Luis Cartuche

Chemical Constituents of Muehlenbeckia tamnifolia (Kunth) Meisn (Polygonaceae) and Its In Vitro α-Amilase and α-Glucosidase Inhibitory Activities

The phytochemical investigation of Muehlenbeckia tamnifolia, collected in Loja-Ecuador, led to the isolation of nine known compounds identified as: lupeol acetate (1); cis-p-coumaric acid (2); lupeol (3); β-sitosterol (4) trans-p-coumaric acid (5); linoleic acid (6) (+)-catechin (7); afzelin (8) and quercitrin (9). The structures of the isolated compounds were determined based on analysis of NMR and MS data, as well as comparison with the literature. The hypoglycemic activity of crude extracts and isolated compounds was assessed by the ability to inhibit α-amylase and α-glucosidase enzymes. The hexane extract showed weak inhibitory activity on α-amylase, with an IC50 value of 625 µg·mL−1, while the other extracts and isolated compounds were inactive at the maximum dose tested. The results on α-glucosidase showed more favorable effects; the hexanic and methanolic extracts exhibited a strong inhibitory activity with IC50 values of 48.22 µg·mL−1 and 19.22 µg·mL−1, respectively. Four of the nine isolated compounds exhibited strong inhibitory activity with IC50 values below 8 µM, much higher than acarbose (377 uM). Linoleic acid was the most potent compound (IC50 = 0.42 µM) followed by afzelin, (+)-catechin and quercitrin.

Chemical composition, antifungal and antibacterial activity of the essential oil from Baccharis latifolia (Ruiz & Pav.) Pers. (Asteraceae) from Loja, Ecuador

The essential oil of aerial parts of Baccharis latifolia (asteraceae) growing wild in Ecuador was obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry (GC/MS) and GC/flame ionization detector (GC/FID). Twenty-nine compounds, representing 90.91% of the oil, were identified. The major components were limonene (33.72%), -phellandrene (10.32%), sabinene (10.28%), β-pinene (6.99%) and α-pinene (5.44%). The antifungal and antibacterial activities were determined by the broth microdilution method. The essential oil from B. latifolia exhibited activity only against Trichophyton rubrum (ATCC 28188) and Trichophyton mentagrophytes (ATCC 28185).

Chemical composition and biological activity of the essential oil of Baccharis obtusifolia Kunth from Loja, Ecuador

The essential oil of aerial parts from Baccharis obtusifolia (Asteraceae) growing wild in Ecuador was obtained by hydrodistillation and examined by gas chromatography–mass spectrometry (GC–MS and GC–flame ionization detector (GC–FID) analysis. Thirty-one individual compounds were identified and constitute 96.1% of the total composition of the oil. The main constituents of the oil were limonene (28.3%), germacrene-D (9.8%), α-pinene (9.0%), β-pinene (8.2%), bicyclogermacrene (6.2%) and δ-cadinene (5.7%). The essential oil showed significant antibacterial and antifungal activity. Baccharis obtusifolia oil exhibited a moderate antibacterial effect against Klebsiella pneumoniae (ATCC 9997) and Enterococcus faecalis (ATCC 29212), and good antifungal activity against Trichophyton rubrum (ATCC 28188) and Trichophyton mentagrophytes (ATCC 28185). In this study, the chemical composition and biological activity of the essential oil of B. obtusifolia (Asteraceae) are reported for the first time.

Antifungal activity of raw extract and flavanons isolated from Piper ecuadorense from Ecuador

The MeOH extract of Piper ecuadorense Sodiro, Piperaceae, was chosen for metabolite isolation and elucidation due to the strong antifungal activity exhibited, measured by means of the broth microdilution method. Two known flavonoids: pinostrobin (1) and pinocembrin (2) were isolated from 4.16 g. of dichloromethane extract by column chromatography, using a gradient of hexane/EtOAc. A total of 20 mg of 1 were obtained from the fraction eluted with hexane-EtOAc 95:5 v/v, and 100 mg of 2 were obtained from the fraction eluted with hexane-EtOAc 85:15 v/v. The MIC values of the MeOH extract was 31.25 µg/mL for Trichophyton mentagrophytes ATCC® 28185 and 62.5 µg/mL for Trichophyton rubrum ATCC® 28188. The MIC value of pinocembrin was 125 µg/mL for Trichophyton mentagrophytes ATCC® 28185 and Trichophyton rubrum ATCC® 28188. Pinostrobin in antifungal test was not active against fungi tested.

Acorenone B: AChE and BChE Inhibitor as a Major Compound of the Essential Oil Distilled from the Ecuadorian Species Niphogeton dissecta (Benth.) J.F. Macbr

This study investigated the chemical composition, physical proprieties, biological activity, and enantiomeric analysis of the essential oil from the aerial parts of Niphogeton dissecta (culantrillo del cerro) from Ecuador, obtained by steam distillation. The qualitative and quantitative analysis of the essential oil was realized by gas chromatographic and spectroscopic techniques (GC-MS and GC-FID). Acorenone B was identified by GC-MS and NMR experiments. The enantiomeric distribution of some constituents has been assessed by enantio-GC through the use of a chiral cyclodextrin-based capillary column. We identified 41 components that accounted for 96.46% of the total analyzed, the major components were acorenone B (41.01%) and (E)-β-ocimene (29.64%). The enantiomeric ratio of (+)/(−)-β-pinene was 86.9:13.1, while the one of (+)/(−)-sabinene was 80.9:19.1. The essential oil showed a weak inhibitory activity, expressed as Minimal Inhibitory Concentration (MIC), against Enterococcus faecalis (MIC 10 mg/mL) and Staphylococcus aureus (MIC 5 mg/mL). Furthermore, it inhibited butyrylcholinesterase with an IC50 value of 11.5 μg/mL. Pure acorenone B showed inhibitory activity against both acetylcholinesterase and butyrylcholinesterase, with IC50 values of 40.8 μg/mL and 10.9 μg/mL, respectively.

