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Article

Gynoxys reinaldii Cuatrec. and Gynoxys pulchella (Kunth) Cass.: Chemical and Enantioselective Analyses of Two Unprecedented Essential Oils from Ecuador

by
Yessenia E. Maldonado
1,
María del Carmen Rodríguez
2,
Karyna Calvopiña
3,4,
Omar Malagón
3,
Nixon Cumbicus
5 and
Gianluca Gilardoni
3,*
1
Programa de Doctorado en Química, Universidad Técnica Particular de Loja (UTPL), Calle Paris s/n y Praga, Loja 110107, Ecuador
2
Carrera de Bioquímica y Farmacia, Universidad Técnica Particular de Loja (UTPL), Calle Paris s/n y Praga, Loja 110107, Ecuador
3
Departamento de Química, Universidad Técnica Particular de Loja (UTPL), Calle Paris s/n y Praga, Loja 110107, Ecuador
4
Facultad de Ciencias de la Ingeniería, Universidad Técnica Estatal de Quevedo (UTEQ), Campus Central, Av. Quito km 11/2 vía a Santo Domingo de los Tsáchilas, Quevedo 120301, Ecuador
5
Departamento de Ciencias Biológicas y Agropecuarias, Universidad Técnica Particular de Loja (UTPL), Calle Paris s/n y Praga, Loja 110107, Ecuador
*
Author to whom correspondence should be addressed.
Plants 2024, 13(24), 3543; https://doi.org/10.3390/plants13243543
Submission received: 26 November 2024 / Revised: 15 December 2024 / Accepted: 17 December 2024 / Published: 19 December 2024
(This article belongs to the Special Issue Chemical Analysis and Biological Activities of Plant Essential Oils)
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Abstract

:
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.

1. Introduction

Since ancient times, in all cultures worldwide, plants have been the main source of organic chemicals. Drugs, venoms, perfumes, and fats have been obtained from vegetal materials, usually as complex mixtures. Since the discovery of morphine, many pure natural products have been identified in botanical species, characterized by biological activities or physiological properties [1]. However, after two centuries of research, most of the biodiversity in Europe and North America has been investigated, obliging chemists to focus on tropical flora, especially in “megadiverse” countries like Ecuador [2].
Thanks to the novelty of the Ecuadorian flora, our group has been investigating the very wide but poorly studied chemical diversity of this country for more than 20 years [3,4]. Initially interested in discovering new non-volatile compounds, we recently focused also on the description of unprecedented essential oils (EOs), with an emphasis on their chemical and enantiomeric compositions, biological activity, and olfactory profile [5,6,7,8,9,10].
The main objective of the present study is to enhance the knowledge about phytochemistry and chemotaxonomy of genus Gynoxys Cass., which belongs to the family Asteraceae, in the province of Loja (Ecuador). This genus is native to Argentina, Bolivia, Colombia, Ecuador, Peru, and Venezuela, but the country with the most described specimens is Ecuador [11,12,13]. So far, seven Ecuadorian species have been described as a part of this unfunded project [14,15,16,17,18,19].
On the one hand, according to the literature, G. reinaldii is an endemic shrub, growing between 2000 and 3000 m above the sea level. It has been recorded in the provinces of Azuay and Loja [20]. On the other hand, G. pulchella is an endemic tree, growing at an altitude of 3500–4000 m, and recorded in the provinces of Bolívar, Tungurahua, and Loja. This species is also known as Senecio pulchellus Kunth [12,20]. These taxa have no reported medicinal use, and this study provides the first description of their essential oil composition and enantiomeric profile.

2. Results

2.1. Chemical Analyses of the EOs

The distillation yields, analytically calculated over four repetitions by weight of dry plant material, were 0.04 ± 0.007% for G. reinaldii and 0.03 ± 0.002% for G. pulchella. The EOs, analyzed on two stationary phases of different polarity, permitted to detect, and quantify a total of 123 compounds, of which only five resulted to be unidentified. In G. reinaldii EO, the total amount of quantified compounds corresponded to 86.3% and 82.8% of the total oil mass on a non-polar and polar column, respectively, whereas in G. pulchella EO, the quantified components altogether corresponded to 90.2% and 91.2%. As is usual for the genus Gynoxys, both essential oils were dominated by the sesquiterpene fraction, including hydrocarbons and oxygenated sesquiterpenoids. About G. reinaldii, the terpene fraction accounted for 54.7–53.4%, whereas G. pulchella EO showed 47.9–50.2%. On the one hand, for G. reinaldii, the second most abundant fraction was constituted by monoterpenes and oxygenated monoterpenoids, whose abundance was 18.7–17.2% on the two columns, respectively. On the other hand, the second main fraction of G. pulchella was composed of non-terpene compounds, principally heavy aliphatic hydrocarbons, whose amount was 34.2–34.3%. The main constituents of G. reinaldii EO (≥3.0 on at least one column) were germacrene D (22.3–22.1%, peak 62), α-pinene (14.2–14.1%, peak 2), (E)-β-caryophyllene (13.6–14.5%, peak 51), n-nonanal (3.0–2.3%, peak 21), and caryophyllene oxide (3.0–3.1%, peak 80). About G. pulchella, the major components were germacrene D (9.5–12.9%, peak 62), caryophyllene oxide (7.2–6.7%, peak 80), (E)-β-caryophyllene (7.0–7.8%, peak 51), n-tricosane (4.9% on both columns, peak 116), 1-docosene (4.0–4.3%, peak 113), α-pinene (3.7–3.0%, peak 2), spathulenol (3.6–3.2%, peak 79), n-heneicosane (3.6–3.5%, peak 112), and α-cadinol (2.1–3.0%, peak 97). The detailed analytical results are shown in Table 1, whereas the GC profiles are reported in Figure 1 and Figure 2.

2.2. Enantioselective Analyses

The enantioselective analyses, depending on the EOs chemical composition and the availability of enantiomerically pure standards, were carried out on nine chiral terpenes and terpenoids, whose results are detailed in Table 2, whereas the GC profiles are represented in Figure 3 and Figure 4. 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 scalemic mixtures, with linalool almost racemic. About G. pulchella EO, only (R)-(−)-α-phellandrene was enantiomerically pure. In both oils, as is usual in many Gynoxys species, germacrene D showed a very high enantiomeric excess (>96%).

