils. Additionally, pretreatment of human neutrophils with the E. purpurea EO or (+)-δ-cadinene suppressed agonist-induced neutrophil calcium mobilization and chemotaxis. Moreover, pharmacophore mapping studies predicted two potential MAPK targets for (+)-δ-cadinene. Our results are consistent with previous reports on the innate immunomodulatory activities of β-caryophyllene, α-phellandrene, and germacrene D. Thus, this study identified δ-cadinene as a novel neutrophil agonist and suggests that δ-cadinene may contribute to the reported immunomodulatory activity of E. purpurea. Full article

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. Full article

The fresh leaves of Gynoxys laurifolia (Kunth) Cass. (Asteraceae), collected in the province of Loja (Ecuador), were submitted to steam distillation, producing an essential oil with a yield of 0.02% by weight. This volatile fraction, described here for the first time, was submitted to qualitative (GC–MS) and quantitative (GC–FID) chemical analyses, on two orthogonal columns (non-polar and polar stationary phase). A total of 90 components, corresponding to 95.9–95.0% by weight on the non-polar and polar stationary phase, respectively, were detected and quantified with at least one column. Major constituents (≥3%) were: germacrene D (18.9–18.0%), (E)-β-caryophyllene (13.2–15.0%), α-pinene (11.0–10.3%), β-pinene (4.5–4.4%), β-phellandrene (4.0–3.0%), bicyclogermacrene (4.0–3.0%), and bakkenolide A (3.2–3.4%). This essential oil was dominated by sesquiterpene hydrocarbons (about 45%), followed by monoterpene hydrocarbons (about 25–30%). This research was complemented with the enantioselective analysis of some common chiral terpenes, carried out through 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin and 2,3-diacetyl-6-tert-butyldimethylsilyl-β-cyclodextrin as stationary phase chiral selectors. As a result, (1S,5S)-(−)-β-pinene, (R)-(−)-α-phellandrene, (R)-(−)-β-phellandrene, (S)-(−)-limonene, (S)-(+)-linalyl acetate, and (S)-(−)-germacrene D were observed as enantiomerically pure compounds, whereas α-pinene, linalool, terpinene-4-ol, and α-terpineol were present as scalemic mixtures. Finally, sabinene was practically racemic. Due to plant wildness and the relatively low distillation yield, no industrial applications can be identified, in the first instance for this essential oil. The focus of the present study is therefore academic. Full article

The study of the essential oil (EO) from aerial parts (stems and leaves) of Valeriana microphylla Kunth (Valerianaceae), collected from the Saraguro community in the southern region of Ecuador, was analyzed for the first time. A total of 62 compounds were identified in V. microphylla EO by GC-FID and GC-MS on nonpolar DB-5ms and polar HP-INNOWax columns. The most abundant components (>5%) detected on DB-5ms and polar HP-INNOWax columns were α-gurjunene (11.98, 12.74%), germacrene D (11.47, 14.93%), E-caryophyllene (7.05, 7.78%), and α-copaene (6.76, 6.91%), respectively. In addition, the enantioselective analysis, carried out on a chiral column, showed (+)-α-pinene and (R)-(+)-germacrene as enantiomerically pure compounds (enantiomeric excess = 100%). The antioxidant activity was high for the radicals ABTS (SC50 = 41.82 µg/mL) and DPPH (SC50 = 89.60 µg/mL), and finally, the EO was shown to be inactive to the enzyme acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), as both values were >250 µg/mL. Full article

