Pharmacology and Phytochemistry of Ecuadorian Medicinal Plants: An Update and Perspectives

A new leaf essential oil from the Andean species Gynoxys szyszylowiczii Hieron. of southern Ecuador: chemical and enantioselective analyses

The essential oil obtained from the dry leaves of Gynoxys szyszylowiczii Hieron. was described in this study for the first time. The chemical analysis, conducted on two stationary phases of different polarity, permitted to identify sixty-four compounds, that were quantified with at least one column. The main components, on a non-polar and polar stationary phase respectively, were germacrene D (21.6-19.2%), α-pinene (4.4-4.9%), n-tricosane (4.3% on both columns), (E)-β-caryophyllene (3.3-4.3%), 1-docosene (3.2-2.8%), α-cadinol (2.8-3.1%), and cis-β-guaiene (2.6-3.0%). This investigation was complemented by the enantioselective analysis of some major chiral compounds, carried out on two chiral selectors based on β-cyclodextrines. As a result, (S)-( +)-α-phellandrene, (S)-( +)-β-phellandrene, and (1S,2R,6R,7R,8R)-( +)-α-copaene appeared enantiomerically pure, whereas α-pinene, β-pinene, terpinen-4-ol, and germacrene D were detected as scalemic mixtures. Finally, linalool was practically racemic. The distillation yield, analytically calculated by weight of dry plant material, was 0.03%.

Bioactive Compound Profiling and Antioxidant Activity of Phytelephas tenuicaulis and Other Amazonian Fruits

The Amazon region is home to many plant species, many of which have not been studied. The objective was to evaluate the physicochemical properties, bioactive compounds, and antioxidant activity of Phytelephas tenuicalis (tintiuk), Grias neuberthii (apai), Euterpe oleracea (acai), and Mauritia flexuosa (brown moriche). Physicochemical analyses were carried out on fresh fruit from local markets. Bioactive compounds (carotenoids, phenolics, vitamin C, and organic acids) were quantified in the freeze-dried pulp by rapid-resolution liquid chromatography (RRLC), and antioxidant activity was determined by ABTS and DPPH assays. The results showed high soluble solids (10.7 °Brix) and ascorbic acid (67.3 mg/100 g DW) in tintiuk; β-carotene (63.4 mg/100 g DW) and malic acid (19.6 g/100 g DW) in brown moriche; quercetin (944.2 mg/100 g DW) and antioxidant activity by ABTS (6.7 mmol ET/100 g DW) in apai; and citric acid (2.1 g/100 g DW) in acai. These results indicate interesting bioactive properties that could increase the consumption of these fruits nationally and internationally, benefiting local farmers and stimulating the development of new products in functional food, medicine, and cosmetics.

New Essential Oils from Ecuadorian Gynoxys cuicochensis Cuatrec. and Gynoxys sancti-antonii Cuatrec. Chemical Compositions and Enantioselective Analyses