3. Discussion

According to the literature, the genus Gynoxys comprises approximately 130 species, of which 34 are recorded in Ecuador and at least 23 are endemic [13,20]. In the present project, 12 species were selected in the province of Loja to be submitted to EO analysis: Gynoxys miniphylla Cuatrec., Gynoxys rugulosa Muschl., Gynoxys buxifolia (Kunth) Cass., Gynoxys laurifolia (Kunth) Cass., Gynoxys cuicochensis Cuatrec., Gynoxys sancti-antonii Cuatrec., Gynoxys szyszylowiczii Hieron., Gynoxys calyculisolvens Hieron., Gynoxys hallii Hieron., Gynoxys azuayensis Cuatrec., Gynoxys pulchella (Kunth) Cass., Gynoxys reinaldii Cuatrec. So far, the EOs of G. miniphylla, G. rugulosa, G. buxifolia, G. laurifolia, G. cuicochensis, G. sancti-antonii, and G. szyszylowiczii have been described and published, whereas G. calyculisolvens, G. hallii, and G. azuayensis are being investigated. Finally, G. pulchella and G. reinaldii are the subjects of the present study [14,15,16,17,18,19].
The EOs distilled from the leaves of G. reinaldii and G. pulchella presented quite similar chemical profiles, typical of the volatile fractions of this genus. In fact, as is usual for the Gynoxys spp., three main fractions can be recognized: a poor monoterpene fraction with a strong presence of α-pinene, a dominant sesquiterpene fraction, and a heavy aliphatic fraction [14,15,16,17,18,19]. In Figure 5, the abundances of the main components in these EOs are compared, expressed as mean percent values on the two columns. Germacrene D is the most abundant compound in both oils, whereas (E)-β-caryophyllene is the second main component in G. pulchella and the third one in G. reinaldii. On the other hand, α-pinene is the second major constituent in G. reinaldii. Compositions where these terpenes were present as main components have already been observed in other EOs from this genus, e.g., in the case of G. rugulosa, G. laurifolia, G. szyszylowiczii, and G. cuicochensis [15,17,18,19]. In G. miniphylla, the main EO component is α-phellandrene, whereas in G. sancti-antonii, it is γ-curcumene. However, in all cases, germacrene D, α-pinene, and (E)-β-caryophyllene are present in relatively high amounts [14,15,16,17,18,19]. Regarding the heavy aliphatic fraction, this is very important in G. pulchella, but almost negligible in G. reinaldii. However, other Gynoxys spp. were characterized by an abundant fraction, as it is the case for G. rugulosa and G. szyszylowiczii [15,19]. Anyway, as a trace or in low amount, most of the analyzed Gynoxys EOs presented heavy alkanes and alkenes, confirming that the corresponding biosynthetic pathway is common within this genus.
For what concerns the enantiomeric composition of these EOs, a graphical comparison between the two is represented in Figure 6. Unlike the chemical analyses, the enantiomeric profiles were not so similar, with some radical differences among the hydrocarbon monoterpenes. In fact, it can be observed that G. reinaldii produced enantiomerically pure (1S,5S)-(−)-α-pinene and (1S,5S)-(−)-β-pinene, whereas G. pulchella presented high enantiomeric excesses of both dextrorotatory forms. A similar but not identical trend could be observed for sabinene. On the other hand, both species produced the same enantiomer of α-phellandrene, whereas β-phellandrene is absent in G. pulchella and its laevorotatory form is enantiomerically pure in G. reinaldii. These results about pinenes and phellandrenes are somehow biosynthetically consistent. In fact, the stereogenic centres in pinenes are formed when the pinyl cation, the direct precursor of both α-pinene and β-pinene, is produced [80]. Similarly, both α-phellandrene and β-phellandrene derive from the same phellandryl cation, sharing the configuration of the only asymmetric carbon [80]. Although a different trend has sometimes been observed, the expected situation is as described here: the same absolute configuration for α- and β-pinene on one side, and α- and β-phellandrene on the other side, within the same species. About linalool and linalool oxide, the two EOs were instead similar. Not only were these enantiomeric mixtures relatively close to racemic, but, also, in both plants, the enantiomeric excess of linalool oxide was in favor of the dextrorotatory form, whereas for linalool, the laevorotatory isomer was dominant. This phenomenon suggested that linalool oxide could be obtained from linalool through an enantiospecific oxidation. Finally, (R)-(+)-germacrene D presented a very high enantiomeric excess in both plants. This condition, where germacrene D is almost enantiomerically pure, is common in the genus Gynoxys, although sometimes the dominant isomer is dextrorotatory, and at other times, laevorotatory.
About a possible biological activity of these EOs, the analytical scale distillation did not permit to carry out any assay with this respect. In fact, in the analytical approach, the EO is distilled over an exact volume of cyclohexane, containing an internal standard. The condensed vapors are extracted through the solvent, avoiding the obtention of a pure volatile fraction. The obtained cyclohexane solution can be directly injected into GC, however this approach usually prevents from any application that requires a pure EO, such as conducting a biological activity test. Nevertheless, some literature exists on the properties of the five major terpene constituents (see Figure 7), whose biological activities can be reflected in G. reinaldii and G. pulchella EOs. For what concerns germacrene D (62), the main property reported is an ecologically interesting attractive effect for the moths of the genus Heliothis and Helicoverpa [81]. However, according to further studies, it seems to be the laevorotatory enantiomer the one responsible for this capacity, whereas G. reinaldii and G. pulchella almost exclusively produced (R)-(+)-germacrene D [82,83]. If the role of (R)-(+)-germacrene D versus Heliothis and Helicoverpa spp. can be excluded, the ecological properties of other abundant terpenes and terpenoids must be mentioned. This is for instance the case of α-pinene (2), (E)-β-caryophyllene (51), and caryophyllene oxide (80), whose antifungal, allelopathic, insect-repellent, and insect-attractive effects have been known for more than 40 years [84]. In particular, on the one hand, caryophyllene oxide (80) demonstrated a good fungistatic activity against Pestalotia subcuticularis, a leaf-spotting fungi, pathogen to genus Hymenaea. On the other hand, (E)-β-caryophyllene (51), whose fungistatic activity was very modest, showed important insecticidal capacity against herbivorous lepidoptera, also threatening the genus Hymenaea. If we consider that Hymenaea spp. produce both compounds, whose relative abundance depends on the ecological necessity of the plant, a similar role could be hypothesized for these metabolites in G. reinaldii and G. pulchella EOs.
After germacrene D, the second main component of G. reinaldii EO was α-pinene (2), probably one of the pharmacologically most investigated terpenes. This metabolite is known for possessing antibacterial, antifungal, anti-leishmanial, anti-inflammatory, antioxidant, neuroprotective, antitumor, insecticidal, and nematocidal activities, with the anti-inflammatory capacity likely being the most important. As expected, its enantiomers present different biological properties, with (1S,5S)-(−)-α-pinene (G. reinaldii) being anti-viral, whereas (1R,5R)-(+)-α-pinene (G. pulchella) is neuroprotective [85,86]. After that, (E)-β-caryophyllene (51) was the third main constituent in both oils, almost reaching 15% in G. reinaldii (similar to α-pinene) and 7% in G. pulchella (similar to caryophyllene oxide). This very common sesquiterpene hydrocarbon has been widely studied, and its anti-inflammatory, neuroprotective, analgesic, antioxidant, sedative, anxiolytic, and antitumor activities have been described. However, also in this case, the anti-inflammatory and anticancer capacities probably are the most important [87,88]. Caryophyllene oxide (80) was as abundant as (E)-β-caryophyllene in G. pulchella EO. This oxygenated sesquiterpenoid is an epoxide, directly deriving from the oxidation of (E)-β-caryophyllene, with which it shares anticancer activity. This property seems to be more evident in caryophyllene oxide than in (E)-β-caryophyllene, and it has been explained by the electrophilic character of the epoxide group [89]. Furthermore, both (E)-β-caryophyllene and caryophyllene oxide showed an interesting analgesic activity as a consequence of their affinity for the CB2 cannabinoid receptors [89].
Finally, spathulenol (79) was a major oxygenated terpenoid in the EO of G. pulchella. Although this compound has not been extensively studied in a pure form about its pharmacology, there is a significant amount of literature on the biological activities of EOs where spathulenol is the most abundant constituent. This is, for example, the case of Psidium guineense Sw., where spathulenol accounted for more than 80% of the total oil composition. On that occasion, both EO and purified spathulenol demonstrated important anti-inflammatory activity, as well as moderate antiproliferative and antimycobacterial capacities against an ovarian cancer cell line and Mycobacterium tuberculosis, respectively [90].
As is usual within natural products, the presence of both enantiomerically pure or scalemic chiral compounds is the result of enantioselective and enantiospecific biosynthetic pathways. The need for a specific chirality in secondary metabolites depends on the different biological properties associated with different enantiomers. In fact, it is well known that, although two optical isomers are characterized by the same physicochemical properties (except for optical activity), they present different biological capacities due to the chiral medium constituted by living organisms (chiral receptors, chiral active sites, etc.). Therefore, when two enantiomers are produced by the same organism in nature, they usually come from different enantioselective biosynthetic pathways in order to play different biochemical roles.

4. Materials and Methods

4.1. Plant Material

The leaves of G. reinaldii were collected on 28 October 2022, from different shrubs, located in a range of 100 m around a central point of coordinates 03°59′42″ S and 79°16′10″ W, at an altitude of about 2600 m above the sea level. About G. pulchella, the leaves were harvested on June 6, 2023, in a range of about 100 m from a point of coordinates 03°41′36″ S and 79°17′49″ W, at about 3140 m above the sea level. The taxonomic identification was carried out by one of the authors (N.C.), based on the specimens conserved at the Missouri Botanical Garden with codes 3,595,614 (G. reinaldii) and 5,813,849 (G. pulchella). Two botanical vouchers were deposited at the herbarium of the Universidad Técnica Particular de Loja, with codes 14,665 and 14,674 for G. reinaldii and G. pulchella, respectively. Both collection places were located in the province of Loja, Ecuador. After collection, the plant materials were dried at 35 °C for 48 h and stored in dark bags until use. This investigation was conducted in compliance of Ecuadorian law, under the permission of the Ministry of Environment, Water, and Ecological Transition of Ecuador (MAATE), with registry code MAATE-DBI-CM-2022-0248. For both G. reinaldii and G. pulchella, the balsamic period was unknown, and the date of collection was not chosen as a function of the chemical profile or the distillation yield. The determination of the balsamic period would need, for each species, a year-long study that would go beyond the objectives of the present project. For the same reasons, no control has been applied to leaf age so far.