Myrcianthes discolor, an aromatic native tree from southern Ecuador, was collected to determine the chemical composition and the biological activity of its essential oil (EO). The EO was obtained by steam-distillation and analyzed by gas chromatography coupled to a mass and a FID detector (GC-MS and GC-FID) and a non-polar DB5-MS column. Enantioselective GC-MS analysis was performed in a chiral capillary column. The antimicrobial, antioxidant, and anticholinesterase potency of the EO was carried out by the broth microdilution method, radical scavenging assays using 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and by measuring the inhibition of the acetylcholinesterase (AChE) enzyme. A total of 58 chemical compounds were identified, corresponding to 94.80% of the EO composition. Sesquiterpenes hydrocarbons represented more than 75% of the composition. The main compounds detected were E-caryophyllene with 29.40 ± 0.21%, bicyclogermacrene with 7.45 ± 0.16%, β-elemene with 6.93 ± 0.499%, α-cubebene with 6.06 ± 0.053%, α-humulene with 3.96 ± 0.023%, and δ-cadinene with 3.02 ± 0.002%. The enantiomeric analysis revealed the occurrence of two pairs of pure enantiomers, (−)-β-pinene and (−)-α-phellandrene. The EO exerted a strong inhibitory effect against AChE with an IC₅₀ value of 6.68 ± 1.07 µg/mL and a moderate antiradical effect with a SC₅₀ value of 144.93 ± 0.17 µg/mL for the ABTS radical and a weak or null effect for DPPH (3599.6 ± 0.32 µg/mL). In addition, a strong antibacterial effect against Enterococcus faecium was observed with a MIC of 62.5 μg/mL and Enterococcus faecalis with a MIC of 125 μg/mL. To the best of our knowledge, this is the first report of the chemical composition and biological profile of the EO of M. discolor, and its strong inhibitory effect over AChE and against two Gram-positive pathogenic bacteria, which encourage us to propose further studies to validate its pharmacological potential. Full article

The present study describes the chemical and enantiomeric composition of a new essential oil, distilled from the dry leaves of Gynoxys buxifolia (Kunth) Cass. The chemical analysis was conducted by GC-MS and GC-FID, on two orthogonal capillary columns. A total of 72 compounds were detected and quantified with at least one column, corresponding to about 85% by weight of the whole oil mass. Of the 72 components, 70 were identified by comparing the respective linear retention indices and mass spectra with data from the literature, whereas the two main constituents were identified by preparative purification and NMR experiments. The quantitative analysis was carried out calculating the relative response factor of each compound according to their combustion enthalpy. The major constituents of the EO (≥3%) were: furanoeremophilane (31.3–28.3%), bakkenolide A (17.6–16.3%), caryophyllene oxide (6.0–5.8%), and (E)-β-caryophyllene (4.4%). Additionally, the hydrolate was also analyzed with respect to the dissolved organic phase. About 40.7–43.4 mg/100 mL of organic compounds was detected in solution, of which p-vinylguaiacol was the main component (25.4–29.9 mg/100 mL). Finally, the enantioselective analysis of some chiral terpenes was carried out, with a capillary column based on β-cyclodextrin chiral stationary phase. In this analysis, (1S,5S)-(−)-α-pinene, (1S,5S)-(−)-β-pinene, (S)-(+)-α-phellandrene, (S)-(+)-β-phellandrene, and (S)-(−)-terpinen-4-ol were detected as enantiomerically pure, whereas (S)-(−)-sabinene showed an enantiomeric excess of 69.2%. The essential oil described in the present study is a good source of two uncommon volatile compounds: furanoeremophilane and bakkenolide A. The former lacks bioactivity information and deserves further investigation, whereas the latter is a promising selective anticancer product. Full article

Conifers are of great economic value in terms of lumber production, important for construction and other uses such as pulp and paper. They are also important sources of essential oils. Conifer species have been vital to the ethnobotany and traditional herbal medicine of many different Native American groups. The objective of this work was to obtain and analyze the essential oils of several conifer species (Abies lasiocarpa, Picea engelmannii, Pinus contorta, Pseudotsuga menziesii, and Thuja plicata) growing in Idaho. The foliar essential oils were obtained by hydrodistillation and then analyzed by gas chromatographic methods, including GC-MS, GC-FID, and chiral GC-MS. The essential oils were obtained in varying yields from 0.66% up to 4.70%. The essential oil compositions were largely dominated by monoterpene hydrocarbons and oxygenated monoterpenoids. The chiral monoterpenoids were generally rich in the (−)-enantiomers for members of the Pinaceae, but the (+)-enantiomers predominated in the Cupressaceae. The essential oil compositions obtained in this work are qualitatively similar, but quantitatively different, to previously reported compositions and confirm and complement the previous reports. However, this is the first comprehensive analysis of the chiral terpenoid components in these conifer species. Additional research on essential oils of the Pinaceae and Cupressaceae is needed to describe the chemical profiles, chemical compositions, and enantiomeric distributions more reliably in the various species and infraspecific taxa of these two families. Full article