The present study belonged to an unfunded project, dealing on the systematic description of unprecedented essential oils (EOs), distilled from 12 species of genus Gynoxys Cuatrec. In this very case, the aim was the first chemical and enantiomeric analyses of two volatile fractions, obtained from the leaves of Gynoxys cuicochensis Cuatrec. and Gynoxys sancti-antonii Cuatrec. These EOs were analyzed by GC-MS (qualitatively) and GC-FID (quantitatively), detecting 89 and 60 components from G. cuicochensis and G. sancti-antonii, respectively. Major components for G. cuicochensis EO, on a nonpolar and polar stationary phase, were α-pinene (29.4-29.6%), p-vinylguaiacol (3.3-3.6%), and germacrene D (20.8-19.9%). In G. sancti-antonii EO, the main compounds were α-pinene (3.0-2.9%), β-pinene (12.9-12.1%), γ-curcumene (19.7-18.3%), germacrene D (9.0% on the polar phase), ar-curcumene (5.3% on the polar phase), δ-cadinene (4.1-4.6%), α-muurolol (3.3-2.4%), α-cadinol (3.0% on both columns), and an undetermined compound, of molecular weight 220. In addition to chemical composition, the enantioselective analysis of the main chiral compounds was carried out on two different chiral selectors. In G. cuicochensis EO, (1R,5R)-(+)-α-pinene, (S)-(+)-β-phellandrene, (R)-(-)-piperitone, and (S)-(-)-germacrene D were enantiomerically pure, whereas β-pinene, sabinene, α-phellandrene, limonene, linalool, and terpinen-4-ol were observed as scalemic mixtures. On the other hand, in G. sancti-antonii EO, the pure enantiomers were (1S,5S)-(-)-α-pinene, (1R,5R)-(+)-sabinene, (R)-(-)-β-phellandrene, (S)-(-)-limonene, (1S,2R,6R,7R,8R)-(+)-α-copaene, (R)-(-)-terpinen-4-ol, and (S)-(-)-germacrene D, whereas β-pinene, linalool, and α-terpineol were present as scalemic mixtures. The principal component analysis demonstrated that G. cuicochensis volatile fraction was quite similar to many of the other EOs of the same genus, whereas G. sancti-antonii produced the most dissimilar EO. Furthermore, the enantioselective analyses showed the usual variable enantiomeric distribution, with a greater presence of enantiomerically pure compounds in G. sancti-antonii EO.

Chemical and Enantioselective Analyses of an Unprecedented Essential Oil from Ecuadorian Aiouea montana: A Natural Source of S-Methyl-O-2-phenylethyl Carbonothioate

Fresh and dry leaves of Aiouea montana (Sw.) R. Rohde (Lauraceae) produced, in a quite high yield (0.88% and 1.60%, respectively), an unpleasantly smelling essential oil. The chemical composition was described in this study for the first time, detecting and quantifying 48 compounds. Major components of fresh and dry leaf essential oils were α-pinene (6.7-10.3%), β-pinene (2.8-3.8%), α-phellandrene (12.6-14.5%), α-copaene (3.1-15.7%), δ-cadinene (0.9-3.3%), and S-methyl-O-2-phenylethyl carbonothioate (58.5-33.3%). The dominant compound was already known in the literature by synthesis; however, it was unprecedented so far in nature. The carbonothioate was identified after purification and structure elucidation, by means of mass spectrometry, NMR spectroscopy, and FTIR spectrophotometry. The spectral results were identical to all data reported in the literature for the same molecule. Furthermore, the enantioselective analysis of the essential oil was conducted on a β-cyclodextrin-based stationary phase. Two chiral constituents, (+)-β-phellandrene and (1R,2S,6S,7S,8S)-(-)-α-copaene, were enantiomerically pure, whereas α-thujene, camphene, β-pinene, α-phellandrene, limonene, linalool, and germacrene D were scalemic mixtures. The different chemical and enantiomeric compositions suggested that enzymatic transformations could occur while drying.

Exploring Southern Ecuador's Traditional Medicine: Biological Screening of Plant Extracts and Metabolites

Ecuador stands as a nation inheriting a profound ancestral legacy in the utilization of medicinal plants, reflective of the rich biodiversity embraced by various ethnic groups. Despite this heritage, many of these therapeutic resources remain insufficiently explored concerning their toxicity and potential pharmacological effects. This study focused on a comprehensive evaluation of cytotoxicity and the potential subcellular targets within various extracts and nine isolated metabolites from carefully selected medicinal plants. Assessing their impact on the breast cancer cell line (MCF7), we subsequently examined the most active fractions for effects on the cell cycle, microtubule network, centrosome duplication, γH2AX foci, and E-cadherin. The investigated crude extracts and isolated compounds from Ecuadorian medicinal plants demonstrated cytotoxic effects, influencing diverse cellular pathways. These findings lend credence to the traditional uses of Ecuadorian medicinal plants, which have served diverse therapeutic purposes. Moreover, they beckon the exploration of the specific chemicals, whether in isolation or combination, responsible for these observed activities.