4.2. EOs Distillation and Samples Preparation

Both plants were analytically steam-distilled in four repetitions as previously described in the literature, i.e., using a modified Dean–Stark apparatus. Each repetition was obtained by distilling the plants over 2 mL of cyclohexane containing n-nonane as an internal standard [15]. Both solvent and internal standard were purchased from Merk (Sigma–Aldrich, St. Louis, MO, USA). A total of four samples for each species were obtained, which could be directly injected into the GC. In the distillation of G. reinaldii, each repetition was carried out from 80.0 g of dry plant material, whereas 84.4, 81.6, 51.6, and 52.0 g of dry leaves were used for G. pulchella. All the cyclohexane solutions were stored at −15 °C until use. The distillation apparatus was assembled with commercial glassware, and it was the same equipment used during the whole project for all the Gynoxys spp. Therefore, although it was not the result of a specific design (except for the modified Dean–Stark), it ensured the same reproducible physical parameters and conditions for all the investigated species. Similarly, the distillation yield was not experimentally optimized, but the distillation time was based on the authors’ experience and was maintained the same for all the species in this project.

4.3. Qualitative Analyses (GC-MS) of the EOs

The qualitative analyses were conducted on a Thermo Fisher gas chromatograph (GC) model Trace 1310, coupled with a ISQ 7000 mass spectrometer (MS) from the same provider (Thermo Fisher Scientific, Walthan, MA, USA). The oven was configured with two capillary columns based on the stationary phases of different polarity (30 m long, 0.25 mm internal diameter, and 0.25 μm film thickness). All the analyses were carried out on both phases, 5% phenyl-methylpolysiloxane (TR-5MS, non-polar) and polyethylene glycol (TR-Wax, polar), respectively, provided by Thermo Fisher Scientific (Walthan, MA, USA). The carrier gas was helium, purchased from Indura (Guayaquil, Ecuador), and set at the constant flow of 1 mL/min. All the elutions were conducted according to the following thermal gradient: 50 °C for 10 min, followed by a first gradient of 3 °C/min until 100 °C, a second gradient of 5 °C/min until 200 °C, and a third gradient of 10°C/min until 230 °C, which was maintained for 20 min. The injector was set at 230 °C and operated in split mode (40:1). The MS electron impact (EI) ion source was set at 70 eV and 250 °C, with the mass analyzer operating in SCAN mode (mass range 40–400 m/z), programmed at 250 °C. The transfer line temperature was 230 °C and the injection volume was 1 μL for all samples. Each component of the EOs was identified by comparison of its mass spectrum and linear retention index (LRI) with data from the literature. The LRIs were calculated according to Van den Dool and Kratz, referring to a mixture of homologous n-alkanes in the range C9–C28, purchased from Merk (Sigma–Aldrich, St. Louis, MO, USA) [91]. The use of two stationary phases of different polarity ensured that practically all the detected compounds could be separated with at least on column. Anyway, even when two constituents coeluted on a column, the identification was often successful, thanks to ion mass extraction.

4.4. Quantitative Analyses (GC-FID) of the EOs

The quantitative analyses were conducted with the same GC instrument, columns, thermal program, and conditions as the qualitative ones, but with a flame ionization detector (FID) instead of MS. The split value in all GC-FID analyses was 10:1. With each column, the EOs components were quantified using isopropyl caproate in a six-point calibration curve, where the six dilutions were prepared as previously described in the literature [92]. Before applying the integration areas to the calibration curves, a relative response factor (RRF) was calculated for each compound based on their combustion enthalpy [93,94]. The calibration standard (isopropyl caproate) was synthetized in the authors’ laboratories and purified to 98.8% (GC-FID). The internal standard was n-nonane, purchased from Merk (Sigma–Aldrich, St. Louis, MO, USA). Both calibration curves showed a correlation coefficient >0.998. Because of its dependence from the combustion enthalpy, the RRF value is practically the same for all isomers. Therefore, with FID, an isomer can be used instead of an original compound as a quantification standard. For this reason, we decided to use isopropyl caproate instead of methyl octanoate, which was originally employed by Alain Chaintreau in his method [93].

4.5. Enantioselective Analyses

The enantiomeric compositions of the EOs were determined using two different enantioselective columns, purchased from Mega, Milan, Italy. The column dimensions were 25 m in length, 0.25 mm in internal diameter, and 0.25 μm in phase thickness, whereas the chiral selectors were 2,3-diacetyl-6-tert-butyldimethylsilyl-β-cyclodextrin and 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin. The enantioselective analyses were carried out in the same GC-MS instrument and with the same MS settings previously described in Section 4.3, but with the following thermal program: 50 °C for 1 min, followed by a thermal gradient of 2 °C/min until 220 °C, which was maintained for 10 min. The injector and transfer line temperatures were set to 220 °C, whereas the carrier gas flow was set to a constant pressure of 70 kPa. The split value was 40:1, and the injection volume was 1 μL. The enantiomers were identified for their mass spectrum and with the aim of enantiomerically pure standards, injected in the same conditions. A mixture of n-alkanes (C9–C28), provided by Merk (Sigma–Aldrich, St. Louis, MO, USA), was also injected in the same conditions to calculate the retention indices. The chiral selectors were chosen according to the enantiomers that had to be separated and for which enantiomerically pure standards were available.

5. Conclusions

The leaves of Gynoxys reinaldii Cuatrec. and Gynoxys pulchella (Kunth) Cass. produced an EO with a distillation yield of 0.04 ± 0.007% and 0.03 ± 0.002%, respectively. On the one hand, the chemical compositions were relatively similar regarding the terpene fractions, but they were substantially different in the heavy aliphatic fractions. On the other hand, the enantiomeric compositions differed, and, as is usual for the EO of this genus, a common trend was not evident. The only exceptions were linalool and linalool oxide, whose respective enantiomeric compositions were consistent with the hypothesis of an enantiospecific oxidation. According to the chemical compositions, these EOs could be characterized by many biological properties, with the anti-inflammatory activity likely being the most important. Once the present project is complete, all the volatile fractions will be compared using proper statistical analysis.

Author Contributions

Conceptualization, G.G.; investigation, Y.E.M., M.d.C.R., K.C. and N.C.; data curation, Y.E.M.; writing—original draft preparation, G.G.; writing—review and editing, O.M.; supervision, G.G. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

The datasets presented in this article are not readily available because they are part of an ongoing study. Requests to access the datasets should be directed to the corresponding author.