Antibacterial and cytotoxic activity from the extract and fractions of a marine derived bacterium from the Streptomyces genus

Abstract Context: Marine natural products are a rich source of potent, selective, and structurally novel compounds. Marine bacteria are considered the most promising source of biologically active compounds which can be applied to treat a wide range of diseases. Objective: The current study was designed to establish the bases for a future marine exploration in the Ecuadorian coast based on the molecular identification of a marine bacterium and its potential use as an antibacterial or cytotoxic compounds source. Materials and methods: Isolation and characterization of the marine bacterium were carried out through microbiological methods from desiccated sediment. Molecular identification was made by means of 16S rDNA analysis. MIC was measured by the microdilution broth method against six pathogenic bacteria: two Gram positive and four Gram negative strains. Cytotoxicity was evaluated by Crystal violet assay against breast adenocarcinoma (MCF7) and ductal carcinoma (T47D and ZR-75-30). Results: Our present study has shown that EtOAc extract and fraction A1 obtained from marine Streptomyces sp. revealed the maximal antibacterial and cytotoxic activity. Enterococcus faecalis was found to be more sensitive strain (MIC 0.78 μg/ml) than the other five bacteria tested. ZR-75-30 and T47D cell lines were found to be more sensitive (IC50 value, 31.88 ± 0.05 and 68.35 ± 0.12 μg/ml) than adenocarcinoma MCF7 (IC50 value was 83.65 ± 0.06 μg/ml). Discussion and conclusion: The results obtained herein indicate that EtOAc extract of Streptomyces sp. has shown a strong antibacterial activity as well as moderate cytotoxic activity which make it a good candidate for metabolite isolation.

α-Glucosidase Inhibition and Antibacterial Activity of Secondary Metabolites from the Ecuadorian Species Clinopodium taxifolium (Kunth) Govaerts

The phytochemical investigation of both volatile and fixed metabolites of Clinopodium taxifolium (Kunth) Govaerts (Lamiaceae) was performed for the first time. It allowed the isolation and characterization of the essential oil and six known compounds: carvacrol (1), squalane (2), uvaol (3), erythrodiol (4), ursolic acid (5), and salvigenin (6). Their structures were identified and characterized by Nuclear Magnetic Resonance (NMR) and Gas Chromatography coupled to Mass Spectroscopy (GC-MS), and corroborated by literature. The essential oil of the leaves was obtained by hydrodistillation in two different periods and analyzed by GC-MS and GC coupled to Flame Ionization Detector (GC-FID). A total of 54 compounds were detected, of which 42 were identified (including trace constituents). The major constituents were carvacrol methyl ether (18.9–23.2%), carvacrol (13.8–16.3%) and, carvacryl acetate (11.4–4.8%). The antibacterial activities were determined as Minimum Inhibition Concentration (MIC) against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa and Micrococcus luteus. The hexane and methanol extracts exhibited activity only against Klebsiella pneumoniae (250 and 500 μg/mL respectively), while the ethyl acetate extract was inactive. The hypoglycemic activity was evaluated by the in vitro inhibition of α-glucosidase. The ethyl acetate (EtOAc) extract showed strong inhibitory activity with IC50 = 24.88 µg/mL, however methanolic and hexanic extracts showed weak activity. As a pure compound, only ursolic acid showed a strong inhibitory activity, with IC50 = 72.71 μM.

Biological Activity and Chemical Composition of the Essential Oil from Chromolaena laevigata (Lam.) R.M. King & H. Rob. (Asteraceae) from Loja, Ecuador

Abstract The chemical composition, antifungal and antibacterial activity of essential oils isolated by hydrodistillation from the aerial parts of Chromolaena laevigata (Asteraceae) growing wild in Ecuador, were evaluated. The chemical composition was analyzed by Gas chromatography/Mass spectrometry (GC-MS) and GC/Flame ionization detector (GC/FID). Twenty-five volatile components were identify in essential oils, corresponding to 96.13 % of the total oils. Essential oils was rich in laevigatin (46.84 %), germacrene D (15. 38 %), viridiflorol (11.37 %), bicyclogermacrene (4.14 %), limonene (4.94 %) and α-pinene (2.85 %). The antibacterial and antifungal activities were studied by the broth microdilution method. The antibacterial activity was tested against Gram-negative bacterial strains [Pseudomonas aeruginosa (ATCC 27853), Klebsiella pneumoniae (ATCC 9997), Proteus vulgaris (ATCC 8427), Escherichia coli (ATCC 25922) and Salmonella typhimurium (LT2)] and Gram-positive bacterial strains [Enterococcus faecalis (ATCC 29212) and Staphylococcus aureus (ATCC 25923)] and antifungal activity was determined against Trichophyton rubrum (ATCC 28188) and Trichophyton mentagrophytes (ATCC 28185). The essential oil from C. laevigata exhibited activity against Trichophyton rubrum (ATCC 28188) and Trichophyton mentagrophytes (ATCC 28185).