Antibacterial activity of plant extracts against Streptococcus equi subsp. zooepidemicus isolates from guinea pigs with lymphadenitis in Ecuador

Lymphadenitis is a commonly occurring and contagious disease in guinea pigs caused by different pathogens, including Streptococcus sp., Staphylococcus sp., and Corynebacterium sp. This study aimed to characterize the bacteria isolated from pus extracted from abscessed mandibular lymph nodes of diseased guinea pigs in Ecuador in 2019 and evaluate the in vitro antibacterial activity of the total extracts of three plant species. Isolates were recovered from three diseased guinea pigs with Lymphadenitis on a farm in Imbabura, Ecuador province. The bacteria were characterized through microbiological, biochemical, and molecular tests as Streptococcus equi subsp. zooepidemicus. Furthermore, the susceptibility of S. equi subsp. zooepidemicus to three plant extracts belonging to the Asteraceae family, Acmella ciliata, Bidens andicola, and Gazania splendens collected in Ecuador, were assessed in vitro by the microdilution method. Our data indicate that all the evaluated extracts showed activity, with a Minimum Inhibitory Concentration (MIC) of 22.50 mg/mL for Acmella ciliata, 11.25 mg/mL for Bidens andicola, and 5.60 mg/mL for Gazania splendens. Bidens andicola extract showed the highest efficacy with a % inhibition of 63.90 at the highest tested concentration (45 mg/mL). This is the first report on the bioactivity of these plant species against S. equi subsp. zooepidemicus.

Phytochemistry, Bioactivity, and Ethnopharmacology of the Genus Lepechinia Willd. (Lamiaceae): A Review

The genus Lepechinia (Lamiaceae) involves several aromatic shrubs that are distributed only in the American continent, inhabiting mountain areas, mainly in the Andean region of South America. Based on the PRISMA approach, we selected and critically analyzed 48 research articles. From a phytochemical point of view, most of the secondary metabolites reported in Lepechinia spp. are terpenes and terpenoids, with a few exceptions comprising flavonoids and other shikimic acid derivatives. On the one hand, sesquiterpenoids of the guajane, aromadendrane, eudesmane, and cadinane groups are characteristic of essential oils, together with (E)-β-caryophyllene as the main representative of its chemical family. On the other hand, abietane diterpenoids are the prevalent compounds described in non-volatile fractions. Many biological activities and traditional medical uses have been reported for both pure metabolites and complex mixtures (e.g., essential oils). Regarding ethno-medical uses, the treatment of muscle pain, headache, toothache, diabetes mellitus, uterine tumors, uterine infections, and diarrhea has been reported. Concerning their verified biological activities, insecticidal, antifungal, antioxidant, and anticholinesterase properties have been described. Furthermore, some data concerning anti-herpetic activity have been reported.

Extraction of Bioactive Compounds from Prestonia mollis Leaves and Their Impregnation into Polylactic Acid Using High-Pressure Technologies: Potential for Biomedical Application

Enhanced solvent extraction (ESE) and pressurized liquid extraction (PLE) have been used for the first time to obtain antioxidant compounds from Prestonia mollis leaves. The effects of pressure (100-250 bar), temperature (55-75 °C) and the composition of the extraction solvent (ethanol, water and hydroalcoholic mixtures) were evaluated according to multilevel factorial designs. PLE provided the largest extraction yields compared to ESE, as well as a greater impact of the operating conditions studied. The highest total phenolic content was obtained when using a hydroalcoholic mixture (CO2/ethanol/water 50/25/25) through ESE at 100 bar and 75 °C. The antioxidant capacity of this extract is related to higher concentration levels of the identified flavonoids: Quercetin 3-O-xylosyl-rutinoside, Kaempferol 3-(2G-apiosylrobinobioside) and Kaempferol 4'-glucoside 7-rhamnoside. This extract was tested for the supercritical impregnation of polylactic acid (PLA), which is a polymer widely used in the biomedical industry. The influence of pressure (100-400 bar), temperature (35-55 °C), amount of extract (3-6 mL) and impregnation time (1-2 h) have been evaluated. The best results were obtained by impregnating 3 mL of extract at 100 bar and 55 °C for 2 h, achieving 10% inhibition with DPPH methods. The extract presented a potentially suitable impregnation of PLA for biomedical applications.