Acknowledgments

We are grateful to the Universidad Técnica Particular de Loja (UTPL) for supporting this investigation and open access publication. We are also grateful to Carlo Bicchi (University of Turin, Italy) and Stefano Galli (MEGA S.r.l., Legnano, Italy) for their support with enantioselective columns.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Huxtable, R.J.; Schwarz, S.K. The isolation of morphine—First principles in science and ethics. Mol. Interv. 2001, 1, 189–191. [Google Scholar] [PubMed]
  2. Megadiverse Countries, UNEP-WCMC. Available online: https://www.biodiversitya-z.org/content/megadiverse-countries (accessed on 12 June 2024).
  3. Malagón, O.; Ramírez, J.; Andrade, J.; Morocho, V.; Armijos, C.; Gilardoni, G. Phytochemistry and Ethnopharmacology of the Ecuadorian Flora. A Review. Nat. Prod. Commun. 2016, 11, 297. [Google Scholar] [CrossRef] [PubMed]
  4. Armijos, C.; Ramírez, J.; Salinas, M.; Vidari, G.; Suárez, A.I. Pharmacology and Phytochemistry of Ecuadorian Medicinal Plants: An Update and Perspectives. Pharmaceuticals 2021, 14, 1145. [Google Scholar] [CrossRef] [PubMed]
  5. Chiriboga, X.; Gilardoni, G.; Magnaghi, I.; Vita Finzi, P.; Zanoni, G.; Vidari, G. New Anthracene Derivatives from Coussarea macrophylla. J. Nat. Prod. 2003, 66, 905–909. [Google Scholar] [CrossRef] [PubMed]
  6. Gilardoni, G.; Tosi, S.; Mellerio, G.; Maldonado, M.E.; Chiriboga, X.; Vidari, G. Lipophilic Components from the Ecuadorian Plant Schistocarpha eupatorioides. Nat. Prod. Commun. 2011, 6, 767–772. [Google Scholar] [CrossRef]
  7. Gilardoni, G.; Chiriboga, X.; Finzi, P.V.; Vidari, G. New 3,4-Secocycloartane and 3,4-Secodammarane Triterpenes from the Ecuadorian Plant Coussarea macrophylla. Chem. Biodivers. 2015, 12, 946–954. [Google Scholar] [CrossRef]
  8. Maldonado, Y.E.; Montalván, M.; Cumbicus, N.; Gilardoni, G. Chemical and Enantioselective Analyses of an Unprecedented Essential Oil from Ecuadorian Aiouea montana: A Natural Source of S-Methyl-O-2-phenylethyl Carbonothioate. ACS Omega 2024, 9, 26495–26502. [Google Scholar] [CrossRef] [PubMed]
  9. Gilardoni, G.; Montalván, M.; Ortiz, M.; Vinueza, D.; Montesinos, J.V. The Flower Essential Oil of Dalea mutisii Kunth (Fabaceae) from Ecuador: Chemical, Enantioselective, and Olfactometric Analyses. Plants 2020, 9, 1403. [Google Scholar] [CrossRef]
  10. Espinosa, S.; Bec, N.; Larroque, C.; Ramírez, J.; Sgorbini, B.; Bicchi, C.; Gilardoni, G. Chemical, Enantioselective, and Sensory Analysis of a Cholinesterase Inhibitor Essential Oil from Coreopsis triloba S.F. Blake (Asteraceae). Plants 2019, 8, 448. [Google Scholar] [CrossRef] [PubMed]
  11. Plants of the World Online. Royal Botanic Gardens. Available online: https://powo.science.kew.org/ (accessed on 12 June 2024).
  12. Tropicos.org. Missouri Botanical Garden. Available online: https://www.tropicos.org (accessed on 12 June 2024).
  13. Arias, R.; Espinosa-Ortega, N.; Revilla, I.; Ansaloni, R.; Tomasello, S. Gynoxys revolutifolia (Senecioneae, Asteraceae): A new species from southern Ecuador. Phytotaxa 2024, 644, 211. [Google Scholar] [CrossRef]
  14. Malagón, O.; Cartuche, P.; Montaño, A.; Cumbicus, N.; Gilardoni, G. A New Essential Oil from the Leaves of the Endemic Andean Species Gynoxys miniphylla Cuatrec. (Asteraceae): Chemical and Enantioselective Analyses. Plants 2022, 11, 398. [Google Scholar] [CrossRef]
  15. Maldonado, Y.E.; Malagón, O.; Cumbicus, N.; Gilardoni, G. A New Essential Oil from the Leaves of Gynoxys rugulosa Muschl. (Asteraceae) Growing in Southern Ecuador: Chemical and Enantioselective Analyses. Plants 2023, 12, 849. [Google Scholar] [CrossRef] [PubMed]
  16. Cumbicus, C.; Malagón, O.; Cumbicus, N.; Gilardoni, G. The Leaf Essential Oil of Gynoxys buxifolia (Kunth) Cass. (Asteraceae): A Good Source of Furanoeremophilane and Bakkenolide A. Plants 2023, 12, 1323. [Google Scholar] [CrossRef]
  17. Gilardoni, G.; Lara, L.R.; Cumbicus, N.; Malagón, O. A New Leaf Essential Oil from Endemic Gynoxys laurifolia (Kunth) Cass. of Southern Ecuador: Chemical and Enantioselective Analyses. Plants 2023, 12, 2878. [Google Scholar] [CrossRef] [PubMed]
  18. Maldonado, Y.E.; Betancourt, E.A.; León, E.S.; Malagón, O.; Cumbicus, N.; Gilardoni, G. New Essential Oils from Ecuadorian Gynoxys cuicochensis Cuatrec. and Gynoxys sancti-antonii Cuatrec. Chemical Compositions and Enantioselective Analyses. ACS Omega 2024, 9, 25902–25913. [Google Scholar] [CrossRef] [PubMed]
  19. Maldonado, Y.E.; Malagón, O.; Cumbicus, N.; Gilardoni, G. A New Leaf Essential Oil from the Andean Species Gynoxys szyszylowiczii Hieron. of Southern Ecuador: Chemical and Enantioselective Analyses. Sci. Rep. 2024, 14, 16360. [Google Scholar] [CrossRef]
  20. Jorgensen, P.; Leon-Yanez, S. Catalogue of the Vascular Plants of Ecuador; Missouri Botanical Garden Press: St. Louis, MO, USA, 1999; pp. 286–288. [Google Scholar]
  21. Adams, R.P. Identification of Essential Oil Components by Gas Chromatography/Mass Spectrometry, 4th ed.; Allured Publishing Corporation: Carol Stream, IL, USA, 2007; ISBN 10-193263321. [Google Scholar]
  22. Buttery, R.G.; Orts, W.J.; Takeoka, G.R.; Nam, Y. Volatile flavor components of rice cakes. J. Agric. Food Chem. 1999, 47, 4353–4356. [Google Scholar] [CrossRef]
  23. Fanciullino, A.L.; Gancel, A.L.; Froelicher, Y.; Luro, F.; Ollitrault, P.; Brillouet, J.M. Effects of Nucleo Cytoplasmic Interactions on Leaf Volatile Compounds from Citrus Somatic Diploid Hybrids. J. Agric. Food Chem. 2005, 53, 4517–4523. [Google Scholar] [CrossRef] [PubMed]
  24. Dugo, P.; Mondello, L.; Zappia, G.; Bonaccorsi, I.; Cotroneo, A.; Russo, M.-T. The composition of the volatile fraction and the enantiomeric distribution of five volatile components of faustrime oil (Monocitrus australatica x Fortunella sp. x Citrus aurantifolia). J. Essent. Oil Res. 2004, 16, 328–333. [Google Scholar] [CrossRef]
  25. Flamini, G.; Tebano, M.; Cioni, P.L.; Bagci, Y.; Dural, H.; Ertugrul, K.; Uysal, T.; Savran, A. A Multivariate Statistical Approach to Centaurea Classification Using Essential Oil Composition Data of Some Species from Turkey. Plant Syst. Evol. 2006, 261, 217–228. [Google Scholar] [CrossRef]
  26. Yu, E.J.; Kim, T.H.; Kim, K.H.; Lee, H.J. Aroma-active compounds of Pinus densiflora (red pine) needles. Flavour Fragr. J. 2004, 19, 532–537. [Google Scholar] [CrossRef]
  27. Bianchi, F.; Careri, M.; Mangia, A.; Musci, M. Retention indices in the analysis of food aroma volatile compounds in temperature programmed gas chromatography: Database creation and evaluation of precision and robustness. J. Sep. Sci. 2007, 39, 4. [Google Scholar] [CrossRef] [PubMed]
  28. Ruiz Perez-Cacho, P.; Mahattanatawee, K.; Smoot, J.M.; Rouseff, R. Identification of sulfur volatiles in canned orange juices lacking orange flavor. J. Agric. Food Chem. 2007, 55, 5761–5767. [Google Scholar] [CrossRef]
  29. Fernandez-Segovia, I.; Escriche, I.; Gomez-Sintes, M.; Fuentes, A.; Serra, J.-A. Influence of different preservation treatments on the volatile fraction of desalted cod. Food Chem. 2006, 98, 473–482. [Google Scholar] [CrossRef]
  30. Mahattanatawee, K.; Perez-Cacho, P.-R.; Davenport, T.; Rouseff, R. Comparison of three lychee cultivar odor profiles using gas chromatography-olfactometry and gas chromatography-sulfur detection. J. Agric. Food Chem. 2007, 55, 1939–1944. [Google Scholar] [CrossRef] [PubMed]
  31. Chen, C.-C.; Kuo, M.-C.; Liu, S.-E.; Wu, C.-M. Volatile components of salted and pickled prunes (Prunus mume Sieb. et Zucc.). J. Agric. Food Chem. 1986, 34, 140–144. [Google Scholar] [CrossRef]
  32. Shellie, R.; Mondello, L.; Marriott, P.; Dugo, G. Characterization of lavender essential oils by using gas chromatography-mass spectrometry with correlation of linear retention indices and comparison with comprehensive two-dimensional gas chromatography. J. Chromatogr. A 2002, 970, 225–234. [Google Scholar] [CrossRef]
  33. Kim, T.H.; Thuy, N.T.; Shin, J.H.; Baek, H.-H.; Lee, H.J. Aroma-active compounds of miniature beefsteakplant (Mosla dianthera Maxim.). J. Agric. Food Chem. 2000, 48, 2877–2881. [Google Scholar] [CrossRef]
  34. Bader, A.; Caponi, C.; Cioni, P.L.; Flamini, G.; Morelli, I. Acorenone in the essential oil of flowering aerial parts of Seseli tortuosum L. Flavour Fragr. J. 2003, 18, 57–58. [Google Scholar] [CrossRef]
  35. Wu, S.; Zorn, H.; Krings, U.; Berger, R.G. Characteristic Volatiles from Young and Aged Fruiting Bodies of Wild Polyporus sulfureus (Bull.:Fr.) Fr. J. Agric. Food Chem. 2005, 53, 4524–4528. [Google Scholar] [CrossRef] [PubMed]
  36. Cho, I.H.; Namgung, H.-J.; Choi, H.-K.; Kim, Y.-S. Volatiles and key odorants in the pileus and stipe of pine-mushroom (Tricholoma matsutake Sing.). Food Chem. 2008, 106, 71–76. [Google Scholar] [CrossRef]
  37. Saroglou, V.; Marin, P.D.; Rancic, A.; Veljic, M.; Skaltsa, H. Composition and antimicrobial activity of the essential oil of six Hypericum species from Serbia. Biochem. Syst. Ecol. 2007, 35, 146–152. [Google Scholar] [CrossRef]
  38. Da Porto, C.; Pizzale, L.; Bravin, M.; Conte, L.S. Analyses of orange spirit flavour by direct-injection gas chromatography–mass spectrometry and headspace solid-phase microextraction/GC–MC. Flavour Fragr. J. 2003, 18, 66–72. [Google Scholar] [CrossRef]
  39. Ka, M.H.; Choi, E.H.; Chun, H.S.; Lee, K.G. Antioxidative Activity of Volatile Extracts Isolated from Angelica tenuissimae Roots, Peppermint Leaves, Pine Needles, and Sweet Flag Leaves. J. Agric. Food Chem. 2005, 53, 4124–4129. [Google Scholar] [CrossRef] [PubMed]
  40. Riu-Aumatell, M.; Lopez-Tamames, E.; Buxaderas, S. Assessment of the Volatile Composition of Juices of Apricot, Peach, and Pear According to Two Pectolytic Treatments. J. Agric. Food Chem. 2005, 53, 7837–7843. [Google Scholar] [CrossRef]
  41. Kollmannsberger, H.; Nitz, S.; Drawert, F. Über die Aromastoffzusammensetzung von Hochdruckextrakten. I. Pfeffer (Piper nigrum, Var. muntok). Z. Für Lebensm. Unters. Und-Forsch. 1992, 194, 545–551. [Google Scholar] [CrossRef]
  42. Yu, E.J.; Kim, T.H.; Kim, K.H.; Lee, H.J. Characterization of aroma-active compounds of Abies nephrolepis (Khingan fir) needles using aroma extract dilution analysis. Flavour Fragr. J. 2004, 19, 74–79. [Google Scholar] [CrossRef]
  43. Tu, N.T.M.; Onishi, Y.; Choi, H.-S.; Kondo, Y.; Bassore, S.M.; Ukeda, H.; Sawamura, M. Characteristic odor components of Citrus sphaerocarpa Tanaka (Kabosu) cold-pressed peel oil. J. Agric. Food Chem. 2002, 50, 2908–2913. [Google Scholar]
  44. Werkhoff, P.; Güntert, M. Identification of some ester compounds in bourbon vanilla beans. Lebensm. Wiss. Technol. 1997, 30, 429–431. [Google Scholar] [CrossRef]
  45. Tunalier, Z.; Candan, N.T.; Demirci, B.; Baser, K.H. The essential oil composition of Acroptilon repens (L.) DC. of Turkish origin. Flavour Fragr. J. 2006, 21, 462–464. [Google Scholar] [CrossRef]
  46. Pozo-Bayon, M.A.; Ruiz-Rodriguez, A.; Pernin, K.; Cayot, N. Influence of eggs on the aroma composition of a sponge cake and on the aroma release in model studies on flavored sponge cakes. J. Agric. Food Chem. 2007, 55, 1418–1426. [Google Scholar] [CrossRef]
  47. Kotseridis, Y.; Baumes, R. Identification of impact odorants in Bordeaux red grape juice, in the commercial yeast used for its fermentation, and in the produced wine. J. Agric. Food Chem. 2000, 48, 400–406. [Google Scholar] [CrossRef] [PubMed]
  48. Mahajan, S.S.; Goddik, L.; Qian, M.C. Aroma Compounds in Sweet Whey Powder. J. Dairy Sci. 2004, 87, 4057–4063. [Google Scholar] [CrossRef]
  49. Flamini, G.; Cioni, P.L.; Morelli, I.; Maccioni, S.; Baldini, R. Phytochemical typologies in some populations of Myrtus communis L. on Caprione Promontory (East Liguria, Italy). Food Chem. 2004, 85, 599–604. [Google Scholar] [CrossRef]
  50. Varming, C.; Andersen, M.L.; Poll, L. Influence of thermal treatment on black currant (Ribes nigrum L. ) juice aroma. J. Agric. Food Chem. 2004, 52, 7628–7636. [Google Scholar] [CrossRef]
  51. Grujic-Jovanovic, S.; Skaltsa, H.D.; Marin, P.; Sokovic, M. Composition and antibacterial activity of the essential oil of six Stachys species from Serbia. Flavour Fragr. J. 2004, 19, 139–144. [Google Scholar] [CrossRef]
  52. Gauvin-Bialecki, A.; Marodon, C. Essential oil of Ayapana triplinervis from Reunion Island: A good natural source of thymohydroquinone dimethyl ether. Biochem. Syst. Ecol. 2009, 36, 853–858. [Google Scholar] [CrossRef]
  53. Shellie, R.; Marriott, P.; Zappia, G.; Mondello, L.; Dugo, G. Interactive use of linear retention indices on polar and apolar columns with an MS-Library for reliable characterization of Australian tea tree and other Melaleuca sp. Oils. J. Essent. Oil Res. 2003, 15, 305–312. [Google Scholar] [CrossRef]
  54. Ngassoum, M.B.; Yonkeu, S.; Jirovetz, L.; Buchbauer, G.; Schmaus, G.; Hammerschmidt, F.-J.H. Chemical composition of essential oils of Lantana camara leaves and flowers from Cameroon and Madagascar. Flavour Fragr. J. 1999, 14, 245–250. [Google Scholar] [CrossRef]
  55. Baser, K.H.C.; Ozek, G.; Ozek, T.; Duran, A. Composition of the essential oil of Centaurea huber-morathii Wagenitz isolated from seeds by microdistillation. Flavour Fragr. J. 2006, 21, 568–570. [Google Scholar] [CrossRef]
  56. Paniandy, J.-C.; Chane-Ming, J.; Pierbattesti, J.-C. Chemical Composition of the Essential Oil and Headspace Solid-Phase Microextraction of the Guava Fruit (Psidium guajava L.). J. Essent. Oil Res. 2000, 12, 153–158. [Google Scholar] [CrossRef]
  57. Cavalli, J.-F.; Tomi, F.; Bernardini, A.-F.; Casanova, J. Composition and chemical variability of the bark oil of Cedrelopsis grevei H. Baillon from Madagascar. Flavour Fragr. J. 2003, 18, 532–538. [Google Scholar] [CrossRef]
  58. Blazevic, I.; Mastelic, J. Free and bounded volatiles of rocket (Eruca sativa Mill.). Fravour Fragr. J. 2008, 23, 278–285. [Google Scholar] [CrossRef]
  59. Ferretti, G.; Maggi, F.; Tirillini, B. Essential oil composition of Hypericum richeri Vill. from Italy. Flavour Fragr. J. 2005, 20, 295–298. [Google Scholar] [CrossRef]
  60. Chen, C.-C.; Ho, C.-T. Gas chromatographic analysis of volatile components of ginger oil (Zingiber officinale Roscoe) extracted with liquid carbon dioxide. J. Agric. Food Chem. 1988, 36, 322–328. [Google Scholar] [CrossRef]
  61. Brat, P.; Rega, B.; Alter, P.; Reynes, M.; Brillouet, J.-M. Distribution of volatile compounds in the pulp, cloud, and serum of freshly squeezed orange juice. J. Agric. Food Chem. 2003, 51, 3442–3447. [Google Scholar] [CrossRef]
  62. Zheng, C.H.; Kim, K.H.; Kim, T.H.; Lee, H.J. Analysis and characterization of aroma-active compounds of Schizandra chinensis (omija) leaves. J. Sci. Food Agric. 2005, 85, 161–166. [Google Scholar] [CrossRef]
  63. Wu, S.; Zorn, H.; Krings, U.; Berger, R.G. Volatiles from submerged and surface-cultured beefsteak fungus, Fistulina hepatica. Flavour Fragr. J. 2007, 22, 53–60. [Google Scholar] [CrossRef]
  64. Karlsson, M.F.; Birgersson, G.; Prado, A.M.C.; Bosa, F.; Bengtsson, M.; Witzgall, P. Plant Odor Analysis of Potato: Response of Guatemalan Moth to Above- and Background Potato Volatiles. J. Agric. Food Chem. 2009, 57, 5903–5909. [Google Scholar] [CrossRef] [PubMed]
  65. Jerkovic, I.; Mastelic, J.; Milos, M.; Juteau, F.; Masotti, V.; Viano, J. Chemical variability of Artemisia vulgaris L. essential oils originated from the Mediterranean area of France and Croatia. Flavour Fragr. J. 2003, 18, 436–440. [Google Scholar] [CrossRef]
  66. Hachicha, S.F.; Skanji, T.; Barrek, S.; Ghrabi, Z.G.; Zarrouk, H. Composition of the essential oil of Teucrium ramosissimum Desf. (Lamiaceae) from Tunisia. Flavour Fragr. J. 2007, 22, 101–104. [Google Scholar] [CrossRef]
  67. Jirovetz, L.; Buchbauer, G.; Shafi, P.M.; Rosamma, M.K.; Geissler, M. Analysis of the composition and aroma of the essential leaf oil of Syzygium travancoricum from South India by GC-FID, GC-MS, and olfactometry. Seasonal changes of composition. Chromatographia 2001, 53, S372–S374. [Google Scholar] [CrossRef]
  68. Marques, F.A.; McElfresh, J.S.; Millar, J.G. Kováts retention indexes of monounsaturated C12, C14, and C16 alcohols, acetates and aldehydes commonly found in lepidopteran pheromone blends. J. Braz. Chem. Soc. 2000, 11, 592–599. [Google Scholar] [CrossRef]
  69. Paolini, J.; Tomi, P.; Bernardini, A.-F.; Bradesi, P.; Casanova, J.; Kaloustian, J. Detailed analysis of the essential oil from Cistus albidus L. by combination of GC/RI, GC/MS and 13C-NMR spectroscopy. Nat. Prod. Res. 2008, 22, 1270–1278. [Google Scholar] [CrossRef] [PubMed]
  70. Bendiabdellah, A.; El Amine Dib, M.; Djabou, N.; Allali, H.; Tabti, B.; Costa, J.; Myseli, A. Biological activities and volatile constituents of Daucus muricatus L. from Algeria. Chem. Cent. J. 2012, 6, 48. [Google Scholar] [CrossRef]
  71. Neves, A.; Rosa, S.; Goncalves, J.; Rufino, A.; Judas, F.; Salgueiro, L.; Lopes, M.C.; Cavaleiro, C.; Mendes, A.F. Screening of five essential oils for identification of potential inhibitors of IL-1-unduced Nf-kB activation and NO production in human chondrocytes: Characterization of the inhibitory activity of alpha-pinene. Planta Medica 2010, 76, 303–308. [Google Scholar] [CrossRef] [PubMed]
  72. Choi, H.-S. Character impact odorants of Citrus Hallabong [(C. unshiu Marcov × C. sinensis Osbeck) × C. reticulata Blanco] cold-pressed peel oil. J. Agric. Food Chem. 2003, 51, 2687–2692. [Google Scholar] [CrossRef]