A new essential oil from the native Ecuadorian species Steiractinia sodiroi (Hieron.) S.F. Blake (Asteraceae): chemical and enantioselective analyses

In the present study, the essential oil from dry leaves of Steiractinia sodiroi (Hieron.) S.F. Blake is described for the first time. The plant material, collected in the Province of Loja (Ecuador), was analytically steam-distilled in a Marcusson-type apparatus, affording an essential oil with a 0.2 ± 0.12% yield. The volatile fraction was submitted to GC-MS and GC-FID analyses, on two stationary phases of different polarity. A total of sixty-seven compounds, corresponding to 95.6-91.2% by weight of the whole oil mass, on the two columns respectively, were detected and quantified with at least one column. The quantification was carried out calculating the relative response factors of each constituent according to their combustion enthalpy. The major components were limonene (25.6-24.9%), sabinene (11.7-12.4%), germacrene D (7.7-7.0%), α-pinene (7.8-6.9%), δ-cadinene (7.3-7.0%), (E)-β-caryophyllene (4.8-4.5%), and bicyclogermacrene (3.6-3.0%). The chemical composition was complemented with the enantioselective analysis of some major chiral compounds, conducted by means of two β-cyclodextrin-based capillary columns. Three constituents, (S)-(+)-α-phellandrene, (R)-(-)-1-octen-3-ol, and (S)-(-)-limonene were enantiomerically pure, whereas (1R,5R)-(+)-β-pinene, (1S,5S)-(-)-sabinene, (R)-(-)-terpinen-4-ol, (R)-(+)-α-terpineol, and (R)-(+)-germacrene D presented an enantiomeric excess. Finally, α-pinene was present as a racemic mixture.

A New Essential Oil from the Native Andean Species Nectandra laurel Klotzsch ex Nees of Southern Ecuador: Chemical and Enantioselective Analyses

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.

A Validated HPLC-UV-ESI-IT-MS Method for the Quantification of Carnosol in Lepechinia mutica, a Medicinal Plant Endemic to Ecuador

The diphenolic diterpene carnosol was isolated from several species of the family Lamiaceae, including Lepechinia mutica, a medicinal plant endemic to Ecuador. The compound has exhibited high antioxidant, anti-inflammatory, antimicrobial, neuroprotective, and antifungal properties, as well as promising cytotoxicity against prostate, breast, skin, leukemia, and human colon cancer cell lines. In this paper, we developed and validated a simple, accurate, and reliable analytical HPLC-UV-ESI-IT-MS method, carried out on a C18 column, which is potentially suitable to quantify carnosol in plant extracts. The procedure complied with the established ICH validation parameters of analytical range (linearity in the range of 0.19-5.64 μg/g dried leaves; REAVERGE = 4.9%; R2 = 0.99907), analysis repeatability (RSD = 2.8-3.6%), intermediate precision (RSD = 1.9-3.6%), accuracy (estimated as % carnosol recovery in the range of 81 to 108%), and robustness. Finally, the LOD (0.04 µg/mg) and LOQ (0.19 μg/mg) values of carnosol/dried leaves were determined. Using this validated method, the content of carnosol in L. mutica was estimated to be 0.81 ± 0.04 mg/g of dried leaves (0.081%).

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

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.