  73. Ledauphin, J.; Basset, B.; Cohen, S.; Payot, T.; Barillier, D. Identification of trace volatile compounds in freshly distilled Calvados and Cognac: Carbonyl and sulphur compounds. J. Food Compos. Anal. 2006, 19, 28–40. [Google Scholar] [CrossRef]
  74. Pennarun, A.L.; Prost, C.; Demaimay, M. Identification and origin of the character-impact compounds of raw oyster Crassostrea gigas. J. Sci. Food Agric. 2002, 82, 1652–1660. [Google Scholar] [CrossRef]
  75. Vinogradov, B.A. Production, Composition, Properties and Application of Essential Oils. 2004. Available online: http://viness.narod.ru (accessed on 20 November 2024).
  76. Shiratsuchi, H.; Shimoda, M.; Imayoshi, K.; Noda, K.; Osajima, Y. Volatile flavor compounds in spray-dried skim milk powder. J. Agric. Food Chem. 1994, 42, 984–988. [Google Scholar] [CrossRef]
  77. Kirimer, N.; Tabanca, N.; Özek, T.; Tümen, G.; Baser, K.H.C. Essential oils of annual Sideritis species growing in Turkey. Pharm. Biol. 2000, 38, 106–111. [Google Scholar] [CrossRef] [PubMed]
  78. Condurso, C.; Verzera, A.; Romeo, V.; Ziino, M.; Trozzi, A.; Ragusa, S. The leaf volatile constituents of Isatis tinctoria by solid-phase microextraction and gas chromatography/mass spectrometry. Planta Medica 2006, 72, 924–928. [Google Scholar] [CrossRef] [PubMed]
  79. Radulovic, N.; Blagojevic, P.; Palic, R. Comparative study of the leaf volatiles of Arctostaphylos uva-ursi (L. ) Spreng. and Vaccinium vitis-idaea L. (Ericaceae). Molecules 2010, 15, 6168–6185. [Google Scholar]
  80. Dewick, P.M. Medicinal Natural Products. A Biosynthetic Approach, 3rd ed.; John Wiley & Sons Ltd.: Chichester, UK, 2009; ISBN 9780470741672. [Google Scholar]
  81. Røstelien, T.; Borg-Karlson, A.K.; Fäldt, J.; Jacobsson, U.; Mustaparta, H. The Plant Sesquiterpene Germacrene D Specifically Activates a Major Type of Antennal Receptor Neuron of the Tobacco Budworm Moth Heliothis virescens. Chem. Senses 2000, 25, 141. [Google Scholar] [CrossRef] [PubMed]
  82. Mozuraitis, R.; Stranden, M.; Ramirez, M.I.; Borg-Karlson, A.K.; Mustaparta, H. (-)-Germacrene D Increases Attraction and Oviposition by the Tobacco Budworm Moth Heliothis virescens. Chem. Senses 2002, 27, 505–509. [Google Scholar] [CrossRef] [PubMed]
  83. Stranden, M.; Liblikas, I.; Koenig, W.A.; Almaas, T.J.; Borg-Karlson, A.K.; Mustaparta, H. (-)-GermacreneD Receptor Neurones in Three Species of Heliothine Moths: Structure-activity Relationships. J. Comp. Physiol. A 2003, 189, 563–577. [Google Scholar] [CrossRef]
  84. Langenheim, J.H. Higher Plant Terpenoids: A Phytocentric Overview of Their Ecological Roles. J. Chem. Ecol. 1994, 20, 1223–1280. [Google Scholar] [CrossRef] [PubMed]
  85. Allenspach, M.; Steuer, C. α-Pinene: A Never-Ending Story. Phytochemistry 2021, 190, 112857. [Google Scholar] [CrossRef]
  86. Salehi, B.; Upadhyay, S.; Erdogan Orhan, I.; Kumar Jugran, A.; Jayaweera, S.L.D.; Dias, D.A.; Sharopov, F.; Taheri, Y.; Martins, N.; Baghalpour, N.; et al. Therapeutic Potential of α- and β-Pinene: A Miracle Gift of Nature. Biomolecules 2019, 9, 738. [Google Scholar] [CrossRef] [PubMed]
  87. Francomano, F.; Caruso, A.; Barbarossa, A.; Fazio, A.; La Torre, C.; Ceramella, J.; Mallamaci, R.; Saturnino, C.; Iacopetta, D.; Sinicropi, M.S. β-Caryophyllene: A Sesquiterpene with Countless Biological Properties. Appl. Sci. 2019, 9, 5420. [Google Scholar] [CrossRef]
  88. Scandiffio, R.; Geddo, F.; Cottone, E.; Querio, G.; Antoniotti, S.; Gallo, M.P.; Maffei, M.E.; Bovolin, P. Protective Effects of (E)-β-Caryophyllene (BCP) in Chronic Inflammation. Nutrients 2020, 12, 3273. [Google Scholar] [CrossRef] [PubMed]
  89. Fidyt, K.; Fiedorowicz, A.; Strządała, L.; Szumny, A. β-Caryophyllene and β-Caryophyllene Oxide—Natural Compounds of Anticancer and Analgesic Properties. Cancer Med. 2016, 5, 3007–3017. [Google Scholar] [CrossRef] [PubMed]
  90. do Nascimento, K.F.; Moreira, F.M.F.; Santos, J.A.; Kassuya, C.A.L.; Croda, J.H.R.; Cardoso, C.A.L.; Vieira, M.D.C.; Ruiz, A.L.T.G.; Foglio, M.A.; de Carvalho, J.E.; et al. Antioxidant, Anti-inflammatory, Antiproliferative and Antimycobacterial Activities of the Essential Oil of Psidium guineense Sw. and Spathulenol. J. Ethnopharmacol. 2018, 210, 351–358. [Google Scholar] [CrossRef]
  91. Van Den Dool, H.; Kratz, P.D. A Generalization of the Retention Index System Including Linear Temperature Programmed Gas—Liquid Partition Chromatography. J. Chromatogr. A 1963, 11, 463–471. [Google Scholar] [CrossRef] [PubMed]
  92. Gilardoni, G.; Matute, Y.; Ramírez, J. Chemical and Enantioselective Analysis of the Leaf Essential Oil from Piper coruscans Kunth (Piperaceae), a Costal and Amazonian Native Species of Ecuador. Plants 2020, 9, 791. [Google Scholar] [CrossRef] [PubMed]
  93. De Saint Laumer, J.Y.; Cicchetti, E.; Merle, P.; Egger, J.; Chaintreau, A. Quantification in Gas Chromatography: Prediction of Flame Ionization Detector Response Factors from Combustion Enthalpies and Molecular Structures. Anal. Chem. 2010, 82, 6457–6462. [Google Scholar] [CrossRef] [PubMed]
  94. Tissot, E.; Rochat, S.; Debonneville, C.; Chaintreau, A. Rapid GC-FID quantification technique without authentic samples using predicted response factors. Flavour Fragr. J. 2012, 27, 290–296. [Google Scholar] [CrossRef]
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Figure 1. Compared GC-MS profiles of G. reinaldii (blue) and G. pulchella (red) EOs from on a 5% phenyl-methylpolysiloxane stationary phase. The numbers refer to peak numbers in Table 1.
Figure 1. Compared GC-MS profiles of G. reinaldii (blue) and G. pulchella (red) EOs from on a 5% phenyl-methylpolysiloxane stationary phase. The numbers refer to peak numbers in Table 1.
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Figure 2. Compared GC-MS profiles of G. reinaldii (blue) and G. pulchella (red) EOs on a polyethylene glycol stationary phase. The numbers refer to peak numbers in Table 1.
Figure 2. Compared GC-MS profiles of G. reinaldii (blue) and G. pulchella (red) EOs on a polyethylene glycol stationary phase. The numbers refer to peak numbers in Table 1.
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Figure 3. Compared GC-MS profiles of G. reinaldii (blue) and G. pulchella (red) EOs on a 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin stationary phase.
Figure 3. Compared GC-MS profiles of G. reinaldii (blue) and G. pulchella (red) EOs on a 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin stationary phase.
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Figure 4. Compared GC-MS profiles of G. reinaldii (blue) and G. pulchella (red) EOs on a 2,3-diacethyl-6-tert-butyldimethylsilyl-β-cyclodextrin stationary phase.
Figure 4. Compared GC-MS profiles of G. reinaldii (blue) and G. pulchella (red) EOs on a 2,3-diacethyl-6-tert-butyldimethylsilyl-β-cyclodextrin stationary phase.
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Figure 5. Compared abundance of major compounds (≥3.0 in at least one oil) in the EOs of G. reinaldii (red) and G. pulchella (black). Abundances correspond to the mean values of the quantitative results with both columns.
Figure 5. Compared abundance of major compounds (≥3.0 in at least one oil) in the EOs of G. reinaldii (red) and G. pulchella (black). Abundances correspond to the mean values of the quantitative results with both columns.
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Figure 6. Compared enantiomeric composition of some chiral compounds in the EOs of G. reinaldii (red) and G. pulchella (black).
Figure 6. Compared enantiomeric composition of some chiral compounds in the EOs of G. reinaldii (red) and G. pulchella (black).
Plants 13 03543 g006
Plants 13 03543 g007
Figure 7. Major terpene constituents of G. reinaldii and G. pulchella EOs (≥3.0 in at least one oil, as a mean value on both columns). The numbers refer to Table 1: α-pinene (2), (E)-β-caryophyllene (51), germacrene D (62), spathulenol (79), and caryophyllene oxide (80).
Figure 7. Major terpene constituents of G. reinaldii and G. pulchella EOs (≥3.0 in at least one oil, as a mean value on both columns). The numbers refer to Table 1: α-pinene (2), (E)-β-caryophyllene (51), germacrene D (62), spathulenol (79), and caryophyllene oxide (80).
Plants 13 03543 g007
Table 1. Qualitative and quantitative compositions of G. reinaldii and G. pulchella EOs.
Table 1. Qualitative and quantitative compositions of G. reinaldii and G. pulchella EOs.
N°Compounds5% Phenyl-MethylpolysiloxanePolyethylene Glycol
LRIG. reinaldiiG. pulchellaLRIG. reinaldiiG. pulchellaLit.
Calc.Ref. [21]%σ%σCalc.Ref.%σ%σ
1heptanal9119010.30.10--118011800.40.08--[22]
2α-pinene93493214.23.813.70.771015101514.13.573.00.55[23]
3α-fenchene9509450.10.02--10531048trace---[24]
4thuja-2,4(10)-diene9559530.10.00--111611160.30.08--[25]
5sabinene9749690.30.080.10.0211131114trace-0.10.03[26]
6β-pinene9789740.20.052.00.46110111020.20.051.70.34[27]
7myrcene9929880.10.030.20.05115911590.10.030.20.04[28]
82-pentyl furan9949840.60.150.60.10122812290.50.080.20.10[29]
9n-decane100010000.20.10--10001000trace----
10α-phellandrene100810020.30.060.60.08115411530.30.090.20.04[23]
11n-octanal101210170.40.130.40.10129512950.20.04trace-[30]
12(2E,4E)-heptadienal102410050.50.080.10.02148214810.90.110.10.01[31]
13p-cymene102910220.30.160.70.14126012540.10.020.50.11[32]
14limonene103110240.10.05--118811890.10.01--[33]
15β-phellandrene103310250.80.20--119711970.60.17--[34]
16(E)-β-ocimene 105010440.10.03--12481246trace---[33]
17cis-linalool oxide (furanoid)107510670.20.020.10.0114611465trace-trace-[26]
18n-octanol108110630.20.03--155515550.20.02--[35]
19cis-vertocitral C10881076--0.10.011206---trace--
20linalool110610950.30.020.20.02154815470.30.020.40.26[36]
21n-nonanal111311003.00.591.00.09138613872.30.380.70.12[37]
22cis-β-terpineol113111400.10.02--159016390.10.01--[38]
23α-campholenal113511220.10.040.10.03147514720.20.05trace-[39]
24citronellal115011480.20.06---------
25verbenol115411400.20.04---------
26isomer of compound 29115911660.10.05--1653-0.30.03---
27ethyl benzoate116711690.10.03---------
28(2E)-nonen-1-al117111570.20.03--152315240.20.02--[40]
29p-mentha-1,5-dien-8-ol118211850.30.05--171817190.30.06--[41]
30terpinen-4-ol118711740.20.03trace-158915890.10.01trace-[42]
31n-dodecane120012000.10.010.10.1712001200trace-0.20.09
32γ-terpineol120411990.20.09--1709-trace----
33isomer of compound 291207-0.10.02--1771-trace----
34n-decanal121512010.40.050.10.02149114930.40.030.50.14[43]
35trans-piperitol121812070.10.05--173617380.10.04--
36pulegone 122812330.20.03---------
37exo-fenchyl acetate 12301229--0.10.0214571458--0.60.15[44]
38(2E)-decenal127212600.70.090.20.02163016300.60.080.40.04[36]
391-tridecene129212900.10.02--135113520.10.01--[45]
40(2E,4Z)-decadienal130612920.10.01--175317930.30.08--[46]
41p-vinyl guaiacol132413092.00.171.40.14218621872.20.150.80.35[47]
42(2E,4E)-decadienal133113150.20.040.40.02179417950.40.030.70.03[48]
43α-cubebene134713480.10.02--152115210.10.05--[49]
44α-ylangene 137613730.40.011.40.14147214720.30.021.40.19[23]
45β-bourbonene13841387--1.20.2814871491--0.80.05[26]
46(E)-β-damascenone138613830.20.040.20.04180218020.10.050.40.11[50]
47β-cubebene 13891387--trace-14691468--0.20.04[51]
48β-Elemene139113890.50.04--15971596s.p. 123---[52]
49n-tetradecane140014000.20.010.40.04140014000.30.030.10.02
50α-gurjunene140714090.30.02--15081507trace---[53]
51(E)-β-caryophyllene1422141713.61.427.00.771574157514.51.17.81.56[33]
52β-copaene143214300.10.000.20.02152115220.10.020.00.01[23]
53sesquisabinene145614570.10.02--16611648s.p. 65---[54]
54unidentified (MW = 204)14581452--1.80.221271---1.90.57-
55α-humulene145814521.10.07--164416441.10.11--[42]
56allo-aromadendrene146114580.10.010.10.02165516550.20.020.10.03[55]
57trans-cadina-1(6),4-diene 14651475--0.10.021505---trace--
589-epi-(E)-caryophyllene146614640.20.01--156815720.10.01--[56]
594,5-di-epi-aristolochene147314710.20.020.20.1416571665s.p. 57-0.10.03[57]
60β-chamigrene147614760.20.04---------
61γ-gurjunene14781475--0.40.09-------
62germacrene D1485148022.32.869.51.021685168522.12.8212.92.10[42]
63(E)-β-ionone 14881487--1.30.1818831889--0.80.04[58]
64cis-β-guaiene 149114920.40.12--166916670.30.03--[59]
65widdra-2,4(14)-diene14911481--0.40.121554---0.60.10-
66α-zingiberene 14941493--1.20.1216941696--2.40.57[60]
67γ-amorphene149614950.10.02---------
68bicyclogermacrene149915002.60.341.00.19170917072.30.321.20.25[61]
69α-muurolene1503150017051700[62]
70(E,E)-α-farnesene150815050.40.050.40.03174317430.30.060.20.03[33]
71β-bisabolene151115050.30.03--17131710s.p. 69---[49]
72germacrene A 15111508--0.70.33-------
73γ-cadinene151815130.30.030.20.11173817380.40.050.10.04[42]
74n-tridecanal 151915090.30.04--180618050.20.04--[43]
75δ-cadinene152215221.40.151.40.18173817371.50.171.10.25[26]
76trans-cadina-1,4-diene153815330.10.02---------
77(E)-nerolidol156715610.20.02--203620330.20.01--[63]
78germacrene D-4-ol158415741.40.17--204220440.10.01--[64]
79spathulenol158515773.60.66211021061.30.263.20.19[26]
80caryophyllene oxide158915823.00.447.21.29194819443.10.326.70.75[65]
81n-hexadecane160016000.30.030.50.04160016000.30.020.20.05
82ledol161216020.20.03--200020070.20.02--[66]
83unidentified (MW = 222)1613---0.80.022181---0.90.05-
84β-oplopenone161616070.20.01--203920510.10.02--[66]
85humulene epoxide II16191608--1.30.0419641972--0.80.12[67]
86n-tetradecanal162116110.40.13--19111910trace---[68]
87allo-aromadendrene epoxide162716390.40.030.40.02209320950.20.020.20.05[69]
88unidentified (MW = 220)1628---0.70.071940---0.80.07-
89junenol163016180.20.03---------
901-epi-Cubenol163616270.30.040.40.02205220460.30.06--[70]
91cis-cadin-4-en-7-ol164416350.20.03--2090-0.20.04---
92epi-α-cadinol165216380.50.240.70.06215321540.80.130.60.09[71]
93epi-α-muurolol 165416400.40.300.60.05217021710.70.110.50.20[59]
94α-muurolol (=torreyol) 16581645--0.70.3721502150--0.50.20[67]
957-epi-α-eudesmol165716620.30.04---------
96unidentified (MW = 220)1660---0.70.052243---0.50.12-
97α-cadinol166616521.60.222.10.13221122112.00.273.00.29[72]
98α-amyl cinnamyl alcohol 16721682--0.80.152010---0.20.02-
99ar-turmerone167316680.10.02---------
100n-heptadecane170017000.30.030.60.07----0.20.03-
101amorpha-4,9-dien-2-ol 170317000.70.071.20.242343-0.60.031.20.90-
102n-pentadecanal172517240.70.061.00.05203120240.70.190.40.09[73]
1031-octadecene17951789--0.50.0218311823--0.20.02[74]
104n-octadecane 18001800--0.50.0618001800--0.20.01-
105cyclopentadecanolide183118320.10.02--225522550.10.01--[75]
1061-nonadecene18951895--0.70.0319341938--0.80.08[76]
107n-nonadecane190019000.10.050.80.05190019000.10.010.80.06-
108(5E,9E)-farnesyl acetone192119130.10.06--236823640.20.03--[77]
1091-eicosene199619870.20.151.40.10205720470.10.011.30.12[78]
110n-eicosane200020000.10.100.60.0520002000trace-2.20.10-
111unidentified (MW = 270)2095---2.40.242136---2.30.26-
112n-heneicosane210021000.30.103.60.59210021000.30.063.50.30
1131-docosene219621890.10.034.00.462234-0.20.084.30.95-
114n-docosane 22002200--1.30.2122002200--1.60.18
1151-tricosene22972289--1.30.292235---1.60.21-
116n-tricosane230023000.50.174.90.94230023000.40.014.91.46
1171-teracosene2397---1.40.322439---1.80.20-
118n-tetracosane240024000.10.010.50.12240024000.20.060.60.15
1191-pentacosene24972486--0.40.092547---0.60.13-
120n-pentacosane 25002500--1.20.4125002500--0.70.56
1211-hexacosene25972596 *0.30.04--2655-0.30.010.60.15-
122n-hexacosane260026000.20.02trace-260026000.20.020.60.20
123n-tetracosanal263726500.10.01--2778-0.10.04---
monoterpenes 16.4 7.4 15.8 5.7
oxygenated monoterpenoids 2.3 0.7 1.4 1.0
sesquiterpenes 44.8 27.5 43.4 31.3
oxygenated sesquiterpenoids 9.9 20.4 10.0 18.9
others 13.0 34.2 12.2 34.3
total 86.3 90.2 82.8 91.2
LRI—Linear Retention Index; Calc.—Calculated; Ref.—Reference; Lit.—Literature; %—Percent amount by weight; σ— Standard deviation; MW—Molecular Weight; * Reference [79].
Table 2. Enantioselective analyses of G. reinaldii and G. pulchella EOs on 2,3-diacetyl-6-tert-butyldimethylsilyl-β-cyclodextrin and 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin stationary phases.
Table 2. Enantioselective analyses of G. reinaldii and G. pulchella EOs on 2,3-diacetyl-6-tert-butyldimethylsilyl-β-cyclodextrin and 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin stationary phases.
EnantiomersLRIG. reinaldiiG. pulchella
Compositionee (%)Compositionee (%)
(1S,5S)-(−)-α-pinene926 a100.0100.012.0 *76.0
(1R,5R)-(+)-α-pinene928 a-88.0 *
(1R,5R)-(+)-β-pinene949 b-100.096.993.8
(1S,5S)-(−)-β-pinene959 b100.03.1
(1R,5R)-(+)-sabinene1008 a-100.066.733.4
(1S,5S)-(−)-sabinene1014 a100.033.3
(R)-(−)-α-phellandrene1019 b100.0100.0100.0100.0
(S)-(+)-α-phellandrene1024 b--
(R)-(−)-β-phellandrene1051 b100.0100.0--
(S)-(+)-β-phellandrene1058 b--
(R)-(−)-cis-linalool oxide (furanoid)1209 a40.718.632.435.2
(S)-(+)-cis-linalool oxide (furanoid)1197 a59.367.6
(R)-(−)-linalool1300 a51.53.062.725.4
(S)-(+)-linalool1301 a48.537.3
(R)-(−)-terpinen-4-ol1338 a65.130.2--
(S)-(+)-terpinen-4-ol1379 a34.9-
(R)-(+)-germacrene D1466 b98.897.698.496.8
(S)-(−)-germacrene D1471 b1.21.6
a 2,3-diacetyl-6-tert-butyldimethylsilyl-β-cyclodextrin; b 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin; * partially resolved.
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Maldonado, Y.E.; Rodríguez, M.d.C.; Calvopiña, K.; Malagón, O.; Cumbicus, N.; Gilardoni, G. Gynoxys reinaldii Cuatrec. and Gynoxys pulchella (Kunth) Cass.: Chemical and Enantioselective Analyses of Two Unprecedented Essential Oils from Ecuador. Plants 2024, 13, 3543. https://doi.org/10.3390/plants13243543