Constituents and Selective BuChE Inhibitory Activity of the Essential Oil from Hypericum aciculare Kunth

A potential source of new inhibitors of cholinesterase enzymes are certain compounds of natural plant origin; therefore, in the study described herein we have determined the chemical composition and the acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities of the essential oil (EO) steam distilled from aerial parts of Hypericum aciculare, which was collected in southern Ecuador. The oil qualitative and quantitative composition was determined by GC-FID and GC-MS using a non-polar and a polar chromatographic column. A total of fifty-three constituents were identified, that accounted for about 98% of the EO content. The hydrocarbon n-nonane (16.4-28.7%) and the aldehyde n-decanal (20.7-23.1%) were the predominant oil constituents. In addition, the EO showed significant inhibition of BuChE (IC₅₀ = 28.3 ± 2.7 μg/mL) and moderate activity towards AChE (IC₅₀ = 82.1 ± 12.1 µg/mL). Thus, the EO from H. aciculare aerial parts is an interesting candidate to investigate the mechanism of selective ChE inhibition by the two ChE enzymes with the aim to discover potential targets to control the progression of the Alzheimer's disease (AD).

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

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.

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

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

Chemical Composition, Antimicrobial and Antioxidant Bioautography Activity of Essential Oil from Leaves of Amazon Plant Clinopodium brownei (Sw.)

The Amazonian region of Ecuador has an extremely rich vegetal biodiversity, and its inhabitants have proven to have a millennial ancestral knowledge of the therapeutic and medicinal use of these resources. This work aimed to evaluate the chemical composition and biological activity of the essential oil obtained from the medicinal plant Clinopodium brownei (Sw.) Kuntze, which is widely spread in tropical and subtropical America. This species is traditionally used for treating respiratory and digestive diseases and is also known for its analgesic properties. Most of the molecules detected on a non-polar column were ethyl cinnamate 21.4%, pulegone 20.76%, methyl cinnamate 16.68%, caryophyllene 8.17%, β-selinene 7.92% and menthone 7.51%, while those detected on a polar column were: pulegone 29.90%, ethyl cinnamate 18.75%, methyl cinnamate 13.82%, caryophyllene 10.0% and menthone 8.04%. The antioxidant activity by the assays, DPPH (2.2-diphenyl-1-picrylhydrazyl) and ABTS (2.2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)), shows the following values of 50% inhibition of oxidation, IC50 DPPH 1.77 mg/mL, IC50 ABTS 0.06 mg/mL, which, compared to the essential oil of Thymus vulgaris (natural positive control), turn out to be less active. Bioautography indicates that the molecules responsible for the antioxidant activity are derived from cinnamic acid: ethyl cinnamate and methyl cinnamate, and caryophyllene. The antimicrobial activity on the nine microorganisms evaluated shows bacterial growth inhibitory concentrations ranging from 13.6 mg/mL for Staphylococcus epidermidis ATCC 14990 to 3.1 mg/mL for Candida albicans ATCC 10231; the results are lower than those of the positive control. Bioautography assigns antimicrobial activity to caryophyllene. The results indicate a very interesting activity of the essential oil and several of its molecules, validating the traditional use and the importance of this medicinal plant from Ecuador.

Essential Oil and Non-Volatile Metabolites from Kaunia longipetiolata (Sch.Bip. ex Rusby) R. M. King and H. Rob., an Andean Plant Native to Southern Ecuador