AMA Style

Maldonado YE, Rodríguez MdC, Calvopiña K, Malagón O, Cumbicus N, Gilardoni G. Gynoxys reinaldii Cuatrec. and Gynoxys pulchella (Kunth) Cass.: Chemical and Enantioselective Analyses of Two Unprecedented Essential Oils from Ecuador. Plants. 2024; 13(24):3543. https://doi.org/10.3390/plants13243543

Chicago/Turabian Style

Maldonado, Yessenia E., María del Carmen Rodríguez, Karyna Calvopiña, Omar Malagón, Nixon Cumbicus, and Gianluca Gilardoni. 2024. "Gynoxys reinaldii Cuatrec. and Gynoxys pulchella (Kunth) Cass.: Chemical and Enantioselective Analyses of Two Unprecedented Essential Oils from Ecuador" Plants 13, no. 24: 3543. https://doi.org/10.3390/plants13243543

APA Style

Maldonado, Y. E., Rodríguez, M. d. C., Calvopiña, K., Malagón, O., Cumbicus, N., & Gilardoni, G. (2024). Gynoxys reinaldii Cuatrec. and Gynoxys pulchella (Kunth) Cass.: Chemical and Enantioselective Analyses of Two Unprecedented Essential Oils from Ecuador. Plants, 13(24), 3543. https://doi.org/10.3390/plants13243543

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