Kaunia longipetiolata (Sch.Bip. ex Rusby) R. M. King and H. Rob. (Asteraceae) is a plant native to southern Ecuador. The dry leaves afforded, by steam distillation, an essential oil that was qualitatively and quantitatively analyzed by GC-MS and GC-FID, respectively, on two orthogonal columns of different polarity. Sesquiterpenes predominated in the volatile fraction, among which α-zingiberene (19.7-19.1%), ar-curcumene (17.3-18.1%), caryophyllene oxide (5.1-5.3%), (Z)-β-caryophyllene (3.0-3.1%), (2Z,6Z)-farnesal (2.6-3.6%), and spathulenol (2.0-2.1%) were the major components. In addition to the identified compounds, two main unidentified constituents (possibly oxygenated sesquiterpenes) with probable molecular masses of 292 and 230, respectively, were detected. They constituted about 5% and 8% (w/w), respectively, of the whole essential oil. The oil chemical composition was complemented with the enantioselective analysis of ten chiral components. Four scalemic mixtures and six enantiomerically pure terpenes were identified. An enantiomeric excess (ee) was determined for (1R,5R)-(+)-β-pinene (65.0%), (R)-(-)-α-phellandrene (94.6%), (S)-(+)-linalool (15.0%), and (R)-(-)-terpinen-4-ol (33.8%). On the other hand, (1R,5R)-(+)-α-pinene, (1R,5R)-(+)-sabinene, (S)-(-)-limonene, (S)-(+)-β-phellandrene, (1R,2S,6S,7S,8S)-(-)-α-copaene, and (R)-(+)-germacrene D were enantiomerically pure. Finally, the non-volatile fraction obtained by extraction of the leaves with MeOH was investigated. Eight known compounds were isolated by liquid column chromatographic separations. Their structures were determined by NMR spectroscopy as dehydroleucodine, kauniolide, (3S,3aR,4aR,6aS,9aS,9bR)-3-hydroxy-1,4a-dimethyl-7-methylene-5,6,6a,7,9a,9b-hexahydro-3H-oxireno[2',3':8,8a]azuleno[4,5-b]furan-8(4aH)-one, novanin, bisabola-1,10-diene-3,4-trans-diol, (R)-2-(2-(acetoxymethyl)oxiran-2-yl)-5-methylphenyl isobutyrate, eupalitin-3-O-glucoside, and 3,5-di-O-caffeoylquinic acid. Literature data about the identified metabolites indicate that K. longipetiolata is a rich source of biologically active natural products.

Constituents, Enantiomeric Content, and ChE Inhibitory Activity of the Essential Oil from Hypericum laricifolium Juss. Aerial Parts Collected in Ecuador

The physical properties, chemical composition, enantiomer distribution, and cholinesterase (ChE) inhibitory activity were determined for a steam-distilled essential oil (EO), with a yield of 0.15 ± 0.05 % (w/w), from H. laricifolium aerial parts, collected in southern Ecuador. The oil qualitative and quantitative analyses were performed by GC-EIMS and GC-FID techniques, using two capillary columns containing a non-polar 5%-phenyl-methylpolysiloxane and a polar polyethylene glycol stationary phase, respectively. The main constituents (>10%) detected on the two columns were, respectively, limonene (24.29, 23.16%), (E)-β-ocimene (21.89, 27.15%), and (Z)-β-ocimene (12.88, 16.03%). The EO enantioselective analysis was carried out using a column based on 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin. Two mixtures of chiral monoterpenes were detected containing (1R,5R)-(+)-α-pinene (ee = 83.68%), and (S)-(-)-limonene (ee = 88.30%) as the major enantiomers. This finding led to some hypotheses about the existence in the plant of two enantioselective biosynthetic pathways. Finally, the EO exhibited selective inhibitory effects in vitro against butyrylcholinesterase (BuChE) (IC50 = 36.80 ± 2.40 µg/mL), which were about three times greater than against acetylcholinesterase (IC50 = 106.10 ± 20.20). Thus, the EO from Ecuadorian H. laricifolium is an interesting candidate for investigating the mechanism of the selective inhibition of BuChE and for discovering novel drugs to manage the progression of Alzheimer’s disease.

Poorly Investigated Ecuadorian Medicinal Plants

Ecuador has, in proportion of its size, one of the richest floras of Latin America and the world; the country also has an immense cultural heritage due to the presence of different ethnic groups that have implemented the use of many wild and cultivated plants, mainly as medicinal remedies. In a recent publication, we have summarized the results of research activities recently carried out on about 120 plants native to Ecuador, which includes the structures of non-volatile isolated compounds, as well as the chemical composition of essential oils (EOs) and the in vitro tested biological activity data. For the sake of completeness, we have collected in this paper the main information obtained from recent ethnobotanical investigations on other important Ecuadorian medicinal plants for which phytochemical, pharmacological, and toxicological studies are, however, still largely lacking. Thus, one of the objectives of this paper is to preserve the traditional knowledge of Ecuadorian Indigenous communities which, being transmitted orally, is in danger of becoming lost. Moreover, it is our intention to stimulate more extensive studies on the rich medicinal flora of the country, which can provide economic and social benefits, especially to the people who traditionally cultivate or collect the plants.

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: α-phellandrene (16.1-17.2%), α-pinene (14.0-15.0%), germacrene D (13.3-14.8%), trans-myrtanol acetate (8.80%), δ-cadinene (4.2-4.6%), β-phellandrene (3.3-2.8%), (E)-β-caryophyllene (3.1-2.0%), o-cymene (2.4%), α-cadinol (2.3-2.6%), and α-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 β-cyclodextrin-based enantioselective column (2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin). A total of six chiral metabolites were analysed and the respective enantiomeric excess calculated as follows: (1S,5S)-(-)-α-pinene (98.2%), (1S,5S)-(-)-β-pinene (11.9%), (1R,5R)-(+)-sabinene (14.0%), (R)-(-)-α-phellandrene (100.0%), (R)-(-)-β-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.

Acaricidal Efficacy of Plants from Ecuador, Ambrosia peruviana (Asteraceae) and Lepechinia mutica (Lamiaceae) against Larvae and Engorged Adult Females of the Common Cattle Tick, Rhipicephalus microplus

Control measures against common cattle tick Rhipicephalus microplus are of the upmost importance because of considerable, deleterious impact on a farm’s economy. Due to resistance phenomena to synthetic acaricides being a constraint in affected farms, the search for plant derivatives as acaricides has increased dramatically in recent years. In this work, essential oils obtained from two Ecuadorian plants, Ambrosia peruviana and Lepechinia mutica (EO_Ap, EO_Lm), traditionally used as insecticides in indigenous communities, were studied on larvae and engorged females at the parasitic stages of R. microplus. Larvae and females were treated with five (0.0625, 0.125, 0.25, 0.50 and 1%) and six concentrations (0.125, 0.25, 0.50, 1, 2 and 4%), respectively, of each EOs_Ap/Lm. A 98–99% larval mortality was achieved with 0.5% of both EOs_Ap/Lm. EO_Ap inhibited oviposition and egg hatching up to 82% and 80%, respectively, and had an overall efficacy of 93.12%. Efficacy of EO_Lm was 72.84%, due to the low influence of EO_Lm on reproductive parameters. By steam distillation and GC-MS analysis, γ-Curcumene was identified as the main constituent (52.02%) in the EO_Ap and Shyobunol (10.80%) in EO_Lm. The results suggest that major components of both essential oils should be further studied as promissory acaricides against R. microplus.

Pharmacological Effects of Grifolin: Focusing on Anticancer Mechanisms

Grifolin is a volatile compound contained in essential oils of several medicinal plants. Several studies show that this substance has been the subject of numerous pharmacological investigations, which have yielded interesting results. Grifolin demonstrated beneficial effects for health via its multiple pharmacological activities. It has anti-microbial properties against bacteria, fungi, and parasites. In addition, grifolin exhibited remarkable anti-cancer effects on different human cancer cells. The anticancer action of this molecule is related to its ability to act at cellular and molecular levels on different checkpoints controlling the signaling pathways of human cancer cell lines. Grifolin can induce apoptosis, cell cycle arrest, autophagy, and senescence in these cells. Despite its major pharmacological properties, grifolin has only been investigated in vitro and in vivo. Therefore, further investigations concerning pharmacodynamic and pharmacokinetic tests are required for any possible pharmaceutical application of this substance. Moreover, toxicological tests and other investigations involving humans as a study model are required to validate the safety and clinical applications of grifolin.